. AIR PRODUCTS

LIQUID HYDROGEN STORAGE SYSTEM

HAZARDOUS CONSEQUENCE ANALYSIS ...

• Report By:. , · ·

-~ · ..

L. L. Cami 11 i

R. E. Linney

L. C. Doe 1 p

25 July 1985

RE~ 1 - 1 October 1985

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AIR PRODUCTS

LIQUID HYDROGEN STORAGE SYSTEM

PREFACE

THIS REPORT EVALUATES THE CONSEQUENCES OF POTENTIAL HAZARDOUS EVENTS

ASSOCIATED WITH THE LIQUID HYDROGEN STORAGE SYSTEM AND PROVIDES A DESIGN BASIS

FOR SATISFYING THE REQUIREMENTS OF THE NRC. THE FREQUENCIES AND PROBABILITIES

OF HAZARDOUS EVENTS ARE NOT PRESENTED IN THIS REPORT. THESE HAVE BEEN

EVALUATED SEPARATELY AND WERE FOUND TO BE SO LOW AS TO MEET AND EXCEED ALL AIR

PRODUCTS CORPORATE STANDARDS. THE COMBINATION OF LOH EVENT PROBABILITY AND

DETERMINISTIC PREVENTION PRODUCES A STORAGE SYSTEM OF THE HIGHEST INTEGRITY

AND EXTREMELY LOW RISK.

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LIQUID HYDROGEN STORAGE SYSTEM

• HAZARDOUS CONSEQUENCES ANALYSIS PAGE I. EXECUTIVE SUMMARY

I I. I tJTRODUCTI ON 4

A. Importance of H2 - H20 Chemistry 4

B. Causal Events Addressed in this Report 4

. I I I. DESCRIPTION OF THE TANK SYSTEM 6

A. System Overview 6

B. Specific Equipment Design 8

IV. HISTORICAL REVIEW OF HYDROGEN RELEASES l 5

.. A. Introduction l 5

B. Data on Liquid Hydrogen Releases l 5

c. Surmnary of Phenomena l 5

• D. Discussion of Release Data l 9 v. METHODS OF CONSEQUENCE ANALYSIS USED 21 A. Gaussian Dispersion Analysis . 21

l. Continuous Release 2. Instantaneous Release

B. Jet Dispersion 25

l . Momentum-Dominated Jets 2. Jet Versus Gaussian Dispersion 3. Orifice Mode 1

c. Blast Pressure 33

l. TNT Sealing 2. TNT Equivalence 3. Maximum Blast Pressures 4. Explosive Limits of Hydrogen

D. Thermal Flux 37

l. Fi reba 11

• 2. Steady-State Flame . _j I i i I I! jl

• v. METHODS OF CONSEQUENCE ANALYSIS USED (Continued) E. Liquid Release Rate

F. Liquid Flashing

G. Liquid Evaporation via Heat Transfer

VI. GENERIC CONSEQUENCE ANALYSIS

A. Catastrophic Tank Failure

1. Drift Without Ignition 2. Drift With Explosion 3. Explosion at Tank Site 4. Fireball at Tank Site

B. Line Severing and Tank Hole

~ l . Gas Release . 2. Liquid Release

c. Vent Stack Releases

• VII. CAUSAL EVENTS A. Earthquake B. Tornado

c. Flood

D. Aircraft Crash

E. Vehicle Impact

F. Tank Venting

G. Structural Tank Failure

H. Tank Overpressure

VI I I. CONCLUSIONS

IX. REFEREMCES

x. APPENDICES

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I. EXECUTIVE SUMMARY

Air Products is proposing to locate a 20,000 gallon liquid hydrogen

storage tank on the site of Commonwealth Edison Dresden Nuclear Power

Plant. The hydrogen will be used to deoxygenate the reactor cooling

water. Reduction of oxygen concentrations greatly reduces the

potential for intergranular stress corrosion cracking in boiling-\~ater

reactor stainless steel piping.

This report presents an analysis of potential hazardous consequences

associated with the 1 i quid hydrogen storage system without

consideration of probability or frequency. The causal events can be

divided into four categories of consequence in descending order of

importance:

A. Major violation of the tank resulting in a total liquid release or

a large spill.

B. External piping rupture resulting in a continuous release of liquid

hydrogen.

C. System-related releases of gaseous hydrogen.

D. Events which have been precluded by design.

Category A events can be caused by tornado missiles and aircraft

impact. The like 1 i hood of al-1 the necessary conditions occurring such

that safety-related structures are damages from large releases is

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judged to be so low as to merit classification as a non-credible

event. If additional assurance is required, a mechanistic protection I

system is described. In the absence of such a system, the extremely

remote possibility exists that a flammable concentration could reach

safety-related structures.

Category 8 events can be caused by earthquakes and unique plant

accidents. All liquid lines of a diameter within a spill could project

flammable concentrations to a safety-related structure are excess-flow

protected. Thus severing of a liquid line cannot produce vapor cloud

drift that causes:

a flammable concentration

an unacceptable explosion pressure

an unacceptable thermal flux

at safety-related structures.

Category C events are endemic with the system. The \l/orst-case event is

the bursting of a rupture disc venting through a 2-inch diameter line.

This does not produce a threatening concentration, explosion pressure

or thermal flux to any safety-related structures.

Cate.gory D events have been precluded by design. An example is

vehicular impact on the tank. This has been eliminated by a suitably

designed barrier system •

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In summary, mechanistic solutions have been described to mitigate the

consequences of perceived causal events such that safety-related

structures are not threatened even though these events may be of such a

low frequency as to be deemed non-credible .

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I I . INTRODUCTION

Hydrogen water chemistry is an important technique for eliminating the

potential for intergranular stress corrosion cracking (IGSCC) in

BWR's. Extensive EPRI-sponsored research has been conducted on this

technique at the Dresden Nuclear Power Plant. These efforts have

demonstrated the effectiveness of hydrogen water chemistry.

Hydrogen \·later chemistry re qui res that substantial amounts of hydrogen

be available on site for injection into the feedwater system. During

the development phase of the hydrogen water chemistry system at

Dresden, hydrogen was furnished by daily delivery of hydrogen in a

pressurized gas form. For the permanent system, Commonwealth Edison

Company intends to have the hydrogen supply stored as a cryogenic

liquid in a tank located at a safe distance from safety-related

structures. The liquid hydrogen would be vaporized at the tank site

and supplied as a gas. The liquid storage system results in

considerable savings and a significant reduction in delivery

frequencies.

The objective of this report is to present a hazardous consequence

analysis of all causal events to the storage tank that could affect

safety-related structures. A further objective is to demonstrate that

any threatening consequences can be mitigated by system design and/or

separation distance. This report does not consider the frequency and

probability of hazards produced by causal events. These have been

18 separately evaluated and deemed to be low enough to present a

responsible level of risk by stringent corporate ~tandards.

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Under normal operating conditions, the tank is essentially risk free .

However, very unusual circumstances can cause violation of the system

with the release of the contained hydrogen. The causal events which

this report considers are as follows:

A. Tornado

B. Earthquake

c. Flood

D. Aircraft Crash

E. Vehicle Impact

F. Tank Failure

G • Tank Overpressure

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III. DESCRIPTION OF THE TANK SYSTEM

A. System Overview

The following describes the hydrogen supply system provided by Air

Products and Chemicals, Inc., ("Air Products") to Commonwealth

Edison for its hydrogen water chemistry program at the Dresden

Nuclear Station.

Hydrogen is stored in both liquid and gaseous form to provide a

continuous supply of gaseous hydrogen. The liquid hydrogen is

stored in a vacuum-jacketed vessel at approximately 135 psig and

-403°F (saturated) and is designed to provide the major source of

hydrogen below 120 psig. The gaseous hydrogen is stored in high

pressure storage tubes at 2200-2400 psig and ambient temperature.

This provides both a back-up to the liquid hydrogen storage and a

primary supply for high pressure hydrogen requirements above 120

psig. Based on data relating hydrogen injection pressures to plant

power 1 evel s it is expected that ·a vast majority of Dresden's

hydrogen gas requirement will originate from the liquid hydrogen

tank. Hydrogen gas stored in the high pressure tubes will be used

only when the plant is operating at low power levels.

The hydrogen supply system can be divided into two main operating

sections, depending on which type of storage (liquid or gas) is

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providing hydrogen. Each section is designed to provide nresden

Unit 2 with a continuous hydrogen flow of 60 scfm and a peak flow

of 125 scfm should Dresden Unit 3 elect to implement hydrogen water

chemistry.

The liquid hydrogen supply section vaporizes the liquid through

ambient air vaporizers. The gaseous supply system uses the high

pressure hydrogen and regulates it through a dual pressure control

manifold to 160 psig. Both sections join together into a common

pipeline that extends to the end of the storage facility. The

station has supplied a house line that starts at the storage

facility, runs 700 ft. underground to the turbine building and

terminates at the condensate booster pumps .

The supply of hydrogen from either storage source is monitored and

controlled by an automatic switchover assembly. This ·assembly,

which utilizes a microprocessor-based controller, receives a signal

from a pressure sensing switch located at the point of hydrogen

feedwater injection. The controller then directs the opening and

closing of pneumatic valves that allow hydrogen gas flow from

either liquid or gas storage. As previously discussed, the liquid

storage is used for pressures greater than 120 psig .

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B. Specific Equipment Design

1. Low Pressure Liquid Storage and Supply Subsystem

a. Liquid Hydrogen Storage Tank

The tank is Air Products and Chemicals, Inc., Model

CLCH-200CP vacuum-jacketed cryogenic liquid storage

vessel. It has a 111 thick aluminum alloy (AL-5083-0)

inner vessel and a 3/8 11 thick carbon steel outer vessel.

The annular space is insulated with high vacuum and

powdered perlite. The inner vessel is construction in

accordance with Section VIII of the ASME Boiler and

Pressure Vessel Code. ·Manufacturing and inspection

records for this specific tank are delineated in Form

U-lA, given in Appendix C.

The tank is sized to hold up to 19,644 gallons (net) of

liquid hydrogen at pressures up to 150 psig. Hydrogen

gaseous equivalence is 2,227,000 scf@ 70°F and 0 psig.

The control piping and valving for the tank are installed

in the factory to minimize field installation. The tank

is constructed so that it can be filled without affecting

the system operation. The tank is supplied with a

pressure gauge, a liquid level gauge, and a vacuum readout

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connection. The pressure and liquid level gauges are

sufficient for normal monitoring of the tank condition.

Pressure and level transmitters have also be added to

allow station personnel to monitor tank liquid level and

system supply pressure from the main control room.

Excess flow protection is provided on the tank's 2" fill

line and the 111 liquid withdrawal line. The 211 fill

assembly consists of a reverse flow check valve and

seismic support from tank to check valve (31 11 distance).

The l" liquid withdrawal line utilizes a

pneumatically-operated positive shutoff valve (per NFPA

SOB), and seismic support from tank to valve (28 11

distance). This pneumatically-operated valve behaves as a

restricting orifice because it is equipped with a limiter

that restricts its movement. In the event of a pipe

break, this restricting orifice will prevent flammable

concentrations from reaching the safety-related

structures. The value in limiting mass flow rate through

the valve is discussed in Sections VI.B.2 and VII.A. In

this case, the restricting orifice has been sized for a

flow rate of 0.3 KG/sec .

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The only remaining large liquid line ( > 1/4" ID), the l" pressure build line, is a closed-loop liquid to gas phase

circuit that both exits and enters the tank. This entire

line is seismically supported, thus precluding the need

for excess flow protection.

Overpressure protection for the tank is satisfied by dual

safety valves and emergency backup rupture discs. The

primary relief system consists of two sets of two 2"

rupture discs and 1/2" safety valves piped into separate

"legs;" The selector valves are interlocked by a tie bar

so that one valve opens when the. other closes. With this

arrangement, one safety valve and two rupture disks are

available at all times. The dual primary relief systems

with 100% standby redundancy allow maintenance and testing

to be performed without sacrificing the level of

protection from overpressure .

