ML20198S355
| ML20198S355 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/07/1997 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-004, GL-97-4, IEB-96-003, IEB-96-3, NUDOCS 9711140029 | |
| Download: ML20198S355 (3) | |
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V 11 e PECO NUCLEAR nco ee.c 965 Ctestertxtd Boulevard
- A Unit of PECO Energy wayne sw was73egi November 7,1997 i
Docket Nos. 50-277 50-278
's l.icense Nos. DPR-44 7
DPR-56 U.S. Nuclear. Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Subject:
Peach Bottom Atomic Power Station, Units 2 and 3 Schedule Clarification Conceming Resolution Approval of Unreviewed Safety Question Associated With Installing Emergency Core Cooling System Pump Suction Strainers -
Dear NRC Officials:
By letter dated May 5,1997. PECO Energy submitted a request for license amendments to Facility Operating License Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station (PBADS), Units 2 and 3, respectively. PECO Energy submitted this request, in accordance with the requirements of 10CFR50.59(c) and 10CFR50.90, in order to facilitate implementation of a plant modification at PBAPS to install new replacement Emergency Core Cooling System (ECCS) pump suction strainers. This plant modification is being instituted in response to NRC Bulletin (NRCB) 96-03,
- Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors? In support of this plant modification, PECO Energy performed a 10CFR50.59 Review which concluded that certain design aspects of the modification constituted an Unreviewed Safety Question (USO), and therefore, a license amendment is required as i stipulated in 10CFR50.59(c).
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As a result of subsequent correspondence and discussions with the NRC regarding these license amendment requests, several issues have been identified in which the NRC indicated that f
additional information is necessary in order to achieve resolution of NRCB 96-03 related issues.
Specifically, the NRC requested additional information conceming the amount of containment overpressure credited in the PBAPS, Units 2 and 3, current design basis in evaluating Net Positive Suction Head (NPSH) requirements for the ECCS pumps. The NRC also requested dgpl Information regarding the minimum containment pressure that would be available under post-LOCA conditions in order to justify the need for containment overpressure in meeting ECCS pump NPSH requirements.
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November 7,1997 Dock:t Nos.60-277 Page 2 50-278 By letier dated September 26,1997, PECO Energy requested that the schedule for completing -
the final resolution of NRCD 96-03 for PBAPS, Units 2 and 3, be extended until December 31, 1998, to allow PECO Energy sufficient time to address and respond to the concems identified by the NRC regarding the ECCS pump NPSH issues, and therefore, achieve a satisfactory long-term resolution for NRCB 96-03. In addition, we also provided clarification regarding the scope of the USO indicating that it specificolly involved the design assumptions used in determining the amount of debris that would be generated under Loss of Coolant Accident (LOCA) conditions and the amount of material that would be transported to the suppression pool (i.e., torus). These design assumptions are considered very conservative (i.e.,100% transport of material was assumed). In our September 26,1997, letter we also requested that the NRC approve the pending license amendments to support installation and startup from the October 1997 refueling outage (3R11) for PBAPS, Unit 3.
By letter dated October 21,1997, the NRC granted our request to defer final resolution of NRCB 96-03 until December 31,1998. Since the USQ is linked with the closure of NRCB 96-03, NRC approval of the USO and issuance of the license amendments is not necessary prior to Unit 3 startup as earlier requested in our September 26,1S97, letter. PECO Energy recognizes the NRC's concerns regarding the need to perform a minimum containment pressure ana!ysis for crediting the use of containment overpressure. As we continue to further evaluate the rwed to credit containment overpressure for ensuring adequate NPSH in working to achieve satisfactory resolution of NRCB 96-03, it may be necessary to re-evaluate the design assumptions originally used to determine LOCA debris generation and its transport to the torus.
Therefore, PECO Energy is requesting that the NRC delay its resolution and approval of the USO and issuance of the corresponding license amendments until we have fully evaluated the issues associated with performing the minimum containment pressure analysis and crediting containment overpressure to satisfy ECCS pump NPSH requirements. We will submit supplemental information to support final resolution of the USQ in a timely manner such that the NRC will have sufficient time to complete its review to support closure of NRCB 96-03 for PBAPS, Units 2 and 3.
This request is further supported by the recent issuance of Generic Letter (GL) 97-04, " Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps," on October 7,1997, which is currently under evaluation. Being able to analyze these issues collectively will afford PECO Energy the opportunity to better evaluate the ECCS pump NPSH concerns and to achieve a more satisfactory resolution of NRCB 96-03 and GL 97-
- 04. This letter is being submitted under affirmation and the required affidavit is enciosod.
If you have any questions or require additional information, please do not hesitate to conatet us.
Very truly yours, 97 Wwyl/n G. A. Hunger, Jr.
Director Licensing Enclosure cc:
H. J. Miller, Administrator, Region I, USNRC (w/ enclosure)
R. S. Barkley, USNRC Senior Resident inspector, PBAPS (w/ enclosure)
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COMMONWEALTH OF PENNSYLVANIA ss.
COUNTY OF C; sic J. B. Cotton, being first duly swom, deposes and says:
Yhat he is Vice President of PECO Energy Company, the Applicant herein; that he has read the foregoing information conceming the license amendment requests for Peach Bottom Abmic Power Station, Units 2 and 3, Facility Operating Licanse Nos, DPR 44 and DPR 56, regarding the resolution of the.
- unreviewed safety question associated with the debris generation and transport methodology used in support of the Emergency Core Cooling System suction strainer modification, and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information, and belief,
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Vice President --
Subscribed and swom to before me this day of
- 1997, jI?otary Public n..am Cg*,8*
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