ML19029A471

Affidavit of Edwin A. Liden & Technical Qualifications

ML19029A471
Person / Time
Site:	Salem
Issue date:	02/21/1979
From:	Liden E Public Service Electric & Gas Co
To:	Office of Nuclear Reactor Regulation
References
Download: ML19029A471 (32)

Text

~- --* *--..,,,

V1, ,

J:. * - - .::r State of New Jersey SS~

County of Essex AFFIDAVIT OF EDWIN *Ao LIDEN EDWIN A. LIDEN, being first duly sworn according to law, deposes and states:

1. I am employed by Public Service Electric and Gas Company as Project Licensing Manager. In that capacity I was responsible for the coordination of licensing activities related to the application to the NRC to install new spent fuel racks in the Salem Unit 1 spent fuel pool capable of holding 1170 elements.

In that capacity, I have become familiar with the design, con-struction, installation and surveillance of these racks, ,as well as the confirmatory testing done by the supplier. A copy of my professional qualifications is attached hereto as Appendix A and incorporated by reference herein. I have reviewed the allegations made regarding each of the admitted contentions in this proceeding.

Coleman's Contentions 2 and 6

2. The only materials used in the fuel storage racks, the rack interties and wall restraints are Type 304 stainless steel and Baral material sealed between an inner and outer stainless steel 1/

shroud~ The shroud protects the Baral from exposure to the spent fuel pool water environment. Baral is a trade name for an aluminum 2/

and boron carbide matrix.-

1/ Application, response to Question 13 dated December 22, 1978.

2/ Application, Amendment 1 at 22.

The material* properties for structural components used in the various analyses of the racks were taken from Appendix I of Section III of the ASME Boiler and Pressure Vessel Code. Type 304 was chosen for its compatibility with the spent fuel pool water, which contains boric acid at a nominal concentration of 2000 ppm boron, ~nd is the same material which is utilized in the present spent fuel racks. Stainless steel of this type has been widely utilized in the nuclear industry. The Licensee is unaware of any corrosion or other deterioration of stainless steel in tmvironrnents similar to the Salem spent fuel pool.

3. Unirradiated stainless fixtures have been exposed in 3/

pools up to 20 years without evidence of degradation.- Zircaloy -

4/

clad u. s. fuel has been in pool storage for up to 18 years:-

• Salem Unit 1 uses Zircaloy clad fuel. The Battelle study concludes that pool operators have not seen evidence that stainless-or-Zircaloy-clad uranium oxide fuel is degraded during pool storage, based on

. 5/

visual examinations and radiation monitoring:-

l/ A. B. Johnson, Behavior of Spent Nuclear Fuel in Water Pool Storage, BNWL~2256, September 1977 at 1. A copy of the Summary section of this report is attached as Appendix B and is in-corporated by reference herein.

4/ Id.

5/ Id. at 2.

• ~

The survey reaches the following conclusions:

Based on current experience and on an assessment of the relevant literature, prospects are favorable to extend storage of spent nuclear fuel in water pools,

• recognizing the following considerations:

Zircaloy-clad fuel has been stored satisfactorily in pools up to 18 years; stainless-clad fuel has been stored up to 12 years.

• Low temperatures and favorable water chemistries are not likely to promote cladding degradation.

There are no obvious degradation mechanisms which operate on the cladding under pool storage con-ditions at rates which are likely to cause failures in the time frame of probable storage.6/

4. The Salem Unit 1 spent fuel pool, with the new racks installed, has the capacity to hold fuel elements for 15 annual refuelings and retain the capacity for a full core discharge or 18 annual refuelings without that capacity. Thus, there has been actual experience with the storage of Zircaloy clad spent fuel for 7/

the period needed to completely fill the Salem spent fuel pool~

6/ Id. at 4. The Batelle report recommends that although there is sufficient evidence of satisfactory integrity of pool stored fuel to warrant extending fuel storage times and expanding fuel storage capacities, some additional exploratory examination of selected pool-stored fuel of selected pool-stored fuel is needed if storage is to move into the 20-100 year timeframe.

7/ At that time (or prior thereto) the older elements would pre-sumably have to be removed from the pool to permit further dis-charges from their reactor.

5. The Licensee has assured that the fabricated racks are built and installed to a high level of quality in accordance with design specifications. As part of this effort, careful control of the manufacturing process and non-destructive testing of the fuel cells was conducted to assure at least 95% leak tightness with a 95% confidence level. (See October 31, 1978 submittal to NRC)

6. The details of the welding processes and other manu-facturing and non-destructive and metallographic examination which assure the high.degree of leak tightness are described in Licensee's October 31, 1978 submittal to the NRC. Also described therein is a helium leak test utilizing a helium mass spectrometer which is capable of detecting *very small pin holes, smaller than any which would be significant in the fuel storage pool environment.