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The 1/2" safety valve is the primary relief device as

specified by the ASME Code and is set to relieve at 1.0

times the Maximum Allowable Work Pressure (150 psig).This

valve is sized to accommodate all "normal" overpressure

demands, such as the loss of the vacuum in the annulus of

the double-wall vessel. The rupture disk is a

"supplemental pressure relieving device" for "unexpected

sources of external heat." The rupture disk is capable of

relieving the maximum vaporization rate caused by a

hydrocarbon fire engulfing the outer shell \'Ii th hydrogen

(highest thermal conductivity) in the annulus. The ASME

Code allows such devices to relieve at 21 percent above

the MAWP. All 2-inch rupture disks on the tank are

specified and purchased to burst at 1.2 MAWP (180 psig) .

The tank is also supplied witl1 a secondary relief system

not required by the ASME codes. The system is totally

separate from the primary relief system. It consists of a

locked open valve, on 1-inch rupture disk, and a secondary

vent stack. The rupture disk is specified and purchased

to burst at 1.33 MAWP (200 psig).

Vessel piping is protected with thermal relief valves.

All outlet connections from the safety relief valves,

rupture devices, bleed valves, and the fill line purge

connections are piped to an overhead vent stack as a

safety precaution-.-- -

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Two lift-plate relief devices are also installed in the

outer vessel. Should a leak develop in the inner vessel

or in the pipe going through the annular space, a positive

pressure would build up inside the jacket. The devices

will relieve any excessive pressure build-up in the

annular space.

Two grounding assemblies are used to arrest static

electricity. One is connected to the frame of the vessel

and the other to the base of the vent stack. Each is

connected with bare wire to ground rods buried in the

earth. During unloading operations, the liquid delivery

trailer ground wire is clamped to the tank or vent stack

ground wire .

Ambient Air Vaporizers

The vaporization of the liquid hydrogen is achieved by the

use of two ambient air vaporizers. The vaporizers feature

a star fin design and aluminum alloy construction. The

design pressure of these units is 450 psig. The units are

piped in parallel so that each unit can operate

independently. Each unit is sized for the 125 scfm peak

flow of the system .

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2. High Pressure Gaseous Storage and Supply Subsystem

a. High Pressure Gaseous Storage Bank

A high pressure storage tube bank is used to meet the high

pressure hydrogen requirement (above 120 psig). The bank

consists of six vessels 24 11 in diameter x 23 1 long. The

vessels are made of carbon steel. The design pressure of

each vessel is 2450 psig and they are built to Section

VIII of the ASME Code. Each vessel has a full flow

rupture disk to provide safe system operation. In

addition, two full flow safety valves are on the storage

bank manifold to en~ure safe operation .

b. Pressure Control Station

Gaseous hydrgoen at ambient temperature will be drawn

directly from the high pressure storage vessels to supply

the station requirements. The delivery pressure is

regulated by the pressure reducing station, located at the

hydrogen storage facility, which reduces the hydrogen

pressure to 160 psig. Two regulators are provided in

parallel to ensure an uninterrupted hydrogen supply should

either regulator malfunction .

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An excess flow check valve is located downstream of the

pressure reducing station. If a hydrogen line were to

rupture downstream of the high pressure system, the excess

flow valve is designed to shut bubble-tight and arrest the

resultant flow of high pressure hydrogen.

c. Discharge Stanchion

A discharge stanchion is provided as a fill connection for

the high pressure gaseous supply. The discharge stanchion

provides a safe, effective means for refilling the

hydrogen system while maintaining uninterrupted system

operation .

3. System Instrumentation and Controls

The hydrogen storage and supply system is designed to operate

completely automatically, requiring only periodic refilling of

the liquid and gaseous hydrogen storage vessels. A Modicon

programmable controller is used to monitor system operation.

and to determine whether the liquid or gaseous storage will be

used for supply pressures greater than 120 psig). The Modicon

also provides automatic shutdown procedures for system alarm

conditions .

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IV. REVIEW OF HISTORICAL HYDROGEN RELEASES

A. Introduction

This section of the report reviews historical evidence on hydrogen

spills and releases to gain insight on the likelihood of ignition

and the impact of confinement on the possibility of detonation.

B. Data on Liquid Hydrogen Releases

Data -from al 1 known sources of 1 i quid hydrogen spi 11 events have

been collected. Table I summarizes test results where the release

mechanism involved a minimal amount of energy. An example would be

the tipping over a dewar into a spill pit. Releases that were more

energetic are summarized in Table II. These include events such as

vessel rupture due to overpressure and bullet penetration.

C. Summary of Phenomenon for Liquid Hydrogen Release Data

Unconfined liquid hydrogen spills have not detonated even when

explosive igniters are used. This observation is based on the

79 releases that ignited but did not explode (see Table I and

I I ) .

Liquid hydrogen releases did not have a strong tendency to

auto-ignite. There were identifiable sources of ignition for

each case that ignited.

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For the 79 releases where an ignition source was provided,

ignition always occurred.

Vessel rupture was not shown to be a reliable source of

ignition (only 3 out of 10 vessel ruptures resulted in

ignition) •

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TABLE I

SUMMARY OF LIQUID HYDROGEN SPILL TEST EXPERIMENTS

Experiment No Ignition

A.O. Little (1958)

5 1 iter spill test

5 liter evaporation

time test

6.6 gal evaporation

tiT'le test

32 gal spill test

32 gal spill test

32 gal evaporation

time test

500 gal spi 11 test

600 gal spill test

5000 gal spill test

NASA White Sands (1980)

700 gal spill test

1500 gal spill test

0

2(NI)

1( NI)

2(NI)

0

2(NI)

1( NI)

0

0

1( NI)

6(NI)

Ignition

No Explosion Explosion

48(SI)

3(SI)

1 (SI)

7(SI)

5(EI)

7(SI)

l(SI)

1( SI)

2( EB)

0

0

0

0

0

0

0

0

0

0

0

0

0

Comments

No ignition

intended

Reference

2

KEY: NI - no igniters; SI - spark igniter; EI - explosive igniter; EB - explosive

~-· -bo-lts

NOTE: All tests were performed under unconfined conditions.

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TABLE II • SUMMARY OF ENERGETIC LIQUID HYDROGEN RELEASES Experiment No Ignition Ignition Comments Reference

No Explosion Explosion

Lockheed ( 1956-57) 3

"Thermos bottle"

heavy impact test 61(NI) 1 ( HW) 0

.. A.O. Little (1958)

5 1 iter vessel 4(NI) 1 (NI) 0 950 psi burs.t

• rupture test - 5 1 iter vessel 3(NI) 1( NI) 0 6800 psi burst rupture test

5 1 i ter bull et

penetration test 1( NI) 0 0 -. :

APCI 9,000 gal tank rupture 0 1 0 no known ignition

source

KEY: NI_ - no igniters; HW - hot wire

---· NOTE: All t~sts were performed under unconfined conditions. -18-

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D. Discussion of Liquid Hydrogen Release Data

As the test data have shown, no detonation of an unconfined liquid

hydrogen spill has occurred. The "unconfined" conditions for these

tests were mostly flat ground with only a shallow diked area and

instrument towers as obstructions. It is well known that when

flammable hydrogen-air mixtures are totally confined (e.g. a long

pipe with closed ends) ignition can result in detonation. No

quantitative data was found on the propensity of semi-confined

liquid hydrogen spills to detonate or not detonate. A 1958 A.O.

Little Report1 qualitatively discussed a test where liquid

hydrogen spills were semi-confined by three walls of a test bay.

The statement is made that "even partial confinement can add

substantially to the magnitude of the pressure wave generated by

the combustion of gases in free space". It is also well known that

objects immersed in a combustible vapor could can act as turbulence

generators. These can cause acceleration of the burning velocity

which could run up to a detonation. These considerations suggest

that the possibility exists for the formation of a "pressure \"lave"

if ignition is delayed and the vapor cloud drifts in an environment

that could provide accelerated combustion.

E. Conclusions of Liquid Hydroge P.elease Data

Air Products has evaluated the likelihood of the following

conditions necessary for the formation of a destructive blastwave

and believe them to be sufficiently remote:

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An aircraft or tornado missile causes a large breach in the

storage tank.

-- The wind blows towards the nuclear power plant.

Ignition is delayed until cloud is near safety-related

structures.

The combustion runs up to a detonation.

The frequency of the causal events times the probabilities of all

the necessary conditional events is judged to be 10\'1 enough to

merit classification as a 11 non-credible 11 event .

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• V. METHODS OF CONSEQUENCE ANALYSIS USED

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A. Gaussian Dispersion Analysis

1. Continuous Point Source

The concentration resulting from~ continuous release of gas

is estimated as follows:

r-

±_ j (Z-H) 2 _ (Z+H )1 0

M 2a 2 - 2a z-· 2a 2

c y z + e z = 2rrU a a e e ( 1 ) w y z

C = kg/m 3 0

M = kg/sec emission rate

Uw = m/sec wind velocity

a ,a = dispersion parameters y z

Z, H = receptor and release heights, m

a and a are taken from the Pasquill-Gifford y z

using the fo 11 owing approximating equations:

a = a ( X + z ) b y v

az = c ( x + x )d v

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correlations

( 2)

( 3)

• The virtual distance is calculated to give 100% concentration at the cloud center at the origin. (4)

Values of a, b, c and d under different weather conditions are

as fol lows:

Parameter b d Weather Stability a c ..

B 0.371 0.866 0.23 0.85

D 0.128 0.905 0.20 0.76

• F 0.065 0.902 0 .12 0.67 The degree to which these relationships reproduce the Pasquill-

Gifford relationships are shown in Figures 1 and 2.

The mass in the flammable region is obtained by integrating

the mass contained between the UFL and LFL envelopes.

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• 2. Instantaneous Point Source The concentration resulting from an instantaneous release

of gas is obtained as follows:

(x-Ut) 2 Y..2 M 2axI 2 2ayI 2 c = e e [ J ( 5)

(27T)3/2 0 xI 0 yI 0 zI

.. r (z-h) 2 + (z+h)

2 ~ (6) [ J = 2azI 2 e 2a 2 zI

I

c = kg/m • M = kg released 0 ! 0 ! 0 ! d" · x , y , z = 1spers1on parameters, m

x, y, z, coordinates of receptor, m from source

x = hori zonta 1, parallel with wind

y = horizontal, perpendicul_ar to wind

z = vertical

u = wind speed, m/sec

h = height of discharge, m

t = time from release, sec

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101

> z z ... u

E ro2 ... 0 u

Figure~

Pasquill-Gifford Dispersion Parameters

11 I 1/1 I I I 111

11 I I I I I /v I--' .... j ,

' ·7 ' ' ' - . / ' ' 'I I f ' . I 1 ..... / J ' ' '

' ' ' 7 . ' . ~ / ' ' . : . I I : I I ' T I I I I,,,..../ I I I I I: I I I I I I I /1 I ''/·/ I I I I::..

I II I V: I . -1 J. rY: I I I 1.0'1 I l/111 I V,I "' .: I I 1u.o I~ 1111

/111 ~B7 ~n UimY U-Hiitl I / . ; --:? -:;.C / .# . ~ -. ,, / ,,

z '/' '/ /7 / ' ,,. ···~ --- . ... •I ~ 5 a:: ... CL

"' Ci ~- 2 ~

I ; / / 7 · /o"' 1 _,..,, 1 , :~ • ----/I /,r / I : I ./ / 1 ....-: I I i........:.......-. I

V #/I I I;/?" ./. E I Yi I I I I . /V/ii/"r J.....-Jr I 11 111 I

... CZ: ... V~J:WW/ •' ~i ,, . I 1111111 I A- EXTRE"'ELT UNST.lBLE > 10 ,, . , / -:> -b .. ,, _,, / ,, ,' B- MCOERA'l'ELY UNSTABLE J / './ I / ./ ; C- SLIGHTLY UNSTABLE; ./ ./ // ..

