Information Notice 1986-89, Uncontrolled Rod Withdrawal Because of a Single Failure

Uncontrolled Rod Withdrawal Because of a Single Failure

ML031250343
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date:	10/16/1986
From:	Jordan E NRC/IE
To:
References
IN-86-089, NUDOCS 8610100105
Download: ML031250343 (4)

-t -SSINS

No.:

6835 IN 86-89

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555 October 16,

1986 IE-INFORMATION NOTICE NO. 86-89:-

UNCONTROLLED ROD WITHDRA4AL BECAUSI If

A SINGLE FAILURE

Addressees

All boiling water reactor (BWR) facilities holding an operating license or a

construction permit.

Purpose

This notice is to alert recipients of a potentially generic problem with a

single failure that can cause both a single control rod drift to the full-out

position and then failure to insert on demand.

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

On July 30, 1986, the Grand Gulf nuclear station experienced an uncontrolled

single control rod withdrawal to the full-out position while at 69 percent power.

When attempting to notch rod 20-45 from position 08 to position 10, the operator

noticed "rod drift" and "rod block" alarms and observed indications that the rod

was at position 12 and continuing to withdraw.

The operator pressed the insert

pushbutton several times and observed the illumination of the."in" light and the

"settle" light.

The repeated notch insertion attempts slowed the rod outward

movement, but the rod continued to withdraw to full-out position 48.

The

control rod took about 3 minutes and 10 seconds to travel from position 08 to

position 48 (which is about normal settle speed).

The operator carried out the actions required by the Alarm Response Instructions.

As a conservative measure, reactor power was reduced to 60 percent for thermal

limit concerns, and a coupling check was performed.

Once control of rod insertion

was regained, the rod was placed at position 44 and back to position 48 to test

the rod withdrawal limiter.

The rod was declared inoperable, fully inserted, and

hydraulically disarmed.

To determine the cause of the event, inspections and bench checks were performed

on withdraw control valve, C11-F422.

(This valve is designated 122 at some older

BWRs.) The valve demonstrated no sign of abnormal operation, and no fouling of

the valve seat was evident.

The licensee concluded that temporary particulate

IN 86-89 October 16, 1986 accumulation on the valve seating surface caused an incomplete closure of the

valve when the withdraw command was terminated, allowing drive water pressure to

leak past the valve and force the drive piston downward.

Subsequently, the withdraw control valve was replaced with a new valve and the

control rod restored to service.

During the upcoming refueling outage, the

licensee plans to check the drive water filters and sample low stagnant points

in the system for particulates.

The licensee has provided additional operator

instructions for control rod/drive malfunctions based on General Electric Service

Information Letter (SIL) 292 that was issued in July 1979.

The procedure

revisions include the following actions to be taken when control rods drive out

with no "withdraw command" present:

1. Application of continuous control rod insert signal until the rod reaches

zero.

If the control rod continues to withdraw from zero, reinsert the

continuous control rod insert signal and hold until either the control rod

drive pressure can be reduced or someone can isolate the affected hydraulic

control unit (HCU) by closing the 103 drive water riser isolation and 105 exhaust water riser isolation valves on the HCU.

2.

If the control rod drive does not respond to the insert signal, have

someone manually scram the rod from the HCU.

3. If the drive continues to demonstrate occurrences of inadvertent withdrawal, the control rod should be inserted to position zero and the drive should be

valved out of service until the fault is located and corrected.

After the

drive is valved out of service, the associated valve no. 122 and control

circuity should be checked and repaired if necessary.

Discussion:

There have been other instances when the withdrawal directional control valve

caused uncontrolled rod withdrawal:

Plant name

Date

Cause

Pilgrim

4/8/78

122 Valve Corrosion Products

Browns Ferry 2

6/24/80 85-40C Valve Failed (85-40C is

TVA designation for 122 Valve)

In addition, there have been events when uncontrolled withdrawal has been caused

by unknown reasons or a collet finger problem.

IN 86-89 October 16, 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.

A

. Jordan, Director

Divi

n of Emergency Preparedness

and Engineering Response

Eric Weiss, IE

(301) 492-9005 Attachment: List of Recently Issued IE Information Notices

Attachment 1

IN 86-09

October 16. 1986

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..:ce .c.

86-05 Suo. 1

86-25 Sup I

86-68

86-67

96-86

86-85

86-84 s6-63

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Oate ot

3Jc'#C:

ssse

main Steam Safetv valve Test

10/16/86

Failures Ana Ring Setting

Adjustments

Traceability And Material

10/15/86

Control of Material Ana

Equipment. Particularly

Fasteners

Coaevnsatory Measures For

10/15/86

Prolonged Periods Of Security

System Failures

Loss Of Offsltt

Power Upon An 10/10/86

Automatic Bus Transfer

Clarification Of Requirements 10/10/86

For fabrication And Export Of

Certain Previously Approved

-

Type S Packages

Enforcement Actions Against

10/3/86

Medical Licensees For

willfull Failure To Report

Misadministrations

Rupture Of A Nominal

9/30/86

40-1ill icuri* Iodine-125

Irachytherapy Seed Causing

Significant Spread Of

Radioactive Contamination

Underground Pathways Into

9/19/86 Protected Areas, Vital Areas,

Material Access Areas, And

Controlled Access Areas

Ss.ec tc

All po-.* reacto'

facilities

holding

an OL or CP ,

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP; fuel

fabrication and

processing facilities

All power reactor

facilities holding

an OL or CP

All registered users

of NAC certified

packages

All NRC medical

licensees

All NRC medical

institution licensees

All power reactor

facilities holding

an OL or CP; fuel

fabrication and

processing facilities

UPhTEO STATES

OL a Operating License

NUCLEAR REGULATORY COMMISSION

CP m Construction Permit

WASHINGTON. D.C. 20Z6

OSFICIAL BUSINESS

PENALTY FOR PAIVATE USE. *m

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