ML20003D251
| ML20003D251 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 03/17/1981 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | Groce R Maine Yankee |
| References | |
| NUDOCS 8103260025 | |
| Download: ML20003D251 (10) | |
Text
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NUCLEAR REGULATORY COMMISSION 2
o WASHINGTON,0. C. 20555 t
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March 17, 1981 Docket No. 50-309
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1 Mr. Robert H. Groce 9
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Senior Engineer - Licensing f
MAR 2 31981 m 8 Maine Yankee Atomic Power Company 1671 Worcester Road
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Dear Mr. Groce:
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We have reviewed your submittals of September 18, 1979 and September 29, 1980, concerning modified spent fuel pin storage at the Maine Yankee Atomic Power Station.
We find that we will need additional information bef' ' we can complete our review and evaluation. The enclosure lists the in ormation required.
Please submit the information requested within 30 days of receipt of this letter to permit a timely review of this issue.
Sincerely.
[L Robert A. Clark, Chief
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Operating Reacters Branch #3 Division of Licensing
Enclosure:
As stated cc: See next page
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Maine Yankee Atcaic Pcwer Corpany CC" E. W. Thurlow, Prtsident Mrs. L. Patricia Dcyle, President Maine Yankee Atomic Power Cowany SAFE POWER FOR MAINE Edtsen Drive Pest Office Box 774 Augusta, Maine 04336 Camden, Maine 04S43 Mr. Donald E. Vandenburgh First Selectman of Wiscasset Vice President - Engineering Municipal Building Yankee Atemic Electric Company U. S. Route 1 20 Turnpike Road Wiscasset, Maine 04578 Westboro, Massachusetts 01581 Stanley R. Tupper, Esq.
Jchn A. Ritsher, Esquire Tupper and Bradley Ropes & Gray 102 Townsend Avenue 225 Franklin Street Scothbay Harbor, Maine 04533 Boston, Massachuse:ts 02110 David Santee Miller, Esq.
Mr. Jchn M. R. Patersen 213 Morgan Street, N. W.
Assistant Attorney General Washingten, D. C.
20001 State of Maine Augusta, Maine 04330 Mr. Paul Swetland Resident Inspector / Maine Yankee Mr. Nicholas Barth c/o U.S.N.R.C.
Executive Director P. O. Box E Sheepscot Valley Conservation Wiscasset, Maine 04578 Association, Inc.
P. O. Box 125 Mr. Charles 3. 3rinkman Alan, Maine 04535 Manager - Washington Nuclear Operaticns Wiseaslett Public Library Association C-E Pover Systems Hign Street Cembustien Engineering, Inc.
Wiscasset, Maine 04578 4353 Cordell Avenue, Suite A-1 Bethesda, Maryland 20014 Mr. Torbet H. Macdonald, Jr.
Office of Energy Resources Director, Criteria and Standards Division State Hcuse Station !53 Office of Radiation Programs (ANR-450)
Augusta, Maine 04333 U.S. Envircnmental Protection Agency Washington, D. C.
20450 Robert M. Lazo, Esq., Chair: nan Atomic Safety and Licensing Board U.S. Environmental Protection Agency U.S. Nuclear Regulatory Ccamission Region I Office Washington, D. C.
20555 ATTN: EIS CCOR3INATOR JFK Federal Building Dr. Cadet H. Hand, Jr., Director Soston, Massachusetts 02203 Bodega Marine Laboratory University of California Bodega Bay, California 94923 Mr. Gustave A. Linenberger Atcaic Safety and Licensing Board State Planning Officer U.S. Nuclear Reguiatory Ccamission Executive Department Washington, D. C.
20555 189 State Street Augusta, Maine 04330 1
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ENCLOSURE MAINE YANKEE ATOMIC POWER PLANT SPENT FUEL P00L EXPANSION MODIFICATION REQUEST FOR ADDITIONAL INFORMATION 1.
In regard to the proposed reracking provide the following additional information:
With the aid of a drawing, descirbe the travel paths of the cid a.
and the new storage racks. Quantify the number of stored spent fuel assemblies that will be stored in the pool at the time reracking.
occurs.
