ML16032A411
| ML16032A411 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 02/04/2016 |
| From: | Ellen Brown Plant Licensing Branch III |
| To: | |
| Brown E | |
| References | |
| CAC MF7050 | |
| Download: ML16032A411 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 4, 2016 LICENSEE: Exelon Generation Company, LLC FACILITY: Clinton Power Station, Unit 1
SUBJECT:
SUMMARY
OF DECEMBER 9, 2015 MEETING WITH EXELON GENERATION COMPANY, LLC, TO DISCUSS PROPOSED SUBMITTAL REALTED TO SECONDARY CONTAINMENT AIRLOCK EXTENSION (CAC NO. MF7050)
On December 9, 2015, the U.S. Nuclear Regulatory Commission (NRG) staff conducted a Category 1 public teleconference with Exelon Generation Company, LLC (Exelon, the licensee) at NRG Headquarters, 11555 Rockville Pike, One White Flint North, Rockville, Maryland. The purpose of the teleconference was to discuss Exelon's proposal to submit a license amendment request supporting the extension of the secondary containment gas boundary to encompass the fuel building railroad airlock at the Clinton Power Station (CPS). The NRG staff notes that this change will also require a revision to the calculated alternative source term to address the additional heat load due to loaded cask, as well as a larger secondary containment volume.
These changes will likely impact the post-loss of coolant accident (post-LOCA) short-term pressure response in secondary containment. Enclosure 1 contains a list of attendees. The licensee presentation is available in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML15342A354.
BACKGROUND:
On December 14, 2014, the licensee changed the facility as described in the updated safety analysis report (USAR) by eliminating the tornado wind and missile loading conditions from the fuel building railroad airlock enclosure walls, roof and associated outer door Seismic Category I design requirements. During inspection activities, the NRG staff identified that licensee personnel failed to obtain a license amendment prior to implementing a proposed change to the plant that resulted in a more than minimal increase in the likelihood of occurrence of a malfunction of a structure, system or component important to safety previously evaluated in the USAR. As a result, on November 6, 2015, the NRG issued a non-cited violation for CPS (ADAMS Accession No. ML15313A464).
Under the existing licensing basis, the licensee must enter the applicable secondary containment technical specification (TS) ACTION statement, when opening the inner railroad airlock door to move the fuel transfer cask in and out of the fuel building. The applicable TS limits opening the airlock dock to a maximum of four hours.
DISCUSSION:
The licensee described the layout of the secondary gas boundary and the proposed extension area. The licensee's intent is to extend secondary containment to the outer airlock door so as to not have to declare secondary containment inoperable when opening the inner airlock to transfer the fuel transfer cask from the airlock into the Fuel Building. It should be noted that as discussed in the NRC staff's inspection report discussed previously, the existing secondary containment boundary is tornado-missile protected; however, the railroad airlock is not. The NRC staff questioned whether the change in dose limits was due to a change in methodology.
The licensee indicated that the existing methodology approved as part of the alternative source term methodology amendment requested (ADAMS Accession No. ML052570461) would be used. Given that the proposed submittal will alter the post-LOCA doses, the NRC staff requested that the licensee include in their application a table of all analysis inputs both pre- and post-LOCA as well as a full description of the drawdown time associated with the fuel handling accident as well as other analyses that will be affected by this change.
The licensee was requested to discuss the various physical modifications to the facilities and any related testing that will be or will need to be conducted. It was noted by the NRC staff that associated testing would need to be reflected in the design bases including the USAR, and the TS BASES. The NRC staff questioned the effect of the volume change on the internal credited design pressure for the railroad airlock with the airlock doors open and closed. This questioning included the affect the extension volume may have on identified high energy line break scenarios, the functioning of building blow out panels, and the environmental qualification of systems, structures, or components important to safety.
Although no TS limiting conditions for operation were identified as needing revision, the NRC staff requested the licensee review whether associated secondary containment TS surveillance requirements will need modification to address applicability to the airlock doors or additions of other testing to assess airlock door operability in accordance with Section 50.36 to Title 1O to the Code of Federal Regulations.
No members of the public were in attendance, and no feedback forms were received. No commitments or regulatory decisions were made by the NRC staff during the meeting.
Sincerely, IRA/
Eva A. Brown, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-461
Enclosure:
List of Attendees cc w/encl: Distribution via Listserv
Attendees Nuclear Regulatory Commission Public Meeting with Exelon Concerning Secondary Containment Extension December 9, 2015 U. S. NUCLEAR REGULATORY COMMISSION Robert Pettis Jerome Bettle Khadijah West Kristy Bucholtz Elba Sanchez-Santiago Eva Brown EXELON GENERATION COMPANY LLC John Schrage Daniel Tapperson Mitch Mathews Nigel Keen Mark Vandermyde Mukesh Gandhi Kenneth Pointer Dale Shelton Mike Heger Duane Avery Roger Weber Brooke Hodel Shane Gardner SARGENT & LUNDY Paul Kish Enclosure
ML16032A411 OFFICE NRR/DORL/LPLI 11-2/PM NRR/DORL/LPLI 11-2/LA NRR/DORL/LPLI 11-2/BC(A)
NAME EBrown (SFigueroa for) SRohrer JPoole DATE 2/02/2016 2/02/2016 2/04/2016