Information Notice 1986-13, Standby Liquid Control System Squib Valves Failure to Fire

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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