Internationale Fachmessefiir dia kerntechnischeIndustrie
nuclex 72CH-4021 Basel/SchweizTelephon 061-32 38 50Telex 62 685 fairs basel
Foire international*des Industriesnucleates
InternationalNuclearIndustries Fair
16-21 October 1972Basel/Switzerland
o
Technical Meeting No. 4/12
Heavy Watsr Production in Canada
RJ. KeatingL.R. Nordby
Atomic Energy of Canada LimitedCan'adian General Electric Co. Ltdi
HEAVY WATER PRODUCTION IN CANADA
byt R.K. KeatingAtomic Energy of Canada Limited
and
L.R. NordbyCanadian General Electric Co., Ltd.
ABSTRACT
This paper is presented to outline the hefivy water production
program in Canada where large scale production is required to satisfy
the requirements of the CANDU program. Three large production plants
have been committed. When all of these plants reach maturity, their ,
combined annual production is expected to be about 1500 Mg.
RESUMJj
Cette note technique est prese'Atee afin del deer ire le
programme d'eau lourde au Canada ou une production de grande envergure
est requise afin de satisfaire aux besoins du programme CANDU. La
construction de trois grandes usines a ete entreprise. Lorsque ces
usines seront completees leui." production annuelle combinSe sera de
l'ordre de 1500 Mg.
AUS2UG
Tjiese Abhandlung umreisst das Programm der
Schwerwasserproduktion in Canada, wo eine Production im grosseii
Masstabe ecforderlich ist, urn die Forderung§n des CANDU-Programms,zu
erfuellen. Drei grosse Pabriken sind im Bau. Wenn dieaa drei Fabriken
ihre Vollendung erreichen werden,
um die 1500 Mg betragen.
wird die jaehrliche G<^atitprodu£tion
- 1 -
INTRODUCTION
.This paper is presented to outline the heavy wator production
program in Canada where large scale production of heavy water is
required to satisfy the requirements of the CANDU Reactor Program.
Three large production plants have been committed, namely the Glace Bay
Plant at Glace Bay, Noxra Scotia, the Canadian' General Elebtric Company
Limited plant at Port Hawkesbury, Nova Scotia and the Atomic En'ergy of
Canada Limited Bruce Heavy Water Plant on Lake Huron in Ontario. When
all of these plants reach maturity, their combined arnual production is
expected to be about 1500 Mg. To appreciate the magnitude of this
production capacity, the present production capacity outside of Canada,
excluding Russia and China, is less than 300 Mg per year.
o
PROCESS DESCRIPTION
The only economic source of large quantities of deuterium is
natural water. The deuterium concentration in natural water varies
with geographical location. , The Atlantic Ocean, off Nova Scotia, has
approximately 155 parts deuterium per million parts hydrogen. Lake
water in the same province and in Lake Huron ranges between 146 and 150
parts per million.
Each of the plants discussed in this paper eirplcys a form of "the
basic "Girdler-Sulfide" process-for enrichment from natural water to an
isotopig percentage of 20-45% and then a vacuum distillation process
to complete the enrichment to reactor rade of 99.75 mol percent D20.
