ML19211D293

Requests That 790703 Application Re Spent Fuel Pool Mods at Unit 1 Be Expanded to Include Unit 2.Forwards Revised Licensing Submittal Rept,Nuclear Energy Svcs,Inc 790301 & 0524 Repts & Revised Tech Specs

ML19211D293
Person / Time
Site:	Calvert Cliffs
Issue date:	01/15/1980
From:	Lundvall A BALTIMORE GAS & ELECTRIC CO.
To:	Reid R Office of Nuclear Reactor Regulation
Shared Package
ML19211D294	List: ML19211D293 ML19211D298 ML19211D299 ML19211D300
References
NUDOCS 8001170454
Download: ML19211D293 (12)

Text

s BALTIMORE GAS AN D ELECTRIC CO M PANY GAS AN D ELECTRIC BUILDING BALTIM OR E, MARYLAN D 21203 ARTHUR [. LU N DVALL, J R.

ViCE Pas seotsef January 15, 1980 so-o Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attn: Mr. Robert W. Reid, Chief Operating Reactors Branch #h Division of Operating Reactors

Subject:

Calvert Cliffs Nuclear Power Plant Units Nos.1 & 2, Dockets Nos. 50-317 & 50-318 Spent Fuel Pool Modification Sunnlementary Information

References:

(a) BG&E letters dated 8/5/77 and 9/7/77 from A. E. Lundvall, Jr. to E. G. Case, same subject.

(b) NRC letter dated 1/h/78 from D. K. Davis to A. E. Lundvall Jr. , Amendments 27 and 12 to Operating Licenses DPR-53 and 69 (c) BG&E letter dated 7/3/79 from J. W. Gore, Jr. to H. R. Denton, Request for Amendment.

Gentlemen :

Reference (a) requested approval of our proposed modifications to the Unit Nos.1 and 2 spent fuel pools to install close-center (high density) storage racks. Subsequent to the receipt of Beference (b), which approved the above request, it was decided to use an alternate design for the Unit No.1 side of the pool. Hence, Reference (c) was submitted requesting approval of a proposed modification to the Unit No.1 side of the spent fuel pool using high density borated storage racks. During their review of that submittal, NRC pointed out that certain portions of the analysis should be resubmitted using different calculational techniques.

Eaclosures (2) and (3), which were prepared by our supplier (Nuclear Energy Services), provide the recommended re-analysis.

Enclosure (1) is a revised version of our Licensing Report, which provides the basis for the proposed modifications as well as analyses of the impact of the changes on supporting systems. This Licensing Report was originally submitted by Reference (a).

Due to the uncertainty associated with the ultimate disposal of spent fuel, we have nov determined that it would be prudent to again increase the storage capacity of the Unit No. 2 side of the pool over and above the capacity approved by Reference (b). Therefore, we request that 1762 300 8001170T5jh.

Mr. R. W. Reid January 15, 1980 your review of the enclosed analyses for Unit No.1 be expanded to include both Units. Enclosure (h) shows the required changes to the Technical Specifications for both Units.

Our present intentions are to modify the Unit No. 1 side of the pool as soon as the enclosed request is approved. hevever, the Unit No.

2 side cannot be remodified for some time due to the delivery schedule for the racks. In the interim, there is a projected need to store spent fuel in the Unit No. 2 side of the pool which has an enrichment greater than the currently approved enrichment for those racks, 3.7 v/o, Reference (b). The greater enrichment, k.1 v/o, has previously been submitted for NRC approval in Reference (c). We, therefore, request that NRC continue their review of that submlttal on an expedited basis.

In summary, the two halves of the spent fuel storage pool vill have the following configurations upon receipt of the appropriate approvals:

Time Frame _ Unit No. 1 Side Unit No. 2 Side Present Original racks (200) Close-center racks (528)

Upon Approval Borated racks (830) h.1 v/o Enrichment (528)

Later Borated racks (830) Borated racks (930)

These proposed changes have been reviewed by our Plant Operations and Safety Review Committee and Off-Site Safety and Review Committee, and they have determined that granting the proposed changes vill not result in an undue risk to the health and safety of the public.

