ML20244B802
| ML20244B802 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/10/1989 |
| From: | Mroczka E NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8904190418 | |
| Download: ML20244B802 (5) | |
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(203) 665-5000 April 10, 1989 Docket No. 50-245 813199 Re:
10CFR50.90 ISAP Topic 2.18 U.S. Nuclear Regulatory Commission 1
Attention:
Document Control Desk Washington, DC 20555 Gentlemen:
Millstone Nuclear Power Station, Unit No. 1 Response to Request for '<dditional Information Spent Fuel Pool Capacity Expansion (TAC No. 68157)
In a letter dated June 24,1988,II) Northeast Nuclear Energy Company (NNECO) requested a change to the Millstone Nuclear Power Station, Unit No.1 Techni-cal Specifications to allow expansion of the spent fu?1 pool storage capa-29,1988,gis request was sgitted to the bility.
Additional information supporting March 1,1989,gugust 22, 1989 g mber 2, NRC Sgf in let ters datedgly 12, 1988, D
and March
- 1988, February 14, 1989, (1)
E. J. Mroczka letter to U.S. Nuclear Regulatory Commission, " Millstone Nuclear Power
- Station, Unit No. 1, Proposed Change to Technical Specifications, Spent Fuel Pool Capacity Expansion," dated June 24, 1988.
(2)
E. J. Mroczka letter to U.S. Nuclear Regulatory Commission, " Millstone Nuclear Power
- Station, Unit No. 1, Proposed Change to Technical Specifications, Spent Fuel Pool Capacity Expansion," dated July 29, 1988.
(3)
E. J. Mroczka letter to U.S.
Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No.1, Request for Additional Information, Spent Fuel Pool Capacity Expansion," dated August 12, 1988.
(4)
E. J. Mroczka letter to U.S. Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No.1, Spent Fuel Pool Capacity Expansion, Additional Information," dated December 2,1988.
(5)
E. J. Mroczka letter to U.S. Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No.1, Spent Fuel Pool Capacity Expansion,"
dated February 14, 1989.
(6)
E. J. Mroczka letter to U.S. Nuclear Regulatory Commission, " Millstone Nuclear Power
- Station, Unit No. 1, Spent Fuel Pool Capacity Expansion--Additional Information," dated March 1,1989.
(7)
E. J. Mroczka letter to U.S.
Nuclear Regulatory Commission, " Millstone Nuclear Power Station, Unit No.1, Response to Request for Additional Information, Spent Fuel Pool Capacity Exp,nsion," dated March 22, 1989.
Ao l 8904190419 990410 PDR ADOCK 05000245 PDC
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'O U.S. Nuclear Regulatory Commission B13199/Page 2 i
April 10, 1989 Subsequently, in a telephone conversation with the NRC Staff on March 23, 1989, the Staff requested additional information concerning the criticality l
analysis associated with the new spent fuel racks..The purpose of this letter is to provide the Staff with the requested information.
This information is
{
provided in Attachment 1.
j We trust the Staff will find this information satisfactory, and we remain available to assist you in the review of this matter.
_ e appreciate the W
timely efforts the Staff has, and continues to, put forth on this matter.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY f
d E. J 7)tt6czka
//
Senior Vice President cc:
W. T. Russell, Region I Administrator M. L. Boyle, NRC Project Manager, Millstone Unit No.1 W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3 l
i
- ?
?i Docket No. 50-245'-
B13199.'
s A
Millstone' Nuclear Power Station, Unit No.1 Spent Fuel Pool Capacity Expansion Additional' Information -
l:
April 1989 1
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U.S. Nuclear Regulatory Commission j
B13199/ Attachment 1/Page 1 April 10, 1989 Millstone Nuclear Power Station, Unit No.1 i
Spent Fuel Pool Capacity Expansion Additional Information l
NRC Ouestion No. 1:
While axial radiation induced shrinkage of Boraflex is suitably considered, there is no discussion of shrinkage of the width.
Discuss the effects of radiation induced Boraflex width shrinkage on reactivity.
Response No. 1:
The previously evaluated sensitivity to Boraflex shrinkage may be used to evaluate the potential increase in reactivity % the assumption of a 2 per-cent shrinkage in Boraflex width after irradiation.
This potential increase, when added. to the previous reference, k-infinity, does not increase the reactivity above 0.90 (calculated at 0.8996, without credit for a small amount of axial leakage).
Thus the racks can accommodate a 2 percent shrinkage in Boraflex without exceeding the design basis k-eff limit of 0.90.
NRC Ouestion No. 2 There is no presentation on the reactivity effects of (radial) nonuniform enrichment within an assembly or the uncertainty which might be involved in the Holtec calculation of gadolinium reactivity and burnup or fuel burnup.
Discuss the effects of radial, nonuniform enrichment within the assembly on reactivity and the uncertainties involved in the calculation of gadolinium reactivity and burnup or fuel burnup.
Response No. 2 Page 4-12 of the June 24, 1988, licensing submittal addresses, in part, the uncertainties associated with burnup calculations in the presence of Gd 0 burnable poison.
These data show that there is a margin of at least 0 0$
2 deita-k available as an allowance for this uncertainty.
No discussion of the effects of nonuniform enrichment variations was included, although previous analyses of similar fuel have shown that distributed enrichments, if included, would result in a lower reactivity, thereby providing an additional margin of approximately 0.01 delta-k.
These considerations provide ar Jrance of an adequate and conservative margin (-0.02 delta-k) for uncertair les in burnup calculations.
In addition, a very large additional margin mcy reasonably be inferred from the fact that the required gadolinium concentrations and burnups used in the analysis are much lower than those normally usod in BWR fuel.
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.I U.S. Nuclear Regulatory Commission B13199/ Attachment 1/Page 2 April 10, 1989 NRC Ouestion No. 3 There is no discussion of the adequacy of procedures or use of Technical Specifications to assure that required minimum gadolinium loadings or fuel.
burnup would be used in the new racks.
Discuss what assurances are in place to ensure that_ the required minimum gadolinium loadings. or fuel burnup would be used in the new racks.
Resoonse No. 3 Technical Specification 5.5.B will be modified to include the gadolinium loading versus enrichment curve (Figure 4.1 of our. June 24, 1988, submittal) to. ensure' that the minimum gadolinium loadings are present for future ~ fuel types.
This license amendment request is expected to be submitted to the Staff by August 1, 1989.
NNECO has verified that the analysis submitted in our license amendment request bounds all fuel types currently in the Millstone Unit No. I spent fuel pool and the reactor. This includes the fuel that is currently being received for Cycle 13.
The K-eff of the spent fuel pool will be maintained less than or equal to 0.90.
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