ML101930236

Response to Draft Request for Additional Information - License Amendment Request to Allow Changes to Secondary Containment Boundary During Shutdown Conditions

ML101930236
Person / Time
Site:	Oyster Creek
Issue date:	07/09/2010
From:	Cowan P B Exelon Corp, Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-10-059
Download: ML101930236 (6)

Text

Exelon Nuclear 200 Exelon Way Kennett Square, PA 19348 RA-10-059 July 9,2010 wwwexeloncorp.com Exelon.Nuclear 10 CFR 50.90 U.S.Nuclear Regulatory Commission A TIN: Document Control Desk Washington, DC 20555-0001 Oyster Creek Nuclear Generating Station Renewed Facility Operating License No.DPR-16 Docket No.50-219

Subject:

Response to Draft Request for Additional Information

-License Amendment Request to Allow Changes to Secondary Containment Boundary During Shutdown Conditions

References:

1)Letter from Pamela B.Cowan to U.S.Nuclear Regulatory Commission License Amendment Request-Changes to Trunnion Room Secondary Containment Boundary,datedFebruary 25, 2010 2)U.S.Nuclear Regulatory Commission facsimile dated June 18,2010, Oyster Creek Nuclear Generating Station-Electronic Transmission, Draft Request for Additional Information Regarding License Amendment Request to Allow Temporary Changes to Secondary Containment Boundary During Shutdown Conditions (TAC No.ME3475)By letter dated February 25, 2010 (Reference 1), Exelon Generation Company, LLC (Exelon)submitted a request to revise the Oyster Creek Nuclear Generating Station (OCNGS)Technical Specifications (TS)to allow the Reactor Building Secondary Containment associated with the Trunnion Room boundary to be relocated on a temporary basis during Cold Shutdown conditions to support refueling and maintenance outage related activities.

Subsequently, on June 18,2010, the U,S.Nuclear Regulatory Commission (NRC)issued a draft Request for Additional Information (RAI)via facsimile (Reference 2).The NRC identified three questions in the draft RAI in which additional information was requestedregardingthe design of penetration seals and the proposed ventilation system testing in the temporary configuration.

The attachment to this letter restates the NRC's questions followed by Exelon's response.Exelon has concluded that the information provided in this response does not impact the conclusions of the: 1)Technical Analysis, 2)No Significant Hazards Consideration under the standards set forth in 10 CFR 50.92(c), or 3)Environmental Consideration as provided in the original submittal (Reference 1).

U.S.Nuclear Regulatory Commission License Amendment Request Trunnion Room Secondary Containment Boundary Response to NRC RAJ Docket No.50-219 July 9,2010 Page 2 There are no regulatory commitments contained in this submittal.

Should you have any questions concerning this letter, please contact Mr.Richard Gropp at (610)765-5557.Ideclareunder penalty of perjury that the foregoing is true and correct.Executed on the 9th day of July 2010.Respectfully, Pamela B.Cowan Director, Licensing and Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Response to NRC Draft Request for Additional Information cc: Regional Administrator

-NRC Region I NRC Senior Resident Inspector-OCNGS NRC Project Manager, NRR-OCNGS Director, Bureau of Nuclear Engineering, New Jersey Department of Environmental Protection ATTACHMENT Oyster Creek Nuclear Generating Station License Amendment Request Response to NRC Draft Request for Additional Information Changes to Trunnion Room Secondary Containment Boundary During Shutdown Conditions Attachment License Amendment Request Trunnion Room Secondary Containment Boundary Response to Draft RAJ Page 1 of 3 Background By letter dated February 25, 2010 (Reference 1), Exelon Generation Company, LLC (Exelon)submitted a request to revise the Oyster Creek Nuclear Generating Station (OCNGS)Technical Specifications (TS)to allow the Reactor Building Secondary Containment boundary associated with the Trunnion Room to be relocated from the Trunnion Room outer wall and door, to the Reactor Building inner walls and penetrations located inside the Trunnion Room.The proposed changes would be instituted on a temporary basis during Cold Shutdown conditions in order to support refueling and maintenance outage related activities.

By facsimile on June 18, 2010 (Reference 2), the U.S.Nuclear Regulatory Commission (NRC)transmitted draft Request for Additional Information (RAJ)questions related to this proposed TS change.The NRC identifiedthreequestions in the draft RAJ in which additional information was requested regarding the design of penetration seals and the proposed ventilation system testing in the temporary configuration.

Each of the NRC's questions are identified below followed by Exefon's response.NRC Question 1 The license amendment request (LAR)states that"engineered designed closure mechanisms" will be used to ensure that penetrations are closed and secured.Provide a description of the closure mechanisms to be used including their construction materials and the method for attachment to the penetrations.

