RS-10-211, Supplemental Response to Generic Letter 2008-01
| ML103490536 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/15/2010 |
| From: | Hansen J Exelon Generation Co, Exelon Nuclear |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| GL-08-001, RS-10-211 | |
| Download: ML103490536 (2) | |
Text
Exelon.
Cxelon Cene!atlon 4300 '/.J1l1f101d koad Nuclear Warrcnv:lle, IL 6oS55 RS-10-211 December 15, 2010 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278
Subject:
Supplemental Response to Generic Letter 2008-01
References:
- 1. NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems, n dated January 11, 2008
- 2. Letter from K. R. Jury (Exelon Generation Company, LLC/AmerGen Energy Company, LLC) to U.S. NRC, "Three Month Response to Generic Letter 2008-01, dated April 11, 2008 II
- 3. Letter from K. R. Jury (Exelon Generation Company, LLC/AmerGen Energy Company, LLC) to U.S. NRC, "Nine-Month Response to Generic Letter 2008-01," dated October 14, 2008
- 4. Letter from P. R. Simpson (Exelon Generation Company, LLC) to U.S. NRC, "Supplemental Response to Generic Letter 2008-01," dated January 16, 2009
- 5. Letter from P. R. Simpson (Exelon Generation Company, LLC) to U.S. NRC, "Response to Request for Additional Information Regarding Generic Letter 2008-01 ,. dated November 10, 2009
- 6. Letter from P. R. Simpson (Exelon Generation Company, LLC) to U.S. NRC, "Supplemental Response to Generic Letter 2008-01," dated January 4, 2010 The NRC issued Generic Letter (GL) 2008-01 (Le., Reference 1) to request that each licensee evaluate the licensing basis, design, testing, and corrective action programs for the Emergency Core Cooling, Decay Heat Removal, and Containment Spray systems, to ensure that gas
December 15, 2010 U.S. Nuclear Regulatory Commission Page 2 accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified.
References 2, 3, 4, 5, and 6 provided the responses to NRC GL 2008-01 for Peach Bottom Atomic Power Station (PBAPS). During a recent NRC inspection at PBAPS, it became apparent that further clarification was required since EGC's previous GL 2008-01 responses did not clearly describe the Core Spray (CS) and Residual Heat Removal (RHR) systems.
Reference 3 describes procedures used at PBAPS to fill and vent the CS and RHR systems.
After the systems are filled and vented, the systems are maintained pressurized by a stay full system. The stay full system provides substantial automatic control, including an alarm that is annunciated in the main control room, to ensure that the CS and RHR systems remain sufficiently full in their standby condition such that the systems can perform their specified safety functions.
These automatic controls include a high point vent accumulator with level switches to vent and alarm in conjunction with a continuous positive pressure applied by the Condensate Transfer system at the system low point (Le., pump discharge check valve). The accumulator provides continuous monitoring to collect and disposition accumulated gas. Level switch set points actuate to operate a solenoid to vent the gas and enable stay full flow to restore the process fluid volume to its acceptable level. In the event of excessive gas introduction or a CS/RHR system leak that is in excess of the stay full system capacity, an alarm is annunciated in the main control room prompting additional action. Alarm response procedures direct appropriate investigation including ensuring the piping is maintained full of water.
EGC's discussion in References 3 and 5 could be interpreted that routine manual venting of the systems were performed during each 31-day surveillance interval. The associated monthly surveillance tests that verify the piping is filled with water allows for different options to satiSfy the surveillance requirement. One option is to verify that the associated annunciator for the applicable system high point vent accumulator is not in an alarm condition. The absence of the alarm provides positive indication that the system is suffiCiently full. If for some reason the accumulator is isolated, the surveillance includes applicable instructions to perform manual venting to confirm the system is sufficiently full.