(See October 31, 1978 submittal to NRC)

7. Exxon Nuclear Co., Inc. has conducted a series of experiments to determine the effect of a leak in the stainless steel. Such a leak could potentially cause some minor corrosion of the aluminum in the aluminum-boron carbide matrix, and the e-volvement of hydrogen gas. Initially, the water leaking in the void between the shroud would compress the gas at the top of the cell until an equilibrium pressure was reached. The hydrogen gas would increase the pressure in the gap between shrouds pushing the water level down until gas bubbles escape at the elevation or the crack.

-s-The worst location for a leak would thus be at the bottom due to the higher static pressure. The pressure would cause the inner shroud to bulge and move toward the center of the cell.

(See October 31, 1978 submittal to NRC).

8. These tests revealed that in the unlikely event that a leak in- a fuel storage cell exists after installation in the water filled storage pool and before fuel is inserted, the worst potential consequence would be failure to be able to insert the fuel thereby losing the affected cell from service. Prior to loading fuel in any location, a procedure will be utilized to determine whether cell swelling exists at that location. (See October 31, 1978 submittal to NRC)

9. If a leak develops in a fuel storage cell with fuel already in place, the most severe result would be that the fuel could not be withdrawn from the storage cell with a force that is within the limits of the fuel handling' crane. In this event, semi-remote tooling will be utilized to provide vent holes in the top of the storage cell annulus to relieve the gas pressure on the fuel assembly and permit routine removal. (See October 31, 1978 submittal to NRC)

10. In another series of tests, Exxon Nuclear examined the ability of the Baral to withstand the spent fuel pool environment.

A number of test coupons of varying configurations, some of which were similar to the storage rack shapes, were exposed to fuel pool type environments for periods up to one year.

The coupons were examined for corrosion rate, pitting, bonding, edge attack and bulging. These experiments showed that simulated storage cells, with a leak simulating hole purposely made in the cell, will sustain aluminum corrosion which will consume only a small percentage of the aluminum in the Boral core a£ter a 40-year exposure. Moreover, while some pitting, edge attack, and internal gas pressurization could occur to Baral plates, the inert B 4

c particles would attach themselves to the corrosive product and would not be dislodged in the process.

11. The Licensee, in addition to these test programs, has committed to a long-term fuel storage cell surveillance program to verify that the spent fuel storage cell retains the material stability and mechanical integrity over its service life under actual spent fuel pool service conditions. Sample flat plate sandwich coupons and short fuel storage cells are provided for periodic surveillance and testing. The samples are fabricated from the same materials and are produced using the same manufacturing and quality assurance procedures specified for the fuel storage cells. One short fuel storage cell and one flat plate sandwich coupon will be prepared such that ~he Boral material will be exposed to the spent fuel pool environment. (The details of the program are discussed in Licenssee's Response to NRC Questions dated December 22, 1978).

The planned frequency of examination would be about one year after rack replacement and about every two years thereafter.

12. I am familiar with the problems encountered at the 8/

Monticello and Connectic~t Yankee- facilities related to spent fuel storage and as discussed below, they present no health and safety problem related to the storage of spent fuel at Salem Unit 1. Initially, the spent fuel racks at these facilities were not supplied by Exxon Nuclear Company, which provided the racks for Salem. Secondly, the quality assurance*program carried out by Exxon and PSE&G already described in paragraph five assures the integrity of the racks. Even if there were to be leaks, the experiments conducted by Exxon demonstrate, as pre-viously described, that no health and safety problem exists.

2

13. The minimum loading of Boron of .02 gms B-10/cm which results in a conservatively calculated K eff of less than 0.95, is assured by specification of a higher average concentration of Boron during the fabrication process. The density of the Bo'ron is assured by the quality assurance program which utilizes chemical analyses and batch traceability to assure the proper loading.

14. The Licensee has analyzed and conducted an experimental program to determine the effect of dropping a fuel assembly over the spent fuel storage racks.

8/ The problems encountered at the Connecticut Yankee facility involved a polymer used as a bonding agent, not Boral.

The local crushing of the cell from such an event is limited to the upper seven inches of the lead-in section, above the rack module upper grid structure and above stored fuel assemblies.

Thus, there would be no impact on the assemblies and no effect on criticality safety. (As described in Description and Safety Analysis Spent Fuel Storage Rack Replacement, Revision 1 at 37 and response A-21 submitted on May 17, 1978).

15. It is alleged that two or more fuel bundles could fail to be inserted fully into the cells due to distortion or swelling of the cell walls. As discussed in paragraph 7, PSE&G will conduct a program to assure that there has been no swelling of a fuel cell prior to loading of spent fuel. (See "Handling, Shipping &

Receiving Inspection, Spent Fuel Storage Racks and.In Plant Testing Program, Spent Fuel Storage, Spent Fuel Storage Racks at* 1-2 appended to the October 31, 1978 submittal.) -

16. The intervenors assert that the fuel handling crane could tip or lift a spent fuel rack module. The spent fuel handling crane has load limiting devices set at approximately 2500 lbs. which render it incapable of lifting or tipping even a single module, which weighs on the order of 32,000 lbs. Morever, the modules are tied together such that the postulated event is not credible.