Response A review of the applicable plant drawings confirms the existence of four known penetrations inside the Trunnion Room.These penetrations include: 1)a floor/deck drain, 2)a piping penetration/hub drain, 3)a ventilation return duct;and 4)a floor ventilation supply opening.The identified Heating, Ventilation and Air Conditioning (HVAC)penetrations (i.e., ventilation return duct and floor ventilation supply opening)will be sealed and secured using a formed sheet metal cover (comparable gauge), screws, and suitable sealant compound.These temporary alterations to the identified HVAC penetrations will be designed in accordance with applicable guidance specified in the American Society of Heating, Refrigerating, andConditioning Engineers (ASH RAE)handbook.The identified floor/deck drain will be isolated by using a mechanical plug containing a rubber gasket that is rated to withstand the Reactor Building differential pressure conditions that could be encountered.

The identified piping penetration/hub drain will be isolated by using a customized rubber cover/boot cut-to-fit due to the multiple pipes routed in this floor penetration.

The cover will be attached to the piping in this penetration using mechanical hose c1amp(s).The rubber material and clamps used will have the proper mechanical properties to withstand the Reactor Building differential pressure conditions that could be encountered.

Attachment License Amendment Request Trunnion Room Secondary Containment Boundary Response to Draft RAI Page 2 of 3 The materials used in the above applications will be procured and dedicated as"augmented quality," which will require receipt inspection in accordance with OCNGS's quality assurance procurement process.It should be noted that the methods discussed above for sealing and securing the identified penetrations in the Trunnion Room might be modified or substituted if a better closure technique is developed.

In addition, if other penetrations are sUbsequently identified in the Trunnion Room that require sealing they will be appropriately evaluated, isolated, and secured in a manner similar to the criteria discussed above based on the configuration and material composition of the penetration.

NRC Question 2 The wording for proposed Technical Specification (TS)4.5.G.3 indicates that following movement of the Secondary Containment boundary to the inner walls of the Trunnion room Standby Gas Treatment System testing shall be performed.

It is unclear what testing is required by this Specification.

Clarify what testing is to be performed and how the proposed TS, as worded, adequately defines this testing.Response The Secondary Containment capability periodic test (Le., TS Surveillance Requirement 4.5.G.2)will be performed on the normal Reactor Building pressure boundary prior to installation of the temporary modification.

Following achieving Cold Shutdown, the proposed temporary modification to the Trunnion Room Secondary Containment boundary will be installed.

Post maintenance testing for the installation will be the operation of the Standby Gas Treatment System (SGTS)to assure that a negative pressure (i.e., greater than or equal to 0.25" of water vacuum)can be established in the Reactor Building with the modified boundary configuration for the Trunnion Room.For the entire duration that the temporary modification is in place, daily observations will be performed to ensure that the penetrations are sealed and secure and the modified boundary remains intact.Periodic testing will be accomplished by performance of normally scheduled SGTS operability testing which verifies that a minimum of 0.25" water vacuum can be established.

Therefore, performing initial and periodic SGTS operability testing following installation of the temporary modification, will ensure that Secondary Containment integrity is maintained in accordance with applicable Limiting Condition for Operation (LCO)requirements specified in TS 3.5.G,"Secondary Containment." NRC Question 3 The proposed change to TS 4.5.G doesnotappear to ensure that the periodic capability test includes the normal reactor bUilding pressure boundary with regards to the Trunnion room.The current requirements of Section 4.5.G would appear to allow the cold shutdown, prior to refueling, capability test to be counted as the periodic, at least once per operating cycle, test if performed under calm wind conditions.

Would the proposed change aI/ow the cold shutdown, prior to refueling, test with the altered reactor building ventilation boundary to be used to satisfy the periodic test requirement?

Attachment License Amendment Request Trunnion Room Secondary Containment Boundary Response to Draft RAJ Page 3 of 3 Response No.The proposed changes to temporarily modify the Secondary Containment boundary for the Trunnion Room will not affect the requirements of TS Section 4.5.G.The Secondary Containment capability periodic test (Le., TS Surveillance Requirement 4.5.G.2)will continue to be performed on the normal Reactor Building pressure boundary.As discussed in response to Question 2 above, once the temporary modifications are made to the Trunnion Room Secondary Containment boundary, initial and periodic SGTS operability tests will be conducted to ensure that the Reactor Building can be maintained at a minimum of 0.25" water vacuum.A post-modification visual inspection will be performed to confirm that the temporary covers installed on the penetrations/openings have been appropriately removed and that the Trunnion Room Secondary Containment boundary has been returned to the normal configuration (Le., outer walls and door).References 1.Letter from Pamela B.Cowan to U.S.Nuclear Regulatory Commission License Amendment Request-Oyster Creek Nuclear Generating Station Changes to Trunnion Room Secondary Containment Boundary, dated February 25, 2010 2.U.S.Nuclear Regulatory Commission facsimile dated June 18, 2010, Oyster Creek Nuclear Generating Station-Electronic Transmission, Draft Request for Additional Information Regarding License Amendment Request to Allow Temporary Changes to Secondary Containment Boundary During Shutdown Conditions (TAC No.ME3475)