IR 05000528/1992017
| ML17306B008 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/17/1992 |
| From: | Richards S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Conway W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 9210010047 | |
| Download: ML17306B008 (20) | |
Text
ig,R REG(((
E Wp
+i
%v>>
'>>+<<+
Docket No.
50-528 50-529 50"530 UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION V
1450 MARIAIANE WALNUTCREE K, CALIFORNIA94596-5366
$ -F'
7 fgjQ Arizona Public Service Company P.
0.
Box 53999, Sta.
9012 Phoenix, Arizona 8507-3999 Attention:
Mr.
W.
F.
Conway Executive Vice President Gentlemen:
Thank you for your letter of August 14, 1992, in response to our Notice of Violation and Inspection Report No. 50-528/92-17, 50-529/92-17, and 50-530/92-17, dated June 29, 1992, informing us of the steps you have taken to correct the items which we brought to your attention.
Your corrective actions will be verified during a future inspection.
Your cooperation with us is appreciated.
Sincerely, ('~'pr -~)M ST A, Richards, Chief Reactor Projects Branch CC:
Mr. 0.
Mark DeMichele Mr. James M. Levine Mr.
R. Stevens Mr.
E.
C.
Simpson Mr.
S. Guthrie Mr. Thomas R. Bradish Mr. Robert W.
Page Ms.
Nancy C. Loftin, Esq.
Mr. Al Gutterman Mr. James A. Boeletto, Esq.
Mr. Charles B.
Br inkman Mr. Aubrey A. Godwin Chairman, Maricopa County Board of Supervisors Mr. Steve M. Olea Mr. Curtis Hoskins Roy P.
Lessy, Jr.,
Esq.
Bradley W. Jones, Esq.
Mr. Jack R.
Newman, Esq.
9210010047 920917 PDR ADOCK 05000528
t
SEP Iy >M bcc w/copy of letter dated 8/1M/92:
Docket File Inspection File Resident Inspector Project Inspector
.Mr. Martin Mr. Faulkenberry G.
Cook R.
Huey Region V/kjh 9/8/92 bcc w/o copy of letter dated M. Smith J. Zollicoffer FRingwald~
JSloan
~
9/l5/92 4~
9/i>/92 Lc% ~
8/19/92:
~~-b HWong 9/lq/92 SRichards 9/3 I/92 RE UEST C
PY RE UEST C
Y7 [
ST COPY RE VEST COPY YES NO YES NO YES NO YES NO SENB TO PDR YE NO
WILLIAMF. CONWAY EXECUTIVEVICEPRESIDENT NUCLEAR RECEIVED NRC REGIO;>.y Arizona Public Service Company P.O, BOX 53999
~
PHOENIX. ARIZONA85072.3999 9Q II>>r
IIuI3 t9 Io r7 102-02233-WFC/TRB/JNI August 14, 1992 U. S. Nuclear Regulatory Commission ATIN:.Document Control Desk Mail Station P1-37 Washington, DC 20555 Reference:
Letter dated June 29, 1992, from S. A. Richards, Chief, Reactor Projects Branch, NRC, to W. F. Conway, Executive Vice President, Nuclear, Arizona Public Service Company
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Units 1,2, and 3 Docket Nos. STN 50-528/529/530 Notice of Violation 50-528/92-17-01 File: 92-070-026 Arizona Public Service Company (APS) has reviewed NRC Inspection Report 50-528, 529, 530/92-17 and the Notice of Violation, dated June 29, 1992.
Pursuant to the provisions of 10 CFR 2.201, APS'esponse is enclosed.
Appendix A to this letter is a restatement of the Notice of Violation. APS'esponse is provided in Enclosure 1.
Per telephone conversations on July 27 and August 7, 1992, between H. J. Wong and S. A. Richards, NRC, and T. R. Bradish, APS, the due date for this response was extended from July 29, 1992, to August 14, 1992. This extension was necessary in order to respond to D. H. Coe's (NRC) request to include valve Sl-609 in our response to the Notice of Violation and to substantiate the probable cause of the incomplete thread engagement.
