CP-201201332, (Cpnpp), Request for Extension of Enforcement Discretion for Multiple Spurious Operation Circuit Interactions Resolution
| ML12326A946 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/08/2012 |
| From: | Flores R Luminant Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CP-201201332, TXX-12165 | |
| Download: ML12326A946 (11) | |
Text
Rafael Flores Luminant Power Senior Vice President P.O. Box 1002
&Chief Nuclear Officer 6322 North FM 56 rafael.flores@luminant.com Glen Rose, TX 76043 Lum inant T 254 897 5590 C 817 559 0403 F 2548976652 CP-201201332 TXX-12165 November 8, 2012 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK NUCLEAR POWER PLANT (CPNPP)
DOCKET NOS. 50-445 AND 50-446 REQUEST FOR EXTENSION OF ENFORCEMENT DISCRETION FOR MULTIPLE SPURIOUS OPERATION CIRCUIT INTERACTIONS RESOLUTION
Dear Sir or Madam:
Luminant Generating Company LLC (Luminant Power) is implementing its plan to resolve multiple spurious operations (MSOs) issues at Comanche Peak, as discussed in the March 6, 2012 public meeting with the NRC. This plan integrates resolution of operator manual actions (OMAs) with modifications to Comanche Peak to resolve fire protection potential circuit interactions. The extent of the physical modifications to the units requires work during each refueling outage through Spring 2014 for Unit 2 and Fall 2014 for Unit 1. Luminant Power received enforcement discretion for noncompliances associated with fire protection concerns involving MSOs in accordance with EGM 09-002, but this enforcement discretion ended on November 2, 2012. Luminant Power requests extension of enforcement discretion for MSOs through March 31, 2015.
Attachment 1 provides a description of the basis for the enforcement discretion request and the history of MSO issues at Comanche Peak. After identification of an OMA issue during the 2008 Triennial Fire Protection Inspection, the NRC and Luminant Power discussed the issue, including issuance and denial of a violation, and exchanged information, clarifying the NRC position on the Comanche Peak fire protection licensing basis. This process concluded in a February 2010 determination by the NRC that the OMA issue constituted a noncited violation and a determination by Luminant Power that plant modifications were required to resolve the OMA issue. Simultaneously, the enforcement discretion time period for identification and resolution of MSO issues specified in EGM 09-002 had begun after extensive communication on MSO issues between the NRC and the industry. Because of the timing and interaction of OMA and MSO issues, as well as the need to expeditiously address the OMA issues that were the subject of a violation, Luminant Power determined that correction of the OMA issues should precede correction of the MSO issues. The resolution of OMAs has a positive impact on MSO resolution as OMA corrective actions potentially preclude some spurious operations. The corrective actions have been planned carefully to ensure that the modifications are safely implemented with minimal impact on the plant. Resolution of OMAs will aid in the resolution of the MSOs.
The physical modifications to address the MSO issues, which began during the Fall 2012 outage, will be completed with the Fall 2014 outage. Attachment 2 provides the Comanche Peak OMA MSO Implementation Plan. Any post outage work (e.g., fire barrier installation) will be completed by December 31, 2014. Revision of the Fire Safe Shutdown Analysis (FSSA) and update of Operations procedures will be completed in the first quarter of 2015. Luminant Power's timely, diligent and substantive efforts to address these issues in the Comanche Peak OMA MSO Implementation Plan warrant extension of MSO enforcement discretion until completion of its Plan in the first quarter of 2015.
U. S. Nuclear Regulatory Commission TXX-12165 Page 2 of 2 11/08/2012 This communication contains the following new or revised commitments which will be completed or incorporated into the CPNPP licensing basis as noted:
Number Commitment Due Date 4510008 Luminant Power will complete the Comanche Peak OMA MSO 03-31-2015 Implementation Plan by the end of the First Quarter of 2015.
The Commitment number is used by Luminant Power for the internal tracking of CPNPP commitments.
Should you have any questions regarding this request, please contact Jack Hicks at (254)897-6725.
Sincerely, Luminant Generation Company, LLC Rafael Flores By: ri red W. Madden Director, Oversight and Regulatory Affairs Attachments 1. Comanche Peak History of Multiple Spurious Operations Issues and Basis for Extension of Enforcement Discretion
- 2. Comanche Peak OMA MSO Implementation Plan c - E. E. Coflins, Region IV G. B. Miller, Region IV B. K. Singal, NRR A. R;. Klein, NRR Resident Inspectors, CPNPP
ATTACHMENT 1 to TXX-12165 COMANCHE PEAK HISTORY OF MULTIPLE SPURIOUS OPERATIONS ISSUES AND BASIS FOR EXTENSION OF ENFORCEMENT DISCRETION to TXX-12165 Page 2 of 7 11/08/2012 1.0 Issue This paper provides a description of the history of the resolution of multiple spurious operation (MSO) issues at Comanche Peak and the basis for Luminant Power's request that enforcement discretion for MSO issues be extended through March 31, 2015.
