ML110540393
| ML110540393 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/02/2011 |
| From: | Sanders C Plant Licensing Branch 1 |
| To: | Heacock D Dominion Nuclear Connecticut |
| Sandeers, Carleen, NRR/DORL, 415-1603 | |
| References | |
| TAC MD7845, TAC MD7846, GL-08-001, FOIA/PA-2011-0115 | |
| Download: ML110540393 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. O.C. 20555-0001 March 2. 2011 Mr. David A. Heacock President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.
Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen. VA 23060-6711 SUB..IECT: MILLSTONE POWER STATION. UNIT NOS. 2 AND 3 - CLOSEOUT OF GENERIC LETTER 2008-01, "MANAGING GAS ACCUMULATION IN EMERGENCY CORE COOLING DECAY HEAT REMOVAL, AND CONTAINMENT SPRAY SYSTEMS" (TAC NOS. MD7845 AND MD7846)
Dear Mr. Heacock:
On January 11,2008, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML072910759). The stated purpose of GL 2008-01 was (a) to request addressees to submit information to demonstrate that the subject systems are in compliance with the current licensing and design bases and applicable regulatory requirements, and that suitable design, operational. and testing control measures are in place for maintaining this compliance; and (b) to collect the requested information to determine if additional regulatory action is required.
GL 2008-01 requested that licensees provide the following information within 9 months of the date of the GL:
(a) A description of the results of evaluations that were performed pursuant to requested actions specified in the GL. The description was to provide sufficient information to demonstrate that you are or will be in compliance with the quality assurance criteria in Sections III, V, XI, XVI, and XVII of Appendix B to 10 CFR Part 50 and the licensing basis and operating license as those requirements apply to the subject systems; (b) A description of all corrective actions, including plant, programmatic. procedure, and licensing basis modifications that you determined were necessary to assure compliance with these regulations; and, (c) A statement regarding which corrective actions were completed, the schedule for completing the remaining corrective actions, and the basis for that schedule.
By letters dated April 7, May 8, and October 14, 2008, January 15, 2009, and January 14,2010 (ADAMS Accession Nos. ML080980543, ML081300282, ML082890266, ML090150378, and ML100190064, respectively), Dominion Nuclear Connecticut, Inc. (DNC or the licensee) provided a response to GL 2008-01 for Millstone Power Station, Unit Nos. 2 and 3 (MPS2 and MPS3, respectively). On February 6, 2009 (ADAMS Accession No. ML090820433), the NRC
O. Heacock -2 completed a special inspection at MPS3 regarding a gas void in the pipe connecting the refueling water storage tank to the suction of the emergency core cooling system pumps. The ultrasonic testing (UT) measurements that identified the gas were being performed to address potential voiding concerns as outlined in GL 2008-01. The NRC staff identified one non-cited violation during this inspection.
The January 14, 2010, letter provided a response to NRC staff questions in a request for additional information (RAI), which are evaluated below:
- In RAI 1, the NRC staff asked for clarification on the schedule for evaluating the Technical SpeCification Task Force (TSTF) traveler and submitting a license amendment, if necessary. ONC stated they intend to evaluate the TSTF traveler and submit a license amendment, if necessary, within 1 year of NRC approval of the TSTF traveler. The NRC staff finds this to be responsive to the GL.
- In RAI 2, the NRC staff asked for clarification on how voids are being detected in the pump discharge piping of MPS2 and for information on how these potential voids are going to be monitored and trended. ONC stated that accessible pipe system high points are monitored on a quarterly basis via UT. Piping system locations that are susceptible to gas accumulation, but are no monitored by UT are manually vented. ONC stated that if gas is found in the piping system, a condition report is initiated, which is used to document and trend gas accumulation in the system. MPS2 procedures direct manual venting of gas if the UT results show that the piping is less that 100 percent full of water.
The NRC staff finds the detection, monitoring, and trending of voids in the discharge piping of MPS2 to be responsive to the GL.
- In RAI 3, the NRC staff requested information on the measures used to guard against gas intrusion and to identify the potential gas intrusion mechanisms at MPS2. ONC stated that they plan to use periodic monitoring, as discussed in the response to RAI 2, to guard against gas intrusion mechanisms such as inadvertent draining, system realignments, and incorrect maintenance procedures. ONC clarified the mechanisms that could cause gas intrusion at MPS2 and why these mechanisms are not a concern at MPS2. The NRC staff finds this to be responsive to the GL.
- In RA14, the NRC staff asked for clarification on how gas accumUlation is determined and information on any follow-up actions that would be taken. ONC stated that gas accumulation is determined by periodic monitoring in accordance with MPS2 and MPS3 procedures. The piping is monitored by UT or, if it cannot be monitored by UT, the piping is manually vented. If a void is detected using proceduralized periodic UT, a condition report is generated and the gas is vented from the system. The NRC staff finds the mechanisms for determining if there is gas accumulation and the follow-up actions to be responsive to the GL.