,/ / I /,- I I : ' . i I 0- NEUTRAL I / 1//1 I I I I I " I E- SLIGHTLY STABLE I

:.;- /I I I I I I 1 11 I F - MOCERATELT st:.BLEI ·V 111; 11 I I 111111 I z

·111111 1111111 I 0 10 l 2

10 1ol 2 ' 10• 2 01S1'ANCE FROM SOURCE (ml

I I I I . I I

I I I I j I!

I I I I 11 ! I I I I 111

I 111111 ..

I I I I I I I

I I I I Ii I

I I I I II I

I I 11111

I i 11111 10'

• 10•

t

E -,o' ~ z .... u i: 5 ~ .. .... 0 u z 2 "' a: 2 .... CL

"' Q • :t 10 1 .... z 0 .... ir 0 s .. . b ..

2

101

4.10° 10 1

•

Figure 2

Pasquill-Gifford Dispersion Parameters

I • I I I I I

I I I I I I 11 I i II I I

I I I I I 1111

I I I 111 I,

u ..

I ! I !

I . I I ; I Ii 11 I Io 1'

I I 11

11111

I I 11111

I 1 11111 :.- (XTR(Mf:lT UNST:.Slf: I •.

I I 9 - M00£1UT(lT UNST.:.81..E . 1 ' ' •. I I C - 51..IGMTlT UNS,t.!!lE ' i I I I I I C - NEUTR4l I I 11 11

I I E- SltGMTLT s-:-.:.e~E I 11 II r _; MOO(R:.TE1..T ST.:IBlE

I I I 11!111 I I 1· 11111 ' 'I I. t 'I '!

• I : 1 1 I I : , I; I I I 1 I ! : I I I I 1 I I I : I I.

' ' ' 'I I,; , LI ' I : I I'

2 !I 10> z s 10' 2 5 10' OISTt.li;::E F'ROM SOURCE (ml

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The dispersion parameters are estimated as follows:

( 7)

(8)

Xv, the virtual source is given by:

2(b+d)

Values of a, b, c and d for different weather conditions

are as follows:

Parameters Weather Stability

B

D

F*

a

0.14

0.06

0.0494

b c

0.92 0.53

0. 92 0. 1 5

0.9542 0.0581

d

0.73

0.70

0.7940

*Based on Appendix B of the Regulatory Guide 1 .78 .

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• V. METHODS OF CONSEQUENCE ANALYSES USED

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B. Jet Dispersion Model

This section of the report describes the dispersion model used to

calculate the consequences of high velocity releases of gaseous

hydrogen. (Pressures above 15 psig).

When a gas is released with considerable momentum in the presence

of a cross wind, a steady state turbulent jet model is used to

estimate the following jet plume properties:

Trajectory of the jet .

Local composition of the jet.

Amount of hydrogen in the jet plume contained between

the upper and lower explosive or flammability limits

The jet model is constructed as follows:

A continuous, steady state, "top hat" model is assumed.

Inspiration of air into the jet due to the turbulent jet

motion and the momentum confrontation with the cross wind

are accounted for.

Inspiration of air into the jet due to atmospheric turbulence

is accounted for .

-25-

•

l

..

•

•

The positive, neutral, or negative buoyancy of the jet

relative to the surrounding air creates a gravitational

force which is accounted for.

The model is expressed by equations describing the following

principles:

Conservation of mass (species balance)

Conservation of X momentum (horizohtal)

Conservation of Z momentum (vertical)

Conservation of energy

Idea 1 gas 1 aw

Geometric relationships

The jet model is similar to the one proposed by Ooms, Mahieu, and

Zelis4 . For momentum-dominated jets, empirical constants in the

model have been adjusted to fit the data by Fan 5 and Hoehne and

Luce6, for centerline trajectories and dilution. When the jet

model is run in some of the extreme modes, good agreement is

obtained with classical examples published in the literature such

as:

continuous Gaussian dispersion

momentum jet in absence of a crosswind

buoyant jet in absence of a crosswind

-26-

..

•

-··

Initialization of the jet model requires the following values to be

set:

DJ' Jet diameter

UJ, Jet velocity

J' Jet density

MOOT, Jet mass rate

When gas at high pressure escapes through a hole, the steady-state

discharge rate is estimated using the standard orifice equations.

These are discussed in the section on orifice models. Because

of the high pressure ratios encountered in this study, gaseous

releases are such that momentum-dominated jet dispersion always occurs .

-27-

•

..

•

• \" ·I• I

V. METHODS OF CONSEQUENCE ANALYSES USED

B. Jet Dispersion Model

1. Momentun-Dominated Jets

All of the gaseous release scenarios in this report occur at

pressure ratios greater than that required for critical orifice

flow. This means that the emerging velocity is supersonic

and that the jet behavior is momentum-dominated. Under

these conditions the jet dispersion process is independent of

buoyancy, crosswind velocity and weather stability. As the

supersonic gas emerges, a series of shocks occur until

sonic velocity at atmospheric pressure is reached. During this

process, the flow envelope expands with little entrainment

of air. Jet initialization is established with the termination

of the shock process during which no dilution is assumed to

have occurred.

Initial jet conditions are obtained by assuming that enthalpy

and kinetic energy are conserved across the shock zo~e. This

leads to the following relationship between the initial jet

diameter and the orifice or hole diameter:

-28-

y

2 h-1 ) / P1 . 1I2 'p . A

( 1 )

•

..

•

•

DJ = initial jet diameter

DH = hole diameter

CW = orifice coefficient

y = Cp/Cv

pl = source pressure, psi a

PA = atmospheric pressure, psi a

Three results of the jet dispersion process are needed for

consequence analyses:

A. MEX, lbs. of hydrogen within the flammable or explosive

limits,

B. VOX, volume of jet cone within the flammable or explosive

limits, n 3; and

C. Z*/DJ, deepest penetration of the jet plume in terms

of jet diameter .

-29-

•

..

•

•

For momentum-dominated hydrogen jets, A and B depend on the

hole diameter as follows:

MEX

vox = so 3 * H ( CW)3/2 * (-2 \ y+l )

3y 2 ( y- l )

3y 2(y-l)

( ' P1 \ 3/ 2

* p A ) , lbs. (2)

*(P \3/2 _l· / ' ft3

\PA I (3)

where DH, Cw, P1 and PA are as previously defined. Values of

a, f3 and Z*/DJ are as follows when DH is given in inches .

Hydrogen Momentum-Dominated Jet

Combustion Limits 0.04 - 0.75 0. 183 - 0.59

Temperature, OF 70 -423 70 -423

a 0. 14 98 8.3416 0.004720 0.2887

f3 361 .8 1 9 '521 2.965 145 .7

Z*/D J 294 1180.5 47.5 221

DJ is related to the hold diameter via equation l .

-30-

•

•

•

V. METHODS OF CONSEQUENCE ANALYSIS USED

B. Jet Dispersion Model

2. Jet Versus Gaussian Dispersion

Whenever liquid is released as a spill or a leak, a vapor

cloud is formed by flashing and vaporization. The cold

hydrogen gas produced is nearly neutrally bouyant (depending

on ambient conditions) and may have little momentum associated

with the vapor cloud formation. Under these conditions

it is appropriate to use Gaussian dispersion models .

When cold or warm hydrogen gas is discharged from a high

pressure source, the vapor cloud is formed with considerable

momentum. The associated jet action produces significant

mixing and dilution during the initial stages of the vapor

cloud formation. Under these conditions, the continuous

Gaussian dispersion model overestimates the amount of

hydrogen in the flammable region and the distance to which the

vapor cloud reaches. This is illustrated in Figures 3 and 4.

Calculated results are presented in Appendix A. The maximum

tank pressure is 150 psig. For this reason, the jet dispersion

model is used in this report to evaluate high pressure, momentum

dominated gas releases .

-31-

: . '

·;

• r l

•

•

10,000

.µ 4--

..s::: u ro Q) 0::

E :::i E

x ro

::'!:::

-I< x

c:: 0

O'> Q) 0::

Q) ..-..Cl ro E E ro ..-1.J...

c::

c:: Q) O'> 0 s...

"O >,

:I:

4--0

l ,000

100

l ,000

100

l 0

Figure _J_

Hydrogen Release from@ l" Hole

----- -- --· --- - --- -·---:::-:::j: ...... .

·-···--···-·-· ....

-;-'--'-c--"-"-'--;-c--+-~~"-"'--"'·~:-.c:':..:! ~_::=_:_:.:. !~~: "-'"'~+"L~.:-"T'-.:='--

_________ 3

_________ 2

-------. 9 ·----- .. 3

. 7

,_,,...._,,_:._:__;__:_'-'1-'---'-'---'--'-'---.. -.. _,_:_c_;_,. __ c ... __ 5

-'--,-,i-~,_..,.,;.-'--'--.. ·~, ~~-~-~-~-'-'-··~-~"~-,_·~-.-~;·~·;~·:_~-,-'-·_.;: -~ --~--i-------.~,,~~:,~,,~_,.-,~.,;...,--;..r,;..,~;.....,~-~---J f-;--+-''7"=-~.c.:..:.'-'-'-';_,,_..cc:... ___ ~,,c:..='-'.:..-'-"·: i .- -,--i-~-i-~- ..• :' '"• ,. .· :-:' ; __ ·:.·: ...

:: ......

J"i''.-:"-""'c=;::.::..:~==.:::::.::.::..:.:=..:.~,L-:....:.:.c.::::::i;::.:..:..:.:.:.:.:.:.;...;.C:::.:..:.;;:~ _____ 5

·--·----~~·-· _ _;_c....;c::.....::.:.;::::~-----2 • / : ·:.: :·: .. ~:::i .. T ..

-~-~-~~~:t~:"~:~: ... ·.. ~1~~~~--±~1:~1,l,:l =::' ·----·- .. ~: _________ .... t= ····:·-c;-": .. ___ 7

·:·-::·:.:·.i::: ..