2.0 Summary After identification of an OMA issue during the 2008 Triennial Fire Protection Inspection, the NRC and Luminant Power discussed the issue, including issuance and a denial of a violation, and exchanged information, clarifying the NRC position on the Comanche Peak fire protection licensing basis. This process concluded in a February 2010 determination by the NRC that the OMA issue constituted a noncited violation and a determination by Luminant Power that modifications were required to address the OMA issue. Simultaneously, the enforcement discretion time period for identification and resolution of MSO issues specified in EGM 09-002 had begun after extensive interactions on MSO issues between the NRC and the industry. Because correcting OMAs associated with the violation potentially correct spurious operation of individual components, Luminant Power determined that correction of the OMA issues should precede correction of the MSO issues. With the exception of the OMA associated with Reactor Coolant Pump (RCP) seal cooling isolation, modifications for all other OMA issues will be completed for both units after the Unit 1 Spring 2013 outage. Comanche Peak will be installing RCP shutdown seals during the Spring and Fall 2014 refueling outages for each unit to address the OMA and various MSOs associated with RCP seal cooling. The physical modifications to address the MSO issues, which began during the Fall 2012 outage, will be completed with the Fall 2014 outage. Any post outage work (e.g., fire barrier installation) will be completed by December 31, 2014. After completion of the modifications the Fire Safe Shutdown Analysis will be revised and the operations procedures will be updated by the end of the first quarter of 2015. The timing of the events, coupled with Luminant Power's diligent pursuit of a comprehensive resolution of the OMA and MSO issues once they were confirmed, provides a compelling basis for extension of enforcement discretion until March 31, 2015.
3.0 Discussion 3.1 Operator Manual Actions During the 2008 Triennial Fire Protection Inspection, documented in NRC Inspection Report 2008-06 (Reference 5.1), the NRC identified as an unresolved item that the Comanche Peak fire protection program relied on unapproved local OMAs to mitigate the effects of potential fire damage to equipment required to achieve and maintain safe hot shutdown conditions. The NRC concluded that the Comanche Peak fire protection program allows local OMAs to respond to spurious operations of equipment other than that equipment required for safe shutdown. However, the NRC found that Luminant Power OMAs included some local actions that were taken in lieu of protection for equipment for safe shutdown.
Therefore, the NRC was concerned that the fire protection program may have provided less physical separation and protection from the effects of fire than required by the approved fire protectionprogram.
In response to the 2008 Triennial Inspection, Luminant Power disagreed with the NRC's unresolved item and submitted to the NRC a description of the licensing basis on the use of manual actions for fire protection. In its submittal of July 24, 2008 (Reference 5.2), Luminant Power stated that NRC guidance, including NRC Regulatory Guide 1.189, Revision 1, FireProtectionfor Nuclear Power Plants, Section 5.3.3, Operator Manual Actions, and NRC Regulatory Issue Summary (RIS) 2006-10, Regulatory Expectations with Appendix R ParagraphIII.G.2 OperatorManual Actions, explicitly allow plants licensed after 1979 to rely on OMAs to achieve and maintain safe shutdown if the OMAs are identified in the plant's licensing basis and approved by the NRC. The FSAR refers to the Comanche Peak Fire Protection Report (FPR) for exceptions to the type of requirements in Section III.G.2 of Appendix R for physical separation and to TXX-12165 Page 3 of 7 11/08/2012 protection from fire effects. In the FPR, OMAs are allowed to achieve and maintain safe shutdown, as part of the licensing basis of Comanche Peak. In SSER 21, the NRC explicitly approved the use of manual actions, based in part on a 1988 inspection of Comanche Peak's use of OMAs. Therefore, Luminant Power concluded that the OMAs identified in the FPR to achieve and maintain safe shutdown were reviewed and approved by the NRC.
Following several discussions and a site visit by NRC inspectors, the NRC determined in its Integrated Inspection in September 2009, documented in NRC Inspection Report 2009-04 (Reference 5.3), that the unresolved item from the 2008 Triennial Inspection was a noncited violation. The NRC concluded that it had not approved manual actions in lieu of protection for equipment required for safe shutdown. The NRC found that Luminant Power stated that one of three methods listed in Section III.G.2 of Appendix R would be used to satisfy the requirements for separation and protection when more than one train of redundant equipment was located in the same fire area, unless another method was justified. However, the NRC concluded that there were no deviations requested to substitute OMAs for recovering the use of required equipment, nor does the SER mention any such, deviations.