LACT Contention 1 and Colemans' Contention 9

17. Alternatives to the proposed expansion of the capacity of the Unit 1 spent fuel pool have been considered. In addition, I would note that the proposed action has a negligible environmental impact.

18. It is not practicable to store the spent fuel from Salem Unit 1 at Salem Unit 2 or either unit of the Hope Creek Generating Station. In the case of Salem Unit 2, since that unit is expected to begin operation shortly and will have an annual discharge of fuel, both unenlarged fuel pools would be full by 1983. Due to the uncertainty in the availability of an In-dependent Spent Fuel Storage Installation ("ISFSI") by that time (EIA at 16), such an alternative could impact adversely on Unit 2 operation, and can be considered only a short term.temporary alternative. Moreove~, the environmental impacts of the extra handling of irradiated spent fuel, such as the dose received by workers during the transfer, would have to be attributed to this alternative inasmuch as the spent fuel pools for the units are completely separated and the element would have to be placed in a cask prior to transfer. If only the Unit 2 fuel pool were expanded, while additional capacity would be provided, it would suffer the same environmental impacts associated with fuel transfer as was the case for the case previously discussed, i.e., those associated with fuel transfer.

19. With regard to storage of Salem Unit 1 spent fuel at the Hope Creek units, it is unlikely that these units would be sufficiently complete to enable fuel to be stored prior to the unmodified Salem unit being full. Storage at Hope Creek would involve replacement of the Hope Creek racks with racks capable of holding Salem 1 Fuel, further lim1ting storage capacity at those units. Again fuel would have to be transported to these units and those impacts weighed against this alternative.

20. Considering that the same problem with spent fuel pool storage is being faced by all utilities, it is unlikely that there will be storage space available at any reactor. The costs associated with such storage would be at least comparable to those associated with the new racks at Salem Unit 1. Moreover, such alternative has no environmental impacts associated with an additional transfer of spent fuel.

21. The Allied-General Nuclear Services ("AGNS") reprocessing plant has not yet been licensed to receive and store spent fuel in the onsi te s*torage pool. I have contacted AGNS and have been informed that in no event will the facility be utilized by AGNS for the storage of reactor fuel absent reprocessing. Considering the President's April 7, 1977 statement deferring indefinitely commercial reprocessing and recycling of the plutonium produced in the u. s. nuclear power programs, the storage capacity of that facility cannot be relied upon.

-ll-

22. The NRC had under review an application by Exxon Nuclear Company for a storage pool and reprocessing facility to be located at Oak Ridge, Tennessee. A construction permit has not yet been issued and in view of the President's announced policy, and the termination of that proceeding by the NRC, reliance upon the construction of a storage pool in time for Salem Unit 1 is not prudent.

23. The fuel storage pool at the Morris, Illinois facility is being utilized for General Electric Company owned fuel which had been leased to utilities or for fuel which General Electric had previously contracted to reprocess. Other spent fuel is not being stored in the absence of an express commitment to do so.

There is no such commitment for Salem. (EIA at 14). Similarly, the Nuclear Fuel Service facility at West Valley, New York is not accepting additional spent fuel for storage, even from those reactor facilities with which it had reprocessing contracts.

(EIA at 14).

24. Should an ISFSI be constructed, the costs would be much higher than those associated with the new racks for Salem Unit 1 inasmuch as a pool structure and supporting systems would have to be erected, and spent fuel transported to such a facility. The environmental impacts associated with constructing such a facility would also be greater than the minor impacts associated with re-placing the racks.

25. All alternatives previously discussed considered that the spent fuel pool could be filled prior to the alternative being needed. This is not quite the case. After the next (second) refueling, scheduled for the first part of 1980, the facility will lose its capacity to discharge a full core from the reactor.

While this capability is not a safety related consideration, it is prudent from an operational standpoint to have such capability.

Therefore the ability to sustain full core discharge capability should be weighed in favor of the proposed fuel rack expansion.

26. The Company has discounted the possibility for disposing of the spent fuel outside the United States. Considering the President's announced.policy statement on nuclear power, i t is unlikely that permission would be granted to export spent nuclear fuel. In fact the President's April 7, 1977 statement on nuclear power policy states that the u. s. is exploring "measures to assure access to nuclear fuel supplies and spent fuel storage for nations sharing common non-proliferation objectives".

27. The Licensee has estimated that a shutdown of Salem Unit 1 with a net electrical output of 1090 megawatts would cause in-cremental replacement power costs alone of $500,000 per day, based on the differential costs of producing energy from Salem as compared to production from other available units in the PSE&G and Pennsylvania New Jersey Maryland ("PJM") Interconnection.

