Information Notice 1986-13, Standby Liquid Control System Squib Valves Failure to Fire
| ML031220585 | |
| Person / Time | |
|---|---|
| Issue date: | 02/21/1986 |
| From: | Jordan E L NRC/IE |
| To: | |
| References | |
| IN-86-013 | |
| Download: ML031220585 (5) | |
L lSSINS No.: 6835 UNITED STATES 1atD ihr NUCLEAR REGULATORY
COMMISSION
Vice President
Nuclear OFFICE OF INSPECTION
AND ENFORCEMENT
FEB 24 198 WASHINGTON, D.C. 20555 Route To: February 21, 1986 IE INFORMATION
NOTICE NO. 86-13: STANDBY LIQUID CONTROL SYSTEM SQUIB VALVES FAILURE TO FIRE
Addressees
All boiling water reactor facilities
holding an operating
license (OL) or a construction
permit (CP).
Purpose
- This notice is to alert addressees
to a potentially
generic problem with explosive
squib valves used in the standby liquid control system. Recipients
are expected to review the information
for applicability
to their facilities
and consider actions, if appropriate, to preclude similar problems occurring
at their facilities.
However, suggestions
contained
in this information
notice do not constitute
NRC requirements;
therefore, no specific action or written response is required.Description
of Circumstances:
During a recent routine surveillance, Vermont Yankee found that squib valves used in both pathways of the standby liquid control system (SLCS) failed to fire. The failure of the squibs to fire was caused by two problems.
One problem was that the plant had changed the wiring in the terminal box to the squib valves firing circuit and the other problem was incorrect
wiring of the connector
that is supplied with the squib valve primer charge.The explosive
primer charge assembly for the SLCS at Vermont Yankee was supplied by Conax Corporation.
The explosive
primer charge assembly has two sets of resistance
wires, i.e., bridgewires, internal to the charge either of which will fire the explosive.
However, some of the charges were manufactured
with incorrect
pin-to-bridgewire
groupings
so that when connected
at Vermont Yankee, two high-side
leads were connected
to one bridgewire
set and two neutral leads were connected
to the other bridgewire
set internal to the explosive
primer.Examination
of spare squibs at Vermont Yankee identified
four others with incorrect
pin-to-brigdewire
groupings.
The squibs are connected
to the plant's wiring via four pin connectors.
Incorrect
wiring at the Vermont Yankee local terminal box resulted in the sequence around the connector
being high, high, neutral, neutral. If the wiring in the terminal box had been according
to the design drawing and had been high, neutral, high, neutral, the squib charge would have fired even Copies to: Withers, Yundt, Lentsch, Orser, Steele, E. Burton, E. Jordan, A. Holm, LIS, C. A. Olmstead, S. Hoag, TNP:GOV REL F:NRC CHRONO, NRC TO PGE, TNP:GOV REL F:NRC IE Information
Notice No. 86-13 PGE OAR Action -None "Unique to BWR's" NO OAR ISSUED NSRD Action -M. H. Malmros
IN 86-13 February 21, 1986 though the pin-to-bridgewire
connection
was incorrect. (See Attachment
1.)In addition, at Vermont Yankee the control room indication
of SLCS circuit status indicated
circuit continuity
due to the presence of a sneak curcuit.At this time, it is not clear whether other primer assemblies, i.e., those manufactured
at a facility in Florida rather than New York, have the incorrect pin-to-bridgewire
groupings.
However, some potentially
suspect primer assemblies
are: Number Primer Part Assembly Plant of Pieces Serial Numbers 1617-139-01 Vt. Yankee 6 (defective)
552-557 1617-139-01 Dresden 6 546-551 1621-240-01 Shoreham 7 635-640, 668 1621-240-01 Duane Arnold 6 669-674 1621-240-01 Susquehanna
19 675-681, 686-697 1621-240-01 Limerick 10 699-708 1621-240-01 Pilgrim 3 659-661 NRC Regional representatives
have contacted
the above facilities
by telephone.
In addition, some of the explosive
primer charge assemblies
were provided to the NORCA Machinery
Company, Great Neck, New York for distribution
outside of the United States.The explosive
primer charge assembly may be tested for correct pin-to-bridgewire
grouping with an ohmmeter that is current limited to no more than 10 millamperes.
Larger currents will cause the charge to explode.Inquiries
concerning
this problem may be addressed
to: Conax Corporation
2300 Walden Avenue Buffalo, New York 14225 Mr. Art Haefner phone: (716) 684-4500 extension
233 IN 86-13 February 21, 1986 No specific action or written response is required by this information
notice.If you have questions
about this matter, please contact the Regional Adminis-trator of the appropriate
NRC regional office or this office.Edwar j./ Jordan, Director Divisi of Emergency
Preparedness
and E'gineering
Response Office of Inspection
and Enforcement
Technical
Contact: Eric Weiss, IE (301) 492-9005 Attachments:
1. Squib Schematic 2. List of Recently Issued IE Information
Notices
Attachment
1 IN 86-13 February 21, 1986 NW 1.6zE HElX.-.'AR/ZIA'6 P/N l ': END VIEW WIRING DIAGRAMS CORRECT X PIN-TO.BRIDGEWIRE
13 1.CONNECTION'
I---I4 I. L INCORRECT
I Z PIN-TO-BRIDGEWIRE
-I CONNECTION
-3 BRIDGEWIRES
,, BRIDGEWIRES
ATTACHMENT
1 -SQUIB SCHEMATIC
Attachment
2 IN 86-13 February 21, 1986 LIST OF RECENTLY ISSUED IE INFORMATION
NOTICES Information
Date of Notice No. Subject Issue Issued to 86-12 86-11 84-69 Sup. 1 86-10 86-09 Target Rock Two-Stage
SRV Setpoint Drift Inadequate
Service Water Protection
Against Core Melt Frequency 2/25/86 2/25/86 Operation
Of Emergency
Diesel 2/24/86 Generators
86-08 86-07 Safety Parameter
Display 2/13/86 System Malfunctions
Failure Of Check And Stop 2/3/86 Check Valves Subjected
To Low Flow Conditions
Licensee Event Report (LER) 2/3/86 Format Modification
Lack Of Detailed Instruction
2/3/86 And Inadequate
Observance
Of Precautions
During Maintenance
And Testing Of Diesel Generator Woodward Governors Failure Of Lifting Rig 2/3/86 Attachment
While Lifting The Upper Guide Structure
At St. Lucie Unit 1 Main Steam Safety Valve Test 1/31/86 Failures And Ring Setting Adjustments
All power reactor facilities
holding an OL or CP All power reactor facilities
holding an OL or CP All power reactor facilities
holding an OL or CP All power reactor facilities
holding an OL or CP All power reactor facilities
holding an OL or CP All power reactor facilities
holding an OL or CP All power reactor facilities
holding an OL or CP All power reactor facilities
holding an OL or CP All PWR facilities
holding an OL or CP 86-06 86-05 OL = Operating
License CP = Construction
Permit