However, as stated in our submittal of July 3, 1979, the proposed increases in the total amount of spent fuel allowed to be stored in the pool may involve a previously unreviewed safety issue.

We have determined, pursuant to 10 CFR Part 170 that this submittal constitutes supplementary information to a previous amendment application (Reference c) and that no additional fee is required.

. ,. /

BALTI RE GAS AND ELt

/f$ .

IC,/ COMPANY I

. !f

/H f<r

!) << u,/pf h, Vice Preside j , Supply

TO WIT:

CITY OF BALTIMORE Mr. A. E. Lundvall, Jr. being duly sworn states that he is Vice President of the Baltimore Gas and Electric Cimpany, a corporation of the State of Maryland; that he executed the foregoing Amendment for the purposes therein set forth; that the statements made in said Amendment are true and correct to the best of his knowledge, information and belief; and that he was authorized to execute the Amendment on behalf of said co ration.

/ I WITNESS my hand and Notarial Scal. ( .( b L' b_/U My Commission expires: 4 Y / ' / , / 'k[ L

" "/

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Licensing Report - Spent Fuel Storage Modification i

1.0 Introduction This report is submitted in support of Bai.timore Gas and Electric Company's application to amend the Calvert Cliffs Units Nos. 1 and 2 Facility Operating Licenses No. DPR-53 and DPR-69 for modification of the h

spent fuel storage facility.

The Calvert Cliffs Nuclear Pbver Plant (CCNPP) spent fuel pool (SFP) was originally designed with the storage capacity of 1-2/3 cores, (h10 fuel assemblies) felt to be adequate for the storage of the discharge (72 assemblies per unit per year) from each reactor for one year prior to its shipment off-site for reprocessing, plus 217 storage locations for core unloading whenever it became necessary.

Spent fuel is not currently being reprocessed on a commercial basis in the United States and no away-from-reactor storage facilities are available. For these reasons, BG&E in August 1977 requested NRC approval of SFP modification at Calvert Cliffs Nuclear Power Plant to allow for storage of 528 spent fuel assemblies in both the North and the South pools.

The South pool was modified as planned. Before work began on the North pool, however, it became apparent that an increase to a total of lb/3 cores (1056 spent fuel assemblies) which would allow operation of Calvert Cliffs until 1983, would not be adequate.

The spent fuel pool at Calvert Cliffs currently has the capacity to store 200 spent fuel assemblies in the North half of the pool (unmodified) and 528 assemblies in the South half of the pool (1977 modification).

Modification of the both halfs of the existing storage facility differing from that modification proposed in 1977 is required for continued operation while accommodating an exrected increase in the inventory of spent fuel assemblics above the capacity of the existing storage facility. The b

modification utilizes a fuel rack design which allows for increased storage capacity without significant modification to the facility.

The proposed modification is to replace the existing fuel assembly storage racks in the spent fuel pool with high capacity poison racks b supplied by Nuclear Energy Services capable of holding 1760 fuel assemblies.

The structural characteristics of the spent fuel storage pool are not altered by the change.

The design provides storage capacity for 830 fuel assemblies in the North half and 930 fuel assemblies in the South half of the pool having a feed enrichment of h.1 veight percent U-235 in UO2 or the b equivalent. The fuel is maintained in a safe and suberitical configuration, ke rrd0.95, during normal and abnormal conditions including the safe shut-down earthquake.

tM2 302

The modification in the North half of the pool consists of nine (9) storage racks with two (2) having eighty (80) storage elements, six (6) having one hundred (100) storage elements, and one (1) having seventy (70) storage elements in a 10 3/32" center-to-center spacing. In the South /hi half of the pool the modification consists of the same nine storage racks plus a tenth rack. The additional storage rack will have one hundred (100) storage elements and sit in the area originally designed for a cask.

Cooling of the spent fuel assemblies normally is achieved by a combination of natural circulation and spent fuel pool cooling.

The North half of the pool is scheduled for rack removal and new installation in the summer of 1980. Under this schedule all the fuel residing in the spent fuel pool can be moved to the South half of the pool. The North pool can then be drained and the modification can be accomplished in

/hi a dry pool. The South half of the pool vill likewise be modified under a schedule such that all the stored fuel can'be transferred to the North pool.