Identify all equipment located below or within the area of influence of a dropped load along the travel paths which is essential in attaining a safe shutdown or in mitigating the consequences of an accidental load drop.
b.
With the aid of drawings describe the old and the new storage racks and their weights. Further, provide a description of the rigging that is interposed between the storage racks and the crane hook.
Identify all cases where the proposed rigging does not meet the requirements set forth in Section 5.1.6(1) of NUREG-0612 " Control of Heavy Loads at Nuclear Power Plants," and explain why they are acceptable.
In the event the overhead crane has not been reviewed by the staff and 2.
found to be in compliance-with NUREG-0554, describe and discuss what additional measures will be implemented in order to augment its reliability during.this mcdification.
In reference to the " Schedule of Change" presented in your September 29, 3.
1980 letter,-it appears that reracking cperations may extend over a 1
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. considerable length of time, i.e., "reracking will be implemented on a phase basis to provide an increasing capacity consistent with the normal 1
l refueling cycle." Describe and discuss the considerations that would lead you to schedule the reracking operations over more than one normal refueling cycle. The discussion should include the relative merits, in terms of reliable load handling operations, of completing the modification in one or more closely spaced refueling cycles as opposed to numerous refueling cycles.
4.
Responses numbered 11 and 12, dated February 15, 1980, state that an empty rack will not be moved over fuel storage racks. In this regard, using Figure 2 of the February 15, 1980 submittal, provide the following additional informa-tion:' Sequentially describe the reracking operations, and the travel paths in sufficient detail so as to enable the staff to conclude all reasonably practical measures will be taken to place the least amount of stored fuel at risk in the event of a load drop..
5.
Describe all of the handling tools and loads that are normally carried above the stored spent fuel.
Verify, in each case, that the maximum potential kinetic energy capable of being developed when dropped from their maximum elevation will be less than the kinetic energy of one fuel assembly and its associated handling tool when it is dropped from the height at which it is normally handled above the spent fuel storage racks.
s 6.
In reg?cd to the short term spant fuel pool storage rack which you propose to insert and remove from the spent fuel cask laydown area in the spent fuel pool provide the following additional information:
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. Describe and discuss -how you meet the criteria in Section 5.1 of NUP.EG-0612
" Control Of Heavy Loads At Nuclear Power Plants", assuming the rack is dropped.
7.
In establishing the adequacy of local cooling in a typical row of 35 storage cells (Appendix B of the September 29, 1980 submittal) it is stated it was conservatively assumed that the storage cells contained consolidated fuel rods that have decayed for a minimum of 120 days. Since, we believe, the decay heat load of freshly off loaded fuel assemblies (3 days decay) may be as much as four times the above assumed heat load, describe and discuss the measures that will be implemented in order to provide assurance that this heat load will be so distributed throughout the pool in such a fashion that the distributed heat load in any row will not exceed that i
assumed in your analysis.
8.
a.
Appendix 3 of the September 29, 1930 submittal states that during a i
full core discharge the decay time in the reactor vessel will be adjusted such that the bulk pool temperature will not exceed 154cp or the cooling capacity of the spent fuel pool cooling system. Since the decay heat load of a recently discharged full core significantly axceeds the capacity of the pool cooling system (assuming a decay time of 4 days), quantify and discuss the required adjusted full core decay-times following each incremental increase in pool heat load due to previous normal discharges up to the pool's full storage capacity. The discussion should be in sufficient detail as to enable the staff to perform an independent review and evaluation, b.
Verify that the decay heat loads have been calculated in accordance with Branch Technical Position APCSS 9-2.
l
.4-9.
Assuming the spent fuel pool centains the maximum possible decay heat load and the pool's bulk water temperature is at its maximum operational value, provide the time interval before bulk boiling occurs under the following conditions:
one of the two spent fuel pool cooling water pumps fails, and a.
b.
all external pool cooling is lost.
- 10. For both the component; cooling water system and the spent fuel pcci cooling systems, identify all deviations frca the positions set for:h in Regulatory Guides 1.13, ~1.25 and 1.29 and demenstrate the accep-tability of the deviations.
- 11. Describe and discuss all modifications that have been cade to the spent fuel pool cooling system that could pcssibly alter its capacity or reliability since the operating license was granted.
