ML20099H737
| ML20099H737 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 02/27/1985 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-32013-TDS, DER-84-106, NUDOCS 8503190475 | |
| Download: ML20099H737 (8) | |
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c Arizona Nuclear Power Project ;7 gn,
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P.O. BOX $2034 e PHOEN!X, ARIZONA 85072-2034 February 27, 1985 ANPP-32013-TDS/TRB U. S. Nuclear Regulatory Commission Region V 1450 Maria Lane - Suite 210 Walnut Creek, CA 94596-5368 Attention:
Mr. D. F. Kirsch, Acting Director Division of Reactor Safety and Projects
Subject:
Final Report - DER 84-106 A 50.55(e) Reportable Condition Relating to Spurious Load Shed Of BOP ESFAS File:
85-019-026; D.4.33.2
Reference:
A) Telephone Conversation between P. Narbut and T. Bradish on December 27, 1984 B) ANPP-31792, (Interim Report) dated January 24, 1985
Dear Sir:
Attached is our final written report of the deficiency referenced above, which has been determined to be Not Reportable under the requirements of 10CFR50.55(e).
Very truly yours, 1
A C q_
1 b
h A LLk E. E. Van Brunt, Jr.
APS Vice President, Nuclear Projects Management ANPP Project Director EEVB/TRB/pik Attachment cc:
See Page Two 8503190475 850227 h.8 PDR ADOCK 05000528
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e Mr. D. F. Kirsch DER 84-106 Page Two cc: Richard DeYoung, Director Office Of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 T. G. Woods, Jr.
D. B. Karner W. E. Ide D. B. Fasnacht A. C. Rogers L. A. Souza D. E. Fowler T. D. Shriver C. N. Russo B. S. Kaplan J. R. Bynum J. M. Allen D. Canady A. C. Gehr W. J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher H. D. Foster D. R. Hawkinson R. P. Zimmerman M. L. Clyde M. Matt T. J. Bloom D. N. Stover J. D. Houchen J. E. Kirby Records Center Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, GA 30339
T FINAL REPORT - DER 84-106 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICE COMPANY (APS)
PVNGS UNITS 1 I.
DESCRIPTION OF DEFICIENCY Two spurious load sheds and sequencer lock-up events of the Unit 1 Train B BOP ESFAS occurred on December 13, 1984.
The loads that were shed were the Train B 4160V switchgear 304 feeder breaker and
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associated 480V load center breakers.
These events occurred prior to fuel load. The plant was in normal operating configuration and alignment and no testing or change of operating conditions were being performed. The two events occurred four hours apart.
EVALUATION Immediately after the first load shed and sequencer lock-up event, several unsuccessful attempts were made to reset the processor in the load sequencer module. Then the BOP ESFAS was deenergized and allowed to cool for approximately 30 minutes. When the system was reenergized and the processor reset, the sequencer operated normally.
Then af ter a period of approximately four hours, the sequencer module went into load shed mode and locked up.
This indicated that one or more components were no longer performing to capacity and were failing after a short period of operation.
The sequencer module was removed from the Unit 1 Train B BOP ESFAS, installed in a Unit 2 system, and retested. After a short period of operation, it failed in the same manner, indicating that the problem was within the sequencer module itself and not attributable to the rest of the ESFAS.
The sequencer module was then removed and put into a test area for further investigation and troubleshooting.
It was found that three components, two integrated circuits and one voltage regulator were failing after a period of time in their normal operating environment.
The sequencer functions associated with the two integrated circuit failures are (1) the test enable lines, which control special testing functions of the Loss of Power / Load Shed (LOP /LS) module, and (2) the one second pulse output to the LOP /LS module.
The function of the voltage regulator is to supply +5 V-de to a portion of the integrated circuit modules.
A review of these component failures by the BOP ESFAS vendor was conducted (see referenced letter) and it was verified that the root cause of the problem was random failures of the components.
These failures do not indicate any inadherent design deficiencies and are eval-uated as an isolated component failures under the plant maintenance program.
Mr. D. F. Kircch DER 84-106 Page Two The BOP ESFAS failure mode addressed herein cannot go undetected be-cause it is readily recognized by alarms on the station annunciator, and immediate action can be taken by the operator to rectify the condition by replacement of the sequencer module with a spare.
II.
ANALYSIS OF SAFETY IMPLICATIONS This condition is evaluated as not reportable under the requirements of 10CFR 50.55(e) and 10 CFR Part 21 since the condition does not consitute a safety significant condition.
Should this failure remain uncorrected for some finite period of time, Technical Specificaitons require that the plant will be brought to shutdown conditions.
Specifically, instrumentation affected by the loss of the Train B BOP ESFAS is covered by Technical Specification 3/4.3.2.
For the most vital instrumentation, the operator is allowed a minimum of one hour prior-to taking action to secure power operation.
Further, the loss of power is covered by Technical Specification 3/4.8.3, which allows the operator a minimum of eight hours prior to taking action
- to secure power operation.