The modification vill then be performed in a dry pool.

Baltimore Gas and Electric Company is responsible for the modifica-tion to the spent fuel storage pool. Nuclear Energy Services is retained to design the spent fuel racks, contract for fabrication, perform analysis pertinent to the modification, and provide technical assistance during installation. Bechtel Power Corporation provided engineering assistance in reviewing the spent fuel pool structural considerations.

2.0 Descrintion of Existing Racks The existing spent fuel storage racks in the North half of the pool are a stainless steel structure consisting of vertical cells fixed to a continuous top deck and grouped in parallel rows with a center-to-center spacing of 18 inches. The storage racks are laterally braced on one another and against the valls of the spent fuel pool. The present design assures a keff of 0 98 or less and meets the reauirements of Seismic Class I.

The existing spent fuel storage racks in the South half of the pool consists of ten stainless steel grid structures. Each spent fuel rack /\

storage cell is supported laterally at the base and top by a framing system.

The base support system is nade un of cross beams which support the fuel storage cells. The entire rack assembly system is free to slide horizontally on the pool floor.

Space is currently provided for the storage of 200 fuel assemblies in the North half of the pool and 528 in the South half for a total of 728 assemblies, nominally 10/3 core.

3.0 Suent Puel Storace Facility Sunnort System 3.1 Svent Fuel Pool Cooline System The spent fuel pool cooling system is described in the Calvert Cliffs Nuclear Power Plant Final Safety Analysis Report, Section 9.4. The flow diagram for the system is contained in the above document as Figure 9-7 1762 303

The pror' sed modification does not require any physical change to the existing cooling system, as shovn by the analysis contained in Section 3.1.2 of this report, except for removal of an existing supply header.

3.1.1 The spent fuel pool cooling system, common to both units is a closed loop system consisting of two pumps in parallel and two heat exchangers in parallel, a bypass filter and a demineralizer. Makeup water comes from either the refueling vater tanks or the demineralized water connection. The heat exchangers are cooled by the service water systems.

The Unit 1 service water cools the No. 11 SFP heat exchanger and the Unit 2 service water cools the No. 12 SFP heat exchanger. For additional heat removal, if required, connections are provided for a te=porary tie-in to the shutdown cooling system of either unit.

The clarity and purity of the water in the spent fuel pool is maintained by the bypass filter and/or the demineralizer. Skimmers remove dust from the pool. An eight inch diameter suction pipe extends down into the spent fuel pool. Loss of the spent fuel pool water is avoided by routing all spent fuel pool piping connections above the water level and providing them with siphon breakers to prevent gravity drainage.

The system provides no emergency functions. Pool level and temperature alarms are provided.

~

3.1.2 Evaluation of the Existine Cooling System for Increased Storage Canacity The spent fuel pool cooling system has been evaluated in accordance [ jQg with Branch Technical Position APCSB 9-2 to determine the effect on the I system of increasing the spent fuel stored in the pool to 2h/3 core (1760 assemblies).

The spent fuel pool cooling system provides adequate capacity and component redundancy to assure the cooling of stored spent fuel, even when theracksforbothpoolgarefull. The maximum decay heat load in the pool increases to 17.28 x 10 BTU /IfR for 21/3 cores stored. The maximum steady

, state pool water temperature which occurs with only one pump operating increases to 152 F, which is in the range of a " safe" maximum spent fuel j{

pool temperature. The maximum normal operating temperature, with both subsystems operable, vill be 12h0F. Therefore, the existing spent fuel pool cooling system is adequate.

Table 3.1-1 outlines the generating of decay heat by the spent fuel. The following assumptions were made:

1. 1/3 Core unloaded 7 days after reactor shutdown.

2. Refueling of Units 1 and 2 vill occur a minimum of two months (60 days) apart.

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-h-3, A fuel cycle is 31h days; total burnup time is 9h2 days; refueling outage lasts 28 days.

h. Batch power is 900 MWth-5 .. Both units have " steady state" cores.

6. Spent fuel cooling system flow is 2780 gpm (with two pumps).

7 Service water flow to the Unit No. 1 spent fuel pool heat exchanger is 3037 gpm and 1869 gpm for the Unit No. 2 heat exchanger.