Luminant Power denied the noncited violation by its letter of November 23, 2009 (Reference 5.4),
providing additional information on the Comanche Peak manual action licensing basis. This information supported the assertion that since before issuance of the initial operating license for Comanche Peak Unit 1 in 1990, the licensing basis allowed credit for OMAs to ensure that one train of the equipment required to achieve and maintain safe hot shutdown is free from fire damage. In particular, Luminant Power stated that the design documents at the time of the NRC acceptance of the OMAs, the FPR, the Fire Safe Shutdown Analysis (FSSA), and the NRC inspections conducted during that time all consistently indicate that OMAs could be used to provide the physical separation or protection required. Detailed information about the FSSA was provided in the response to the violation, recounting its initiation in the early 1980s, its revision after SSER 12 was issued, and the inclusion in the FSSA calculations issued after 1985 of OMAs that were required to keep one train free of fire damage. In addition, Luminant Power provided an affidavit from an engineering consultant who was directly involved in the FSSA work, including support,for the NRC's fire protection audits in 1987 and 1988. He stated that it was his understanding that the NRC inspectors were aware that some of the OMAs were to align required FSSA systems that were credited for FSSA, which supported Luminant Power's position that the NRC approved the OMAs that ensured that one train of the equipment required to achieve and maintain safe hot shutdown is free from fire damage.
In February 2010, the NRC responded to Luminant Power's denial of the noncited Violation, concluding that there was a violation (Reference 5.5). The NRC explained that the susceptibility to fire damage of the examples cited in the violation was not clearly stated in the FSSA, which comprised seven documents, only three of which were submitted for NRC review. The three documents submitted on the docket did not contain the clear statements in the non-docketed documents that the alternative at Comanche Peak to certain protection and separation requirements was OMAs to restore the required functions after fire damage occurred. Although the NRC inspectors in 1987 and 1988 reviewed the non-docketed calculations in the FSSA that clarified the purpose of the OMAs in question, the NRC explained that such use of the calculations does not constitute approval of the use of those OMAs, absent an explicit approval statement. Following the NRC's determination in February 2010 that the OMAs in question had not been approved by the NRC, Luminant Power evaluated the OMAs to confirm the identification of all such OMAs in order to plan the necessary plant modifications to resolve the OMA issues.
3.2 Benefits of Implemented OMA Modifications The following summarizes the benefits of the OMA modifications implemented to date. All of the modifications identified are being performed for both units with a single exception identified below. The OMA modifications not yet implemented for Unit 1 are scheduled to be implemented during the Spring to TXX-12165 Page 4 of 7 11/08/2012 2013 refueling outage. The OMA modifications for Unit 2 were implemented during the Fall 2012 refueling outage. Some non-outage installation of fire barrier material exists on several of the Unit 2 modifications and are scheduled to be installed by the end of 2012.
Modifications have been implemented for Unit 1 to resolve OMAs for the Charging System, the Auxiliary Feedwater System, and the Safety Chilled Water System. The modifications to the Charging System negate the need for Operator Manual Actions (OMAs). One of these modifications made changes to the charging pump recirculation valves that preclude spurious closing due to circuit interactions with MOV control cabling which could compromise the charging pumps. Another modification resolved spurious closure of the RCP seal injection isolation valves due to interactions with the MOV control circuits which could potentially close the seal injection path. The third modification made changes to the wiring for the charging flow control valve to mitigate circuit interactions that could spuriously close the flow control valve and interfere with charging flow. All of these OMA modifications contribute to resolution of MSOs on the Charging System.
The modifications to the Auxiliary Feedwater System also negate the need for OMAs. The first modification resolved circuit interactions with the turbine driven auxiliary feedwater pump. One portion resolved control circuit interactions that could spuriously lower pump speed compromising flow.
Another portion resolved circuit interactions that could potentially trip the turbine driven auxiliary feedwater pump. The second modification resolved control circuit interactions that could spuriously close several auxiliary feedwater isolation MOVs and interfere with flow. Both of these modifications also contribute to resolution of MSOs in the Auxiliary Feedwater System.
The change to the Safety Chiller flow control valves (this is Unit 1 specific) resolved an interaction with the control circuits of the flow control valves and made both units the same with respect to interactions on these valves.