This combination of processes has been used successfully at the USAEC
Savannah River Plant for almost 20 years.b
"GS" ENRICHIEiG PROCESS
i /, ~ ~The "Girdlern-Sulfide" process is a dual temperature isotopic'- - o i
exchange process. The process fluids are hydrogen julfide (HSS) gas
and natural water (H2p>. h di.agx&oatic representation of the Enrich-
ment Unit of the Port HawJeesbury Plant and the Bruce Pl<*nt is presentedin Fig. 1. These fluids are <
towers operating at pressures
through two different tempera
is represented on Fig. 2. " At
:ountercurrently passed through contacting
of approximately 20 atmospheres and
:ure zones. This count?: current contacting
a lower process teuiperature, the deuterium
atoms tend to concentrate in the water. At a higher process temperature
the deuterium atoms tend less to| concentrate in the water. An Enrich-
ment Stage is therefore a pair oip counter cur rent contacting towers or
tower sections, one operating,at a low temperature and the other at a
high temperature. By optimizing sufficient contacting trays in the hot
and cold sections of each stage and by providing a nuiri>er of stages in
series, enrichment to any desired deuterium .isotopic percentage level
may bs achieved. The lowest practicable t.emperature for the cold tower
(or section) to operate at is approximately 27°C, below which a hydrate
(H2S.>5H20) would form at the operating pressure. The hot tower (or
section) operating temperature is limxted to approximately 130°C to
limit the partial pressure of water vapour in the gas; phase to an
acceptable percentage. As the maximum deuterium" extraction is 20 per-
cent, 35,000 kg of natural water must be processed for each teg of
production. Large supplies of thermal and electrical energy are
required by this process. Continuity of this energy supply has proven ,,
to be very important to the production capacity factors of large single
train units.
DISTILIATION PROCESS '
The final reactor grade product is obtained u&ing a vacuum '
distillation process which is relatively simple and is generally well
known in principle. An overhead stream at a few isotopic percenbage
points less thars the feed stream is recycled to the "GS" Enriching Unit
the distillate is drawn off,''as reactor grade product.
PRODUCTION PLANTSc c i i
CANADIAN GENER&t, ELECTRld PORT HAWKESBURY HEAVY WA ER PLANT
In 1966 a p l a n t with a production' capac i ty of 0.048 Mg/hr was
committed at Per t Hawkesbury, ijJdva S c o t i a , by t h e Canadian General
E l e c t r i c Company Limited. The Jengineering and cons t ruc t ion c o n t r a s t o r'I '
for t h i s p l an t was The Lumraus Company.i
The feedwater and makeup for the recirculat;.ng cooling water
system is taker, from a fresfh water reservoir. Steam i« supplied by a
nearby thermal generating station of the Nova Scotia Power Commission
as exhaust steam from an 80 MW(e) back pressure turbine.1 Electrical
. power can be supplied either directly f ron this generating station or \ '
from the interprovincial grid.
The basic elements of the plant consist of three first stage
fractionating tower pairs (hot and cold) operated in. parallel, one
second stage pair, one third stage pair, plus a vacuum distillation
unit. -- The design concentration factors for these elements are 4:1, 6:1,
130:1 and 3:1 respectively.
Several unique features were employed in the design of this
plant, the most significant of which was the stacking of the hot and
*cold towers in the first and second stages {see Fig. !3). The ratio of -
cross sectional area to column height was such that the cold tower
could be stacked on top cf the hot tower and stilh stay well within
desirable diameter to height ratios. This concept eliminated one tower.,
skirt, two tower heads and a substantial amount of piping and valving
per tower pair. The first stage towers are perhaps the largest pressure
vessels in the world, being approximately 95 meters high and 9 meters
in diameter.
Other significant features include the cascading of gas rather
than- ] iquid from the first to second stage and from second to third
stage. The cascading of the gas stream not only provides a transport
medium for deuterium from one stage to the next but also transports
he^at, thereby making it unnecessary to supply additional heat to the
second and third stages. The recirculating H2S gas stream is heated
and cooled within the first stage pressure vessel, by direct contact .
with the process water which in turn is heat exchanged with steam and
cooling ,water m external tubej-in-shell heat exchangers. The process
design includes several extensive heat recovery heat exchange systems.
! ' °The vacuum distillationj finishing unit is a Sulzer SUM propietary
I ' '
design ut i l iz ing two packed toilers. The f irst tower has a packing mesh>and the second tower has 162 tlobes, packed with copper gauze, operatingin parallel . Product draw offproduct concentration.