;~~~~~\~~~~~~~~~~~~:7~ ~'=''c70:: ~.:- ... --.-.. ---. -·---------- -- 6 .---+~-'-'-""";..;co;c.:i----5

----------~,..,;-,,.,.~.,:;.;c:;;;::;::::;:~---4 ·----··--·--··

2 3 5 7 R 9

2 3 4 5 5 I! 9 I

10 100 l ,000 10,000

l ,000

• c

+J 4-

..r::::. u 100 ltl Q)

0:::

E ::i E ...... x ltl

N :::E: 0 < '7°

10

• 10

s::: 0 ...... Ol Q)

0:::

Q)

> ...... Vl 0

..--a. x w 1.0 s:::

s::: Q)

Ol 0 ~

-0

( ,_

>, :c 4-0

• .D 0. l

Figure 4

. ______ ..:._;..____; _____ : __ ._:.:_.: ·············-················· ·····

__ i ~-: ... ~-~~~::::~1:::-::l:::1~~C}~~~-;~ :~~~ :; :· ~:-:-· ... :.~-=~:~:~::_:_.::: ~~~l~~!:~~::~F-~~i~~j~=FY:t. \~~~~=~~~; !~~~~~:~:~~·: .. y::.:

_:~:-------~~:-• .. --~-~l ;' :~~:~~?:~~L:.~~~-~-~-=·~~Y- .'.:;;;!~~j:~Flf:~ ;=~~=~ _: ..... 7~~~~~7~~:~:~i·~~-~~i+ :::::.;::·:::-:-::-!·:::=!::::i::::_;_::::::·:·_ .. : :::'.:-:'. . . . ' ··:--:--~------- G

' __ ...;..._.;...... ·-----··· -· _____ :_.; ______ 5

----:----- ------ ~ ~E~j~t;~~~m~::~",10µ~;;~·:,:u1srn ~!~~:::2~r0~~~::' · .::L ___ . 3

!!1~!.-~~?-;~~~~J.~: ·····- -----··-·--·-··-···- .. '·--·' I "71.----..C....-C..,....~r-,.;..,.__: __________________ -··-·--· • l°

.. ·:: - . ------------ .. ·.·-.··.·-=_:_.~=----~-89-=~;;.o:~==;:./..::,~~:c...;..:._;_;_:...c:.:,+~-----i..-__: ____ ,_____ - - ·- -

c=========-"-"'-'=-'--'·..:.··;.:.· -"' ... '---'---'------------'"---=:=-~~::_-~~-.::: -.~.:~=t=== ~ ·=======.::.:....:.:.-.:._:__;. _______ -.--:--. -~--- ·--+--- 5

·---...:_. _____ ---~----4

. ... J ========~-'-'-==-=-"----'-'--.c....;.-'--'--'-.. '--.'---· -·- --·--+--- 3

···-

2 3 4 5 6 :; 9 1 n 0

2 3 4 5 671391

10 100 l ,000 10 ,000

.: j! ii ii ij

It

~ V. METHODS OF CONSEQUENCE ANALYSIS USED

•

-·

B. Jet Dispersion Model

3. Orifice Model

When gas is released through a hole, the steady state discharge

rate is computed as subcritical or supercritical flow through

an orifice. The standard equations used for this purpose are

given in Table IV. The orifice coefficient is taken to be

that given by Shapiro7 for a sharp-edged orifice with a zero

velocity of approach. This is represented by equation 2 in

Table IV .

-32-

.;

~ i

'i! . I! ,,I. . I . ! . -

•

..

•

•

r c

r

=

=

=

=

Table IV

Orifice Discharge Rates

Downstream pressure, psi a

Upstream pressure, psia

y

(Y; l )"'): y

PL/PH

Sub Critical Gas Flow

r > r c

0 2gc (~\[ 2/Y (l+l/Y)J n = CWAPH RTMl·J Y-llr -r 0

n = lb moles/sec

cw = orifice coefficient

A = area, in 2

R gas constant lb ft = = 1545 lb mole 0 R

cw (from Shapiro) = 0.85 + 0.104167r - 0.875r 2 +

Super Critical Flow

r < r c I Y+l I

Y-1 \/ 9cY

0

( y~ l ) n = CWAPH I RTM\.J , lb moles/sec Same units as above

( l )

0.52083r3 (2)

;

( 3)

I ·i

' i ! ij ,,

• V. METHODS OF CONSEQUENCE ANALYSES USED

•

•

C. Blast Pressure

This Section presents the basis for estimating worst-case blast

overpressures produced by a liquid hydrogen vapor cloud explosion.

l. TNT Scaling

The concept of scaling the effects of vapor cloud explosions

to those produced by some equivalent amount of TNT has long been

used to estimate the damage from postulated events. The

Standard Review Plant (NUREG-0800) and Regulatory Guide l .91

both endorse this concept for evaluating the effects of

vapor cloud explosion on nuclear power plants. The standard . 8

reference, U.S. Army Technical Manual TMS-1300 , was used in

this report to calculate the following blast parameters:

Peak Positive Incident Pressure

Peak Positive Normal Reflected Pressure

Positive Incident Impulse

Positive Normal Reflected Impulse

For liquid releases where the explosive vapor cloud is in

contact with.the ground, the hemispherical TNT curves were

used (Figure 4-12 from TMS-1300). When the vapor cloud is in

free-air, such as a gaseous vent stack release, calculations

were made using spherical TNT curves (Figure 4-5 from TMS-1300)

-33-

• The hemispherical and spherical TNT curves were reproduced for this report and are given in Figures 5 and 6, respectively .

•

• -34-

•

.

•

-· ... ~ ... ... ~ < " .,. '7 .... u < z 8 .., .;, ~ ....

Figure _5_

Blast Parameters for Hemispherical TNT Explosions

1 ... 1~ -- 3

!~Ii

'

,., ........

-- 3

-~1~ I ... Cl.

10 n."'

n.'-

o. n."'

10

100

10

13:,~ _J 3

3:,~ _J 3

0.01

100

SCALED GROUND DISTANCE ZG = RG/W 113

Pao• Peak roaitiYe !ec:1deat Pres:;ure, ;:si

°?;0

• ?eU. lier.at! n Io.c:1dent ?resaure, rli

Pr • Pe&ll. ?oa1t1Ye !ionn.al P.erlc::ted ITesaure, rai

P- • Peak flegat1 '/J . /J L ;..r • Sc&.led Want 1..enr.b. ol Poa l the P?iue, !"'t/lb-

v '/) , /) v;tr • Scaled ilan Len«tb ot !'legatin Pl:ue, rt/lb'"' U • ~bock P"roo~ Velocity. fT./u

u • Partlcl• ·1e1ocit7, rt/u

'rl • Charge 'Jelgbt, lb•

R • ,a.d.la.l D1•taoc• t"rca l..'h&.r;•, n. le• Scaled Crou.od Dht&l'lce,!t/lbl/l

.s

, ·~ ~ 1 ~ ~ ... , ·~ t

1 <

~ . i . -" ., .ii

"' .; ~

.? :..

l

•

..

•

~ ... < ·~

..... .,.. M

-~ > < z 8 M

..; .

Figure 6

Blast Parameters for Spherical TNT Explosions

,~ !...'- ~

.

·~Is - 3

.. Is - 3

~1; - .3

·~ Q.

·~ Q. Q.~

o. ~

P • r ... t Pod Un I.J:icid.ent i"r'w•sun:. p.1 .. .P;

0 • P•U. hg•tln Incident ~•sure, pel

SCALED OISTANC£

P • PH& Poelt1T9 !ors&l Rene~ Pre•"'". pd r

P- • PHJl .. ,.u.,. Sorwial P.atl•c=t.ed. ?reUUZ'9 I pd / tv113 • Sc&led lhit Pooiti" Il>cidc>t :r..p.u.o, poi-./lbl/l 1~/l • Sc&l.ad llAit Seg&Un Incl4.nt.\ t.:puJ..e, pd .... /lbl/l t • fV11l • Scaled l.ID.it PmlUn 1onA.l- a.nert-4 ilrpW.ae ,-p.t-../lbl/l

1~trfl-/l • Sc.J.ed Un1t l•c•Un lorw.al. Ren.ct.ff. I.ap.&..Ue, P91--1a113 .:,.,in• s.&le4 n.. or ArrtT&J. or BJ.u• v .... •/lbi/l

100

::I

:::>

.~r ....J -3

~r ....J ::> 3

·~1~

01~ 3

0.1

.!'I; 3

10

t tv113 • Sc&.l..ed Potiltln D.u-atlcm or Po.1th• ?hue, ... /lbl/l t~/] • Sc&.l.K !•&•ti.,. D..u-aUCD ot Poeltlni PhM•. u/lb113

~· V. METHODS OF CONSEQUENCE ANALYSES USED

C. Blast Pressure

2. TNT Equivalence

The NRC Regulatory Guide 1 .91 states that "a reasonable upper

bound to blast energy potentially available" is a mass equivalence

of 240 percent for hydrocarbons.

In this report, we have assumed that the TNT equivalence for

hydrogen is 520 percent of the mass in the explosive range.

This is equivalent to assuming that 20 percent of the available

• combustion energy performs as TNT.

•

3. Maximum Blast Pressure

The overpressure at the center of a TNT explosion exceeds one

million psi. The overpressure at the center of a vapor cloud

explosion is much less than this. A report prepared for the

9 British government after the Flixborough vapor cloud

explosion calculates that the theoretical upper limit for a

vapor cloud explosion confined under adiabatic conditions would

be about 8 atmospheres (120 psi). The report recognizes that

the practical upper limit of overpressures would be some fractions

-35-

•

•

of the theoretical upper bound. It suggests that the practical

upper limit is approximately one atmosphere (15 psi). For the

calculation of liquid hydrogen vapor cloud explosion overpres-

sures, this report will assume that the theoretical upper

limit of 120 psi can be realized.

4. Explosive Limits of Hydrogen

The explosive or detonation limits of hydrogen-air mixtures

have been taken to be 18.3 to 59 volume percent as reported

in the NASA Hydrogen Safety Manual TMX-5245410 .

-36-

• V. METHODS OF CONSEQUENCE ANALYSES USED

..

•

0. Thermal Flux

1. Fireball

Since the majority of the heat radiated from the fireball

occurs while it is spherical or near spherically shaped,

damage estimates are most often made assuming a spherical

fireball of constant diameter with a specified duration.

Estimates for fireball diameter and durations taken from

various sources in the lite~ature are listed below:

Hardee & Larson,

Thermal Hazards from Hydrogen Fireballs11

1

Fireball diameter, D = 0.64 (wfT) 3, m

Wf = weight of fuel, kg

T = flame temperature, °K

assuming adiabatic flame temperature, T = 2318°K ~

D = 8.47 Wf 3

Hord,

12 How Safe is Hydrogen

1 D = 7.93 wf3' m

1 Fireball Duration, t = 0.47 wf3, sec

-37-

• Crawley, Effect of Ignition of a Major Fuel Spillage13 D = 26 ( WMW/J' §' ft; wf, lbs

for hydrogen,

1 D = 8.186 (wf) 3, m;wf, kg

High,

The Saturn Fireball

0.320 D = 9.82 WP ft

Wp = weight of propellant (fuel +oxidant), lbs

• for hydrogen WP = 8. 94 wf

7. 77 wf 0. 320

, m; wf kg D =

0.320 t = 0.232 WP , sec; wp lbs

0. 320 t = 0.602 wf sec; wf' kg •

Gayle & Brans ford,

Size and Duration of Fireballs from Propellant Explosions

0.325 D = 9.56 ep • ft; w l bs. p'

0.325 D = 7 .677 wf m· wf' kg •

0,349 lbs t = 0.196 WP sec; wp

-· 0.349 t = 0.555 wf • sec; Wf kg -38-

•

•

•

Table V summarizes the estimated fireball dimensions for

a release of 5273 kg of hydrogen. Since there is excellent

agreement between the various sources, it would seem

reasonable to use the average dimensions for damage estimates .

-39-

•

,•

•

Hardee & Larson 11

Hord 12

Crawley13

High14

TABLE V

FIREBALL DIMENSIONS

FOR 5273 kg of HYDROGEN

Diameter, m

147.4

138. 0

142.5

120.6

Gayle & Bransford15 124 .4

Average Estimates 135

.:.40_

Duration, sec

8 .18

9.35

8.77

• The thermal flux from a fireball, I, as a function of the distance from the center of the fireball as follows: I = 4 / d rnT - , r >

4r2 ( 1 )

2

where:

E = emissivity of flame ::: 0.085

5.67 x lo- 11 2

cr = Stefan-Boltzmanns Constant = kW/m °K

T = flame temperature ::: 2318°K

d = fireball diameter = l 35m .. r = distance from center of fireball, m

I = 6.27 ~ 105, kW/m2for r 135 r~ > -2- m (2)

• For distances from the center of the fireball in units of feet, I

6 75 106 2 = · x , kH/m for r > 222 ft. 2

( 3) r

·-· -41-

•

..

•

•

V. METHODS OF CONSEQUENCE ANALYSES USED

D. Thermal Flux

2. Steady-State Flame

Thermal radiation from a jet flame is estimated as follows.

