ML110670424
| ML110670424 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 02/25/2011 |
| From: | Lynch T Constellation Energy Group, EDF Group, Nine Mile Point |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC ME3736 | |
| Download: ML110670424 (6) | |
Text
Thomas A. Lynch P.O. Box 63 Plant General Manager Lycoming, New York 13093 315.349.5205 315.349.1321 Fax CENGSM a joint venture of Constellation
- EneM, g.yf NINE MILE POINT NUCLEAR STATION February 25, 2011 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
Document Control Desk
SUBJECT:
Nine Mile Point Nuclear Station Unit No. 2; Docket No. 50-410 License Amendment Request Pursuant to 10 CFR 50.90: Extension of the Completion Time for an Inoperable Diesel Generator - Supplemental Information Responding to NRC Follow-up Probabilistic Risk Assessment Review Questions (TAC No. ME3736)
REFERENCES:
(a) Letter from S. Belcher (NMPNS) to Document Control Desk (NRC), dated March 30, 2010, License Amendment Request Pursuant to 10 CFR 50.90:
Extension of the Completion Time for an Inoperable Diesel Generator -
Technical Specification 3.8.1, AC Sources - Operating (b) Letter from T. A. Lynch (NMPNS) to Document Control Desk (NRC), dated June 1, 2010, License Amendment Request Pursuant to 10 CFR 50.90: Extension of the Completion Time for an Inoperable Diesel Generator - Response to NRC Acceptance Review Comments (TAC No. ME3736)
(c) Letter from S. Belcher (NMPNS) to Document Control Desk (NRC), dated January 14, 2011, License Amendment Request Pursuant to 10 CFR 50.90:
Extension of the Completion Time for an Inoperable Diesel Generator -
Response to NRC Request for Additional Information (TAC No. ME3736)
Nine Mile Point Nuclear Station, LLC (NMPNS) hereby transmits supplemental information requested by the NRC in support of a previously submitted request for amendment to Nine Mile Point Unit 2 (NMP2)
Renewed Operating License NPF-69. The initial request, dated March 30, 2010 (Reference a), as supplemented by Reference (b), proposed to modify Technical Specification (TS) 3.8.1, "AC Sources -
Operating," to extend the Completion Time for an inoperable Division 1 or Division 2 diesel generator d4\\ooI
Document Control Desk February 25, 2011 Page 2 (DG) from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days. NMPNS responded to a request for additional information relating to the NRC staff's probabilistic risk assessment (PRA) review in Reference (c). The supplemental information, provided in the Attachment to this letter, responds to follow-up PRA-related NRC questions that were discussed in a telephone conference between NRC and NMPNS staff members and subsequently provided in an e-mail from the NRC to NMPNS on February 8, 2011.
This supplemental information does not affect the No Significant Hazards Determination analysis provided by NMPNS in Reference (a). Pursuant to 10 CFR 50.91 (b)(1), NMPNS has provided a copy of this supplemental information to the appropriate state representative. This letter contains no new regulatory commitments.
Should you have any questions regarding the information in this submittal, please contact John J. Dosa, Director Licensing, at (315) 349-5219.
Very truly yours, STATE OF NEW YORK TO WIT:
COUNTY OF OSWEGO I, Thomas A. Lynch, being duly sworn, state that I am the Nine Mile Point Plant General Manager, and that I am duly authorized to execute and file this supplemental information on behalf of Nine Mile Point Nuclear Station, LLC.
To the best of my knowledge and belief, the statements contained in this document are true and correct.
To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other Nine Mile Point employees and/or consultants, Such information has been reviewed in accordance with company practice and I believe it to be reliable.
Subscribed and sworn before me, a Notary Public in and for the State of New York and County of this
- day of
, 2011.