-l3-The Staff, looking at the long term economic impacts other than the short term incremental effects, factored in a capacity factor range of 60-70% to arrive at annual replacement costs associated with the discontinuance of operation on the order of $300,000 to 9/

$350,000 per day.- Using either figure, these costs would still be far in excess of the costs associated with the proposed modification, i.e., $3300 per fuel assembly or $3,000,000 for the entire cost 10/

of replacing the racks~

9/ EIA at 18-l9 10/ Id. at 19

-.14-LACT Contention 3

28. PSE&G has also made application to the NRC to expand The Salem Unit 2 fuel pool capacity to 1170 elements utilizing racks supplied by Exxon Nuclear Company, Inc. Thus, as a result of this modification, there will be no need nor incentive to store spent* fuel from Salem unit 2 at Salem Unit 1.

29. Since the spent fuel storage facilities for the two Salem units are completely separate, if Unit 2 fuel were hypo-thetically to be stored at Unit 1, spent fuel transfer from Unit 2 to Unit l in a transfer cask would be required.

30. Truck casks which would have to be used for the transfer can acconnnodate only one Pressurized Water Reactor fuel assembly.

The cask would have to be sealed, decontaminated and then opened in the Unit 1 cask pool. This process is slow and cumbersome.

There is therefore no incentive for storing Unit 2 or Hope Creek spent fuel in the Unit 1 spent fuel pool.

31. The Hope Creek Generating Station utilizes two boiling water reactors. Five assemblies for these units are different in size from those utilized in Salem Unit 1 and cannot be stored in the new fuel storage racks in the Salem Unit 1 fuel pool.

Neither is there additional room in the Salem 1 spent fuel pool to place new racks to acconunodate such fuel.

EDWIN A. LIDEN

/

Sworn and subscribed to before me this  ?.. /qday of February, 1979.

NOTARY PUBLiC OF r~c'i'/ JE!~S~Y My Commission Expires Mar. 18, l:J70

APPENDIX A TECHNICAL QUALIFICATIONS EDWIN A. LIDEN PROJECT LICENSTNG MANAGER PUBLIC SERVICE ELECTRIC AND GAS COMPANY My name is Edwin A. Liden. My business address is 80 Park Place, Newark, New Jersey. I am Project Licensing Manager in the Engineering and Construction Department of Public Service Electric and Gas Company and have served in this capacity since 1977. In my present position, I am responsible for directing the licensing activities for the Salem Nuclear Generating Station.

I was graduated from the State University of New York Maritime College with a Bachelor of Marine Engineering degree in 1963. I also served in the u. S. Merchant Marine as a licensed engineering officer.

From 1963 to 1966, I was employed by Newport News Shipbuilding and Dry Dock Companyo I was certified by the NRC as Shift Test Engineer on the A2W and ClW naval nuclear power plants. I was the senior shipyard representative on shift during refueling and over-haul operations on both the USS Enterprise and USS Long Branch.

From 1966 to 1967, I was staff engineer at Combustion Engineering, Inc., working on fuel channel development for the heavy water organic cooled reactor (HWOCR) project.

From 1967 to 1970, I was department head at the Saxton Nuclear Facility and, in that capacity, held a Senior Reactor Operator license. I was responsible for nuclear plant maintenance, performance, health physics, radiochemistry, radwaste and nuclear fuel.

From 1970, when I joined PSE&G, until 1977, I have participated in the licensing process for the Salem Nuclear Generating Station which included preparation of the FSAR, Environmental Report, and Safety and Environmental technical specifications.

I am a member of the American Nuclear Society.

EAL:kd 2/15/79

--*. BNWL ~-2256; __ .

• . ...'l!

UC-70

.~*.":--***

.. ...~:* ; ;.\; ':,. ...

.. .. ~ ~

~ ~:-. :"' . . ... -:-~: . . .

~-~- ..... :**:::* .-

-* - . . t.- = *. . **;....:- *. *.._-: ..

-~

J-

• l

. - **-~ - _*.;-

I* ,1. . . . . . . .-':':. -

• • • =~-----

• - ...~

.... *-**.-:......... -~-*

.~ -:-_

- ......* . - *e .!.:f :"'~,~:~:3:; ::;::: ~

BNWL-2256 UC-70

~

....'l.'.

.... =*. *.***

BEHAVIOR OF SPENT NUCLEAR FUEL IN WATER POOL STORAGE b.Y~.

A. B. Johnson, Jr.

-i..~-.~-

. ,. S~ptenmer--.::-1~77 BATTELLE .

Pacific Northwest Laboratories Richland, Wash"i.ngton 99352

• ~-*

..... L

• • ~*:-.

