ML15293A440
| ML15293A440 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 10/20/2015 |
| From: | Jim Barstow Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC MF5687, TAC MF5688 | |
| Download: ML15293A440 (5) | |
Text
200 Exelon Way Exelon Generation Kennett Square PA 19348 www.exeloncorp.com 10 CFR 50.90 October 20, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353
Subject:
Response to Draft Request for Additional Information Regarding Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings
References:
- 1. Letter from James Barstow (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "License Amendment Request -
Proposed Changes to the Technical Specifications to Address Transient Secondary Containment Conditions," dated February 2, 2015
- 2. Letter from David Helker (Exelon Generation Company, LLC) to U.S.
Nuclear Regulatory Commission, "License Amendment Request -
Supplement, Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings,"
dated August 11, 2015
- 3. Electronic mail message from Richard Ennis, U.S. Nuclear Regulatory Commission, to Glenn Stewart, Exelon Generation Company, LLC, "Draft RAls - Limerick Units 1 and 2 - Transient Secondary Containment Conditions (TACs MF5687 & MF5688)," dated September 15, 2015 By letter dated February 2, 2015 (Reference 1 ), as supplemented by letter dated August 11, 2015 (Reference 2), Exelon Generation Company, LLC (Exelon) submitted a license amendment request (LAR) for Limerick Generating Station (LGS), Units 1 and 2. The proposed amendment would allow for brief, inadvertent, simultaneous opening of redundant secondary containment personnel access doors during normal entry and exit conditions.
The NRC staff reviewed the information provided that supports the proposed amendment and identified the need for additional information in order to complete their evaluation of the amendment request. The draft request for additional information (RAI) was sent from the NRC to Exelon by electronic mail message on September 15, 2015 (Reference 3).
Subsequent discussion with the NRC established October 23, 2015, as the due date for the response to the RAI. The response to the RAI is provided in the attachment to this letter.
U.S. Nuclear Regulatory Commission Response to Draft Request for Additional Information Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings Docket Nos. 50-352 and 50-353 October 20, 2015 Page 2 Exelon has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, that were previously provided to the NRC in Attachment 1 of the Reference 1 and Reference 2 letters. Exelon has concluded that the information provided in this response does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration under the standards set forth in 1 O CFR 50.92. In addition, Exelon has concluded that the information in this response does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.
There are no regulatory commitments in this letter.
In accordance with 1 O CFR 50.91, "Notice for public comment; State consultation,"
paragraph (b), Exelon is notifying the Commonwealth of Pennsylvania of this RAI response by transmitting a copy of this letter and its attachments to the designated State Official.
If you have any questions or require additional information, please contact Glenn Stewart at 610-765-5529.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 201h day of October 2015.
James Barstow Director, Licensing and Regulatory Affairs Exelon Generation Company, LLC
Attachment:
Response to Draft Request for Additional Information Regarding Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings cc:
Regional Administrator - NRC Region I w/ attachment NRC Senior Resident Inspector - Limerick Generating Station NRC Project Manager, NRR - Limerick Generating Station Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection
ATTACHMENT Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 Docket Nos. 50-352 and 50-353 Response to Draft Request for Additional Information Regarding Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings
Response to Draft Request for Additional Information Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings Docket Nos. 50-352 and 50-353 Attachment Page 1 of 2 By letter dated February 2, 2015 (Reference 1 ), as supplemented by letter dated August 11, 2015 (Reference 2), Exelon Generation Company, LLC (Exelon) submitted a license amendment request (LAA) for Limerick Generating Station (LGS), Units 1 and 2. The proposed amendment would allow for brief, inadvertent, simultaneous opening of redundant secondary containment personnel access doors during normal entry and exit conditions.
The NRC staff reviewed the information provided that supports the proposed amendment and determined that additional information was needed to complete their review. The following question was provided.
