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NORTHEAST UTILETIES cenerei Omce. . seicen street. Bernn, connecticut

3 '* =a P.O. BOX 270* * * * ' * * " " " ' ,

HARTFORD. CONNECTICUT 06141-0270 iL L J [E[C7 (203) 665-5000 |

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March 26, 1993 i

Rocket No. 50-336B14425

Re: Technical Specification i

3.4.10

U.S. Nuclear Regulatory Commission *

Attention: Document Control Desk ,

Washington, DC 20555t;

Gentlemen: !,

Millstone Nuclear Power Station, Unit No. 2,

Request for Enforcement Discretion iReactor Coolant System - Structural Integrity

Limitina Condition for Operation ;:

Introduction it

Northeast Nuclear Energy Company (NNECO) hereby requests enforcementdiscretion sssociated with compliance with Millstone Unit No. 2 Technical '

Specification (TS) 3.4.10, Reactor Coolant System ' - Structural Integrity.This request is being made pursuant to the provisions of 10CFR2, Appendix C,-

,

Section VIII, " Exercise of Discretion." This enforcement discretion is !

necessary to afford NNEC0 sufficient time to effect a temporary ' repair to ;provide additional structural integrity to a section of service water supply '

piping which provides cooling to the 480-Volt Vital AC Switchgear Room. We

believe that enforcement discretion is warranted in this case' to avoid anunnecessary plant transient and the associated operational risk since thercquest involves minial safety impact. We further believe .it to beconsistent with the b ' a and safety of the public.

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Backaroundi

On January 13, 1993, Millstone Unit No. 2 was_ phased to the grid to return to .!service following the steam generator replacement and refuel outage. |

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On January 25,-1993, a hydrostatic pressure test was performed on a section of lthe service water piping which supplies cooling water to _ the west 480-Volt i

s Vital AC Switchgear Room Cooling Coils X-181A and 1818, in accordance with the ,

requirements of Section XI of the ASME Boiler _ and Pre.;sure Vessel Code. .Aflaw in _ a 2"' Schedule 40 Copper-Nickel supply pipe to the cooling coil was ;

'

| discovered during the system hydrostatic test. The small weeping leak existed ;

only at hydrostatic test pressure of 110 pounds per square inch gauge (psig)..

9304010016 9303a?6 kDR ADOCK 05000336 \ I .!pPDR - -

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U.S. Nuclear Regulatory CommissionB14425/Page 2 !

March 26, 1993 :

No leakage has been detected at normal system operating pressure of ;

approximately 38 psig. !

In a letter dated February 24, 1993,"' RNEC0 requested relief from ASMEBoiler and Pressure Vessel Code Section XI requirements pursuant to'

1

10CFR50.55a(g)(6)(1), in response to Generic Letter (GL) 90-05. The !

attachment to that letter provided descriptions of actions taken by NNECO tomake interim repairs to the leak in this piping as an alternative to an IWA- ;7000 replacement.

In a telephone conference between NRC Staff and NNECO personnel on March 22,1993, the Staff expressed concern with certain aspects of the February 24, .

1993, relief request. Subsequent discussions on the subject resulted in the '

Staff indicating that GL 90-05 was not applicable to this particularsituation. Further, the Staff took the position that NNECO was not incompliance with the TS 3.4.10, Reactor Coolant System - Structural Integrity. i

The subject 2" ASME Code Class 3 supply line is not leaking at normaloperating pressure. The Staff's interpretation is that TS 3.4.10 applies to :

the subject service water line. It is NNECO's understanding that although the |line is not leaking, the Staff considers the structural integrity to be in ,

question as a result of the leakage discovered during the hydrostatic pressure |

test. |,

Attachment 1 provides a detailed review of NNECO's proposed alternative to the irequirements of ASME Section XI IWA 4000/7000 in accordance with the !

requirements of 10CFR50.55a(3)(ii).,

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Reauirements for Which Enforcement Discretion is Reauested

While NNECO continues to evaluate the applicability and interpretation of !TS 3.4.10 regarding this issue, we hereby request enforcement discretion }

! associated with compliance with Millstone Unit No. 2 TS 3.4.10. This .