Figure 7 shows the jet cone in the flammable region (LFL =

0.04 mole fraction). The diameter of the jet is given by

equation l of Section V. B. The volume of the jet cone, VOX,

is given by equation 3 where beta for a burning hydrogen

release is taken as 40. The maximum diameter, OM, of the

jet is computer from the volume of the jet as follows:

OM = 2 4 VOX - DJ ft ( ) 1/2

lTZ* '

where:

Z*/DJ = 121 . 5

vox = volume of flammable cone, ft 3

DJ = jet diameter, ft

Z* = length of flammable cone, ft

The integrated thermal flux to any point receptor is given

as fol lows:

IR = thermal flux, kW/m2

IR = 4

e:aT

Z*

J cosp R2 0

-42-

DdZ

( 1 )

( 2)

•

..

•

) ::E Cl J

/

'

~k _.I

• l

Figure ]_

Thermal Radiation from a Jet Flame

Cl

z

,,.z

s... 0

+> 0. QJ u QJ c::

( J

...., Cl

•

..

•

•

The integral represents the view factor where:

cos

• (

•

(_

--·

Figure 8

10 ____ .-:--:---:--:-=:-~c-:--:r===-:-:-::===='.7:"'.":':~=--,-,--,-,---,---,-;:;:--o-:~-;-::-,,,.-,..-=-~~-,,,--;-:-.,...,.--=..---,--~-:--:-:-:=:.,.,.--::-~=:-:-:-:-:--::-==::===:-:"'7-:::==== g +i~~':-::--·-':-:·--=·-=-=·,,:.-··:-::::.:-·'::-.::==-=:.07-=::,::::~_==-=·-:="~=':='::"°=::'=;=·-'''·::-:::S:;.,-;T:::::h:.:::e=r=iTi=a""l-:':-R:::a=d=1:...:.·a=-=t~-;=~b=-h:,.:,'::!-F,..!.r~o:.::::m~a-'-:.:='J-=e:..::t_' .!..F_!_la:::,m~e=-·__.;...:;'"=::;_-.::-::::·::-=-"'--::-:·:_::__:;-::::-=~-=-::::--=:~-=~;_==_,=::-;;-f~---'==--~~~:f::::--::====i

:~ :·~ ~--::.::~::::=:5:::::=::~§.~-====:::: '=-~E~::~=3::.~~l:::::~~::===-=::_::;::__-o::= :-' : -~~'--=: -: =~~~=~::~,=--~=?::::=======f_-===== s_ 7 -1. :;:.::-.::=~=~::_~~~~~:~".:_~~~'7-:~:_=--=-~:::=~i::::=~~~~:==-=.=-=::=:~~~:'!::-:=::.=~: ::,-~:='-. :· ;~~~-:=:=.~=.:~~=~~~~~~

6 i - :_ -· I -·---·- -- _,_

5 -1 ·::-:::-.::.:::-:~::..=-==:_--f-----f--:-1==--:~--:-:..:;::-:--=:::.:::::c-:- 1- _----=--=

4 ___ ... :·--:.::-·: ~ .:-:~:: -----·----- ... :· _:: .. -:. -::.:-::. :: .. -; - ~~,;::· $-~ :-

3

1 - - --

9 -- -8

7

6

:::~:::::~

• V. METHODS OF CONSEQUENCE ANALYSES USED

..

•

•

E. Liquid Release Rates

In this section~ worst-case liquid flowrates are estimated given

that a pipe is severed or a hole is created in the tank below

the 1 iquid level.

The worst-case pipe break geometry (i.e. maximum flowrate) is a

full diameter cleavage of the pipe as it exits the annular space

of the storage vessel as shown in Figure 9. For this case, there

would be negligible friction losses in the short pipe length

so only entrance and exit losses are considered in determining

fl owra tes.

The relationship between mass flowrate and pipe size for a break

geometry can be calculated from the continuity equation and the

standard pressure drop equation as follows:

M = pVA ( 1 )

\vhere M = mass fl owra te

p = 1 i quid density

v = 1 i quid velocity

A = area of pipe

-44-

•

..

•

--·-

Figure 2_

Worst-Case Liquid Hydrogen Pipe Break Geometry

Liquid Hydrogen Vessel

P< 150 psia

/

Ambient

P = 14. 7 psi a

Square-edge k ;:. 0.34

Full-diameter Break

k = 1 . 0

•

..

•

•

(zk)

where 6P = pressure drop

~k = summation of loss coefficients = 1 .34

Combining equations 1 and 2 and solving for mass flowrate in

terms of the pipe diameter yields,

M =

Equation 3 was calculated using the maximum normal operating

( 2)

( 3)

pressure of the liquid hydrogen storage tank ~f 135 psig and is

plotted on Figure 10.

-45-

•

u Q) Vl -O'l ..::.:. Q) .µ rt! c::

Q) O'l s... rt!

..c > u

Vl

·o

.i:: Q) O'l 0 s...

-~ "'O -~ .er _J

E ~

E ......

•

100

10

1.0

0. 1

0.01

Figure l_Q_

t1aximum Liquid Hydrogen Discharge Rate vs. Hole Diameter

1-~~:-:: :-::-~: '''' 1-:.:=:=-::.: :. : ! I j-,_

__________________________ ,

-------- -----------'--'-

~-'-'-' "-' -'-' "-' -'-'"''-_c.---'-7-- ---------- _,

!-~~::.;.,::·--1 .. · : ~; ; • • ' ···-·-·-····· . :!~'.~:~:~--- ·--~--:

__ _:_ ___ _:__:__c_ _ _:_ ______ --- -- 2

·i

!

' ~~~ .. :=q===~- 1 -'--'-·~--· '-' -·-'"''-'-' ~---'--'-'--'--~·------ .:- .l 7

3 4 5 6 7 8

Hole Diameter, inches

,·":-S:·

•

•

•

V. METHODS OF CONSEQUENCE ANALYSES USED

F. Liquid Flashing

When liquid hydrogen at elevated pressures experiences a decrease

in pressure, rapid vaporization or 11 flashing 11 of a fixed fraction

of the tank contents occurs. The percent of liquid hydrogen flash

evaporation is given as a function of the initial pressure in

Figure 11 •

-46-

•

s:: 0

+J tO N

•r-s.... 0 0. tO > w .. ~ ·Vl tO r-l.J...

s:: QJ c:n

•[ :c -0

:::l 0-

__J

4-0

+J s:: QJ u s.... QJ

0..

-·

Figure ~

Percent of Flash Vaporization vs. Tank Pressure

I~~:-~-~=£~---~~~~-=~-=~·~~=::/_ ---~---1- ~:-1 - - - --!---;-;- ----:---- -1:: ______ ----·

I 1····

i

I

I I

··-· ·----~-- / :::::::=_-,_-:---=::-: _! . -····-·-·· . ·-·----·- i··-----····-··

···-- . ···--··-·I·--··--···· I

u 0 40 80

. ·; ··-·--

: -···

120

I

i -,

i I !

I i.

' ,_.

··-l-1

.. I

! . : . . i

; 1 ·

160

I-·

i i

!

- I .. -- --I .. :- -------·---l-------·--· ··---

---·--- ---··-1------·--·-----· ·- ------·-------!----- ----·-·-·:-· -··-. ---·--·-·-··-- !··-··- --··- ---· -------" ·- ···-·-· ··-- -+-··-·---··-·'--·-··---

. -- . -·--· -------!·-··----·- , ___ _ .: __________ j_ _________ : ____ _

·- -- -----·-··· !- ·------- : ______ .. _

·-- --·-- ·-1-- -- ---1 -- --- - --------------

·- --- := : __ :-:~-----·:::= ~-= i

. I ··-·1

i

200

--~~

•

..

•

-··

V. METHODS OF CONSEQUENCE ANALYSES USED

G. Liquid Evaporation Via Heat Transfer

The violation or bursting of the liquid hydrogen tank will cause a

sudden release of the contents of the tank. The exposure of the

contents of the tank (at 150 psig) to atmospheric pressure will

result in 35 percent of the liquid content being flash vaporized.

The unvaporized liquid will be distributed on the ground over some

unknown area. This liquid will also vaporize due to heat transfer

from contact with the ground. This unsteady state vaporization

process can be estimated using the equations shown in Table VI. If

65 percent of the liquid spills on the ground (7,404 pounds or

1,738 cubic feet), this \'lill cover an area approximated by the

following:

? Area = 1 ,738 x 12/L, ft-

Where L is the average depth of

the liquid pool in inches

( 1 )

The time it takes to vaporize the spilled liquid can be evaluated using the

heat transfer equations in Table VI for different assumed values of L~

Assumed soil and other ·properties are as follows:

p = 150 lb/ft3

, density

k = 1.0 BTU/hr ft °F, thermal .conductivity.

-47-

:.

•

•

Cp

H

Lv

=

=

=

0.2 BTU/lb °F, heat capacity

35 BTU/hr ft2

°F, film heat transfer coefficient

192.6 BTU/lb, heat of vaporization

The time dependent vaporization rates are given in Tables VII to XI for pool

depths of 1/8, 1/4, 1/2, and 1 and 2 inches. The time to achieve complete

vaporization is shown in Figure 12 function of pool depth. One might expect

tank rupture to be violent and to distribute liquid over a wide area resulting.

in an effective pool depth of less than 1 inch. This would result in complete

vaporization within 10 seconds.· This result would suggest that the vapors

created by liquid flashing and those formed by ground evaporation would

effectively drift as a single vapor cloud .

-48-

Table -~L

AIR PRODUCTS

LIQUID HYDROGEN CUSTOMER STATION TANK

QDOT = Heat Transfer Rate, BTU/Hr

QDOT = A * H * CTa - Tb> * EXP CHA2 * T/K/RHO/Cp) * ERFC CH * CT/K/RHO/Cp)A.5)

A= Surface Area Containing Spill, ftA2 H = Film Heat Transfer Coeifficient, BTU/Hr/ftA2/deg F Ta= Temperature of Soil, deg F Tb = Temperature of Liquid Hydrogen = -423 deg F

~ T =Time from the Beginning of the Spill, Hrs.

§Q!b EBQEsB!!s§~

K = Thermal Conductivity, BTU/Hr/ft/deg F RHO = Density, lb/ftA3 Cp = Heat Capacity, BTU/lb/deg F

ERFC = Complimentary Error Function

VDOT = Vaporization Rate, lb/Hr

Lv = Latent Heat of Vaporization, BTU/lb

VDOT = QDOT/Lv

LJNST~ADV STATE VAPORIZATION

TABLE liI

A, FT2 1.6685E+05 RHO,#/FT3 1.5000E+02

T,SEC O.OOOOE+OO

1.5000E-01 2. 5000E-01 3. 5000E-01 4.5000E-Ol 5.5000E-01 6.5000E-01 7.5000E-01 8.5000E-01 9.5000E-Ol 1. 0500E+OO 1. 1500E+OO

.. 1 • 2500E +00 1.3500E+OO 1 • 4500E +00 .1. 5500E+OO ·1. 6500E+OO · 1 . 7500E +00 1.8500E+OO 1. 9500E+OO 2.0500E+OO

TA,DEG F 7.0000E+Ol Cp,BTU/#/D 2.0000E-01

VDOT,#/HR O. OOOOE +00

1.4554E+07 1.4277E+07 1.4090E+07 1.3941E+07 1.3815E+07 1.3703E+07 1.3603E+07 1.3511E+07 1.3426E+07 1.3346E+07 1.3271E+07 1.3201E+07 1.3134E+07 1.3070E+07 1.3009E+07 1.2950E+07 1.2894E+07 1.2839E+07 1.2787E+07 1.2736E+07

TB, DEG F -4.2300E+02

Lv,BTU/# 1.9260E+02

INV,# 7.4038E+03

6.9995E+03 6.6029E+03 6.2115E+03 5.8243E+03 5.4405E+03 5.0599E+03 4.6820E+03 4.3067E+03 3.9338E+03 3.5631E+03 3.1944E+03 2.8277E+03 2.4629E+03 2.0999E+03 1.7385E+03 1.378BE+03 1.0207E+03 6.6401E+02 3.0882E+02