- In RAI 5, the NRC staff requested additional information on gas voids that were found in the pump suction lines of MPS3. Condition reports were generated to address gas voids found in the suction lines at MPS3. ONC stated that if the source of gas could be eliminated, it was, and if a vent valve was not local to the void, then a vent valve was installed to allow venting of the void. Two recent gas voids were discovered in
D. Heacock -3 emergency core coolant system (ECCS) supply lines at MPS3. The first void was formed due to system design; therefore DNC installed a vent valve to support venting at the location in the future. The second void was due to gas stripping during maintenance.
DNC determined the source of gas could not be eliminated; therefore DNC recalculated the allowable gas for this location and will vent this location when gas is identified. The NRC staff finds this to be responsive to the GL.
- In RAI 6, the NRC staff requested additional information on the licensee's training program with respect to gas intrusion. DNC stated that Engineering Support training is provided quarterly to MPS2 and MPS3 personnel. DNC stated that the training in 2009 included general GL 2008-01 issues. Operations personnel also receive training on the procedures that require verification that the ECCS is full. DNC also stated that training on Institute to Nuclear Power Operations (INPO) Significant Operating Event Report 97 01 and INPO Significant Event Report 2-05 are included in MPS2 and MPS3's licensed Operator Requalification Training and Nuclear Licensed Operator Continuing Training programs, which are provided every 2 years. The NRC staff finds this training to be responsive to the GL.
Based upon the information provided in DNC's response to GL 2008-01 for MPS2 and MPS3, the NRC staff finds MPS2 and MPS3 response to the GL to be acceptable. Consequently, your GL 2008-01 response is considered closed and no further information or action is requested of you. Notwithstanding, an inspection using Temporary Instruction (TI) 2515/177, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems (NRC Generic Letter 2008-01)" (ADAMS Accession No. ML082950666) may be performed by the NRC's Region I staff. TI 2515/177 is confirmatory in nature in that it directs NRC inspectors to selectively verify that the licensee has implemented or is in the process of acceptably implementing the commitments, modifications, and programmatically controlled actions described in the licensee's response to GL 2008-01 and the plant-specific information supports a conclusion that subject systems operability is reasonably ensured.
If you have any questions regarding this letter, please feel free to contact me at (301) 415-1603.
~eIY' Carleen J. nders, Project Manager Plant Lice mg Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-336 and 50-423 cc: Distribution via Listserv
D. Heacock - 3 emergency core coolant system (ECCS) supply lines at MPS3. The first void was formed due to system design; therefore DNC installed a vent valve to support venting at the location in the future. The second void was due to gas stripping during maintenance.
DNC determined the source of gas could not be eliminated; therefore DNC recalculated the allowable gas for this location and will vent this location when gas is identified. The NRC staff finds this to be responsive to the GL.
- In RAI 6, the NRC staff requested additional information on the licensee's training program with respect to gas intrusion. DNC stated that Engineering Support training is provided quarterly to MPS2 and MPS3 personnel. DNC stated that the training in 2009 included general GL 2008-01 issues. Operations personnel also receive training on the procedures that require verification that the ECCS is full. DNC also stated that training on Institute to Nuclear Power Operations (INPO) Significant Operating Event Report 97 01 and INPO Significant Event Report 2-05 are included in MPS2 and MPS3's licensed Operator Requalification Training and Nuclear Licensed Operator Continuing Training programs, which are provided every 2 years. The NRC staff finds this training to be responsive to the GL.
Based upon the information provided in DNC's response to GL 2008-01 for MPS2 and MPS3, the NRC staff finds MPS2 and MPS3 response to the GL to be acceptable. Consequently, your GL 2008-01 response is considered closed and no further information or action is requested of you. Notwithstanding, an inspection using Temporary Instruction (TI) 2515/177, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems (NRC Generic Letter 2008-01)" (ADAMS Accession No. ML082950666) may be performed by the NRC's Region I staff. TI 2515/177 is confirmatory in nature in that it directs NRC inspectors to selectively verify that the licensee has implemented or is in the process of acceptably implementing the commitments, modifications, and programmatically controlled actions described in the licensee's response to GL 2008-01 and the plant-specific information supports a conclusion that subject systems operability is reasonably ensured.
If you have any questions regarding this letter, please feel free to contact me at (301) 415-1603.
Sincerely, IraJ Carleen J. Sanders, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-336 and 50-423 cc: Distribution via Listserv DISTRIBUTION:
PUBLIC LPLI-2 R/F RidsAcrsAcnw_MailCTR Resource RidsNrrDorlDpr Resource RidsNrrDorlLpl1-2 Resource RidsRgn 1MailCenter Resource RidsNrrPMMilistone Resource Anthony Uises, NRR RidsNrrLAABaxter Resource D. Woodyatt, NRR Warren Lyon, NRR DCunanan, NRR Accession Number: ML110540393 "By Memo Dated OFFICE LPL1-2/PM LPL 1-2LA DSS/SRXB LPL1-2/BC NAME CSanders ABaxter (SUttle for) AUlses" HChernoff DATE 2128/11 2/28/11 2/8111 3/2/11 OFFICIAL RECORD COpy