WITNESS my Hand and Notarial Seal:
My Commission Expires:
TONYA LJONES Ila 4r in the State of NewY0
/ Iate Oswego County Reg. No. 01J.Q603354, My ComTLisEon Expies TAL/DEV7
4 Document Control Desk February 25, 2011 Page 3
Attachment:
Nine Mile Point Unit 2 - Supplemental Information Regarding the Proposed Extension of the Completion Time for an Inoperable Diesel Generator from 72 Hours to 14 Days cc:
Regional Administrator, Region I, NRC Project Manager, NRC Resident Inspector, NRC A. L. Peterson, NYSERDA
ATTACHMENT NINE MILE POINT UNIT 2 SUPPLEMENTAL INFORMATION REGARDING THE PROPOSED EXTENSION OF THE COMPLETION TIME FOR AN INOPERABLE DIESEL GENERATOR FROM 72 HOURS TO 14 DAYS Nine Mile Point Nuclear Station, LLC February 25, 2011
.1 ATTACHMENT NINE MILE POINT UNIT 2 SUPPLEMENTAL INFORMATION REGARDING THE PROPOSED EXTENSION OF THE COMPLETION TIME FOR AN INOPERABLE DIESEL GENERATOR FROM 72 HOURS TO 14 DAYS By letter dated March 30, 2010, as supplemented by letter dated June 1, 2010, Nine Mile Point Nuclear Station, LLC (NMPNS) requested an amendment to the Nine Mile Point Unit 2 (NMP2) Renewed Facility Operating License NPF-69. The proposed amendment would modify Technical Specification (TS) 3.8.1, "AC Sources - Operating," to extend the Completion Time for an inoperable Division 1 or Division 2 diesel generator (DG) from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days.
NMPNS responded to a request for additional information (RAI) relating to the NRC staff's probabilistic risk assessment (PRA) review by letter dated January 14, 2011. This attachment responds to follow-up PRA-related NRC questions that were discussed in a telephone conference between NRC and NMPNS staff members and subsequently provided in an e-mail from the NRC to NMPNS on February 8, 2011.
Each individual NRC follow-up question is repeated (in italics), followed by the NMPNS response.
Supplemental RAI-8t In RAI 8f, the licensee stated that there were no fire protection separation requirements deficiencies in the plant. However, PRA peer review finding 3-6 (Table 1 of the March 30, 2010 submittal) identifies a door between Division 1 and Division 2 switchgear which is currently blocked open, and there is a design change (not yet implemented) to put an automatic latch to close the door on a fire alarm. The licensee is requested to provide a discussion on the current plant design of this doorway and assess the impact on the fire PRA results (or why there is minimal/zero impact).
Response
There are no doors either between or into the Division 1 and Division 2 standby switchgear rooms that are blocked open. The doors currently held open by a door stop are fire door C261-23 for entry into the Control Building stairwell at elevation 261' and door C261-25 within the stairwell leading to the lower elevation stairs (see Figure 12c-1 of the January 14, 2011 NMPNS submittal). The specific issue addressed by these doors is mitigation of flooding resulting from a major break of one of the water-filled pipes in the Control Building corridor at elevation 261'. These breaks are postulated to result in flooding in the corridor, leading to water entering the Division 1 and Division 2 standby switchgear rooms and resulting in both divisions of emergency AC and DC power being disabled concurrently. Blocking open the two identified doors diverts water to a lower elevation where the impact is non-consequential from a PRA perspective.
Breach permits authorizing the blocking open of doors C261-23 and C261-25 have been issued in accordance with plant procedures. An approved modification will replace the door stops for both doors with a new door hinge design. The new hinge will normally keep these doors open but will allow the doors to close if smoke is detected.
The doors that are blocked open do not affect the Fire PRA assumptions that have been utilized in the risk assessment for the proposed DG Completion Time (CT) extension. These doors are not part of a 3-hour rated fire barrier that is credited in the fire safe shutdown analysis.
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ATTACHMENT NINE MILE POINT UNIT 2 SUPPLEMENTAL INFORMATION REGARDING THE PROPOSED EXTENSION OF THE COMPLETION TIME FOR AN INOPERABLE DIESEL GENERATOR FROM 72 HOURS TO 14 DAYS Supplemental RAI-9c The response indicates that for fire scenarios, recovery of the DGs unaffected by fire is credited. For non-fire scenarios, it is stated that recovery of the out-of-service DG is not credited. It is not clear to the NRC staff if the out-of-service DG (i.e., the DG which is out for a 14-day extended outage) is assumed recoverable for a fire scenario, which would not be appropriate for the risk calculations for this LAR.
The licensee is requested to clarify its response to this RAI.
Response
For both fire and non-fire events, the PRA does not credit recovery of the DG that has entered the extended CT. In addition, recovery is not credited for a DG that is affected by a fire event.
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