-4. •l966E+01

H,BTU/HR/F 3. 5000E +01 INV,# 7.4038E+03

QDOT,BTU/HR O. OOOOE +00

2.8032E+09 '2.7497E+09 2.7138E+09 2.6851E+09 2.6608E+09 2.6393E+09 2.6199E+09 2.6022E+09 2.5858E+09 2.5704E+09 2.5560E+09 2.5424E+09 2.5295E+09 2.5172E+09 2.5054E+09 2.4942E+09 2.4833E+09 2.4729E+09 2.462BE+09 2.4530E+09

K,BTU/HR/F 1.0000E+OO L, inches 1.2500E-01

INV/INVO 1.0000E+OO

9.4539E-Ol 8.9183E-Ol 8.3897E-01 7.8666E-01 7.3483E-Ol 6.8342E-01 6.3238E-01 5.8169E-01 5.3132E-01 4.8125E-01 4.3146E-01 3.8193E-01 3.3266E-01 2.8362E-01 2.3482E-01 1.8623E-01 1.3786E-01 B.9685E-02 4.1711E-02

-6.0734E-03

UNSTEADY STAT~ VAPORIZATION

TABLE 1U.II L~q~~ci Hyci~~g~n V~p~~~z~t~~n

A, FT2 8.3424E+04 RHO,#/FT3 1.5000E+02

T,SEC O.OOOOE+OO

1.5000E-01 2.5000E-Ol 3.5000E-Ol 4.5000E-01 5.5000E-Ol 6.5000E-Ol 7.5000E-Ol 8.5000E-01 9.5000E-Ol 1.0500E+OO 1.1500E+OO

~ 1.2500E+OO . 1.3500E+OO 1.4500E+OO

.1.5500E+OO 1.6500E+OO 1.7500E+OO 1.8500E+OO 1.9500E+OO

.2.0500E+OO 2.1500E+OO 2.2500E+OO 2.3500E+OO 2.4500E+OO 2.5500E+OO 2.6500E+OO 2.7500E+OO 2.8500E+OO 2.9500E+OO 3.0500E+OO 3.1500E+OO 3.2500E+OO 3.3500E+OO 3.4500E+OO 3.5500E+OO 3.6500E+OO 3.7500E+OO 3.8500E+OO 3.9500E+OO 4.0500E+OO 4.1500E+OO 4.2500E+OO

TA,DEG F 7.0000E+Ol Cp,BTU/#/D 2.0000E-01

VDOT,#/HR O.OOOOE+OO

7.2772E+06 7.1383E+06 7.0451E+06 6.9707E+06 6.9075E+06 6.8517E+06 6.8014E+06 6.7554E+06 6.7128E+06 6.6730E+06 6.6356E+06 6.6003E+06 . 6.5668E+06 6.5348E+06 6.5043E+06 6.4750E+06 6.4468E+06 6.4197E+06 6.3935E+06 6.3681E+06 6.3436E+06 6.3198E+06 6.2966E+06 6.2742E+06 6.2523E+06 6.2310E+06 6.2102E+06 6.1899E+06 6.1701E+06 6.1507E+06 6.1317E+06 6.1132E+06 6.0950E+06 6.0772E+06 6.0597E+06 6.0426E+06 6.0258E+06 6.0092E+06 5.9930E+06 5.9771E+06 5.9614E+06 5.9460E+06

TB, DEG F -4.2300E+02

Lv,BTU/# 1.9260E+02

INV,# 7.4038E+03

7.2017E+03 7.0034E+03 6.8077E+03 6.6140E+03 6.4222E+03 6.2318E+03 6.0429E+03 5.8553E+03 5.6688E+03 5.4834E+03 5.2991E+03 5.1158E+03 4.9334E+03 4.7518E+03 4.5712E+03 4.3913E+03 4.2122E+03 4.0339E+03 3.8563E+03 3.6794E+03 3.5032E+03 3.3277E+03 3.1527E+03 2.9785E+03 2.8048E+03 2.6317E+03 2.4592E+03 2.2873E+03 2.1159E+03 l.9450E+03 1.7747E+03 1.6049E+03 1.4356E+03 1.2668E+03 1.0984E+03 9.3060E+02 7.6321E+02 5.9629E+02 4.2982E+02 2.6379E+02 9.8194E+Ol

-6.6971E+01

H,BTU/HR/F 3.5000E+01 INV,# 7.4038E+03

QDOT,BTU/HR O.OOOOE+OO

1.4016E+09 1.3748E+09 1.3569E+09 1.3426E+09 1.3304E+09 1.3196E+09 1.3099E+09 1.3011E+09 1.2929E+09 1.2852E+09 1.27BOE+09 1.2712E+09 1.2648E+09 1.2586E+09 1.2527E+09 1.2471E+09 1.2417E+09 1.2364E+09 1.2314E+09 1.2265E+09 1.2218E+09 1.2172E+09 1.2127E+09 1.2084E+09 1.2042E+09 1.2001E+09 1.1961E+09 1.1922E+09 1.1884E+09 1.1846E+09 l.1810E+09 1.1774E+09 l.1739E+09 1.1705E+09 1.1671E+09 1.1638E+09 1.1606E+09 l.1574E+09 1.1543E+09 1.1512E+09 1.1482E+09 1.1452E+09

K,BTU/HR/F 1.0000E+OO L, inches 2.5000E-01

INV/INVO 1.0000E+OO

9.7270E-01 9.4592E-01 9.1948E-01 8.9333E-01 8.6742E-01 8.4171E-01 8. 1619E-01 7.9085E-01 7.6566E-01 7.4063E-01 7.1573E-01 6.9097E-01 6.6633E-01 6.4181E-01 6.1741E-01 5.9312E-01 5.6893E-01 5.4484E-01 5.2086E-Ol 4.9696E-01 4.7316E-Ol 4.4945E-01 4.2583E-01 4.0229E-01 3.7883E-01 3.5545E~01

3.3215E-01 3.0893E-01 2.8578E-01 2.6271E-01 2.3970E-01 2.1677E-01 1~9390E-01

1.7110E-01 1.4836E-01 1.2569E-01 1.0308E-01 8.0538E-02 5.8054E-02 3.5629E-02 1.3263E-02

-9.0455E-03

UNSTEADY STATE VAPORIZATION

A, FT2 4.1712E+04 RHO,#/FT3 1.5000E+02

T,SEC O. OOOOE+OO

1.5000E-01 4.5000E-01 7.5000E-01 1.0500E+OO 1.3500E+OO 1 • 6500E +00 1.9500E+OO 2.2500E+OO 2.5500E+OO 2.8500E+OO 3.1500E+OO

,. 3. 4500E +00 3.7500E+OO 4. 0500E +00 4.3500E+OO 4.6500E+OO

( ,. 4. 9500E +(>

UNSTEADY STATE VAPORIZATION

TABLE X

A, FT2 2.0856E+04 RHO,#/FT3 1.5000E+02

T,SEC 0. OOOOE +00

1.5000E-01 6.5000E-01 1.1500E+OO 1.6500E+OO 2.1500E+OO 2.6500E+OO 3.1500E+OO 3.6500E+OO 4. 1500E +00 4.6500E+OO 5.1500E+OO

.. 5. 6500E +00 6.1500E+OO 6.6500E+OO 7. 1500E +00 7.6500E+OO

ce 8.1500E+OO 8.6500E+OO 9.1500E+OO 9.6500E+OO 1.0150E+01 1.0650E+Ol 1 • 1150E +01 1. 1650E+O 1 1.2150E+01 1.2650E+01 1.3150E+01 1.3650E+01 1.4150E+01 1.4650E+01 1.5150E+01 1.5650E+01 1.6150E+01 1.6650E+01 1.7150E+01 1.7650E+01 1.8150E+01 1.8650E+01 1.9150E+01

TA,DEG F 7. OOOOE +01 Cp,BTU/#/D 2.0000E-01

VDOT,#/HR O.OOOOE+OO

1.B193E+06 1.7129E+06 1.6589E+06 1.6187E+06 1.5859E+06 1.5577E+06 1.5329E+06 1.5106E+06 1.4903E+06 1.4717E+06 1.4543E+06 1,4382E+06 1.4230E+06 1.4086E+06 1.3950E+06 1.3821E+06 1.3698E+06 1.3581E+06 1.3468E+06 1.3360E+06 1.3256E+06 1.3156E+06 1.3060E+06 1.2967E+06 1.2877E+06 1.2789E+06 1.2705E+06 1.2623E+06 1.2543E+06 1.2465E+06 1.2390E+06 1.2316E+06 1.2245E+06 1.2175E+06 1.2107E+06 1.2040E+06 1.1975E+06 1.1912E+06 1 . 1850E +06

TB, DEG F -4.2300E+02

Lv,BTU/# 1.9260E+02

INV,# 7.4038E+03

7.3533E+03 7. 11 OBE +03 6.8776E+03 6.6507E+03 6.4287E+03 6.2108E+03 5.9965E+03 5.7855E+03 5.5774E+03 5.3720E+03 5.1690E+03 4.9684E+03 4.7699E+03 4.5735E+03 4.3790E+03 4.1863E+03 3.9954E+03 3.8061E+03 3.6184E+03 3.4323E+03 3.2476E+03 3.0643E+03 2.8824E+03 2.701BE+03 2.5225E+03 2.3443E+03 2.1674E+03 1.9917E+03 1.8170E+03 1. 643•1E+03 1.4709E+03 1.2995E+03 1. 1290E+03 9.5954E+02 7.9101E+02 6.2342E+02 4.5673E+02 2.9094E+02 1.2601E+02

H,BTU/HR/F 3.5000E+01 INV,# 7.4038E+03

ODOT,BTU/HR O. OOOOE +00

3.5040E+08 3.2991E+08 3.1951E+08 3.1177E+OB 3.0544E+08 3.0002E+08 2.9524E+08 2.9095E+08 2.8704E+08 2.8344E+OB 2.8011E+08 2.7699E+OB 2.7406E+08 2.7130E+OB 2.6868E+08 2.6620E+08 2.6383E+08 2.6157E+OB 2.5940E+08 2.5732E+OB 2.5532E+08 2.5339E+08 2.5154E+08 2.4974E+08 2.4800E+08 2.4632E+08 2.4469E+08 2.4311E+08 2.4158E+08 2.4008E+08 2.3863E+08 2.3721E+08 2.3583E+08 2.3449E+08 2.3318E+08 2.3190E+08 2.3065E+08 2.2942E+OB 2.2823E+08

K,BTU/HR/F 1.0000E+OO L, inches 1.0000E+OO

INV/INVO 1.0000E+OO

9.9317E-01 9.6043E-01 9.2893E-01 8.9828E-01 8.6829E-01 8.3886E-01 8.0992E-01 7.8142E-01 7.5332E-01 7.2557E-01 6.9816E-01 6.7106E-01 6.4426E-01 6.1772E-01 5.9145E-01 5.6543E-01 5.3964E-01 5.1408E-01 4.8873E-01 4.6359E-01 4.3864E-Ol 4.1389E-01 3.8931E-01 3.6492E-01 3.4070E-01 3. 166'1·E-01 2.9274E-01 2.6900E-01 2.4542E-01 2.2197E-01 1.9867E-01 1.7552E-01 1.5249E-01 1.2960E-01 1.06B4E-01 8.4202E-02 6.1689E-02 3.9296E-02 1.7020E-02

UNSTEADY STATE .VAPORIZATION

TABLE M

ce A, FT2 1.0428E+04 RHO,#/FT3 1.5000E+02

T,SEC O.OOOOE+OO

1.5000E-01 1.0500E+OO 1.9500E+OO 2.8500E+OO 3.7500E+OO 4.6500E+OO 5.5500E+OO 6.4500E+OO 7.3500E+OO B.2500E+OO 9. 1500E+OO