1 enforcement discretion is necessary to permit reactor operation for up to |

7 days while NNECO designs, fabricates, and installs an " engineered clamp" to' '

1 provide added assurance that the structural integrity of the subject service :

water supply line is maintained. This temporary repair sequence is expected >

to require approximately 7 days. i

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(1) J. F. Opeka letter to U.S. Nuclear Regulatory Commission, " Millstone' i

Nuclear Power Station, Unit No. 2 Modification to Pipe Relief Request ,

from ASME Code Section XI Requirements," dated February 24, 1993. j<

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U.S. Nuclear Regulatory CommissionB14425/Page 3March 26, 1993 '

Discussion of Circumstances Surrounding the Situation /Need for PromptAction /Why Situation Could Not Be Avoided

NNECO believes that our previous course of action to resolve this issue wouldhave precluded the need to seek enforcement discretion. However, the Staff's .

anticipated denial of the February 24, 1993, GL 90-05 relief request has ;

changed the planned course to resolve this issue. Our current understanding,

of the Staff's position, as communicated in several telephone conversations onMarch 24, 1993, results in the following sequence of events:

NNECO understands that since the issue is noncompliance with the correctiveaction requirements of IWA 5250 following a hydrostatic test, the provisions >

of GL 90-05 are not applicable and the February 24, 1993, relief request will ;

be denied. At present, the appropriate code repair cannot be made on-linesince it involves defect excavation and weld repair near sensitive turbineelectric-hydraulic control equipment. Welding in this area has a highprobability of causing electro-magnetic interference which could result inelectronic signal perturbations sufficient to lead to a turbine trip. t

Therefore, attempting a code repair is not prudent.

Because the hydrostatic test results were not satisfactory, the Staff believesthat structural integrity of the subject piping has not been demonstrated.Accordingly, the provisions of TS 3.4.10, Reactor Coolant System - StructuralIntegrity are believed not to be met. .

As a result, NNECO requests enforcement discretion to allow sufficier.. time to ;

effect an interim repair to provide added assurance of .the structuralintegrity of the subject line.

Discussion of Compensatory Actions

In response to the hydrostatic pressure test leakage, NNEC0 performed anassessment using GL 90-05 accepted methodology to verify operability of thisportion of the service water system. The results of this assessment were suchthat no compensatory measures are necessary and the system will perform its

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design requirements in a manner unchanged from original design. :

Once the TS Limiting Condition for Operation potential noncompliance was ,'

identified, NNEC0 explored measures to resolve the situation. The applicableaction statement for the noncompliance discusses restoring structuralintegrity or isolating it from service. Given that the structural integritycould - not be easily improved, component isolation was the remainingalternative. NNECO initially- considered this as a possible solution, butrejected it since we believed that isolation would decrease the measure ofsafety and would be contrary to our safety ethic. Additionally, NNECO had :

determined the component to be operable and no leakage existed at normaloperating conditions.

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fB14425/Page 4March 26, 1993

During the period of time for which the enforcement discretion is in place,the joint containing the defect will be monitored a minimum of once per shift. |

Additionally, in the unlikely event that a leak should occur, operator action :can be taken to isolate the leak (isolation valves are present, operators' are ;capable of shutting the valves). -

;

Safety Sionificance and Potential Consecuences of Reouest !

The purpose of this request is to provide a one-time approval for operationfor 7 days with the subect 2" service water supply line in a degradedcondition.

NNECO believes that the safety significance of this request is minimal. The,

potential consequence of this request is that it will afford NNECO the '

opportunity to effect an appropriate alternate repair (design and install anengineered clamp) to enhance the structural integrity of the service watersystem.

Details of the Safety Assessment are discussed later in the No Significant :

Hazards Consideration section of this letter. :

Discussion Justifyina the Duration of the Reouest

The proposed enforcement discretion is for one-time approwl of reactor ioperation for up to 7 days with a potential loss of structural integrity inthe 2" service water supply to the vital switchgear cooling coils. Continuedoperation is based on an operability assessment of the piping in a degraded -

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state using the guidance of GL 90-05 and the draft ASME Code Case N-513.NNECO believes that the 7 days will provide sufficient time to install a .

temporary structural replacement (i.e., an engineered clamp). This clamp will !meet the requirements of the draft ASME Code Case entitled, " TemporaryStructural Replacement Requirements for Class 2 and 3 Piping." '

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Basis for No Sionificant Hazards Consideration,

'NNECO has concluded that the time period to design and install the engineeredclamp for which there is potential for loss of structural integrity does notinvolve a significant hazards consideration (SHC) in that this request forenforcement discretion would not: t

(1) Involve a significant increase in the probability or consequences of anyaccident previously evaluated.

