IR 05000445/2005005
| ML061010278 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 04/07/2006 |
| From: | Laura Smith Division of Reactor Safety IV |
| To: | Blevins M TXU Power |
| References | |
| IR-05-005 | |
| Download: ML061010278 (12) | |
Text
April 7, 2006
SUBJECT:
ERRATA FOR COMANCHE PEAK STEAM ELECTRIC STATION - NRC INTEGRATED INSPECTION REPORT 05000445/2005005 AND 05000446/2005005
Dear Mr. Blevins:
Please replace page 4 of the Summary of Findings, pages 33, 34 and 35 of the Report Details, and Page A-2 of Supplemental Information in NRC Inspection Report 05000445/2005005 and 05000446/2005005, dated February 13, 2006, with the enclosed revised pages. These changes are necessary to revise the characterization of the Non-Cited Violation of Section 40A5.2 from a Technical Specification 3.8.1 violation to a 10 CFR Part 50, Appendix B, Criterion XVI violation.
During and subsequent to the inspection process, we discussed this Technical Specification 3.8.1 violation with your staff and did not come to full agreement regarding the technical basis for the violation. Your staff provided a position paper, which is enclosed. They continue to believe that the failure of Relay 27BX1/ST1 was not aging related. However, we were not able to identify a mechanism that was not aging related that would also cause the described manufacturing defect to manifest itself 16 years after placing Relay 27BX1/ST1 in service. The differing view points make it not clear exactly when the relay became inoperable, calling into question the validity of the Technical Specification 3.8.1 violation. In cases like this, Section 8.1.2 of the NRC Enforcement Manual directs us to cite against the root cause of the initial Technical Specification violation. In this case, the root cause was inadequate corrective action, a violation of 10 CFR Part 50, Appendix B, Criterion XVI.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be made available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRCs document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
TXU Power
-2-Should you have any questions concerning this inspection update, we will be pleased to discuss them with you.
Sincerely,
/RA/
Linda Smith, Chief Engineering Branch 2 Division of Reactor Safety Docket Nos.: 50-445, 50-446 License Nos.: NPF-87, NPF-89 Enclosures:
1. Errata pages for NRC Inspection Report 05000445/2005005 and 05000446/2005005 2. Position Paper Related to NCV 050000446/2005-05 cc w/enclosures:
Fred W. Madden, Director Regulatory Affairs TXU Power P.O. Box 1002 Glen Rose, TX 76043 George L. Edgar, Esq.
Morgan Lewis 1111 Pennsylvania Avenue, NW Washington, DC 20004 Terry Parks, Chief Inspector Texas Department of Licensing and Regulation Boiler Program P.O. Box 12157 Austin, TX 78711 The Honorable Walter Maynard Somervell County Judge P.O. Box 851 Glen Rose, TX 76043 Richard A. Ratliff, Chief Bureau of Radiation Control Texas Department of Health 1100 West 49th Street Austin, TX 78756-3189
TXU Power
-3-Environmental and Natural Resources Policy Director Office of the Governor P.O. Box 12428 Austin, TX 78711-3189 Brian Almon Public Utility Commission William B. Travis Building P.O. Box 13326 Austin, TX 78711-3326 Susan M. Jablonski Office of Permitting, Remediation and Registration Texas Commission on Environmental Quality MC-122 P.O. Box 13087 Austin, TX 78711-3087
TXU Power
-4-Electronic distribution by RIV:
Regional Administrator (BSM1)
DRP Director (ATH)
DRS Director (DDC)
DRS Deputy Director (RJC1)
Senior Resident Inspector (DBA)
Branch Chief, DRP/A (CEJ1)
Senior Project Engineer, DRP/A (TRF)
Team Leader, DRP/TSS (RLN1)
RITS Coordinator (KEG)
Regional State Liaison Officer (WAM)
NSIR/DIPM/EPHP (REK)
Only inspection reports to the following:
J. Dixon-Herrity, OEDO RIV Coordinator (JLD)
ROPreports CP Site Secretary (ESS)
SUNSI Review Completed: __LJS ADAMS: / Yes G No Initials: LJS___
/ Publicly Available G Non-Publicly Available G Sensitive
/ Non-Sensitive DOCUMENT: R:\\_REACTORS\\_CPSES\\2005\\CP2005-05 errata2.wpd RIV:DRS\\EB2 C:EB2 RIV:C:DRP/A DLLivermore:nlh LJSmith CEJohnson
/RA/
/RA/
/RA/
04/06/06 04/06/06 04/07/06 OFFICIAL RECORD COPY T=Telephone E=E-mail F=Fax
ENCLOSURE Revised Pages for NRC Integrated Inspection Report 05000445/2005005 AND 05000446/2005005
Enclosure-4-
Green. A Green self-revealing noncited violation of Appendix B, Criterion XVI was identified for failure to implement effective corrective actions for a significant condition adverse to quality. Specifically, station service water Pump 1-01 was returned to service on October 20, 2005, and after two hours of operation tripped on an electrical fault on Phase C of the motor leads. The degraded electrical condition of the motor lead had been identified during restoration from the pump maintenance, but the actions taken to ensure the pump was reliable failed.