CONTENTS 1

SUMMARY

ANO CONCLUSIONS 5

INTRODUCTION 10 SCOPE OF FUEL POOL SURVEY .

12 NUCLEAR FUEL- STORAGE IN WATER POOLS .

12 STORED FUEL INVENTORIES .

13 MAXIMUM FUEL BURNUPS .

14 FUEL POOL RESIDENCE TIMES.

FUEL PERFORMANCE DURING POOL STORAGE. 16 SURVEILLANCE METHODS . 16 POOL OPERATOR OBSERVATIONS ON FUEL BUNDLE CORROSION 17 HANDLING. FAILED FUEL IN BASIN STORAGE. . 18 Procedures for Handling Defective Fuel. . 18

• Nuclear fuel Services Experience with Defective Fuel . 19 Humboldt Bay Reactor, Failed Stainless Stee.l Fuel . 20 Storage of Defective Zircaioy-Clad Power Reactor Fuel. 20 Fuel Defect Mechanisms . 21 Fuel Failure Statistics. 21 Types of Defects . 22 Significance of Defective Fuel Behavior in Pool Storage . 22 MECHANICAL DEGRADATION OF FUEL BUNDLE. MATERIALS DURING FUEL

• HANDLING OPERATIONS 23 Pool Operator Observatio.ns on Mechanical Damage. 24 Su1T111ary of Fuel Handling Accidents from Reactor Incident Reports . 25 Mechanica 1 Damage to the Pool. 27 ii

RANGE OF POOL STORAGE CONDITIONS . 28 FUEL POOL WATER CHEMISTRIES . 30 Effects of Boric Acid Pool Chemistry . . 35 FUEL POOL AND FUEL ROD TEMPERATURES . . 36 FUEL ROD RADIATION LEVELS . 37 FUEL POOL MATERIALS 37 FUEL BUNDLE MATERIALS . . . 43 MATRIX OF FUEL STORAGE CONDITIONS 43

.GALVANIC COUPLES 47 RADIOCHEMICAL CHARACTERIZATION OF FUEL POOL WATERS 48 EUROPEAN SPENT FUEL STORAGE EXPERIENCE . 52

SUMMARY

OF FUEL POOL SURVEY. . . . . 53

• PRELIMINARY ASSESSMENT OF POTENTIAL DEGRADATION MECHANISMS FOR MATERIALS IN POOL. STORAGE * * * . . ~ . . . . . . . * . . 55

~OTENTIAL DEGRADATION: PROCESSES~FUEL BUNDLE MATERIALS .

• 55 Eva 1uati on of Fue r"'.'s i de.* Cladding* Degradation Mechanisms 56 Hydriding Effects -1n* Zirca loy . .* . 56 Hydriding Effects in Stainless Steel. ST Fission Product Attack 57 Helium Embrittlement . . ..* . . 58 Evaluation of Water-Side Cladding Degradation Mechanisms. * . . . . * . * . . . 59

• -* The Aqueous Corrosion Environments 59 Oxidation of Fuel Bundle* Materia.ls 60 iii

Boric Acid.Pool Chemistry . 62 Effects of Radiation on Corrosion. 63 Bio 1ogi c.a 1 Corrosion . 64 Effects of Crud Layers 65 Residual Stresses in Irradiated Fuel Cladding. 65 Stress Corrosion Cracking

• 67 Stress Corrosion of Austenitic Stainless Steel 67 Stress Cracking of Zirconium Alloys 68 Galvanic Corrosion 68 Crevice Corrosion . 69 Galvanically-Induced Hydriding* of Zirconium Alloys 69 Pitting Carros ion* * . . ,* 71 Corrosion* Behavior a*t Fuel Defects*

• 72 CORROSION OF FUEL POOL EQUIPMENT . 72 STATUS OF OTHER SPENT FUEL STORAGE OPTIONS. .* 75 ASSESSMENT OF MATERIALS BEHAVIOR IN FUEL POOLS -

SUMMARY

. 76 REFERENCES

• 79 ACKNOWLEDGMENTS 85

'APPENDIX A - PRELIMINARY ASSESSMENT OF CLADDING STRESSES IN RODS LOCATED IN FUEL STORAGE BASIN . A-1 APPENDIX A - REFERENCES . . A-6 DISTRIBUTION

• e I

• Distr-1 iv

TABLES 1 Sunmary of Canadian and U.S. *Fuel Pool Inventories. 12 2 Maximum Fuel Burnups on Stored Commercial Fuel . 13 3 Maximum Fuel Bundle Residence. Times in Pool Storage . 14 4 Burnups and Pool Residence Times for Reprocessed L*

Fuel 25 5 Su11111ary of Incidents Involving Mechanical Damage to Irradiated Fue.1 Bundles - 1974-76

