ML080950468
| ML080950468 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 04/04/2008 |
| From: | Clemens R P Omaha Public Power District |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LIC-08-0040, TAC MD7043 | |
| Download: ML080950468 (5) | |
Text
Omaha Pu&/Ic PDwer Olstrlel I'H(, lO()/i Fort Calhoun Station P.O. Box 550 Fort Calhoun, NE 68023 April 4, U. S. Nuclear Regulatory Attn: Document Control Washington, DC
- 1. Docket No. 50-285 Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk), "Fort Calhoun Station, Unit NO.1 License Amendment Request (LAR) "Modification of Surveillance Requirements for Emergency Mode (Remotely Operated)
Dampers in Containment Air Cooling and Filtering System," dated October 19, 2007 (L1C-07-0092) Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk), "Revision to Technical Evaluation of Fort Calhoun Station, Unit NO.1 License Amendment Request (LAR) "Modification of Surveillance Requirements for Emergency Mode (Remotely Operated)
Dampers in Containment Air Cooling and Filtering System," dated December 12, 2007 (L1C-07-0104) (ML03461006) Email from NRC (M. T. Markley) to OPPD (T. C. Matthews), "Request for Additional Information," dated March 27,2008 (ML0808800092)
Fort Calhoun Station Response to Request for Additional Information License Amendment Request Re: Dampers in Containment Air Cooling (MD7043) The Omaha Public Power District's (OPPD) response to Questions 4 and 5 of Reference 4 is attached.
In a teleconference held on April 1, 2008, the NRC indicated that these two questions could be answered separately as they are related to approval of Reference 2 as supplemented by Reference
- 3. As discussed during the teleconference and noted in the response to Question 5, OPPD is making a regulatory commitment to revise the Basis of Technical Specification (TS) 3.6 in accordance with TS 5.20, "Technical Specification Basis Control Program," to clarify that that the emergency mode dampers are separate and distinct from the fusible link automatic dampers. The Basis change will be implemented along with the approved amendment, prior to startup from the 2008 refueling outage.
U.S. Nuclear Regulatory Commission L1C-08-0040 Page 2 Please note that following NRC approval of Reference 2 and installation of the associated modification, position indication of the emergency mode dampers will still be provided in the control room but will no longer serve a safety related purpose. Therefore, OPPD proposes to delete its Regulatory Guide 1.97 commitment to monitor the position of these dampers. If you should have any questions regarding this submittal or require additional information, please contact Mr. Thomas C. Matthews at (402) 533-6938.
Executed on R. R. Clemens Division Manager -Nuclear Engineering RPC/mie Fort Calhoun Station Response to Request for Additional Information License Amendment Request Re: Dampers in Containment Air Cooling (MD7043)
LIC-08-0040 Attachment Page 1 OMAHA PUBLIC POWER DISTRICT (OPPD) FORT CALHOUN STATION (FCS), UNIT NO.1 DOCKET NO. 50-285 FORT CALHOUN RESPONSE TO REQUEST FOR ADDITIONAL LICENSE AMENDMENT REQUEST DAMPERS IN CONTAINMENT AIR COOLING LI C-08-0040 Attachment Page 2 FORT CALHOUN RESPONSE TO REQUEST FOR ADDITIONAL LICENSE AMENDMENT REQUEST RE: DAMPERS IN CONTAINMENT AIR Are the containment air-cooling and filter system (CACFS) and the associated air filters safety-related?
Yes. The containment air cooling and filtering System (CACFS) is a related, Class 1 seismic system. As discussed in a teleconference held on April 1, 2008, the high efficiency particulate air (HEPA) filters were verified to be a critical quality element (CQE) component, which makes them related. A submittal (Reference
- 1) unrelated to References 2 and 3 erroneously stated that the HEPA filters are not CQE. Technical Specification 3.6(3)(a) indicates that the emergency mode dampers will be verified to be in their accident position and the fusible link damper operation will be checked for operability.
If the emergency mode dampers are being fixed in the accident configuration please discuss how the fusible link affects the damper position.
The fusible link dampers are a separate set of dampers from the emergency mode dampers. The fusible link dampers are located at the bottom of the plenum and direct the discharge downwards.
The fusible link dampers are held closed against gasketed flanges by chains with fusible links. On an increase in temperature, the fusible links part and counter balances open the dampers. Assuming the ductwork fails during the design basis accident, air discharged from the fans will be directed through the fusible link dampers, reinforcing the tendency of the cooled mixture to go to the bottom of the containment building.
Thus, there is no direct relationship between the fusible link dampers and the emergency mode dampers. Placing the emergency mode dampers into their accident position causes the CACFS to operate in filtered air mode only. The requirement to verify operability of fusible link automatic damper operation is historical and References 3 and 4 did not propose a change to that requirement.
The emergency mode dampers operate using a solenoid valve that supplies control air pressure to a piston operator.
The modification will permanently remove control air to the piston operators causing the valve springs to set the emergency mode dampers into their post-accident filtration position.
As noted on Page 13 of Attachment 1 of Reference 3, the limit switches will still notify control room operators, via the qualified safety parameter display system (QSPDS), and the emergency response facilities (ERF) plant computer if the dampers are not in their accident position.
L1C-08-0040 Attachment Page 3 Since the signal is still active, it was considered a good practice to maintain the surveillance requirement to verify the position of the emergency mode dampers each outage. Emergency mode damper position indication will still be provided in the control room. However, since the emergency mode dampers cannot change state, the display will be considered for information only. As emergency mode damper position indication will no longer serve a safety related purpose following the modification, OPPD proposes to delete a Regulatory Guide 1.97 commitment to monitor the position of these dampers. As discussed during a teleconference held on April 1, 2008, the Omaha Public Power District (OPPD) is committing to revise the Basis of Technical Specification (TS) 3.6 in accordance with TS 5.20, "Technical Specification Basis Control Program," to clarify that that the emergency mode dampers are separate from the fusible link automatic dampers. The Basis change will be implemented along with the approved amendment prior to startup from the 2008 refueling outage. References Letter from OPPD (S. K. Gambhir) to NRC (Document Control Desk), "Submittal of Revision 1 to Engineering Analysis Supporting Compensatory Measures Implemented as a Result of GSI-191 ," dated February 17, 2006 (L1C-06-0014) Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk), "Fort Calhoun Station, Unit NO.1 License Amendment Request (LAR) "Modification of Surveillance Requirements for Emergency Mode (Remotely Operated)
Dampers in Containment Air Cooling and Filtering System," dated October 19, 2007 07-0092) Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk), "Revision to Technical Evaluation of Fort Calhoun Station, Unit NO.1 License Amendment Request (LAR) "Modification of Surveillance Requirements for Emergency Mode (Remotely Operated)
Dampers in Containment Air Cooling and Filtering System," dated December 12,2007 (L1C-07-0104)) (ML03461006)