III. CORRECTIVE ACTION The corrective action for the Unit 1 Train B BOP ESFAS was to replace sequencer module with a unit from spares and put the system back into service. The failed sequencer module has been repaired by replacing the two integrated circuits and voltage regulator, retested and returned to-spares.
IV.
REFERENCE Letter, Sorrento Electronics to Bechtel Power Corporation, February 20,.
1985, MIC No. 239867.
SorrCnto Electronic) 11045 Sorrento Valley Cow San Diego, California 9212 (619) 4F7-882 February 20, 1985 Bechtel Power Corporation h
12440 East'Icaperial H18 way Norwalk, CA 90650 Atens Mr. E G. Dingham Project Engineerin5 Manager Subj ect s Arizona Nuclear P'ower Project BOP ESFAS Reliability and Maintenance Support
Reference:
Your latter dated December 28, 1984, same subject
Dear Mr. Bingham:
The primary purpo[e of this letter is to prov'ide y'on with the resuits of our reliability ' investigation regarding several BOP ESFAS Module f ailures Additionally, which have occured at tha Palo Verde Nuclear Generating Station.
it presents reconusendations to enhance long-term supportability of the equipmenG A.
Hodule Failures 18-20, 1984-and January 8-17, 1985, Mr.
During the period of December Evi Rendel, GA Support Engineer, provided onsite troubleshooting and repair assistance to ANPP maintenance personnel. A surmary of the module f ailures which he encountered 'and his corrective action is presented in the Table 1.
Based on a thorough review of tliese failures by the BOP EShAS designer and our reliability engineer, we con' elude that the failures are clearly This con-random and do not indicate any inherent design deficiencies.
clusion is also supported by the fact that.the system faay have,been subjected to abnormal conditions during a lengthy start up, including extremely high temperatures high ground noise, and an incident of ground coonected to power.
B.
Equipment Supportability In response to your refcienced letter, the following provides.r.wo rusintenance strategios which will optimize the long te'rm supporta-bility of the equipment.
A DNiston of GA Technologies Inc.
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Maximum onsite maintenance supp' ort - a strategy of high f
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ANPP self-reliance, including a.
Test.8et(s)
A complete test cabinet that simulates the total BOP ESFAS operation for test and comprehensive trouble-shooting capability to the piece part level.
It uti-lizes a bank of spara modules (7) which is lef t in the auto test mode until a replacement module is required.
The test set can also be used as hands-on learn'ing
- device, b.' Spe'ra Hodules -
Two spare $6dules for each design (four) per train, or 24 total for the station. This considers a one module insurance level against incorrect troubleshooting, and assumes independent parts storage for each unit (Train
.A and E).
L c.
Spara Parts Five year spare part stock for each unit, based on an ana-lysis of the equipment design, including identification of critical /non-critical parte, part count, part availability (e.g. high threshold logic), failure rates, etc. Initial recommendation is 30% of total part count for critical it'eus 20% for non-critical, and 10% for low failure rate or readilg obtainable. parts or components.
d.
Training and Publications
- Onsite training for ANPP personnel concerning test set operac tion and module troubleshooting and repair techniques. An operational and maintenance manual would also be included with each test set.
l e.
Technical Support T
OA Field Service Support as required.
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2.
Minimum onsite amintenance suppnet - A strategy of minimum.
I" ANPP self-reliance by caly stocking modules onsite and re-lying on CA's San Diego facility for module repair and test.
We recommend that the first strategy of maximum onsite maintenance
.' support capability be given serious consideration, in view of the availability requiremen.ts at Palo Verde.
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In summary, the results of our reliability investigation indicate no~ deficiency in the design of the equipment. We also recoseend a plan to provide maximum onsite maintenance support.
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' Mr. Bingham, I look forward 'to further comanunications with you to addreas our recessmendations for increasing availability of the BOP i
RSFAS at Palo Verde.
t
- Regards, A
r a
A.L. Chandler Hanager, Logistice Support ect Ted Chandler Milt Jones Dennis Nau Zvi Rendel Bob Weddel Jirn Winso-e f
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140. OF FAILURES /sve.uis
'- CAUSE CORRECTITR ACTION
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CRTSTALNALTUNCfION IINiutollE LOAD w.yue m - 002 1
ULN2003A (DARLINCION REPLACEb.-
IDAD SEQUENCER
.003 1
PAIR) FAILED V.
1 POOR RIBBON CABLE TO BE REFLACED
'j tohD SEQUENCEE - 006 CatefBCTION e,
I4AD SEQUENCER - 010 2
j, 17406N (HEK INTERTER) FAILED REPLACED VOLTAGE REGULAIOR PAILED REPLACED FBEVAS
- 016 1
R-S TLIP-TLOP YAILED~
REPLACED
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L0e/LS
- 002
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I ULH 2002A (DARLINION PAIR).
IC AND SOCEET FAILED TO BE REPLACED TUIAL........ 7 e
5 TABLE 1 SUtMARY OF 100ULE FAILURES /EVEFIS-1 f
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