• 26 6

• Char.acteristics of Canadian Fuel Storage Pools 31 7 Characteristics of U.S. Fuel Storage Pools 32 8 Spent Fuel Pool Water Quality Specifications 33 9 Fuel Pool Water Ch*emistry Specifications 34 10 Sunmary of Materials in Fuel Pools . 38 11 Fuel Bundle Materials* 47 lZ Matrix of Fusl Storage Conditions 48 13 Principal .~ctivation P"rOducts Released from Fu!!l Bundles During Pool Storage . 49 14 Principal Fission Products Released to Fuel Pool Waters . 49 15 Radionucljde Concentrations in Fuel Storage Pools, uCi/ml

• so A-1 Fuel Dimension Specifications. A-4

.v

FIGURES 1 G.E. Morris Operation - Fuel Pool. 7 2 G.E. Morris Operation - Spent Fuel Bundle (b) Being Transferred from IF-300 Shipping Cask (c) to BWR Storage Canister (a). A PWR Canister also is shown (d) 8 3 G.E. Morris Op~ration - Fully-Loaded Storage Canister Being Transported to a Pool *storage Location . 9 4 Schematic - Morris Operation Spent Fuel Storage Pool Facilities 29 5 PWR Stainless Steel Fuel Storage Module - G.E. Morris Operation. 39 6 BWR Stainless Steel Fuel Storage Modu*le - G.E. Morris Operation. 40 7 Fuel Storage Canister. 42 8 Typical PWR Fuel Rod 44 9* BWR Fuel Assembly 45 10 PWR Fuel Assembly 46 . '

A-1 Cladding Hoop Stress Versus Gap Pressure A-3

• i i

I r

I r'

vi

e* BEHAVIOR OF SPENT NUCLEAR FUEL e IN WATER POOL STORAGE

SUMMARY

AND CONCLUSIONS Storage of irradiated nuclear fuel in water pools (basins) has been stan~ard practice since nuclear reactors first began operation "'34 years ago. Pool storage is the starting point for all other fuel storage candi-date processes and is a candidate for extended interim fuel storage until policy questions regarding reprocessing and ultimate disposal have been resolved.

This report assesses the current performance of nuclear fuel in pool storage, the range of storage conditions, and the prospects for extending residence times. The assessment is based on visits to five U.S. and Canadian fuel storage sites, representing nine storage pools, and on dis-cussions* with operators of an* additional 21 storage pools. Spent fuel storage *experience from British pools. at Winfrith and Windscale and from a German pool at Karlsruhe (WAK) also is* sunmarized.

At the end of 1976 there were * -8700 power reactor fuel bundles in 1

storage in U.S. pools. Approximately 90% of the bundles have Zircaloy cladding; the rem~inder have stainless steel cladding~ Approximately 70,000 Zircaloy-clad bundles (-..so*cm lo.ng) were* stored in Canadian pools at the end of 1976.

Maximum pool residence for Canadian fuel is_l4 years. Zircaloy-clad U.S. fuel has been in pool storage up to 18 years. Experimental stainless-clad. fuel has been stored up to 12 years; commercial stainless-clad fuel has been stored up to 7 years; unirradiated stainless steel fixtures have been exposed in pools up ta ...,z9 years without evidence of degradation.

Maximum burnups for stored commercial fuel are "*33,000 MWd/MTU for both Zircaloy- and stainless-clad fuel.

Perceptions regarding the status of the stored spent fuel are based principally on visual observati.ons

'during fuel . handling operations and on vis.ible portions of ~he bundles: during storage. Radiation monitoring of 1

water and air in pool *storage areas also is conducted to detect evidence of radiation releases from the stored fuel.

The results of the *survey indicate that pool operators have.not seen evidence that stainless- or Zircaloy-clad uranium oxide fuel is degrading during pool storage, based on visual examinati~ns and radiation monitoring.

Irradiated Canadian Zircaloy-clad fuel was returned to a reactor after up to 10 years of pool storage, with satisfa*ctory performance. Shippingport fuel was removed from pool storage to a hot cell inspect.ion in air after 4 years in pool storage. There*was no visual evidence of degradation and no radiation releases occurred.

• Mechanical damage to spent. fuel during reactor discharge and fuel handling in the poo 1s is minima 1. The number of incidents where fuel was dropped during fuel handling operations appears to have been less than a dozen cases. in 1974 to 1976. Only two cases were identified where fuel damage resulted in breached cladding.

Several hundred fuel bundles. having rods which developed Cladding defects during reactor* exposures* are in pool storage. Radioactive gases were' expelled to. the. reactor* coolant and.therefore are not released from the* reactor-induced cladding defects during pool storage .. However, non-

. gaseous fission products are released to the pool water. Steady-state radi oacti vi ty* concentrations fn pool water can be maintained in the range 10- 3 to 10- 4 1JCi/ml with.ion exchange and filtration. Higher. values (up to "'°.5. uCi/ml) occur during fuel discharges at reactor pools. Spent fuel with defective cladding-has been stored, shipped and reprocessed, frequently on the same basis. as intact fuel.