Should the pool contain 21/3 cores and one unit must be shutdevn and derneled, the shutdown cooling system would be utilized to supplement the SFP cooling system.

3.2 Spent Puel Pool Makeun Makeup water comes from the refueling water tanks. Neither the design basis nor the functional requirements for makeup to the spent fuel pool is affected by the increased storage capacity. Because the temperatures vill be maintained consistent with values stated in the FSAR makeup require-ments for the lov evaporative losses remain the same.

3.3 Heatinc and Ventilation - Seent Puel Pool Neither the design requirements nor the operational function of the spent fuel pool heating and ventilation system is affected by the new modification to the pool. Temperatures remain within the range for which the system was designed and, therefore, do not necessitate changes to the system.

Spent fuel pool air is drawn through HEPA filters and discharged to the constantly monitored plant vent. If the activity level becomes too high, the air can be diverted into charcoal filters for the removal of iodine and other radioactive particulates after it leaves the HEPA filter bank.

The air is then discharged from the charcoal beds to the plant vent.

3.4 Spent Puel Pool Buildine - Structural Analysis The spent fuel pool is a reinforced concrete structure with a 3/16" thick stainless steel liner plate for leak tightness. The pool is 92 feet long, 25 feet vide, and 39 feet deep, with a 2 foot vall dividing the two halves. A slot in the vall has removable gates allowing for the movement of fuel between the two halves of the pool. The pool is an intergal part of the auxiliary building and designed as a Seismic Class I structure in accordance with Section 5.6.1 of the Calvert Cliffs Nuclear Power Plant FSAR.

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TABLE 3.1-1 Schedule of Decay Heat Output of Spent Fuel Atount Size of Stored In Time After Time Of HeatGeneratgon Unit Discharce Pool Removal Burn Un BTU /HR (x10 )

1 1/3 1/3 Td 942d 9 155 b

2 1/3 2/3 67d 942d ,

3.217 1 1/3 3/3 39hd 942d 0 968 2 1/3 h/3 h09d 3h2d 0.835 1 1/3 5/3 691d 942d 0.515 2 1/3 6/3 - 751d 9hed 0.478 1 1/3 7/3 1033d 942d 0.367 2 1/3 8/3 1093d 942d 0.352 1 1/3 9/3 1375d 942d 0.141 2 1/3 10/3 1435d 942d 0.135 1 1/3 11/3 1717d 942d 0.117 2 1/3 12/3 1777d 942d 0.11h 1 1/3 13/3 2059d 9h2d n.106 2 1/3 1h/3 2119d 942d 0.105 1 1/3 15/3 2h01d 942d 0.100 2 1/3 16/3 2h61d 942d 0.100 1 1/3 17/3 27h3d 942d 0.096 2 1/3 18/3 2803d 942d 0.096 1 1/3 19/3 3085d 942d 0.093 2 1/3 20/3 3145d 942d 0.093 1 1/3 21/3 3h27d 942d 0.091 TOTAL = 17.28 x 106 BTU /HR 17'62 306

The load carrying capability of the floor has been evaluated by Bechtel Power Corporation, the original design organization. The results of the evaluation shows that the existing design is adequate.

The pool floor vill support the high capacity racks as a free standing structure during all design conditions.

h.0 Accident Analysis h.1 Loss of Snent Fuel Pool Coolant System Increasiggthespentfuelstoragecapacityresultsinaheat load of 17.28 x 10 BTU /HR. In the event of a complete loss of cooling capacity, the heat up rate, assuming an adiabatic pool, is 3.6 F/hr. The time required to heat un from 152 P to 210 F is 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />. This is sufficient timetorestgrecooling. Because the pool was designed for a heat up rate of 20.2 x 10 BTU /HR, the heat load increase is acceptable. The increase

/hi in heat load does not alter existing facility design basis.

h.2 Loss of Make Un As discussed in Section 9.h.5 of the Calvert Cli-ffs FSAR, total water loss cannot occur. In the event of a partial water loss, the fuel assemblies remain covered with water,and no radioactivity is released.