There are no regulatory commitments contained in this letter. Should you have any questions concerning this letter, please contact Mr. Kenneth M. Nicely at (630) 657-2803.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 15th day of December 2010.
cc: NRC Regional Administrator - Region I Senior Resident Inspector - Peach Bottom Atomic Power Station
Text
Exelon.
Cxelon Cene!atlon 4300 '/.J1l1f101d koad Nuclear Warrcnv:lle, IL 6oS55 RS-10-211 December 15, 2010 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278
Subject:
Supplemental Response to Generic Letter 2008-01
References:
- 1. NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems, n dated January 11, 2008
- 2. Letter from K. R. Jury (Exelon Generation Company, LLC/AmerGen Energy Company, LLC) to U.S. NRC, "Three Month Response to Generic Letter 2008-01, dated April 11, 2008 II
- 3. Letter from K. R. Jury (Exelon Generation Company, LLC/AmerGen Energy Company, LLC) to U.S. NRC, "Nine-Month Response to Generic Letter 2008-01," dated October 14, 2008
- 4. Letter from P. R. Simpson (Exelon Generation Company, LLC) to U.S. NRC, "Supplemental Response to Generic Letter 2008-01," dated January 16, 2009
- 5. Letter from P. R. Simpson (Exelon Generation Company, LLC) to U.S. NRC, "Response to Request for Additional Information Regarding Generic Letter 2008-01 ,. dated November 10, 2009
- 6. Letter from P. R. Simpson (Exelon Generation Company, LLC) to U.S. NRC, "Supplemental Response to Generic Letter 2008-01," dated January 4, 2010 The NRC issued Generic Letter (GL) 2008-01 (Le., Reference 1) to request that each licensee evaluate the licensing basis, design, testing, and corrective action programs for the Emergency Core Cooling, Decay Heat Removal, and Containment Spray systems, to ensure that gas
December 15, 2010 U.S. Nuclear Regulatory Commission Page 2 accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified.
References 2, 3, 4, 5, and 6 provided the responses to NRC GL 2008-01 for Peach Bottom Atomic Power Station (PBAPS). During a recent NRC inspection at PBAPS, it became apparent that further clarification was required since EGC's previous GL 2008-01 responses did not clearly describe the Core Spray (CS) and Residual Heat Removal (RHR) systems.
Reference 3 describes procedures used at PBAPS to fill and vent the CS and RHR systems.
After the systems are filled and vented, the systems are maintained pressurized by a stay full system. The stay full system provides substantial automatic control, including an alarm that is annunciated in the main control room, to ensure that the CS and RHR systems remain sufficiently full in their standby condition such that the systems can perform their specified safety functions.
These automatic controls include a high point vent accumulator with level switches to vent and alarm in conjunction with a continuous positive pressure applied by the Condensate Transfer system at the system low point (Le., pump discharge check valve). The accumulator provides continuous monitoring to collect and disposition accumulated gas. Level switch set points actuate to operate a solenoid to vent the gas and enable stay full flow to restore the process fluid volume to its acceptable level. In the event of excessive gas introduction or a CS/RHR system leak that is in excess of the stay full system capacity, an alarm is annunciated in the main control room prompting additional action. Alarm response procedures direct appropriate investigation including ensuring the piping is maintained full of water.
EGC's discussion in References 3 and 5 could be interpreted that routine manual venting of the systems were performed during each 31-day surveillance interval. The associated monthly surveillance tests that verify the piping is filled with water allows for different options to satiSfy the surveillance requirement. One option is to verify that the associated annunciator for the applicable system high point vent accumulator is not in an alarm condition. The absence of the alarm provides positive indication that the system is suffiCiently full. If for some reason the accumulator is isolated, the surveillance includes applicable instructions to perform manual venting to confirm the system is sufficiently full.
There are no regulatory commitments contained in this letter. Should you have any questions concerning this letter, please contact Mr. Kenneth M. Nicely at (630) 657-2803.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 15th day of December 2010.
cc: NRC Regional Administrator - Region I Senior Resident Inspector - Peach Bottom Atomic Power Station