Phase C of the motor leads was replaced prior to returning the pump to service.
The failure to take effective corrective actions was the performance deficiency.
The violation was more than minor because the pump was returned to service with a degraded motor lead. At the time of the event, Unit 1 was defueled and did not require an operable station service water pump. However, Unit 2 was required by Technical Specifications 3.7.8 to have at least one operable station service water pump from the opposite unit. With Unit 2 at 100 percent power, a significance determination was performed using Appendix A of Manual Chapter 0609. The finding was determined to be of very low safety significance (Green) because it did not represent a loss of system safety function, was not an actual loss of safety function for a single Unit 2 train, did not involve equipment or function specifically designed to mitigate a seismic, flooding, or severe weather initiating event, and did not involve the total loss of any safety function that contributed to external event initiated sequences. The cause of this finding is related to the crosscutting aspects of problem identification and resolution.
The event was entered into the corrective action program as Smart Form 2005-004220 (Section 4OA3.2).
- Green. A Green self-revealing non-cited violation of 10 CFR 50, Appendix B, Criterion XVI was identified for failure to take prompt and adequate corrective action for a condition adverse to quality. Specifically, on October 19, 2004, an unplanned loss of the preferred offsite power caused the Unit 2, Train B, 6.9 kV safeguards bus to de-energize. A degraded Agastat relay delayed the normal power supply breaker from opening for 30 seconds, which delayed powering the bus from the alternate offsite AC power supply or the emergency diesel generator. This issue had crosscutting aspects in the area of problem identification and resolution because the licensee previously identified that aged Agastat relays were unreliable and should be replaced if they were in service greater than 12 years. The failed relay had been in service for 16 years.
The licensees failure to identify the cause and implement corrective actions to prevent repetitive failures of safety related Agastat relays was a performance deficiency. The violation was more than minor because it impacted the Mitigating Systems Cornerstone objective of availability, reliability, and capability of systems that respond to initiating events. Using Inspection Manual Chapter 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, the finding was determined to be of very low safety significance because the likelihood of a medium or large break loss of coolant accident coincident with a loss of offsite power, which are the only conditions where the deficiency would cause a non-negligible change in the baseline risk
Enclosure-33-The inspectors determined that the direct visual inspections, coupled with mirror assisted visual inspections were capable of detecting, identifying and characterizing small boric acid deposits, if present, as described in NRC Bulletin 2004-01. This fact was determined via direct inspection during the licensee inspection of the pressurizer and associated steam space piping connections.
6. Identified deficiencies that required repair No deficiencies were identified.
7. Impediments to effective examinations There were no impediments that adversely affected effective bare metal visual examinations. In all examination cases, mirror insulation was required to be removed.
The examination of the pressurizer safety and power operated relief valve line welds was supplemented by a mirror to allow examination of the downhill side of the welds.
The dose rates were acceptable, and the inspectors received approximately 50 mRem to complete the in-plant portion of the temporary instruction.
8. Techniques used for augmented inspections Augmented inspections were not required.
9. Appropriateness of follow-on examinations Follow-on examinations were not required.
.2 (Closed) URI 05000446/2005009-01: Inoperability of Emergency Power to a Safety Bus Introduction. A Green self-revealing noncited violation of 10 CFR 50, Appendix B, Criterion XVI was identified for failure to take prompt and adequate corrective action for a condition adverse to quality.
Description. On October 19, 2004, an unplanned loss of the preferred offsite power caused the Unit 2, Train B, 6.9 kV safeguards bus to deenergize. A degraded Agastat relay exceeded its 0.5 second time delay setpoint and prevented the normal power supply breaker from opening for 30 seconds. Both the EDG and the alternate power supply were delayed from powering the bus due to a breaker interlock with the normal supply. This delay rendered both the EDG and alternate offsite AC power supplies inoperable. The 30 second delay in providing power to the safeguards bus would have resulted in the station not meeting the 10 CFR Part 50, Appendix K, Emergency Core Cooling System Evaluation Models Acceptance Criteria, for that equipment train.