- 12. - Assuming that pool boiling were to occur what would be the maximum possible boil off rate? Identify and quantify the makeup rate capability of all scurces of makeup water which cceplies with Regulatory Guide 1.13
" Spent Fuel Storage Facility Design Basis" and Regulatory Guide 1.25
" Quality Group Classifications and Standards for Water-Steam-and Radio-Waste-Centaining Components of Nuclear Pcwer Plants". Also, indicate the required length of time before makeup water could be made available from each of these sources.
- 13. Indicate if these proposed modifications ccnform with NRC position on spent fuel pool.medification entitled "0T Position for Review and Acceptance of Spent Fuel Storage and Hancling Applicaticns", issued en April 14,
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1978 and later amended on January 18, 1979.
If not, identify and justify the deviations.
- 14. Provide sufficient details (discussion, sketches and schematics) of the racks, rack base supporting structures, racks arrangement in the pool, the spent fuel pool, and all gaps (clearance and expansion) of the rack structure and fuel bundles.
- 15. Provide a description of all items (weights, heights, and kinetic energy) which may be moved over the spent fuel assemblies and the pool floor liner. State which of these items is the critical one for the fuel pool and for the fuel pool liner.
- 15. Describe the codifications which are required to the present racks.
Explain in detail the load path along which all postulated forces are transmitted to the spent fuel pool structures.
- 17. Verify that the increased compressive loads on the plastic insulator have been considered and that no degradation occurs which could decrease its insulating integrity.
- 18. Indicate how the increased loads on the slab have been considered.
The increased loads should include all loads resulting from the racks and loads generated from heavy drop accident.
- 19. Provide the load combinations, the acceptable criteria and the reference standards or' papers used in the design of the spent fuel racks. Also, provide a discussion on the fabrication techniques (include welding) that will be used during the ccnstruction of the racks.
. 20. For the accident drop of any heavy object (including the fuel assembly and shipping cask) over the fuel pool provide the following:
a.
The assumptions, method of analysis, ductility ratios anc allowable stresses or strains used in the analysis to insure that the leak-tightness of the fuel pool liner is maintained.
b.
The code and load combination used in the design of fuel pool liner and the slabs.
c.
The assumptions, method of analysis, the calculated and allowable stresses for the concrete slab which is affected by this accident.
Also, discuss the effects and consequences of a direct drop over the liner versus a direct drop over the fuel pool racks (straight, inclined and through). State which is more critical in the design of the liner plate and the concrete slab.
- 21. Provide step by step detailed discussion on how the seismic effects on the racks have been considered. Provide, also, a discussion on the sliding and stability of the racks, the friction forces due to the sliding, the floor response spectra or time history, the damping values and applicability of Regulatory Guide 1.92.
- 22..Due to the gaps between assemblies and the wall of the guide tubes, additional loads will be generated by the impact of the fuel assemblies during a postulated seismic excitation and sliding.
Provice the justifications and the numerical values of these dynamic magnification factors due to the impact. Provide, also, sufficient O
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7 details describing the gaps, the guide tubes and the boundary conditions of the fuel bundle inside the guide tubes.
- 23. With regard to the issue of heavy drop accident (straight, through, and inclined) over the spent fuel racks, provide the following:
a.
Sketches, schematics and discussions regarding the shape of the impact area.
b.
Detail justification on why there will be no geometric distortion of the racks and how the structural criteria established for this case can be met.
- 24. Discuss the method used to account for the sloshing water on the fuel pool and fuel racks.
- 25. Provide a detail'ed discussion of the analysis used to calculate the stresses due to the fuel handling uplift accident, thermal loads, dead loads and friction loads. The model used and t'he assumptiens made should also be provided.
~26.
Due to thermal or seismic movement, fricticn forces will be present between the racks and the fuel pool liner. Discuss how these friction forces have been incorporated in the analysis.
l Provide also the numerical values with justifications of the coefficient of friction used in the analysis.
- 27. Provide design details to allow us to evaluate the compatability of the materials of construction and the poison material in the redesigned racks with respect to galvanic arid other corrosion processes.
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28.
If venting of the " containment pocket" for the poisen material is not provided, explain the method used to mitigate the effects of gas buildup.
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