The range of storage conditions in fuel pools is outlined below:

• Water Chemistries.

• BWR and ISFSI(a) pools:

Oxygen-saturated deionized water PWR pools:

Oxygen-saturated deionized water + -v2000 ppm boron as boric acid. :

(a)Independent Spent Fuel Storage. Installation; *the only U~S. ISFSI pools which now store spent**fuel are GE-Morris and Nuclear Fuel Services.

2

70 to 120°F (20 to 50°GJ.*bulk *.* .. *., .. ..

water temperatures Pools with adequate he~t exchange';." capacity maintain temperatures below 100°~_., . e.v~.n .. with freshly-discharged fuel; clad temperatures,, for freshly-discharged fuel are

"'18°F {10°C) above th~~tj~ik*:~~ter temperatures. Mild

• ~:.- ..

temperature- trans i ent~/t*wi.thfn *... *-.r,.*,* .* "-:'.

the range cited above, have occurred in pools ~uring. t~porary shutdown of heat exchangers. *****"'":.;;::..

.= *~!:,;~*:

• • Materials Pool wa.lls--painted concrete, stainless. stee-1, fiberglass Fuel canisters and racks--stainless steel or aluminum alloys Grapples and .

hoists--stainless-

• ;"-."'f).

or chromium-plated steel Detailed, systematic: ~xami.!"ations._.of.fuer bundle materials_ have not been conducted specifically -t<f"lifine ,. s.tor-'";ge behavior, because of the expectation that the fuel would be reprocessed after relatively short pool residence-.. A1so, there is. mini ma.l *reason to expect that the corrosion~r.esistant fuel bundle* materials would degrade in the relatively benign* storage: environments over the*!.~xpected: storage period .. Over the range* Of pool 'storage expe".'i.~* c:ffiid above, there have been no obser-vations. which raise concerns. However, it is not now* clear how long*

pool storage of spent . .,- ......

-~

fuel may be extended~ If storage ti"mes of the spent fuel inventory are expected'~to*.. ~~tend into the 2Q~to-100-year time frame, there is an increasing. i~centi.ve t~----[~"rmi_.n~;;~~et~e~~~\t:~s.low degradation mechani*sms

.......... ~. - .. *. . .. *-*

. are: *oper.ative. *'..;;.::-;:.('~~.;"'.

- :~

.. **' *..:!-.:;~.~::.;:~--... . . ..

..Jur.t.hef!.~'a:S.Su'fances

. . . *.r*:  :,;.*., .... ~. ** ......

regarding fuel *cladding integrity can be based on seTected destructive exa_ms.* of spent fuel having a previous exam* history, which defined the-:- re~*~lts .of the reactor expos.ifte.-* Also, p_e~iodic visual and non-destructive* surveillance of se~cted stainless- and Zircaloy-clad

.. bundles. can p~ovide* a_ systemat:f ~;.~'stained

..... .. . approa.ch .

to verify the. integrity of* the s.pent fuel inventory. Sucti an approach, of limited scope, has in fact begun in Germany (Karlsruhe). The ~.~spe_ctions also should include fuel having reactor-induced def~cts. Unless ~vidence of degradation develops in exploratory* investigations, a-*~_~urveillance~*-program involving large numbers of bundles is not justified *.. : ~~.

3

.:,*e*-* e To define certain aspects of long~tenn {20-to-100-year} spent fuel and pool equipment integritys. some laboratory investigations may be useful. Any detailed fuel investigations and laboratory studies should consider the action of poss.ible degradation mechanisms on either interior or exterior cladding surfaces and on lifting members such as fuel bundle bails.

Cladding stresses are not expected to be high, but whether they are sufficient to participate in certain slow degradation mechanisms is not clear. Pitting or other localized corrosion, particularly of stainless steel, cannot be ruled out by present levels of inspection, again in reg.ard to very long exposures.

Based on- current experience- and on an assessment of the re 1evant 1iterature, prospects are** favorable to extend storage of spent nuclear fuel in water pools*, recognizing the following* considerations:

... Zirca:loy-clad fuel has been stored satisfactorily in pools up to 18 years; stain less-cl ad fue 1 has been stored up to ll years.

Low- temperatures* and* favorable water chemistries are not 1ikely to. promote, cladding degradation.

... There are no. obvious. degradationmechani.sms. which operate on I

the: cladding under* pool storage conditions at rates which are likely to cause failures in the. ti~e frame of probable star.age.