The licensee had a previous opportunity to correct the degraded Agastat relay issues.
On October 7, 2002, EDG 1-02 unexpectedly started due to a degraded Agastat relay.
The licensee concluded that the failure could have been caused by aging and formed a corrective action plan to replace all safety related Agastat relays that had been in service for greater than the licensee established 12 year lifetime. EVAL-2003-001440-01-01 stated that the main effect of aging on these relays was an increase in setpoint
Enclosure-34-drift. The licensee issued SMF-2004-003528 to track the root cause and corrective actions associated with the faulty Agastat relays. Also, the NRC previously identified that Agastat relays used in the 6.9 kV bus transfer circuitry were exhibiting setpoint drift (SMF-2002-001504 and Inspection Report 05000445/2003006; 05000446/2003006).
The relay that failed in October 2004 was 16 years old.
Analysis. The licensees failure to identify the cause and implement corrective actions to prevent repetitive failures of safety related Agastat relays was a performance deficiency.
The violation was more than minor because it impacted the Mitigating Systems Cornerstone objective of availability, reliability, and capability of systems that respond to initiating events. Using Inspection Manual Chapter 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, the finding was determined to be of very low safety significance because the likelihood of a medium or large break loss of coolant accident coincident with a loss of offsite power, which are the only conditions wherein the deficiency would cause a non-negligible change in the baseline risk profile, is less than or equal to 1E-6 per year. Therefore, the change in core damage frequency will be less than 1E-6 per year. The violation has a problem identification and resolution crosscutting aspect because the licensee had previously identified that aged Agastat relays can cause these types of problems but had failed to take effective corrective actions in a timely manner. The licensee captured the issue in their corrective action program as SMF-2004-003528.
Enforcement. 10 CFR Part 50, Appendix B, Criterion XVI, "Corrective Action," requires, in part, that measures shall be established to assure that conditions adverse to quality, such as failures, deficiencies, and deviations, are promptly identified and corrected.
Contrary to the above, the licensee failed to take prompt and adequate corrective action for a condition adverse to quality. Specifically, on August 13, 2003, the licensee identified that Agastat relay 27BX-1/ST exceeded its 12-year expected service life, and scheduled an interim calibration check to be performed during refueling outage 2RF07.
Due to 2RF07 outage duration reduction in October, 2003, the interim calibration check was deferred to 2RF08, in the Spring of 2005. On October 19, 2004, the Agastat relay exceeded its time delay setpoint and delayed the normal power supply breaker from opening when the Unit 2, Train B, 6.9 kV safeguards bus deenergized during an unplanned loss of preferred offsite power. Because this issue is of very low safety significance and has been entered into the corrective action program as SMF-2004-003528, this violation is being treated as a Non-Cited Violation, consistent with Section VI.A of the NRC Enforcement Policy: NCV 05000446/2005005-05, Inoperability of Emergency Power to a Safety Bus Due to Degraded Relay.
4OA6 Meetings, Including Exit Exit Meeting Summary The inspectors presented the results of the inservice inspection to Mr. M. Lucas, Vice President of Nuclear Engineering, and other members of licensee management on
Enclosure-35-October 21, 2005. Licensee management acknowledged the inspection findings. The licensee confirmed that any proprietary information reviewed by the inspectors was not retained by the inspectors.
On December 15, 2005, the inspector debriefed the preliminary results of the emergency preparedness inspection to Mr. M. Blevins, Senior Vice President and Chief Nuclear Officer, and other members of his staff who acknowledged the findings. The inspector confirmed that proprietary information was not provided or examined during the inspection. After additional information was provided by the licensee on January 11, 2006, the inspector presented the inspection results to Mr.R. Flores, Vice President, Nuclear Operations, and other members of his staff who acknowledged the findings.
On January 31, 2006, Mr. N. O'Keefe presented the inspection results of the URI in regards to Agastat relays to Mr. T. Hope and D. Snow of your staff, who acknowledged the finding, by teleconference.
The inspector presented the resident inspection results to Mr. R. Flores, Vice President, Operations, and other members of licensee management on January 12, 2006. The inspectors confirmed that proprietary information was not provided or examined during the inspection.