In addition to the modifications for the Charging System and Auxiliary Feedwater System identified for Unit 1, there were additional modifications for Unit 2. A motor operated valve (MOV) was added to the Charging System to assure that normal charging can be isolated without any OMAs. The MOV was added due to physical proximity of the existing redundant isolation valves. The vent valves on the charging pump suction line were modified to resolve circuit interactions that could potentially preclude closing of the vent valves. Changes on the control circuits for the charging pump suction valves from the volume control tank and the refueling water storage tank were implemented that partially resolve the OMAs for these MOVs. All of these modifications contribute to resolution of MSOs in the Charging System.
For the Auxiliary Feedwater System a modification was implemented to resolve spurious interactions which could potentially isolate the steam supply to the turbine driven auxiliary feedwater pump and interfere with pump operation. Another modification resolved circuit interactions with control circuits of MOVs whose spurious operation can lead to draining the condensate storage tank. Thismodification is also an MSO scenario resolution.
3.3 Multiple Spurious Operations (MSOs)
Prior to, during, and after this same time period, the NRC and industry have been conducting extensive discussions on the MSO issues, together with cable functionality fire tests to improve understanding of fire-induced circuit failures and their potential to cause MSOs that could affect safe shutdown after a fire.
The nuclear industry, through NEI and EPRI, performed a series of cable fire tests in 2001 on actual circuit designs used in nuclear power plants, and NRC Research subsequently conducted cable fire tests on other aspects of actual plant circuit designs. Results of the industry tests were considered in NEI's development of NEI 00-01, Guidancefor Post-FireSafe-Shutdown Circuit Analysis, which was revised in
Attachment I to TXX-12165 Page 5 of 7 11/08/2012 May 2009 and is currently in the process of additional revision. Results of the NRC tests are still being analyzed to identify any additional testing that may be needed.
With the issuance of Regulatory Guide (RG) 1.189, Revision 2 on November 2, 2009, the NRC provided licensees guidance as to how to address some longstanding issues related to fire-induced circuit failures and disposition MSO circuit analysis issues. In EGM 09-002, the NRC specified the period of enforcement discretion for identification and resolution of MSO issues as three years after the issuance of Regulatory Guide (RG) 1.189, Revision 2.
At the time that RG 1.189, Revision 2 and EGM 09-002 were issued, Luminant Power was contesting the OMA violation based on the licensing basis allowing credit for OMAs to ensure that one train of the equipment required to achieve and maintain safe hot shutdown is free from fire damage. It was not until February 2010, when the NRC rejected Luminant Power's position that the need for plant modifications to address both OMAs and MSOs was established.
The MSO issues were identified in March 2010 by the MSO Expert Panel, based on a review of 78 MSO scenarios, of which 11 were determined inapplicable to Comanche Peak and 39 were already adequately modeled and included in the FSSA. The remaining 28 scenarios, of which 13 were identified as required and 15 were identified as important to safe shutdown, needed to be addressed by the FSSA. These comprised the non-conforming items which were entered into the Comanche Peak corrective action program.
In 2011, the NRC conducted its Triennial Fire Protection Inspection and identified additional MSO issues.
These were MSOs affected by issues related to SSER 12 alternate circuit failure criteria previously approved by the NRC for high/low pressure interfaces and MSOs affected by the centrifugal charging pump suction motor operator valve interactions for a control room/cable spreading room fire. Luminant Power added these issues to the MSO issues identified by the MSO Expert Panel for resolution in accordance with the guidance in RG 1.189, Revision 2.
3.3 Comanche Peak OMA MSO Implementation Plan Modifications Upon confirmation of the need for a combination of evaluations and plant modifications for both OMAs and MSOs, Luminant Power developed a comprehensive implementation plan, the OMA MSO Implementation Plan, for implementation of modifications during refueling outages beginning in 2011, which was as soon as was feasible. Many of the OMA and MSO modifications must be implemented during a unit outage. Luminant Power prioritized the modifications by the need to first address the violation from the 2008 Triennial Inspection, which was confirmed in 2010, because the OMAs in question may prevent single spurious operation. This resulted in scheduling the OMA modifications for completion before the MSO modifications, although one MSO modification is scheduled for the Unit 2 refueling outage currently underway in October 2012. Because of the timing and interaction of OMA and MSO issues, as well as the need to expeditiously address the OMA issues that were the subject of a violation, Luminant Power determined that correction of the OMA issues should precede correction of the MSO issues. The corrective actions have been planned carefully to ensure that the modifications are safely implemented with minimal impact on the plant. Resolution of OMA will aid in the resolution of the MSOs. The resolution of.OMAs will also potentially preclude spurious operations. Thereforeonce the OMAs are addressed, some of the MSOs will be resolved and it will be more straightforward to address the remaining MSOs. The extensiveness of the modifications means that completion of all modifications will not occur until the end of the Fall 2014 outage for Unit 1. Any post outage work (i.e.,
Thermo-Lag installation) will be completed by December 31, 2014.