• * - ,
is intermittent and automatic*"based on
\- 4 _
BRUCE HEAVY WATER PLANT
The Bruce Heavy Water Plant with a production capacity of
0.096 Mg/hr is owned by Atomic Energy of Canada Limited and is being
commissioned and operated by Ontario Hydro. This plant, located on
the shore of Lako Huron in Ontario,, was committed in late 1968 with
construction beginning in 1969. The plant is beinc, engineered and
constructed by The Lummus Company. The first Enriching Unit of the '
plant is expected to achieve initial production in November 1972. The
second Enriching Unit is expected to be in production in late 1972.
The process feedwater and cooling water -is taken frorrr and
returned to Lake Huron. The steam requirements of the plant can be
provided by either the Douglas Point Muclear Power Station or the
Auxiliary Steam Plant. This plant with three oil fired boilers was
constructed specifically cor this purpose. With this duplication the
reliability of the staam supply is expected to be very good.
The process design of tre Enriching Unit was based on and is
almost identical to the Enriching Unit at the CGE plant, andv therefore
needs no further description. The doubled production capacity is
accomplished by using two identical Enriching Units operating in
parallel (see Fig. 4). •"
The three stag^ Finishing Unit is a Lummus design using sieve-
trayed towers, and is designed to produce 0.096 Mg/hr of reactor grade
heavy water with a deuterium concentration of 30% as its feed.
GLACE BAY HEAVY' W&TER PLANT
In 1963 The Deuterium Coinpany of Canada Limited committed a
Heavy Water Plant at Glace Bay,; Nova Scotia. This plant was to have
;. Iused sea water from the Atlantic Ocean,{for feed and cooling purposes
I 'J
and was to begin production in 1967. However, plagued with a varietyof., problems, including* labour difficulties and corrosion problems
!associated with the use of sea water, it eventually became apparent
that extensive modifications wo'|ald be required before the plant could
go into production. Commission Log efforts ceased in 1969. The plant• r' '
lay idle unti l ] ate in 1971 whsu the Federal Governriient of Canada
- 5 -
provided the funds to AECL to rehabilitate the plant. AECL now
cbolds a long term lease on the plant and has complete management
responsibility.
The rehabilitation rprogram was initiated quickly and is no\/
progressing rapidly. The work is being undertaken by Canatom Mon-Max.
The rehabilitation program is extensive and, involves re-design
of tha basic process. The original plant was to produce reactor grade
D20 entirely using the "GS" process. The rehabilitated plant will use
the^'GS" process in three stages to produce approximately 20 isotopic
percent D2o and will complete the concentration using a vacuum
distillation unit. Because of the "GS" unit "redesign and the addition
of the Finishing unit, the design capacity-of the rehabilitated plant
will" be 0.053 Mg/hr whereas the original plant was to produce approx-
imately 360 Mg/year at a 95% capacity factor. A fresh water reservoir -
is being created to provide fe^dwater and makeup for s recirculating -
fresh water cooling system. The first D20 production from the plant is
expected early in 1975 with the plant reaching maturity by 1979.
COMMISSIONING'AND OPERATING EXPERIENCE
CANADIAN GENERAL^1 ELECTRIC PORT HAWKESBPRY HEAVY WATER PLANT
Commissioning of utilities at the CGE plant started during May
of 1969 but was halted iin June due to the demolition by fire of the
main electrical substation. Co?waissioning recomnenced in October but
was halted again in January 1970 when a four-hour steam failure resulted
in severe damage to equipment d)b§ to freezing.