The potential for loss of structural integrity during the time periodwill not result in a significant increase in the probability orconsequences of an accident previously evaluated in Chapter 14 of the ;

Millstone Unit No. 2 Final. Safety Analysis Report (FSAR) because thereis reasonable assurance that the flaw will not progress during this time ;

period to the point of catastrophic structural failure. An operability |!

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U.S. Nuclear Regulatory CommissionB14425/Page 5 }March 26, 1993 |

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assessment has been performed in accordance with the requirements ofGL 90-05. This assessment indicates that the component will remainoperable throughout the time period. As such, the weld defect does notinvolve a significant increase in the probability or consequences of any i

accidents previously evaluated, i

(2) Create the possibility of a new or different kind of accident. Il

The potential for loss of structural integrity during the time period ,

does not create the possibility of a new or different kind of accident i

from any previously analyzed in Chapter 14 of the Millstone Unit No. '2 ;

FSAR. There are no new credible failure modes introduced. The piping ,

in its degraded state has been evaluated and demonstrated to remain i

operable for all design basis loading conditions, i.e., precsure, :deadweight, thermal, and seismic. In addition, the - area has been !

reviewed for potential wetting and flooding. This review determinedthat the spray shield will preclude wetting of adjacent components and !

that any leakage which develops will be contained and diverted with the :cofferdam and drain system.

(3) Involve a significant reduction in the margin of safety. t

The potential for loss of structural integrity during the time period !does not involve a significant reduction in the margin of safety. The ;

piping in its degraded state has been evaluated and demonstrated to ,

remain operable for all design basis loading conditions, i.e., pressure,

deadweight, thermal, and seismic using the guidance of GL 90-05. As isuch, the defect in the weld does not involve a significant reduction in - |the margin of safety. |

fBasis for No Irreversible Environmental Consecuences

The requested enforcement discretion has no environmental impact since the '

request, if approved, will allow Millstone Unit No. 2 to continue to operate L

throughout the time required to design and install an engineered clamp.Continued operation, given the no SHC determination, does not affect any ;

accident analyses, the associated radiological consequences, nor the systems iassociated with the control of radiological or nonradiological effluents. L

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$.,umma rV ju

The Millstone Unit No. 2 Plant Operations Review Committee and Nuclear Review fBoard have approved this request for an enforcement discretion and concur with :the above determinations. ;

We wish to emphasize our conclusions that this proposed request for ienforcement discretion involves no undue safety risk nor irreversible ,

environmental consequencas. We are therefore requesting this action to allow i

continued plant operation as there is no safety issue threatening safe plant |:

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March 26, 1993 '

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operation. Avoiding an unnecessary plant shutdown is in the best interest of ;

the health and safety of the public, our customers, and shareholders.!

We believe the above information provides a complete basis for approval of the !requested enforcement discretion relief from TS 3.4.10. We will continue to jkeep you informed on matters relevant to this request.

Should the Staff require any additional information to respond to this request I

for enforcement discretion on an expedited basis, NNECO remains available to ii

!provide such information promptly.

Very truly yours, ;

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NORTHEAST NUCLEAR ENERGY COMPANY,

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FOR: J. F. Opeka .

Senior Vice President |

C WS &BY: E. A. DeBarba ;

Vice President j|

cc: T. T. Martin, Region I Administrator '

G. S. Vissing, NRC Project Manager, Millstone Unit No. 2P. D. Swetland, Senior Resident Inspector, Millstone Unit Hos.1, 2,

and 3 ;

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Mr. Kevin McCarthy, DirectorRadiation Control UnitDepartment of Environmental ProtectionHartford, Connecticut 06106

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Docket No. 50-336B14425

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Attachment 1

Millstone Nuclear Power Station, Unit No. 2

!Use of a Proposed Alternative toASME Section XI in Accordance with the

Requirements of 10CFR50.55a(3)(ii)

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March 1993,

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, NORTHEAST UTILITIES.

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USE OF A PROPOSED ALTERNATIVE TO ASME SECTION XI REQUIREMENTS f!;

UNIT: Millstone Unit 2 NCR # 293-026 DATE: 1/25/93 '

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TIME: 09:50.