The referenced letter requested a description of the actions being taken to resolve the issue of feedwater isolation valve failures. 'These actions are described in Enclosure 2.
. If you should you have any questions regarding this response, please contact Thomas R. Bradish of my staff at (602) 393-5421.
Sincerely, gyp 5)
WFC/TRB/JJN f
Enclosures:,
Appendix A - Restatement of the Notice of Violation 2.
Enclosure 1 - Reply to the Notice of Violation 3.
Enclosure 2 - Feedwater Isolation Valve Action Plan cc:
J. B. Martin J. A. Sloan
APPENDIX A
.RESTATEMENT OF NOTICE OF VIOLATION50-528/92-1 7-01 NRC INSPECTION CONDUCTED APRIL 12, 1992-MAY30, 1992 INSPECTION REPORT NOS. 50-528, 529, AND 530/92-17
RESTATEMENT OF NOTICE OF VIOLATION50-528 92-I 7-01 During an NRC inspection conducted on April 12 through May 30, 1992, a violation of NRC requirements was identified.
In accordance with the "General Statement of Policy and Procedure for NRC Enforcement Action," 10 CFR Part 2, Appendix C, the violation is listed below:
Unit 1, 2, and 3 Technical Specifications 6.8.1 state in part:
'Written procedures shall be established, implemented, and maintained covering the activities..."
recommended in Appendix A of Regulatory Guide 1.33, Revision 2, February, 1978." Regulatory Guide 1.33, Revision 2, Appendix A, recommends procedures
.
for performing maintenance on safety-related equipment.
Procedure 30DP-9MP02, "Fastener Tightening/Preload," Revision 1.06, Step 3.1.5, states that "all bolts, stud bolts, and cap screws shall be engaged so that the bolts extend completely through the nuts.
The minimum condition that meets this criteria is for the end of the bolt to be flush with the face of the nut."
Contrary to the above, as of May 30, 1992, the NRC inspector identified the following safety-related components which had less engagement of the packing gland retaining nuts than required by procedure 30DP-9MP02:
2AFA-Y-014, 2AFA-V-067, 2AFA-HV-032, 2AFB-V-040, 3AFA-Y-151, 3AFA-Y-067, 3AFB-Y-023, 3AFB-V-083, 3AFB-V-094, and 3AFB-V-130. Additional deficiencies were identified by the licensee in Units 1 and 3.
This is a Severity Level IV violation (Supplement I) applicable to Units 1, 2, and 3.
ENCLOSURE't REPLY TO NOTICE OF VIOLATION 50-528/92-1 7-01 NRC INSPECTION CONDUCTED APRIL 12, 1992-MAY30, 1992 INSPECTION REPORT NOS. 50-528, 529) AND 530/92-17
REPLY TO NOTICE OF VIOLATION50-528 92-17-01 Reason For The Yiolation The reason for the violation was failure to followestablished procedures.
Arizona Public Service Company {APS) has reviewed the work history. of sixty documented cases of incomplete thread engagement to determine whether these bolted connections were reworked after full thread engagement was procedurally required.
APS has determined that five valves have been reworked and complete thread engagement was not achieved-.
when the valves were placed in service.
These valves are as follows: 1SI-609, 1AF-30, 1AF-32, 3SI-609, and 2AF-32. APS has determined that none of the sixty documented cases of incomplete thread engagement would have adversely affected the ability of the valves to perform their function.
An investigation was conducted to determine the cause for the incomplete thread engagement.
In the first case (1 SI-609), the work was performed by a contractor and an APS mechanic.
That contractor is no longer working at PVNGS. The APS mechanic was interviewed but was unable to recall any specifics of this work from the previous outage.
However, in the interview, the APS mechanic demonstrated that he is knowledgeable of the requirements for achieving full thread engagement.
