ML20198B842
| ML20198B842 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 12/11/1998 |
| From: | Geoffrey Edwards PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-22, NUDOCS 9812210165 | |
| Download: ML20198B842 (2) | |
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. PECO NUCLEAR n c e c - neev 9
Nuclear Group Headquarters A bNir or lYCO ENfRGY -
965 Chesterbrook Boulevard Wayne. PA 19087-5091 December 11,1998 7
Docket Nos. 50-352 50-353 l-License Nos. NPF-39 NPF-85 i
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U.S. Nuclear Regulatory Commission Attn: Document Control Desk l
' Washington, DC 20555 I
Subject:
Limerick Generating Station, Units 1 and 2 Response to Request for Additional Information y
Regarding Review of Individual Plant Examination i
of Extemal Events
Reference:
Telecon between NRC (B. Buckley, A. Rubin, A. Busiik) and PECO Energy Company, (D. Helker, V. Aggarwal, D. Fiorello, A. Ouaou, J. Phillabaum) on November 30,1998 1
Dear Sir:
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Your Request for Additional Information (RAI) which was transmitted by letter dated l
November 13,1998, requested us to inform you in writing by November 30,1998, on how we will address the' question regarding the effects of the new probable maximum precipitation (PMP) at Limerick Generating Station (LGS). As discussed in the reference telecon, it was i
agreed that the telecon and this follow-up letter would satisfy your request.
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i The telecon discussed the result of PECO's document review for the design basis PMP described in the LGS Updated Final Safety analysis Report (UFSAR) in Section 2.4. The i
review concluded that the maximum flood water surface elevation in the vicinity of the Diesel Generator Building is approximately 218 feet. The nominal ground elevation at the entrance to the building is 217 feet and slopes away from the structure. Therefore, PECO does not expect flooding of the Diesel Generator Building for the design basis PMP. It was noted that the LGS UFSAR was updated in Revision 8 dated 11/98 to reflect the increased width of flow i.
i outlets 3 and 4.
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9812210165 981211 I
i PDR ADOCK 05000352;'
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w December 11,1998 l
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l The telecon then discussed our approach to responding to the question regarding the effects of the revised PMP based on Generic Letter (GL) 89-22, " Potential for increased Roof Loads and Plant Area Flood Runoff Depth at Licensed Nuclear Power Plants due to Recent Change l
in Probable Maximum Precipitation Criteria Developed by the National Weather Service."
PECO Energy proposes to perform a sensitivity analysis to assess the impact of the revised PMP on safety related systems and structures. The analysis will calculate runoff based on l
rainfall intensity values provided in GL 89-22 and determine water surface elevation at the l
critical collection points. Water ingress into the buildings will be evaluated using more l
realistic assumptions, such as increased site flow outlet widths, availability of additional outlets which resulted from removal of construction buildings, and physical changes to the plant entrance doors and openings.
The sensitivity analysis will not recalculate flow elevations versus time as in the original PMP analysis. The results of the sensitivity analysis will be reported in accordance with the schedule for responding to the RAl.
The NRC agreed that using realistic assumptions and actual site conditions to analyze the effect of revised PMP based on GL 89-22 was a reasonable approach.
If you have any questions or require any additional information, please contact us.
l Sincerely,
$ NSlFosz Garrett D. Edwards l
Director, '.icensing l
cc:
H. J. Miller, Administrator, Region 1, USNRC A. L. Burritt, USNRC, Senior Resident inspector, LGS i
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