On April 7, 2006, Ms. Linda Smith and Mr. Dan Livermore presented a change in the characterization of the Agastat relay green NCV from a Technical Specification 3.8.1 violation to a 10 CFR 50, Appendix B, Criterion XVI violation to Mr. Tim Hope, who acknowledged the change, by teleconference.
ATTACHMENT: SUPPLEMENTAL INFORMATION
Enclosure A-2 05000445/2005005-03 NCV Trip of Emergency Diesel Generator Due to Lube Oil Check Valve Installed Backwards (Section 4OA3.1)05000445/2005005-04 NCV Trip of Station Service Water Pump Due to Degraded Motor Lead (Section 4OA3.2)05000446/2005005-05 NCV Inadequate Corrective Action Impacts Operability of Emergency Power to a Safety Bus Due to Degraded Relay (Section 4OA5.2)
Closed 05000446/2005009-01
URI Inoperability of Emergency Power to a Safety Bus (Section 4OA5.2)
Discussed None LIST OF DOCUMENTS REVIEWED Section 1R08 Inservice Inspection Activities (71111.08)
Boric Acid Evaluation Unit 1 Containment Boron Leaks 1RF11, draft report Procedures Number Title Revision STA-737 Boric Acid Corrosion Detection and Evaluation
TX-ISI-8 VT-1 and VT-3 Visual Examination
TX-ISI-11 Liquid Penetrant Examination for Comanche Peak Steam Electric Station
TX-ISI-302 Ultrasonic Examination of Austenitic Piping Welds
WLD-106 ASME/ANSI General Welding Requirements 2 with Procedure Change Notice 4
Enclosure Position Paper Related to NCV 05000446/2005005-05 NCV Description The Analysis section (page 34) states that The licensees failure to identify the cause and implement corrective actions to prevent repetitive failures of safety related Agastat relays was a performance deficiency. The Enforcement section (page 34) states Technical Specification 3.8.1 required the licensee to restore either the alternate offsite transmission source or the EDG to the onsite Class 1E AC electrical distribution system within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Contrary to the above, neither the alternate offsite transmission source nor the EDG was capable of supplying the Class 1E AC electrical distribution within the response time assumed in the accident analysis. This condition existed for an extended duration, in excess of the 12-hour TS limiting condition for operation.
Discussion As documented in SMF 2004-003528 and also in a failure analysis report prepared by Southwest Research Institute (SWRI) in January 2005, the failure of this relay (27BX1/ST1) was determined to be caused by particles that entered either the variable-length orifice groove or the port between the clean cavity and the orifice groove. This was likely a vendor defect as SWRI noted in their report that... there is significant probability that at least some of the particles in the clean areas were introduced during relay fabrication. The particles restricted air flow through the timing structure and lengthened the time delay. Therefore, TXU Power believes that this was a random equipment failure and that aging was not a factor in the failure of relay 27BX1/ST1.
Although aging was determined to have been a factor in the failure of safety related Agastat relays at Grand Gulf, aging was not a factor in the failure of relay 27BX1/ST1.
Comanche Peaks E7000 model Agastat relays are different from the GP model Agastat relays at Grand Gulf because the GP model relay, which is not a time delay relay, is constructed differently from the E7000 model relay. Another difference between the Grand Gulf application and CPSES is that the Grand Gulf GP model relays are in a continuously energized state. At the time relay 27BX1/ST1 failed, a schedule had been implemented to replace the E7000 Agastat relays which perform a safety function and had been in service beyond 12 years (including relay 27BX1/ST1).
Currently all E7000 Agastat relays that perform a safety related function have been replaced.
Because this was considered to be a random equipment failure and not age related, TXU Power believes that the Class 1E AC electrical distribution system can be assumed to be operable per the TS 3.8.1 until the relay failed on October 19, 2004.
Based on discussions with NRC Region IV personnel, TXU Power believes that the NRC used the time from the last successful surveillance until the relay failed and then applied the SDP t/2 criteria for this condition to determine that the safety bus had been inoperable for greater than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. However, TXU Power believes that use of
Enclosure this criteria is limited to the SDP process and it is not an appropriate criteria to determine whether or not a performance deficiency existed.
As described above, TXU Power believes that the failure of relay 27BX1/ST1 was due to a random equipment failure and was not age related. For this reason, TXU Power believes that the Class 1E AC electrical distribution system should not be considered inoperable for greater than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.