Commissioning of the plafet with nitrogen gas resumed in April
1970 and continued through unti
the system. By the end of July
and a pressure of 120 Jw/w8 was
was observed during the first
L June when the first n2s was added to
the system had been purged of nitrogen
being maintained. The first enrichment
if August, subsequently the first
drum of reactor grade heavy wait jir was drawn from the Unit on
September 29th, 1970. * '
- 6 -
Production continued until the latter part of October when^the ,
system pressure was increased to 1700'kn/m2 and the operation of the
towers became unstable. In late November one of the first stage towers
was removed from service and it was found that the sieve trays at the'
top of the hot tower had been partially plugged by deposits of iron
sulfide. The deposition occurred at this location because of tha
inverse solubilirry of iron sulfide and was attributed to small con-
centrations of iron in solution in the feedwater. The partial plugging
of the holes created greater than normal differential gas'pressures • ;
across the tray s which ultimately" caused some tray damage. -As a
consequer.'e the total plant was taken out of service December 25th,1970
for traycleaning and repair. 1
Toward"the end of the period whSn the plant was out of service,
the remaining equipment was thoroughly inspected. It was found that
several heat exchangers with Type 304 stainless steel tubes showed an
advanced stage of pitting. Exchangers tubed with Type 316 stainless •
steel did not show any significant signs of deterioration. It was
decided to change 28,400 forty-foot Type 304 tubes to Type 316 stainless
steel tubes. As an interim measure anr in-line- flccculation system was
added to remove iron from the feedwater and immediate steps were taken
for the addition of a ,#iarifier. The exchanger modifications were
completed and the total plant was back in production in May 1971.
During October the plant was again shut down co make the
necessary connections for the clarifier in the feedwater system.
During this shutdown, one 'f.irst stage tower was opened for inspection
and there was no trace of deposit on the hot tower sieve trays. The
clarifierv was put into service, in early December 1971 and was fully
operational by early January 1972. " ' , ' . ^ '
Foam,promoting impurities in the feedwatef are believed,to be -
responsible for intermittent tbwer instability. The clarifier system f
has provided a marked improvement in this situation and work is
currently underway to tp°rovide further improvements. This experience
has demonstrated the need for very high gua3ity''px"ace>';S feedwatar and
has resulted in additional feedvrafcer /treatment system being committed /'
in thede&ign of the Bruce and Glace Bay plants.
Tn the last year eight'total plant.shutdowns, and eleven partial
plant shutdowns were experienced due oto losses °of steam and/or =,
electrical power, • Each of these interruptions resulted *in several
days of production loss due to startup time arid time to re-establish
equilibrium conditions in the, process. Modifications 5to the steam and
elri.irical supply are jibw in, progress to provide a greater continuity
-of these vital services. ' * :
In spite of the lack of "energy continuity, tiie ,fir,st stage, the
second, stage and Finishing Unit have each demonstrated enrichment
capabilitiestin excess of design expectations. In addition £-he thiough-
put capabilities in the second stage, third stage °and Finishing Unit
have also, been demonstrated in excess of-design-, .Throughput's of up to \
90% have been experienced - in the first stages. " '-" '
3RUCE HEAVY WATEft Pl^ANT - "' ' =
The commissioning of the = Enriching UnPitSc is, in progress.'•* Only
minor dalriys have been encountered, gtnerally with some' of the rotating
1 X equipment and valves. The^ utility, systems are('in operation and although
full load cqnditions have not been established, no commissioning delays
are expected. The Finishing Unit has'1 been, commissioned and has -been in
operation for several months upgrading a large quantity of low grade
( 1 — 2%, D2o;j heavy water. This1 Unit h,as ably demonstrated its ability0
^ to saf isfy "..the design criteria* ,. ' , " , ° -
* Although the clarifier system will not be available for ij
comtiiission'irg" until the fall" op 1972, production., is not expected to be
seiriously limited due %o foaming problems because Lake Huron water is
= generally of very good quality! in,this respecti, i . o /(
' \ • ll ' ' f °* Becauae of duplication df,,fche energy supply systems, continuity
' of energy supply «ktid thus the tesign capacity factor should be assured.-
, PRCMPUCTTPW
rThe expected ccjaal^ti
discussed in .this paper
considered *»'• i« guit«
r
ve^prj
fidtikctioh frosv«a^h of the plantson vig*[ 3.;- «he*c estuwteu are
artd' cannot5 be construes as targets.