.. 1 • 0050E +O 1 1.0950E+Ol 1.1850E+Ol .1. 2750E+Ol 1.3650E+Ol

ce 1.4550E+Ol 1.5450E+01 1.6350E+01 1.7250E+01 .1.8150E+01 1.9050E+01 1.9950E+01 2.0850E+01 2. 1 750E +01 2.2650E+Ol 2.3550E+Ol 2.4450E+01 2.5350E+Ol 2.6250E+Ol 2.7150E+Ol 2.8050E+Ol 2.8950E+Ol 2.9850E+Ol 3.0750E+01 3. 1650E +01 3.2550E+Ol 3.3450E+Ol 3.4350E+Ol 3.5250E+Ol 3.6150E+01 3.7050E+Ol

• 3. 7950E+01

·- 3. 8850E +01 3.9750E+Ol 4.0650E+01 4~1550E+Ol

4.2450E+Ol

TA,DEG F 7.0000E+Ol Cp,BTU/#/D 2.0000E-01

VDDT,#/HR O. OOOOE +00

9.0965E+05 8.3413E+05 7.9918E+05 7.7374E+05 7.5322E+05 7.3583E+05 7.2065E+05 7.0713E+05 6.9490E+05 6. S:372E+05 6.7342E+05 6.6385E+05 6.5491E+05 6.4652E+05 6.3861E+05 6.3113E+05 6.2403E+05 6.1728E+05 6.1083E+05 6.0467E+05 5.9877E+05 5.9310E+05 5.8766E+05 5.8241E+05 5.7736E+05 5. 72L18E+05 5.6776E+05 5.6320E+05 5.5878E+05 5.5449E+05 5.5033E+05 5.4629E+05 5.4237E+05 5.3855E+05 5.3483E+05 5.3121E+05 5.2768E+05 5. 242LlE+05 5.2089E+05 5.1761E+05 5. 1441E+05 5.1128E+05 5. 0822E-H)5 5.0523E+05 5.0230E+05 4.9943E+05 4.9662E+05 4.9387E+05

TB, DEG F -4.2300E+02

Lv,BTU/# 1.9260E+02

INV,# 7.4038E+03

7.3785E+03 7.1638E+03 6.9604E+03 6.7642E+03 6.5737E+03 6.3879E+03 6.2061E+03 6.027BE+03 5.8528E+03 5.6806E+03 5.5111E+03 5.3441E+03 5.1794E+03 5.0169E+03 4.8563E+03 4.6977E+03 4.5409E+03 4.3859E+03 4.2325E+03 4.0806E+03

.3.9303E+03 3.7814E+03 3.6338E+03 3.4877E+03 3.3428E+03 3.1991E+03 3.0566E+03 2.9153E+03 2.7752E+03 2.6361E+03 2.4980E+03 2.3610E+03 2.2250E+03 2.0899E+03 1.9558E+03 1.8226E+03 1.6903E+03 1.5588E+03 1. 428:2E+o:::;. 1.2985E+03 1.1695E+03 1.0414E+03 9.1396E+02 7.8732E+02 6.6142E+02 5.3625E+02 4. 117BE+02 2.8801E+02

H,BTU/HR/F 3.5000E+Ol INV,# 7.4038E+03

QDOT,BTU/HR 0.0000E+OO

1.7520E+08 1.6065E+08 1.5392E+OB 1.4902E+OB 1.4507E+OB 1.4172E+OB 1.3880E+08 1.3619E+08 1.3384E+08 1.3169E+OB 1.2970E+08 1.2786E+08 1.2614E+OB 1.2452E+08 1.2300E+08 1.2156E+08 1.2019E+08 1.1889E+08 1.1765E+08 1.1646E+08 1.1532E+08 1.1423E+08 1 . 131 BE +08 1.1217E+08 1 . 1120E +08 1 . 1026E +08 l.0935E+08 1.0847E+OB 1.0762E+08 1.0680E+08 1.0599E+08 1.0522E+08 1.0446E+08 1.0372E+08 1.0301E+08 1.0231E+08 1.0163E+08 1.0097E+08 1.0032E+08 9.9692E+07 9.9075E+07 9.8472E+07 9.7883E+07 9.7307E+07 9.6743E+07 9.6191E+07 9.5650E+07 9.5120E+07

K,BTU/HR/F 1.0000E+OO L, inches 2.0000E+OO

INV/INVO 1 . OOOOE +00

9.9659E-01 9.6758E-01 9.4011E-01 9.1362E-01 B.8789E-01 8.6278E-01 8.3823E-01 8. 1 415E-01 7.9051E-01 7.6726E-01 7.4436E-01 7 . 21 8 1 E -i) 1 6.9956E-01 6.7760E-Ol 6.5592E-01 6.3450E-01 6.1332E-01 5.9238E-Ol 5.7166E-01 5.5115E-Ol 5.3084E-01 5.1073E-01 4.9081E-Ol 4.7106E-01 4.5149E-01 4.3209E-01 4.1285E-01 3.9376E-01 3.7483E-01 3.5604E-01 3.3740E-Ol .::, . 1889E-O 1 3.0052E-01 2.8228E-Ol 2.6416E-01 2.4617E-01 2.2830E-01 2. 1055E-01 1.9291E-01 1.7538E-01 1.5796E-01 1.4065E-01 1~2344E-Ol

1.0634E-Ol 8.9336E-02 7.2429E-02 5.561BE-02 3.8900E-02

10

9

8 .

• 7 ( 5 - -

..

• 9 -8

7

6

5

4

3

(_ 2

• l_

Figure 12

... ... :::

. .::...:...::.:_: .. ::_;·_:_ ::.: -·····- ...... :·:-:1.-:::: :-:.:c ... : : :- ~~--f-·

·i- ·-·· i.-:·:·:_ ... i

. - . - . ---···-··-- . • . i ' : ::.:~:~:::::::l::::=:::::::·.:. :::.~--·=:__: ::-::::::::::::~ ,:::::-.::-==-:::~t==-=:~ -.:::_: j. -· , .. .... I : .1 . I -· ..

~~----'-·-------,},(.·_·. '-· ··-~~•-: .... :r- .

I : ·. ~ . ! f.

--·---- ·---·-1-· . - ::.:_ :_;_-_;:._:_:::· i--· __ :- ··-. --·· . s... :o. : o.------+-----J ··----··- _-:. __

'>Ir:.-·--·· =:: :- __ ;·-:::I "." ... -·.·:-· : ::__-__ ::.·_ -1_

- ,_ -- - -- --.:.:::c . J_ ·:: _::~:~=~:::: -: ltl ,...., -· .:-:------+

. ·;· : . 1-·····-· .. ,, ..... -;-····-·· ·····--- ·-·•·-·-·-·--·-·~ . . ,. ·-1 ·-····· .. ··-·· ,-... ·.·.-.. · ·-·-····-··-!·-···----··-· -------l

.. j . .•.. ·-·-·· -~ I · · -·- . ·:.--:..:~1:-::.:::~.:.:.-:.:.:::::=:.===-,_-____ ·_, ,-. ~~·r--~·.---. ~r----:--:.-.. ~~, ~-.~1~.--.-t-:-:~•-::~-.=~:i.~-·=-=:_-~~+-~-:__-=_-._~1,_-_---1 __

! .A. 1-·- ! ... L.... --:::~~~1~:· -:~=--==!.--~---.·-

0 1.0 2.0

•

..

•

•

VI. GENERIC CONSEQUENCE ANALYSIS

A. Catastrophic Tank Failure

This section documents the parameters necessary to determine the

effects of a catastrophic tank failure on a nuclear power plant.

The following modes of occurrence in the aftermath of tank failure

are considered for a full 20,000 gallon tank of liquid hydrogen.

Drift without ignition

Drift with explosion

Explosion at tank site

Fireball

For all modes of occurrence, the instantaneous or "puff" Gaussian

dispersion model (Section V. A. 2.) is used with F weather

stability to calculate the worst-case consequences. The

damage-estimate parameters are shown for the minimum flash

vaporization (1 ,846 kg) and the instantaneous vaporization of the

entire tank contents (5,273 kg).

-49-

I l i !

,'1!

It

•

•

•

VI. GENERIC CONSEQUENCE ANALYSIS

A. Catastrophic Tank Failure

1. Drift Without Ignition

The peak hydrogen concentration as a function of downwind

distance from the tank failure is shown on Figure 13. This

estimates the maximum hydrogen concentration as an unignited

cloud passes over .

-50-

Figure l1_

•

..

• · t-; -~:~---~:=:-1--_~ - p;J -·~: . - ·-----i-- +> - ·a... I - -w 1-~~~~~--;--~~~~~-1-~~~i-~-t~~~~~-_-1~---~w=--__;;c----~-~i~~~~~--1--_c~--~~--l

!,: :: ~ . » _1 I ~ ~ . ~ ;; - . - -·-- --

I - -· ·--·- ·--·-· ·---j ··-----·--:y--~ -! -·--1:-:-'--·---·--· 1· ·----- - ---i o '-" ! '-° ----·--· -··-------\

-·--·-·--- :_---·--·--·--1 ··-----------.----- ··--1--·-·· --- --·--·----·--·- ·--·-· - !-- ·:-: . s::: : -··1 .-~ ·----·--· -:- -·-··--:~~_::::.::::r-:::::-:-.:-::::J, =~==-----:-.::-.:-:-::- -::_-:jl ·-/~' -~~--:-_·:-:·--:::-::::- ~:.-: ··: ·: \, ·: . Q_. - ·~ --: :-:·-:::::::.=. :-=~= ~ -·=-~-==:t=-:=

•O

___ ;_:~: ___ -,' _ _:_ __ ;·:·· - -___ j,_..·-~=-:~ ~-;:_~-::.--.=·:.+--!::.: __ -___ - - ..::; u_ . -- . - _:_:::_~;::=~~_::::___ ::_=.::::_T_:::-_=:·_-1 · - ·--- - · - - • ---·----·-·- 1 ·-·- • e o

. -· ·- . ! . -~ ! - - . - i-· - - l --· 0 -·- ..•

I r• Tl~· I ~ f :-~ I ... !->~ ! l - --- -=-. I -·-1p --· 1- -,-:_-:::·:_·:=::::.-: :-_: :-• . ... , - I ! -· ---·-·-----------· I I .. i ,.;._ I -----·- -- ! ----- - . I I - i

. lo ·

•

•

..

•

•

VI. GENERIC CONSEQUENCE ANALYSIS

A. Catastrophic Tank Failure

2. Drift With Explosion

The weight percent of the release quantity in the explosive

range (18.3 - 59 volume%) is shown as a function of downwind

distance in Figure 14. The maximum percent in the explosive

range for flash and total vaporizati~n is approximately 51

percent at distances of 700 and 1,100 feet, respectively .

Using this weight percent and the hydrogen to TNT equivalence

of 520 weight percent (Section V. C. 2.), the maximum TNT

yields are 10,768 pounds TNT for flash vaporization only and

30,765 pounds TNT for total vaporization. Figure 15 shows

both the peak positive incident and normal reflected

overpressures for these two yields as functions of distance

from the blast center. The positive impulse verses the

corresponding overpressure are given in Figure 16 for incident

properties and in Figure 17 for reflected properties.

Both the impulse and the peak overpressure are necessary

parameters to determine the dynamic response of safety-related

structures. This concept of dynamic response strength of

structures is illustrated on Figure 16 for the threshold of

partial demolition of residential brick construction. This

curve represents many "data points" for homes damages during

World War II from known size bombs at various standoff

-51 -

•

•

• \ ,

d . t 17 1s ances . Brick buildings subjected to incident

impulses/overpressures to the right and above this curve would

receive more severe damages. Points to the left and below the

curve would be under the threshold for this damage criterion.