SCVB-RAl-6
Subject:
Proposed Changes to Surveillance Requirements 4.6.5.1.1.b.2 and 4.6.5.1.2.b.2 Provide assurance that adequate administrative controls will be exercised to control secondary containment personnel door openings, specifically, to address how the door openings will be controlled to be "brief" for even "inadvertent" simultaneous openings as described in the proposed changes to the Technical Specification 3/4 6.5 Bases. Furthermore, provide assurance that the functional capability of the secondary containment will still be maintained when the personnel doors are simultaneously opened. Note that the frequency and door opening time of both planned activity and inadvertent events involved with simultaneous door openings should be subject to control. Provide justification for such a control.
Response
The supplement letter, dated August 11, 2015 (Reference 2), stressed that the intent of the proposed change is to allow for brief, inadvertent, simultaneous opening of redundant secondary containment personnel access doors during normal entry and exit. The proposed change does not involve planned simultaneous opening of redundant secondary containment personnel access doors. For situations that involve planned simultaneous opening of the doors, secondary containment will be declared inoperable and the appropriate Technical Specification (TS) action will be followed.
For inadvertent, simultaneous opening of the doors, the administrative controls involve the fact that both doors are under continuous control of the individuals accessing the doors, and that the doors are promptly closed following entry and exit, restoring the secondary containment boundary. The phrase "being used for entry and exit" in the proposed change ensures that the time both doors may be open simultaneously is limited to the time it takes to traverse through a door, typically less than 1 O seconds, which is insignificant.
In addition, secondary containment personnel access doors are equipped with a monitoring system which consists of local indicating lights, a local audible alarm, and main control room annunciator lights and alarm. When one door is open, the indicating light above the opposing door that is still closed is lit to warn personnel against opening the door. When both doors are opened simultaneously, the indicating lights above both doors are lit and an instantaneous, local audible alarm is annunciated notifying the individuals controlling the doors that secondary containment has been breached and to immediately close the doors. Also, if the doors are opened for greater than 1 O seconds, an alarm is annunciated in the main control room to notify operators of the breach so that additional action can be taken to investigate the condition and restore the secondary containment boundary.
Response to Draft Request for Additional Information Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings Docket Nos. 50-352 and 50-353 Attachment Page 2 of 2 The TS surveillance requirements require verification that at least one door is closed in each secondary containment penetration. The intent of these requirements is to not breach secondary containment at any time when secondary containment is required. Therefore, secondary containment personnel access doors are normally kept closed, except when the access is being used for entry and exit. As noted previously, secondary containment personnel access doors are equipped with a monitoring system to assist station personnel in complying with these requirements. The frequency of inadvertent, simultaneous opening events is minimized, when the access is being used for entry and exit, through communication (e.g.,
Supervisory Briefs) to station personnel to not open a secondary containment personnel access door if the indicating light is illuminated.
The functional capability of the secondary containment is maintained when the personnel access doors are inadvertently, simultaneously open for a brief period of time due to the fact that the minimal time the doors are open is substantially bounded by the current design analyses for the secondary containment in conjunction with the operation of the Standby Gas Treatment System (SGTS). For a loss of coolant accident coincident with a loss of offsite power, the SGTS would not start until 18 seconds after the event. Eighteen seconds bounds the time, typically less than 10 seconds, that redundant secondary containment personnel access doors would be inadvertently, simultaneously open. As a result, there would not be any impact on the ability for the SGTS to draw down secondary containment to the TS required vacuum condition. The dose analysis assumes that secondary containment is not drawn to a vacuum condition for 930 seconds during which time no credit for differential pressure or filtering is taken. Surveillance testing has shown that the SGTS can draw down secondary containment well within 60 seconds. Therefore, the functional capability of the secondary containment is maintained when the personnel access doors are inadvertently, simultaneously open for a brief period of time.
References:
- 1. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "License Amendment Request - Proposed Changes to the Technical Specifications to Address Transient Secondary Containment Conditions," dated February 2, 2015.
- 2. Letter from David Helker (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "License Amendment Request - Supplement, Proposed Changes to the Technical Specifications to Address Secondary Containment Personnel Access Door Openings," dated August 11, 2015.