'''j ^
- 8 - -
Although Canada presently has requirement si for more .heavy water
than we are able to produce/ and is arranging several purchases abroad,
it is expected that domestic production will excejed the, committed
domestic requirements by 1974. ,'
CONCLUSIONS ' ii
\ Although setbacks have been encountered in, the heavy water
production program, the present situation with ea'jsh cf the plants is
such that chere is little uncertainty that the expectations will be
achieved. , jrhe difficult portion of the learning icurve associated with
large scale production plants is now behind us. 'i
* * * * * * f^fr I * *
\ , O
"A
tABLEI HEAVY WATER PLANT DATA
LOCATION
OWNER
ENGINEER
OPERATOR
DESIGN CAPACITY
ENERGY REQUIREMENTS
STEAM
ELECTRICAL
CONTRACT PLACEDMl
CONSTRUCTION COMMENCED
CONSTRUCTION COMPLETE ,
UNIT NO. 1
UNIT NO. 2
riRST HEAVY WATER
PORTHAMCaMmYHMP
Point Tiipper, N.S.
CGE
CSE/Lummus
CGE
0.048 Mg/hr
875 x 106 BTU/hr
27 MW
August 196B
November 1966
December 1969
' —
September 1970
i i
_ mucEHwr
'•>•}
Douglat Point, Ont.
AECL "
tummus
Ontario Hyoro
0.096 Mg/hr
'^750 x 106 BTU/hr
68 M *
Jenuarv 1968
March iflfiCi
!•
January 1972
July197|
iii
htovenrtixrt 1972
ECL PLANT
, H
tijladp Bay, N£).i \ . . \i
.--•>' ^ ' I1
Ctouienum of CtntdaI etiBd to AECL
Caniitom/Monrmxc
1
AECL
i
0.063 Mg/hr
326 x 106 BTU/hr
27 MW
RnovnMructionJanuary 1972
1974
o
1976
IJO0O0O 19
FIRST STAGE( 3 IN PARALLEL) A, B & C
SECONO STAGE THIRD STAGE
HOT TOWER COLD TOWE R
HYDROGEN SULPHIDEDEPLETED IN DEUTERIUM
FEED WATER*
COLD SECTION 9O°F
DEUTERIUM ENRICHEDWATER iD2O)
HYDROGEN SULPHIDEENRICHED IN DEUTERIUM
HOT SECTiON 262°F
DEPLETED WATER
HYDROGEN SULPHIDEGAS FLOW =
WATER FLOWi
ENRICHED WATER
¥ TO,, ;FINISHING SECTION
FIGURE 1 DIAGRAMATIC REPRESENTATION OF ENRICHING PROCESS(TYPICAL OF PORT HAWKESBURY AND BRUCE PLANTS)
TOWER WALL LIQUID
'DEUTERIUMTRANSFER REGION
FIGURE 2 DIAGRAMATIC REPRESENTATION OF HjS GAS - HjOLIQUID CONTACTING IN A
GAS FLOW PERFORATEDLATES
T O W E R
.-<*'
T16000-
14000-
12000-
10000-
I 4a| Bnno-
6000-
4000-
2000-
0
J " •
a
o
/ .
/ . < >
y'g/r It? '4&^^ , ^ ' jgP^V . -r-tTITtni
19*3 1974 | | ie '
- -
J
'V'.1 I1*
* - *
; * :
c
r
//
*
* /
v/r
-
^ -
J
t
VEAB
- ii •,'?
11; it
* * '
." *'- ~ ;
•*
/
fJ
9 f l ' l
1079 • ' - « * ; 1881 H iM
it
' &': * $ '
/
>
1
2 1883 19b4
-
••<*•
<-*•-
Jfri"1'
• * * • * ft
1 J -1
FIGURE 4 A VIEW OF BRUCE HEAVY WATER PLANT WITH DOUGLAS POINTNUCLEAR POWER PLANT IN FOREGROUND.
*."•* toX^n*- , - W W - » P V J * - , - , ^ ^ ^ ^ i
•" I <•-'
1 ! _
pi