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!1.0 ORIGINATOR j

1.1 DESCRIPTION OF FLIN

The flaw is in an area of lack of fusion between the socket velded !tee and the veld. The flav vas detected during system hydrotest t

following recent system modification. A leak existed only at i

hydrostatic test pressure.t

Piping / Component Drawing No.: 2"-HUD-130/25203-20135 Sheet 121i

fP&ID No.: 25203-260084

1.2 HARDSHIP / DIFFICULTY OF A CODE REPAIR i

fThe flav vas detected while the plant was in operation. A Coderepair vill require velding in the vest 480 switchgear room. :Control systems within the room have sensitive electronics which

!could be adversely affected by electrical interference resulting ~ lfrom velding and may cause a turbine trip.Ji1.3 DESCRIPTION OF PROPOSED ALTERNATIVE I

No throughwall leak exists while the system is at normal operating3pressure. As a precautionary measure, however, an engineered :"

clamp will be installed as a temporary replacement. The i

engineered clamp vill meet the requirements of the draft ASMU CodeCase entitled " Temporary Structural Replacement Requirements for |Class 2 and 3 Piping."

|1.4 SAFETY SIGNIFICANCE: System Interaction Evaluation i

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Flooding: Location of the veld is within the confines of a !cofferdam with adequate drainage capabilities.

;rJet Spray: There is no spray currently and the type of defcet- !vould not lead to the increase in a leak path. However, a spray }shield has been installed.

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Loss of Flow: Existing procedures specify compensatory measures [upon loss of cooling to the room. i

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Other Interactions: PE0 rounds once per shift minimum within_theroom vould identify a degrading condition.

Failure Consequences? None,

bImpact to Safe Shutdown Capability? None presently, current :defect orientation and magnitude vould minimize the potential for [any impact. Installation-of an encapsulation device vill be

iconsidered to further enhance the ability to retain leakage.Docs 60.32 jee Page 2 of 5' 3/25/93 I

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., NORW 2AST UTILITIES,,

USE OF A PROPOSED ALTF%ATIVE TO ASME CECTION XI REQUIREMENTS

1.5 ROOT CAUSE INVESTIGATION

Root Cause Description: Lack of fusion between the veld and thesocket velded tee.

Other Systems Affected: Nor.e

1.6 AUGMENTED 1NSPECTION (must be completed within 15 days of flavdetection)

Assessment of overall degradation of the sffected system:

Minimal to no effect. All other velds passed system hydrotest.

Additional examinations required (based on root cause) -- specifyneumber of inspection locations -- also specify frequency ofinspections: (ten most susceptible and accessible locations forhigh energy piping system and five for moderate energy piping

!system)|I

None '

Description of areas selected for aumented inspection:

Only t.x specific weld in question.

Forwarl augmented inspection results _ to NUSCO Supervisor, StressAnalysis Engineering Unit when completed.

7.0 STRESS ANALYSIS UNIT

2.1 DESIGN DETAILS

System: Service Vater Supply to Vital ACSwitchgear Rooms Cooling Coils X-181A & 181B

Component: 2"-HUD-130

Piping Size & Schedule: 2" Schedule 40

Nomf. sal Vall Thickness: 0.154"

Safety Code Class: Class 3

Material: SB466-706

Design Press' ire: 100 psig,

Design / Operating Temperature: 100*F/80*F

Code Minimum Vall Thickness: 0.014"

Docs 60 'J '< Page 3 of 5 3/25/93.

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USE OF A PROPOSED ALTERNATIVE TO ASME SECTION XI REQUIREMt'NTS'

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2.2 FLAV CHARACTERIZATION|!

Flav Description / Size: (i.e., flav size, adjacent vall thickness, !single / multiple flav, total area examined, etc.)

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The flav is an' area of lack of fusion between the socket veld tee !and the veld. Leak exists only at hydrostatic test pressure. No <

1eak vat observed during normal operation. !,

Flav Location: The small veeping leak is located at 3:00 looking *

north at veld V-1 of AVO M2-92-17685. .

;Examination Method: A small veeping leak (very low rate) was !found only during the hydrostatic presssure test in accordance |with ASME Section XI.

Flav Type: Pinhole due to lack of veld fusion. t

iReference UT Measurement Report: None. Defect located in jrecently made veld.

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2.3 PRELIMINARY FLAW EVALUATION SUMMARYe

Preliminary Operability Assessment Details:

Method Used: Technical evaluation attached to NCR.

Limiting Flav Size: Not estimated. Flav not expected to increase '

in size.

