ML14325A060
| ML14325A060 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 11/19/2014 |
| From: | Stoddard D G Dominion Nuclear Connecticut |
| To: | Document Control Desk, NRC Region 1 |
| References | |
| 14-526, EA-14-092 | |
| Download: ML14325A060 (6) | |
Text
ýPDominiolll Dominion Nuclear Connecticut, Inc.5000 Dominion Boulevard, Glen Allen, VA 23060Web Address:
www.dom.com November 19, 2014U.S. Nuclear Regulatory Commission Attention:
Document Control DeskWashington, DC 20555-0001 Serial No.MPS Lic/MAEDocket No.License No.14-526RO50-423NPF-49DOMINION NUCLEAR CONNECTICUT, INC.MILLSTONE POWER STATION UNIT 3REPLY TO A NOTICE OF VIOLATION; EA-14-092 Pursuant to the provisions of 10 CFR 2.201, Dominion Nuclear Connecticut, Inc. (DNC)herein provides a reply to the Nuclear Regulatory Commission (NRC) letter datedOctober 20, 2014 regarding final significance determination for a white finding withassessment follow-up and notice of violation.
The finding was identified during an NRCSpecial Inspection conducted at Millstone Power Station (MPS) to review multiplefailures of the MPS Unit 3 turbine-driven auxiliary feedwater pump.The enclosure provides DNC's response to the violation as specified in the Notice ofViolation EA-14-092.
The enclosure provides:
(1) the reason for the violation, (2) thecorrective steps that have been taken and the results achieved; (3) the corrective stepsthat will be taken, and (4) the date when full compliance will be achieved.
If you have any questions or require further information, please contact Mr. William D.Bartron at (860) 444-4301.
Sincerely, Daniel G. StoddardSenior Vice President
-Nuclear Operations
Enclosure:
Reply to a Notice of Violation EA-14-092 Commitments made in this letter: NoneI/
Serial No. 14-526Docket No. 50-423Page 2 of 2cc: Regional Administrator U.S. Nuclear Regulatory Commission Region I2100 Renaissance Blvd., Suite 100King of Prussia, PA 19406-2713 M. C. ThadaniSenior Project ManagerU.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 B 111555 Rockville PikeRockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Serial No. 14-526Docket No. 50-423Enclosure REPLY TO A NOTICE OF VIOLATION EA-1 4-092MILLSTONE POWER STATION UNIT 3DOMINION NUCLEAR CONNECTICUT, INC.
Serial No. 14-526Docket No. 50-423Enclosure, Page 1 of 3NOTICE OF VIOLATION "During an NRC Special Inspection conducted from February 3 through July 21, 2014,which included on-site inspection and in-office review of documents, and for which aninspection exit was conducted on July 21, 2014, a violation of NRC requirements wasidentified.
In accordance with the NRC Enforcement Policy, the violation is listed below:10 CFR 50, Appendix B, Criterion XVI, "Corrective Action,"
- requires, in part, thatmeasures shall be established to assure that conditions adverse to quality, such asfailures, malfunctions, deficiencies, deviations, defective material and equipment, and non-conformances are promptly identified and corrected.
Millstone Unit 3 Technical Specification (TS) 3.7.1.2.b, "Auxiliary Feedwater System,"
requires that at least three independent steam generator auxiliary feedwater pumps and associated flow paths be OPERABLE with one steamturbine-driven auxiliary feedwater pump capable of being powered from anOPERABLE steam supply system. The TS is applicable in Modes 1, 2 and 3.Millstone Unit 3 TS Limiting Condition for Operation Action Statement 3.7.1.2(c) states that, with one turbine-driven auxiliary feedwater pump inoperable, restorethe affected equipment to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOTSTANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the following 12hours.Contrary to the above, from August 11, 2013, to February 3, 2014, measuresestablished by Dominion Nuclear Connecticut, Inc. (Dominion) were not sufficient to assure that a condition adverse to quality involving Millstone 3 turbine-driven auxiliary feedwater (TDAFW) pump was promptly identified and corrected.