In order to assess the potential damage to a nuclear power

plant, similar curves to this must be generated for

safety-related structures .

-52-

• • • : I

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' ' ' ' ' .. !

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: I ·11: !I i I ! I ! : ! I ·1 ii I j i I i ! ; '. t I ; ! :::: I t .. 1 I 1 1 1 i ! r I 1 + I I : : 1 • ! 1 : 1 ; ro

1 . ·-: ·;·rr ... ,-TiT ·-J T_ r;- ·rni _-r TIT. ·-Tm·: . d--1: ~- --1-1_ 1T TT . ,-:- :-'; ' i ~ : . ! l : i ., j ~ ! . j ! ! ! !- ; ! ) ! : : ~ ] l l ; : lO ,,1 Iii/ II! 1111 i1:1: I! I ! :111 ' : :::r

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~~--~~ -40··· ---·- --- -- -···•- ·-----·---·•• ------ ----·--•··- -;·-'-i_ ; ; I ; : ;-:-, • ---:~+~··· ·-·-·1· 1 J : j : ··r++-+-· -4-h- ~--+-·~._. : i .;: ; : : ' i ' : ; ' ; i i I i I I II I I Ii : : i i ; l i ii j i i II i i I I i i : ! . ! ~; L -~ i ; Vl_ l : ; : i i I ; i ! . ! I : I i : l I i I I ! ! ; ' I i i I ' I i I I I : 11 1 I \ l::t I !fl

"'TS-in: ; : --------- i': ; : : ! i ! I ; I' H '1it· +rr-1,,trn -int lt, -t1-11-· I I I I Iii I rn+, --:,: 1~-~~li·~·\, \} , • . , 1 , . , , , 1 , : 1 , ! 1 , 1 1 1 1 1 1

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!·

..,, . 30- ·--- -----· ··--·-'--· ·-··----·· ___ ;_ ____ l __ _:_.;_ ·-~-· -- ' . I . I ' ' I I ' ' I 'rt ' . : :a , , .. , .. i , .. . . , .. . : ! : ; I , ! .. , ' , , , I ! , ! , I I i ~ : I : .. i ! I r_l_I_ i ~:::r ; ·-. .....:.-(!): 1 I 1 , • 1 ! ' , , : ; 1 ; ' • i 1 : ' ; : 1 / 1 I I / / I I I j 1 I I j I 1 1 i 1 · ' I , .. ·ro ' i 'o·

c~j ~:Jl +' · i , ' . o insl ant v P6~;·, ti on! f :EnHf¥.a ~ds ~ +--'LlJ 11 ________ -l+++.J:lli ] 1 i j}_I J ~- ] ! ! ~ j ! ! i i : i ; ! : 0 Fla h Vap dza·t.on !o'n YIC~'p ~l1s10 pJ;)j 11111' n ! 1,1 .- _, i I 11· 1~ l_l!ii .,. i: r I :3:r, .• _:/-rj_ ,~ · 4- . . : i : 1 , 1 ! ! 1 1 1 1 1 - \ , • ., · 1 · ·1 ·· · - I+ ·1·· j- -j ' rl I i '""""' · 1 ri::::i:

0 ' 0 _______ -·----··-· .......... - .... ------··-···- ·-------~-i _ _:_L!_l_ 1 Ii I I I I I I · i I! I I I- 1 I. - I I I!! I 1 I~ ro' I 'g ~- i 1 ' · · i : ' i : I i i i i I I l I l I 'I I 1· 11 1 I 1 i 11 l- 1 ' 1· -1--1-· j : · 'fr· -r-c..

•

•.-CA c.

Q) s... :J Vl Vl Q)

• 0

•

3_ __ _

Fi 0ure l5..

Incident and Reflected Overpressure vs. Distance from Blast Center

::.:::-~

-· ······· :.c!''' '=-~:'.""''-7L~":---~:: ______ _

: :c.+:: :· :,~::::~r='--: '"'~='~7';:=:=-== . : :~_=(':,::::,::~~!~~~-~~,::-~:::--

. - . ·-·- ·-- ·--· ·-· ~.....:: .h(;,-·:::: .:: .. ::: .::·::- ::··:=·-·-i:c-r--:.==-=- ·::::--==.:=·--. --- . . : .... -· ·t· ··---···· ·- r····-·· ... · 1' . - . _ .. :_=.·;_:I;_._~-·-: .. :~:-:-.: .• _~-;·_~---;·:::·~---.·-__ -_-_: ___ ~-:;;_~--~~-_·;~:_.;.~_;;~,_---~~-_-· -·_·_::_'.-~~--~~-~-~·:·;i:,:--~_-:.--_-_~_

z.. ~~~;:;;~::~~~-~:~~~:.:_:_ :::.::::~ . •:-L~:~: : 1~~=:: :~:.=-:::~:~~::~ =~=: - - · - ==1 - - -0 200 400 600 800 1000 1200 1400

Distance from Blast Center, ft.

•

104 .. VI E

VI

• a. QJ VI ::i c.. E

.µ 103 c QJ -0

u c

• 10

Figure 16

Incident Impulse vs. Peak Incident Overpressure Vaporization 30,765 lbs. TNT for Total

10,768 lbs. TNT for Flash Vaporization Only ·:::,::·.: ... : l

'""'8~~~=C"-'c,;c:~~~~c:..c:~=.:~~~~ft~!~f:~--: ~==="-"-=.:..:..:======"-''==="'F==~~"'-i-==========='-'-'--'---'-''----' ---'-·'-"''-·'-------.. ·-'--'

2 3 4 5

'•

.:._:.)

·• 3

-ki-.,...l-~~-;.-~-l-,....~..,.-'..~,...;._,....+.....,...;.,.,,...._.;....+,-h--.,....:...,.+..~+..,._:..,.,.,.,.,..,~.,,;-,..,..,.,.;-,.,,..,;-,.-:::+~-:-:c.t------1 ·"-'"""4-'-'-'-'~-'-"'""-""'-~---9 ,j'~:::.· :-,'=jc:"'J.~i"-'·:.: .jjc i: "·· ·.: .. ,.. .... ___ S

7 ~=~~~~~~=~~;=~~:f==.~-~~-?~·~·~~~=~~~~E~.i.~~=~~~~;~r~~'.~~~~;i~~~~~-i=~-~ .. -~ .. ~ .. ·~·;_·;_·~· ___ 6

5

3

.\ 6 7 8 I

~;,03 2 3 4 5 6 7 io 2 ' '

10 2 3 4 5 6

Peak Incident Overpressure, psi

... 2

•

..

•

•

Vl E

Vl c.

QJ Vl

::i c. E ...... -0 QJ .µ u QJ

10

Figure .!l

Reflected Impulse vs. 30,765 lbs. TNT for

Peak Reflected Overpressure Total Vaporization

10,768 lbs. TNT for Flash Vaporization Only ~~~~m±IBI~~-fil!ISJ'~ITIIIT.:I:Irr···~ ·-~-. ·-·-,, ---···-··-------~ : ~===-=:-:.~~r~. ~·~~: .. ~~~:~::::·:·: . :=· ..• ·

:. : .. : : .. i========"+"="'l'==""""==;==-============c.:....'-"--'-'""-"''-".:;."...;'-'---__;_-.;.._-'--'---"'---------·····-

····_·_:,.i,_ .... :::!. ·······f··· .1 . . . i .. ·\·

·; 8

.b

-- 7

i::=::===:::~~~~§::~~~~~~~~~;E~~~~~~~~~~~:o.f~~"""~T':':.:,.;.,'7--'~~,;..;.;.-:-:-;-;.,,.;;.;,.;:.;;;:-:f'-:-;.;.;-:-:c~~-'.~;_~,-T·~-·;...-J------6 ·----· 5

----- 3

' . ---·---~-- ---~---~~

-:'~*===~' .... :-'~"":~:;c~'"'-""'"'":_; : .. ; _:· ---- 6 . : :

•

•

•

VI. GENERIC CONSEQUENCE ANALYSIS

A. Catastrophic Tank Failure

3. Explosion At Tank Site

For an explosion at the tank site, the instantaneous Gaussian

dispersion model with a virtual source predicts 45.5 weight

percent of the release in the explosive range (see Figure

14). The blast parameters calculated for the maximum 51

weight percent and plotted in Figures 15 through 17 can be

conservatively applied for an explosion in place with the

blast center located at the tank. The reason for this is that

the dista~ces would be only 4 percent less than those for the

maximum weight percent when the 1/3 scaling TNT curves are

used (TMS-1300).

The closest safety related structure (control room) at Dresden

is 700 feet from the tank location. From Figure 15, the peak

incident overpressure at 700 feet is 2.5 psi for the total

vaporization of a full tank. When this incident pressure is

plotted on Figure 16, one can easily see that it fails outside

-0f the damage criterion for residential brick construction.

This strongly suggests that the heavily-reinforced concrete

safety-related structures would sustain such blast parameters

with insignificant or no damage .

-53-

•

•

•

VI. GENERIC CONSEQUENCE ANALYSIS .

A. Catastrophic Tank Failure

4. Fireball at Tank Site

When a large release of liquid hydrogen ignites immediately

upon release, fireball combustion is the expected result.

This is because the rapidly expanding vapor cloud will only

have premixed at the outer regions of the cloud in contact

with the ambient air. The inner core will consist of vapors

above the upper flammability limit and burning will occur only

in the outer layer. The fireball will initially expand

hemispherically, being fueled by the expanding inner core. As

the buoyancy forces of the hot gases begin to dominate, the

fireball will rise and become more spherically shaped. By the

time the fireball lifts from the ground to form the classic

mushroom-shaped oblate spheroid, the thermal radiation will.

decrease significantly as the fireball rapidly cools11 .

The estimates for the fireball size, duration and thermal

radiant flux are given in Section V. D. 1 .• Equation 3 for

the thermal flux as a function of distance from the fireball

center is plotted on Figure 18. For the estimated 8.77 second

duration, the thermal flux required to ignite wood of 26.6

kW/m2 will occur about 500 feet from the tank15 . Since

safety related structures at the Dresden site are greater than

700 feet from the tank, the effects of a fireball would be

insignificant to these structures.

-54-

•

•

•

VI. GENERIC CONSEQUENCE ANALYSIS

B. Line Severing and Tank Hole

1. Gas Release

Hydrogen gas escaping from a line or a hole in the tank will

do so at greater than sonic velocity. The continuous vapor

cloud formation is treated as a momentum-dominated jet

discussed in Section V. B. The pounds of hydrogen in the

explosive region, MEX, (LEL = 0.183, UEL = 0.59) is given by

equation 2 of Section V. B. This is converted to an

equivalent TNT by assuming a 20% yield and that at 100% yield

one pound of hydrogen is equivalent to 25.96 lbs. of TNT. The

ma~imum reach, Z*, for the Jet plume is also defined in

Section VI. B. for various release conditions. It is assumed

that a hole is formed releasing a horizontal jet in the

direction of a safety related structure. Explosion is assumed

to occur originating at the mid point of the jet, Z*/2. If X

is the distance from the tank, then R the distance from the

center of the blast to the receiving object is:

R = X - Z*/2, ft (1)

The scaled blast distance is given as: (MEX in lbs.)

z = R (2) (MEX* YIELD* TNT)l/3

-55-

•

..

•

•

Using the blast pressure curve for spherical TNT explosions

(TM5-1300) discussed in Section V. C., blast pressures can be

estimated as a function of distances from the tank. These are

shown in Figures 19 and 20 for the follOl'ling conditions:

Tank Pressure (MAX) 150 psig

Gas.Temperature -423°F

LEL (detonation) 0.183

UEL (detonation) 0.59

Hole Size 1 /2 to 4 inches

As seen from Figures 19 and 20 releases from holes up to 4

inches in di