Luminant Power has consistently communicated to the NRC the schedule for implementation of the
Attachment I to TXX-12165 Page 6 of 7 11/08/2012 modifications, including the fact that completion of all modifications will not occur until the conclusion of the Fall 2014 Unit 1 outage. For example, in the second half of 2010, Luminant Power informed the NRC of its plans for addressing the MSOs, in addition to the OMAs, in the course of informal meetings, including a working meeting at NRC Region IV. During the 2011 Triennial Fire Protection Inspection, the NRC's inspection of the circuit analysis area included discussion with Luminant Power of the plans for resolving MSOs through plant modifications. On March 6, 2012, the NRC held a public meeting at Region IV for the purpose of discussing Luminant Power's plans and schedules for making modifications to resolve fire protection circuit interactions related to MSOs (Reference 5.6). The NRC's summary of the meeting includes a copy of the Comanche Peak OMA MSO Implementation Plan, showing the completion of all modifications with the Fall 2014 outage. Any post outage work (e.g., fire barrier installation) will be completed by December 31, 2014. A current copy of the OMA MSO Implementation Plan is enclosed as , listing the modification projects currently being implemented during the ongoing outage through the completion of the plan.
Compensatory Actions Pending the Modifications Prior to full resolution of the MSO issues, Luminant Power has identified additional compensatory measures that are being implemented to provide enhanced defense in depth to the fire protection program. Fundamentally, the Comanche Peak fire protection program relies on a defense in depth philosophy with the following objectives:
- To prevent fire from starting;
- To detect rapidly, control, and extinguish promptly those fires that occur;
- To provide protection for structures, systems, and components important to safety so that a fire that is not promptly extinguished by the fire suppression activities will not prevent the safe shutdown of the plant.
Each MSO issue that requires a physical plant change has been evaluated to determine whether a fire watch is required. In addition, Luminant Power has evaluated, for those MSO issues requiring physical plant changes, whether a temporary post-fire safe shutdown procedure change would reduce or eliminate the risk associated with that issue, while also taking into account the ALARA program and employee safety. These additional compensatory measures will increase the defense in depth of the fire protection program prior to full implementation of the modifications, while the modifications will result in a permanently improved and more robust program, enhancing overall plant safety.
4.0 Conclusions The need to make modifications to address the OMA and MSO issues was only established in 2010, upon the NRC's denial of the OMA violation dispute. Since that time, Luminant Power has been working diligently to address MSO issues at Comanche Peak and has been in regular communication with the NRC about its modification projects and their schedules. The schedule for full implementation of Comanche Peak MSO corrections extends beyond the EGM 09-002 November 2, 2012 enforcement discretion termination date because the need to make modifications was only confirmed in 2010, and OMA issues need to be addressed at Comanche Peak before the MSO issues. Luminant Power is focusing first on the completion of the OMA modifications in its pursuit of a safer and more robust plant. Its timely, diligent and substantive efforts to address both of these issues in the Comanche Peak OMA MSO Implementation Plan warrant extension of MSO enforcement discretion until March 31, 2015.
5.0 References 5.1 NRC Triennial Fire Protection Inspection Report 05000445/446-2008006 dated July 3, 2008, from Linda J. Smith of the NRC to Mike Blevins.
Attachment I to TXX-12165 Page 7 of 7 11/08/2012 5.2 Letter logged TXX-08105 dated July 24, 2008, from Rafael Flores of Luminant Power to the NRC submitting Comanche Peak Licensing Basis on Use of Manual Actions for Fire Protection.
5.3 NRC Integrated Inspection Report 05000445/446-2009004 dated October 27, 2009, from Wayne C. Walker of the NRC to Rafael Flores.
5.4 Letter logged TXX-09136 dated, dated November 23, 2009, from Rafael Flores of Luminant Power to the NRC submitting Denial of Finding on NRC Integrated Inspection Report 05000445/446-2009004.
5.5 NRC Response to Comanche Peak Disputed Non-Cited Violation 05000445/446-200904-05 from Roy J. Caniano of the NRC, to Rafael Flores.
5.6 NRC Summary of Meeting with Luminant Generation Company, LLC, Regarding Planned Modifications to Resolve Fire Protection Circuit Interactions dated March 12, 2012, from Geoffrey Miller of the NRC to Rafael Flores.
ATTACHMENT 2 to TXX-12165 COMANCHE PEAK OMA MSO IMPLEMENTATION PLAN