Specifically, in spite of the TDAFW pump experiencing three overspeed tripsduring this timeframe, Dominion did not identify that the pump was operating in anadverse configuration due to the installation, on May 12, 2013, of an inappropriate cam follower bearing within the turbine control valve linkage.
This discrepant condition rendered the TDAFW pump inoperable for periods of time exceeding thelimiting condition for operation specified in Millstone 3 Technical Specification (TS)3.7.1.2.This violation is associated with a White Significance Determination Process finding."
Serial No. 14-526Docket No. 50-423Enclosure, Page 2 of 3Response to Notice of Violation
- 1) Reason for the violation, or, if contested, the basis for disputing the violation or severity levelThe reason for the violation is that DNC did not perform adequate troubleshooting todetermine the direct cause of repeat failures of the TDAFW pump to run as expected.
The direct cause of the TDAFW pump overspeed trips on November 4, 2013, December18, 2013, and January 23, 2014, was the installation of an incorrect cam followerbearing (made by Sealmaster) which caused the steam control valve linkage tointermittently stall in the open position.
The incorrect cam follower bearing had beenshipped from Dresser-Rand with a correct certificate of conformance (C of C) and withthe same part number as the correct bearing (made by Heim). Acknowledgement ofthis discrepancy was formally recognized when Dresser-Rand later issued a notification in accordance with 10 CFR 21 on this issue.After replacement of the Unit 3 Sealmaster bearing with another Sealmaster bearingfollowing the January 23, 2014 trip, DNC had additional discussions with Dresser-Rand regarding failure mechanisms.
On January 30, 2014, it was determined that Dresser-Rand had shipped the incorrect cam follower bearings to Millstone.
The correct camfollower bearing (by Heim) was installed on February 3, 2014.In addition, on January 31, 2014, DNC verified that the cam follower bearing on the Unit2 TDAFW pump was the correct bearing.2) Corrective steps that have been taken and the results achievedThe cam follower bearing was replaced, the governor was adjusted, and the TDAFWpump was tested satisfactorily.
No additional overspeed trips have occurred since thecam follower bearing was replaced with the proper bearing.DNC has implemented a TDAFW pump troubleshooting guide. The TDAWF pumptroubleshooting guide includes methods for validating assumptions and conclusions specific to the TDAFW pump (e.g., pull test technical basis and acceptance criteria).
The troubleshooting guide also includes industry standards such as those in theElectrical Power Research Institute (EPRI) Terry Turbine Maintenance Guide -AFWApplication.
DNC also revised procedure MA-AA-103, "Conduct of Troubleshooting."
The procedure now includes a requirement to assign a manager the responsibility to provide oversight of complex troubleshooting team leads (TTLs). The responsibilities of the managerinclude ensuring assumptions and conclusions are properly validated.
These changeswere implemented during troubleshooting activities performed after August 25, 2014.Two case studies were developed based on the results the root cause evaluation performed for this issue. The first case study included a review of INPO'S "Traits of a Serial No. 14-526Docket No. 50-423Enclosure, Page 3 of 3Healthy Nuclear Safety Culture,"
and was delivered to first line supervisors and above.The second case study is associated with the engineering issues identified in the rootcause evaluation.
This case study was delivered to the engineering staff duringengineering support continuing training in July and August 2014.During the recently conducted Millstone Unit 3 refueling outage, blueprinting wasperformed on the TDAFW pump's steam control valve linkage using vendor suppliedproprietary drawings to ensure the linkage meets optimum tolerances.
- 3) Corrective steps that will be takenEffectiveness reviews will be performed to assure the adequacy of the implemented corrective actions.4) Date when full compliance will be achievedThe specific condition adverse to quality was identified and corrected.
Thus, theTDAFW pump has been returned to full compliance regarding the discrepant condition (i.e., inappropriate cam follower bearing) described in the violation.
The finaleffectiveness review of the corrective actions is scheduled for completion by January30, 2015.