ML20004F776
| ML20004F776 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay, Palo Verde |
| Issue date: | 04/22/1981 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| Shared Package | |
| ML20004F773 | List: |
| References | |
| NUDOCS 8106220327 | |
| Download: ML20004F776 (1) | |
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UNITED STATES
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g NUCLEAR REGULATORY COf.1 MISSION r.
REGION V 8
1900 N. CALIFORNIA BOULEVAAO 4
SUITE 202, WALNUT CREEK PLA2A g*,,e a WALNUT CREEK. CALIFORNIA teses April 22,1981 Docket Nos. 50-528, 50-529, 50-530 Arizona Public Service Company P. O. Box 21666 Phoenix, Arizona 85036 Attention: Mr. E. E. Van Brunt, Jr.
Vice President, Nuclear Projects Gentlemen:
The enclosed infonnation notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time. If further NRC evaluations so indicate, an IE circular or bulletin will be issued to recomend or request specific.ltcensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, R. H. Engelken Director
Enclosure:
IE Infonnation tiotice No. 81 15 cc w/ enclosure:
F. W. Hartley, ApS 8106220] D
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s SSINS No.: 6835 Accession No.:
8011040286 IN 81-15
.UNfTED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFMCEMENT
' WASHINGTON, ' D.C.
20555 April 22, 1981 V
IE Information Notice No. 81-15: DEGRADATION OF AUTOMATIC ECCS ACTUATION CAPABILITY BY ISOLATION OF INSTRUMENT LINES
' Description of Circumstances:
0n March 23, 1981 at Georgia Power Company's Hatch Unit 2, an instrument technician, while investigating a drywall low-pressure alam, focnd that seven of eight isolation valves _were closed.
The eighth valve was found s1.ightly open and was considered as being functionally closed.
These safety-related valves'(also identified as panel or root valves) isolated twelve instruments
- that automatically actuate emergency core cooling systems (ECCS), reactor protection system, and containment isolation systems on high drywell pressure.
The capability for manual actuation of the affected systems was continuously available from the control room. However, had a loss-of-coolant accident occurred, all systems would. have been actuated by a redundant signal of low 4
reactor water level, except for the automatic depressurization system.
Those valves discovered to be closed were opened, valve alignment checks were per-formed, and no other discrepancies were found.
Tnese isolation valves were incorrectly identified as instrument drain valves and were closed on March 9, 1981 during completion of a valve lineup procedure. The drain valves that were L
beingf elosed were on other safety-related lines that were of the same size and appearance as the high drywell pressure instrument lines that were isolated.
t-Another event involving closure of some similar isolation valves was recently reported by the Peach Bottom Unit 2 licensee on April 1,1981. The closed valves were found by a licensee employee who was troubleshooting an intennit-tent drywell pressure. switch trouble alann. Only one isolation valve was found fully closed, whercas two other valves were found one-eighth turn open (but considered closed for review of protective system responses). Redundant channels were verified to be operabic; thus, no automatic protective or i
emergency cooling system actuation would have been lost from the high drywell i
pressure. signal.
- This information is provided as an early notification of a possibly signi-ficant matter that is stil1~ under review by the NRC staff.
In case the continuing NRC review finds tnat specific licensee actions would be appro-priate, an IE bulletin or circular may be issued.
In the interim, we expect that licensees will review this information for applicability to their oper-ating procec'ures, paying particular attention to valve aliSrment checklists and requirements for independent verification of valve alignments including
. instrument valves.
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IN 81-15 April 22, 1981 Page 2 of 2 No written response to this information notice is recuired.
If you need additional information with regard to this matter, contact the Director of the
. appropriate NRC Regional Office.
' Attaihment:
Recently issued IE Information Notices 4
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Attachment IN 81-15 April 22, 1981 P.ECENTLY ISSUED IE I!!FORMATI0fl NOTICES f
Information Date of Notice No.
Subject Issue' Issued to 81-14
_ Potential Overstress of 4/17/81 All power reactor Shafts on Fisher Series -
facilities with an 9200 Butterfly Valves OL with Expandable T Rings 81-13 Jamned Source Rack in a 4/14/81 Specified Irradiator Gamma Irradiator licensees 81-12 Guidance on Order Issued 3/31/81 All BWR facilities January 9,1981 Regarding with an OL or CP Automatic Control Rod Insertion on Low Control Air Pressure 81-11 Alternate Rod Insertion 3/30/81 All BWR facilities for BWR Scram Represents with an OL or CP a Potential Path for Loss of Primary Coolant 81-10 Inadvertant Containment 3/25/81 All power reactor Spray Due to Personnel facilities with an Error OL or CP 81-09 Degradation of Residual 3/26/81 All power reactor Heat Removal (RHR) System facilities wiUi an OL or CP 81 08 Repetitive Failures of 3/20/81 All power reactor
- Limitorque Operator SNB-4 facilities with an Motor-to-3haf t Key OL or CP 81-07 Potential Problem with 3/16/81 All power reactor Water-Soluble Purge Dam facilities with an Materials Used During OL or CP Inert Gas Welding 81-06 Failure of ITE Model 3/11/81 All power reactor K-600 Circuit Breaker facilities with an OL or CP OL = Operating Licenses CP = Construction Permits
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