4.3 Liould and caseous Releases The storage of additional spent fuel assemblies in the spent fuel pool vill not result in any additional liquid release from the plant.

Because the added capacity represents longer term storage of vell-cooled fuel, further releases of gaseous or volatile fission products is expected to be negligible. After 300 days decay, much of the iodines and Xenon has decayed. Because of the long half life of Kr-85, detectable levels remain in older fuel. Air samples taken from around the spent fuel pool after the first Unit 1 refueling do not shov Kr-85 at detectable levels and it is not expected to become significant as fuel storage increases. Increased fuel storage vill have no observable impact on concentrations of airborne radio-activity in the auxiliary building. Therefore, the design is acceptable with regard to gaseous releases.

h.h Fuel Handling The storage of an increased number of spent fuel assemblies in the spent fuel pool vill not alter the analysis and consequences of the design basis fuel handling accident as presented in the FSAR, Section 14.5 1762 307

_7-h.5 Onerational Radiation Exnosures Storing the fuel for longer periods of time yields a greater amount of non-volative fission products and corrosion products released from the SFP. The SFP filter and demineralizer vill remove this radioactive material, thereby preventing higher activity levels from building up in the pool. The increase in filter and demineralizer change out because of the greater activity accumulated does not result in significant nan rem expen-diture when compared to the total annual man rem exposures.

Measurements taken in the SFP area both before and after the first Calvert Cliffs refueling outage indicate that the radiation levels are independent of the number of assemblies in the pool.

5.0 Alternative Evaluation With the current capacity of the spent fuel pool storage facility, Calvert Cliffs vill lose the ability to discharge a full core in spring of 1981. The Unit 1 refueling in 1982 vill completely fill the spent fuel pool. This can be seen in Table 5.0-1.

If the North half of the spent fuel pool was modified identically to the recent South pool modification, full core discharge capability would be extended until Spring of 1983. Capacity would be reached in Spring of 1984 vith the Unit 1 refueling.

The proposed modification, however, to both halves of the spent fuel pool, extends until Spring.1988 the full core discharge ability. The pool v;ald not be full until Spring 1989

/fi The alternative to the poison design modification is termination of reactor operation in 1983 (Unit 2) and 1984 (Unit 1).

Neither a licensed fuel reprocessing facility nor a licensed independent storage facility is available at this time. EG&E does not have another nuclear power plant to which spent fuel can be shipped. Hi6h capacity poison racks vill allow for continued plant operation while allowing additional time for the development of off-site storage.

If Calvert Cliffs terminated operations, replacement power vould be derived principally from operation of fossile plants. Daily replacement energy, at current rates, vould cost $1 Million.

6.0 Installa tion BG&E will be responsible for the installation of the spent fuel racks. Nuclear Energy Services vill provide technical assistance.

The overhead cranes in the auxiliary building at Calvert Cliffs vill be used for removing the racks from the trucks on which they vill arrive, lifting up to the 69" elevation, where the pool is located, and lovering them into the pool.

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Table 5.0-1 SCHEDULE OF CORE DISCHARGES

~

Unit 1 Unit 2 Accumulative Date Out # Assyn Date Out # Assys Inventory Up to 1/79 228 h/79 72 300 10/79 72 372 h/80 72 hhh 10/80 72 516 h/81 73 589 10/81 73 662 h/82 72 734 10/82 72 806 h/83 72 878 10/83 72 950 h/8h 73 1023 10/8h 73 1096 h/85 72 1168 10/85 72 1240 h/86 72 1312 10/86 72 1384 h/87 73 1h57 g 10/87 73 1530 h/88 72 1602 10/88 72 1674 h/89 72 17h6 1762 309

All spent fuel vill be moved from the North half of the pool into the South spent fuel nit prior to the spent fuel pool modification. The North pool vill be drained and hydrolazed to allow for dry removal of the b

old racks and installation of the new racks.

Similarly, the South half of the pool vill be modified after all fuel is moved into the new poison racks in the North half.

h The removed racks vill be decontaminated, boxed, and shipped off-site for burial.

The total exposure anticipated in replacing the racks in both halves c,f the spent fuel pool is 7 50 man rem.

h I

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