Period of Time to Reach Limiting Flav Size: To be determined!based on planned monitoring. '

Evaluation Reference: NCR disposition. I

2.4 END OF CYCLE FLAV EVALUATION SUMMARY

Final Operability Assessment Details: '

Method Used: (i.e., LEFM, area reinforcement, vall thinning.ASME Code Case)

Area reinforcement per the Draft ASME Code Caso.:

Estimated Vall Erosion Rate: Flav is assumed to be a pinhole I

since a leak exists only at hydrostatic test pressure. The flav .Iis caused by a lack of fusion between the socket velded tee and'the veld. Erosion rate for 90 Cu - 10 Ni is negligible. No leakexists during normal system operation.

Projected Flav Size: 1" diameter hole with nominal val' 'acidethe flaw is qualified for design loads.

Period of Time to Permanent Repair / Replacement: The next outave |that's planned for ten days or more.|

DOCS 60.32 joc Page 4 of 5 3/2h/93|

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NOI 81 EAST UTILITIES,

!USE OF A PROPOSED ALTERNATIVE TO ASME SECTION XI REQUIREMENTS ;

)Provide a Discussion of Evaluation of Design Loading Conditions:

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Design loads qualified include deadveight, pressure, safe shutdown Iearthquake (SSE). Thermal loads are considered negligible as the i

pipe operating temperature is lov (80*F). -|i

Evaluation Reference: Calculation MP2-131-269-EM, Rev. 0- |

Discussion of Augmented Inspection Results: No augmented linspection was performed. Pinhole leak at veld is due to lack of '

fusion and is considered an isolated condition. i

3 :F

Expanded Augmented Inspection Requirements: None.i

2.5 FLAV MONITORING,

Walkdown Frequency: (for leak monitoring) The joint containing.

the defect vill be monitored a minimum of once per shift. '

Frequency of Follow-up NDE: (for erosion rate assessment).

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Since the material is Cu-Ni and the veld is new, erosion rates arecurrently assumed to be negligible. UT measurements vill beperformed if leakage increases. Data to be evaluated by Stress '

Analysis.!

2.6 ADDITIONAL COMMENTS (scope, limitations, and specific |s

considerations) |None '

>2.7 EXCEPTIONS TO GL-90-05/ DRAFT ASME CODE CASE,

Not applicable '

2.8 REFERENCES / INPUTS i

o ASME B&PV Section III.

- 1971 Edition and Addenda to Summer 1973- 1974 Edition

o ASME Draft Code Case N-513 entitled, " Evaluation Criteria for *

Acceptance of Flavs in Class 3 Piping" ,

c GL 90-05 Issued June 15, 1990 i

ASME Jraft Code Case entitled, " Temporary StructuraloReplacement Requirements for Class 2 and 3 Piping."

o Calculation MP2-131-269-EM, Rev. O

o Drawings 25203-20135, Sheets 99 & 99H25203-20135, Sheets 100 & 100H25203-20135, Sheets 121 & 121H

Originator, Supervisor, Stress Analysis Engineering Unit, Unit-Director,cc:

- Nuclear RecordDOCS 60.32 jee rage 5 of 5 3/23/93

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!no to cooling coil x-istA and .of the new' |

The supply and return pi it fit ifications were |tly toX-1815 were modified sli The '

ing y g loads were placed on.

coolf.g coils to the exiperformed to ensure that no new pThe modiflost on is intended to help

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the cooling coils.-reduce future cooling coil tube leaks.d

l nt F

This NCR is dipositioned "BSB AS-IS" antil the p aThe REw0RK will-!

conditions permit the "RSWORX" of the weld..Tustification for this jpermanently repair the weld. i

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disposition is as follows: |

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181B (lowerwar-ss-ts_. .

The supply piping (2*-EUD-130) to cooling coil 1-coil) developed a small weeping leak when the sys eAll other joints .~

-|tm ,

formed. The idrostatic pressure test.hydrostatic pressure test was t 3:00, looking north at weld - |meet the requirements of themaall weeping leak is locatedw-1 of AWo M2-92-17685 (ees attached weld map) .

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i the leak did ~;.

At the hydrostatic test pressure of 110 ps g,The water wept from the weld at a very.