1of4
e In the second, third, and fourth case (1AF-30, 1AF-32, and 3SI-609), the work was performed by contractors which are no longer working at PVNGS. The valves appear to have been restored to the as-found condition. 'APS has concluded that the contractors considered the studs/bolts and nuts to be completely engaged since little or no thread was exposed and may not have been aware of APS's specific requirement for the bolt/stud to be flush with the end of the nut.
I r
In the fifth case (2AF-32), one of the packing gland bolts was one-sixteenth inch short of being flush with the nut.
The APS mechanic involved in replacing the packing was interviewed regarding this condition. The mechanic remembered replacing the stem on the valve but could not recall any difficulties achieving full thread engagement.
The mechanic was fully aware of the requirements for full thread engagement.
The specific circumstances which led to the failure to follow the procedural requirement could not be determined.
APS believes that the most probable cause was the lack of knowledge of the requirement to achieve the stud/bolt flu'sh with the nut. This was substantiated when the training records for the contractors were reviewed and itwas determined that five of the six contractors had not completed training courses which specifically address the requirements for thread engagement.
APS has implemented or will implement corrective actions to address the probable cause.
2 of 4
Except for 2AF-32 as discussed above, nine of the ten valves listed in the Notice of Violation as having incomplete thread engagement have not had the nuts removed/restored since full thread engagement was required.
The requirement for full thread engagement was established in 1984 as corrective action for Deficiency Evaluation Report (DER) 84-53 which first documented the issue of thread engagement.
As a result of the DER, an evaluation was performed using a statistical sample.
APS determined that no safety significant conditions existed, and that the valves previously installed were acceptable for continued use. APS has performed an engineering review of documented instances of incomplete thread engagement since the issuance of DER 84-53 and has confirmed that the conclusion reached in DER 84-53 remains valid.
APS has evaluated the sixty documented cases of incomplete thread engagement.
APS has determined that none of the conditions identified would have adversely affected the ability of the valves to perform their function.
Briefings have been conducted with maintenance personnel, including the APS mechanics known to have been involved in two of the cases at issue, on the requirements for fasteners.
3of4
Corrective Ste s That Will Be Taken To Avoid Further Violations APS will revise the applicable initial training courses for APS maintenance personnel to include this event and the requirements for full thread engagement.
APS will develop an initial training course for contract personnel which will-include this event I
and the requirements for fullthread engagement.
Additionally, APS will include this event in the "Industry Events" course for APS and contractor personnel
~
This is to be completed by October 1, 1992.
Date When Full Com liance Will Be Achieved
'Full compliance was achieved on June 25, 1992, when the last Material Non-Conformance Report was dispositioned for the valves.
4of4
ENCLOSURE 2 FEEDWATER ISOLATION VALVEACTION PLAN NRC INSPECTION CONDUCTED APRIL 12, 1992-MAY30, 1992
\\
INSPECTION REPORT NOS. 50-528, 529, AND 530/92-17
FEEDWATER ISOLATION VALVEACTION PLAN APS is investigating the root cause(s)
of the Feedwater Isolation Valve failures associated with the "M" 4-way valve.
This investigation is currently in progress.
The investigation team is gathering industry, vendor, subvendor, and plant-specific data.
However, the June 9, 1992, failure of SG-132 "M"4-way valve which was discussed in the subject inspection report is unlike previous failures at Palo Verde which readily exhibited a failure mode.
Previous failures exhibited gross seal degradation and/or dislocation of 0-ring seals.
None of the seals removed from SG-132, which failed on June 9, 1992, exhibit this type of failure.
At this time, component parts of recently-failed valves are being or have been catalogued, inspected, photographed, and compared to nominal values. APS willcomplete the root cause evaluation to determine which corrective actions would be most effective.
The investigation is expected to be completed by September 30, 1992.
Engineering is also evaluating the best mechanism to retain the 0-ring for interface between the "M" 4-way valve submanifold and the actuator.
Additional data is being pursued to determine alignment tolerances and design basis for the diameter and location of the 0-ring. Prior to designing and approving the modification, this information will be reviewed to ensure no adverse consequences are created.
This evaluation is expected to be completed by October 1, 1992,