Recomnendations

• There is sufficient evidence of satisfactory integrity of .

pool-stored fuel to warrant extending fuel storage times and expanding fuel storage. capacities *

• Exploratory examination of selected pool-stored fuel is

• warranted, parti~ularly if the stored fuel inventory is expected to move into the 20-to-100-year time frame,. to define* whether slow degradation of* the. fuel bundle materials is operative. To be effective, the examinations must involve bundles having previous destructive examinations wt)ich define

. the effects of the reactor exposure, followed by substantial pool exposures. Periodic visual and non-destructive surveillance of selected bundles can provide further assurance of sustained fuel bundle integrity.

. 4 .

-- --'"Ii_'

State of New Jersey SS.

County of Essex AFFIDAVIT OF ROBERT L. MITTL ROBERT L. MITTL, being first duly sworn according to law, deposes and states:

-1. I am General Manager - Licensing and Environment of Licensee, Public Service Electric and Gas Company. In that capacity, I am familiar with the design and Gonstruction of the Salem Nuclear Generating Station and Hope Creek Generating Station.

2. PSE&G plans to increase the spent fuel capacity of Salem Unit 2 to 1170 elements by making essentially the same modifications as for Unit 1.

3. With regard to the Hope Creek Generating Station, because of the projected operating dates, the Company has not yet decided on the ultimate number of spent fuel elements to be stored in each pool. At this time, however, the Company is considering the storage capability for 1.6 cores. As presently contemplated, the design would_ be such that additional racks could be added should that become necessary.

4. PSE&G has applied to the NRC to amend its license for Salem Unit 1 to increase the storage of spent fuel resulting from the operation of that unit. The additional capacity of the new racks was based upon the needs of that unit and the size of the existing fuel pool. It provides for 15 annual discharges while maintaining the capability for a full core discharge.

5. PSE&G has never considered nor has it any plans to utilize the spent fuel storage capacity of the Salem Generating Station for storage of any other facilities' fuel.

ROBERT L. MITTL Sworn and subscribed to )

" ,,-1 'f-'

before me this _:,../ ~* day )

of February, 1979. )

BARBARA V. , , ~ ..

A NQT l r\~~I;;:

' .AR{ PUBLIC OF 1~:':"' *~..,."

Mv Com * ~* . -" Jt;(.,f {

• m1s.,1on Expires f'/0:1. R l *~;o'1

""J .........

. UNITED STATES OF AMERJ:CA

• NU~ REG~T~RY COMMISSI~

Before the.Atomic Safety and Licensing Board In the Matter of )

)

PUBLIC SERVICE ELECTRIC AND GAS ) Docket No. 50-272 COMPANY, et al. )

)

(Salem Nuclear Generating )

Station, Unit. l) * )

CERTIFICATE OF SERVICE I hereby certify that copies of the following documents:

1. "Licensee's Motion For Summary Disposition"

2. "Licensee's Statement Of Material Facts As To Which There !s No Genuine Issue To Be Heard"

3. "Licensee's Memorandum In Support Of Its Motion For Summary Disposition" all dated February 27, 1979, in the captioned matter, have been served upon the following by deposit in the United States mail this 27th day of February, 1979:

Gary L. Milhollin, Esq. Chairman, Atomic Safety and Chairman, Atomic Safety Licensing Board Panel and Licensing Board U.S. Nuclear Regulatory 1815 Jefferson Street Commission Madison, Wisconsin 53711 Washington, D.C. 20555 Mr. Glenn o. Bright Barry .Smith, Esq.

Member, Atomic Safety and Office of the Executive Licensing Board Panel Legal Director U.S. Nuclear Regulatory U.S. Nuclear Regulatory Commission Commission Washington, D.C. 20555 Washington, D.C. 20555 Dr. James C. Lamb, III Mark L. First, Esq.

Member, Atomic Safety and Deputy Attorney General Licensing Board Panel Department of Law and 313 Woodhaven Road Public Safety Chapel Hill, N.C. 27514 Environmental Protection Section Chairman, Atomic Safety and 36 West State Street Licensing Appeal Board Panel Trenton, N.J. 08625 U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Richard Fryling, Jr., Esq.

Assistant General Solicitor Public Service Electric Carl Valore, Jr., Esq.

Valore, McAllister, Aron

& Westmoreland

& Gas Company Mainland Professional Plaza 80 Park Place P. o. Box 175 Newark, N. J. 07101 Northfield, N. J. 08225 R. William Potter, Esq. Office of the Secretary Assistant Deputy Public Advocate Docketing and Service Section Department of the Public Advocate U.S. Nuclear Regulatory Division of Public Interest Commission Advocacy. Washington, D. c. 20555 Post Of £ice Box 141 Trenton, N. J. 0.8601 June D. MacArtor, Esq.

Deputy Attorney General Sandra T. Ayres, Esq. Tatnall Building, P. o. Box 1401 Department of the Public Advocate Dover, Delaware 19901 520 East State Street Trenton, N. J. 08625 Mr. Alf.red c. Coleman, Jr.

Mrs. Eleanor G. Coleman 35 "K" Drive Pennsville, New Jersey 08070