;the

mot spray any water.The water seeping from sne pinhole drips ontoj

dfloor inside of the cooling coil water coffer am. flow rate.

the recent IDCL test the maximum pressure at the 6"4

Durink connection to the cooling coils was approximately|

The connection is located at' approxlsately' above~ ,

:

The leak is located approximately 20of elevation difference and normalbranc -.

|65.psig.elevation 17'.- The 20'iction, throttled vale (s)) will '!the 6" take-off. th |pipe fr i h these lossesbe eline loses (i.e, reduce the pressure at the leak.' W tpressure at the leak will be ~ approximately half ofTharafore, un$er operational

,

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hydrostatic test pressure.pressura no leakage is expected..

did not spray

Daring the hydrostatic pressure test the leak:

it would be directed towards the cooling-ooils and a r pit the leak were to enlarge and start to spray,-!

i lenum - I

any water. Opeirationand not towards any electrical equipment. t once a shift.personnel walkdown the switchgear room at leasoperation personnel would.'fIf the leak was to become worse,d notify malntanancebecome aware of the condition anIf the leak-was to start spraying water a sprayto ensure thatj

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personnel. shield and/or a soft patch, would be installed er ,

no vital equipment could be sprayed. j.

itchgear|

It should be m:ted that velding in the wast 480V swwhile the plant is operational.:

room is not recommended,l cabinets are located in the >

steam t.trbine EHC controThe ERC control system could be adversely ii the plant

affected if welding is performed in the roca wh leswitchgear room.' ,

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is operational. *

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RIJ2pnrien erriaLatox vea ro.an-co2i

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k the leak at theKrwcRI Thehas been written to rewort non-operational)II and..

'next available opportun!.ty (i.e. planicint will be repaired in acecrdanca with ASHE SecAwo 152-93-01582 tion

ill be excavatedthe f ollowing stops;- The vald in the araa of the laak vand it necessary the antire veld will be renoved.

td to a:asure- The excavated area vill be LP inspec e ,

solid base natal is present. with thed- The wald will be repaireS in acoor ance

NUSCo wald manual CMS-004.- The vald will be visually inspected per

ill be

- once the veld is reworked the pipe whydrostatic pressure tasted in accordance with

SP-21219.

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sENT BY3WCNDC Document Sves. I 1- 5-93 110:2Ba3 3 Document oorwicosa 212 BD5 CT50;c 3 \,

REF: RRM 90-015

Case N-XXX Tamporary Structural Replacement Requirama7. ts for

- 2 -6 ~=, ua. w.sInquiry: What alternativas to the rules of IWA 4000 may be used forthe tamporary replacement of m=== 2 and 3 piping using anginmared

-han*mi clamping devions?

Reply: It is the opinion of the Committee that the followingalternative rules eay be used for temporary replacement of Class 2and 3 piping, NPS 6 and smaller, instead of rules of IWA-4 COO.

1.0 scope

1.1 Piping (ptpas, tubes, Sttings, and flanges) cay be tamporarilyreplaced using the rules of this Casa.

1.2 This Case may not be used for piping larger than NPS 2 when thenominal operating temperature ar pressure exceed 200F or 275 psi.

1.3 These rules are also appH-able to welding ends of pumps, valves,and pressure vamaalm. Tamporary replacement at other locations inpumps, valves, and pressure vaman?a is excluded.

1.4 These rules do Imt apply to sealants, lubricants, 0-rings, or gasketmaterial.

1.5 The tamperary replacamentin ac::ordance with this Case ray Ismainin marrica only until the next refueling cutage, at which time the ,, gdefect shall be repaired cr replaced in accordan * with IWA-4000.' W

2.0 Repair /Renia-nt Plan

A Repair / Replacement Plan shall be developed in accordance with IWA-4140(b). Additionally, this plan shallidentify the following:

a. Defect characterization methodb. Design requiremants !

c. Monitoring requirements [d. Safety precautions ;

3.0 Athma YnWe Agency

The services of an Autho:1med Inspection Agency shall be used. The 1'

Owner shall ncr*Jy the Authorized Inspe:* ann Agency prior to starting '

replacement and keep the Inspector informed of the progress so thatri-5y inspe*1mm may be perforned. ,

I

'"The rete.w in this Coce Case aIn in accordance with Section XI 1989'

Edition with 1991 Addenda. ;

,

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: 1- s-ss rio rem : occuasnt services- 252 sos syso = a

p p :ccuoc oscumans sves.' I3r 9z- 47,

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. 4.0 Defect CharW-=MmThe defect aize cod location and the apparent cause shall be determined.The dafort size abaH be suitably bounded to aamunt for nondestructive

-

eram' nation uncertaintica and lim _t+= Mans. If the defect size cannot bedirectly determined, a conservative bound of the actual defect aire shan bemade and documented.

5.0 Design Was

General Design Raquirements. The icHowing general designrequirenants shall be included in a Repair /Replacemant Plan and

5.1

shall be twe=M in the analysis of the clamping device and piping; ad kS enmtal and corrosive effects of esalant composition on O.k'Envi.a.

pipe, clamp, and bolts shall be considered.

The defect size used in the design of tbe temporaxy'

replacemicit shallinc2ude any projected growth anticipatedb.

from installation until the defect will be repaired.

Clamp components, exmpt those identified in paragraph dc.below, shall be considered pressure retaining.

If additional supports are required to satisfy 5.1, 5.2, or 5.3,they may be considered non-pressure retaining items and shalld.

~

be designed in aN with the requiraments of the yConstruction Code for the systam or as pemitted by reiA-4170 J(c) or (d). -.j

Clamping Devicz. The fcDowing special requirements apply to the g5.2design of the temporary clampix.g device:

No crsdit shall be taken for structurni capability of the,

ia.

)=,a1 = nt,

Pressurs reta',r.ing cla cp device items shall meet thei/

requirements of NC-3200 with the azeep*0.cn of reference tob.

[iNC-6000.

Strasses induced by pressure, assuming postulated fullcircumfartntial severance of the pipe at the flaw location,c.using ntm'nal system oparating conditions, shall comply withlevel A Service Limits of SectionIII. k

The Isrt=~==nt device may be integraDy orka*mily

connected to the pipe. Serrated contact surfaces cf thad.

replam. ment device are acceptable provided they do not sIfect,

j structuralintegrity cf the pipe.'

A factor of safety of 5 shan be appaled to the friction loadtransfer capability of the friction con"=-Hm, but should not

.

2.

be applied to the structural design of the II1ction connection.

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- *. 4o* ~ g ., *$ENT BY:cCN00 Documsnt Sves. I 1- 5-93 110:27t/J t Document 33rvices. 212 635 8T30:a g 40,

'*

e..c.,4;,,u,4 ISI 72-+7If a coefficient of friction greater than 0.3 is used for frictiontype cannections, the clamping davice shall have anarperimentally determined t~**M-4mt of friction for eachinter".aoe dacign (e.g., serrated or non-serrated) and each~~h'~ tion of intarface material P-numbars.

5.3 piping ryttam. The following special require.mants apply to thedesisn of the piping system:

a. If vibration is the apparent cause of the defect er the defectc.an be propagated by vibration, the pfping system vibrationshall be corEdered.

b. The temporary piping syntam conffguration shall be analyzedin accordance with the Owne.r's requirements, and althar theCC::struction Code or Section III.

The effects of the stiffness and weight of the clamping devicec.shall be considered in the analysis of the piping syntam. Whenthe defect is caused by erosion or carrosion, the base materialthickness at the load transfer area shall be detennined andprojected to the time the defect will be repaired. TheywA;sid wall thickness shall be used when evaluating thepiping system.

d. The constrt*cing effects of the clasping device shall beconsidered whan evaluating the affects of thornal experron ofthe piping system.

6.0 MaM1 Requirmmants

66.1 Materials used for pressure retaining items of the temporaryreplacement device shall be permitted by Ekction III, or a Section IIICode Case, for use as a Class 2 pressure boundary naterial.

Pressuri rwtaining material for the clamping device shall meet theIW:Araments of NC-2000, except NC-2f,00, and shall be cert.+fied asrequirw! by NCA-3967.4. All other requirumants of NCA-3800 do notapply.

6.2 If additional supports are required to satisfy 5.0, the mate.e shallroset the req-hmants of the Construc'.*.on Code for the systam, cr as.

permitted by IWA-4170(c) or (d).

7.0 Fabrication and Installation Regt.irariants

Walding performed as part of the fabrication and ins'41ation of the cIsretpshall be accort.phshed in ac=ordance with the requirements of IWA-4000under the Owner's Repeir/Replacemant Program. _An Ahg_shall be used.

@g shall be documented on an NIS-2 Form. 41 ode symbol sDtag.Waldin

r reg'@or7rchibitedh

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