ML20012E066

RO 90-01:on 900228,reactor Operator Received Servo Fault Alarm.After Directed Shutdown,Complete Loss of Linear Power Channel Noted.Caused by Corroded Connector at Detector Leads.Connector Replaced.Part 21 Related

ML20012E066
Person / Time
Site:	05000128
Issue date:	03/09/1990
From:	Ives T TEXAS A&M UNIV., COLLEGE STATION, TX
To:	Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
REF-PT21-90-038-000 90-01, 90-1, PT21-90-038-000, PT21-90-38, NUDOCS 9003300021
Download: ML20012E066 (2)

Text

.

p.

m '..

1 o.

+

1.;.

TEX AS ENGIN EERING EXPERIM ENT STATION TEXAS ~ A&M UNIVERSITY COLLEGE STATON, TEXAS 77643 3575 l'

E 9 March 1990~

NUCLEAR SCIENCE CENTEP 409/845-7551... ~.-w m

n._:=hbkhk! if;'\\

.fN

'Mr. Robert D. Martin jj:

hl i

I

. Regional Administrator g; $lggQ I

U.S. Nuclear Regulatory Commission j

l i

- Region' IV, 611 Ryan Plaza Drive L

a Suite 1000 o

Arlington, Texas 76011-

~

Dear Mr. Martin:

I am forwarding the final report of the reportable occurrence of 28' February 1990.

This. report. is-being submitted in accordance.with the reporting requirements of Technical Specification 6.6.2 for License R-83, Texas Engineering Experiment

.. Station / Texas A&M University System.

-Respectfully,.

f y

Thomas W. Ives,, Manager

. Reactor. Operations TWI/ym Enclosure oc:' Dr. K. R. Hall, Deputy Director, TEES Dr. K. L. Peddicord, Assistant Director, TEES Dr. J. W. Poston, Head, Nuclear Engineering Mr. F. Jennings, Chairman, Reactor. Safety Board Mr. S. - H. Weiss, USNRC, Washington,- D.C.

Mr. D. E. Feltz,. Director, NSC Dr. J. A. ' Reuscher, Director, Nuclear Research Reactor Programs, NSC L

Mr. B. Ernsti American Nuclear Insurers

~

~9'0033O0021 900309 k

PDR ADOCK 05000128 S

PDC g

YY l@0 -$13" neseancn ano oevetoeueur von usnxino

f-U K

+

y 4

-4;

7

e 1.-

4 - '

n

!S Reportable Occurrence 190a01 4

Failure'of Linear Power _ Channel Operation-

+

as Specified in the Technical Specification ll r

DESCRIPTION-

[

,t i

F J On; Friday ~ ; 28 ' February 1990, at approximately 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, the reactor operator.

~

received; a Servo Fault Alarm.

The operator looked at-the~ linear power meter and V

noted an indication of approximately 50%.

The ' Senior-Reactor-Operator soon after -

-t the alarm,' noticed.the : Log Channel and both Safety Channels reading Lapproximately

+

1 1005.-

The Senior Reactor Operator directed a shutdown and the Reactor Operator -

t i

performed a normal shutdown of the reactor.

During the shutdown a complete loss of-E.

j theLLinear Power Channel was noted. -Troubleshooting _of the Linear Channel ' began.

J

?

';immediately. 'The Electronics. Technician found a corroded connector at the detector jkv leads.

Ontthe sameLevening of the occurrence, the connector was replaced and. pre- '

M d

parations were started for a power calorimetric to be performed > the. following day.

I"

.The Linear ~ Channel-high v'oltage was left on overnight.

The following morning, the Ldetector was not responding' properly to the decay. gammas from.the core.

After h.

f troubleshooting it was found that the -voltage connections. to the detector had been W

reversed 'following initial; maintenance causing an. incorrect response. to the gammas 4

from the< detector. 'Arter-the leads were properly connected, the detector.' responded ~

asLexpected toithe decay gammas and the neutron source.

O g;

SAFETY: ANALYSIS AND EVALUATION The nfailure' of the linear power channel during reactor operations resulted ? in -

U.

-immediate ' action to prevent - operation of the reactor without one 'or the ' Reactor:

9 Control Systems required in' Tech Spec 3,2.1.

Therefore, i this : incident falls. under

' the : reporting nreqtiirements for Reportable-Occurrences of Tech Spec _'1.29(c).

As' soon:as itjas; determined that the channel was malfunctioning,' operations personnel commenced:aireactor shutdown.

The ' loss of the linear power l measuring channel did

.not ? result?in? any. safety. limits = being exceeded Land all automatic safety.. systems

.i

[

remained : operable throughout the incident.

The corroded connector was the only.

.g problem found in the whole Linear-Power Measuring Channel'.

After,. replacement of

- ithis connector, no other_ problems were observed.

-4

. CORRECTIVE MEASURES Fb11owingallcorrectivemeasures,.a'. power.calorimetricwasbeguntheafternoonof' I

-1' March 1990. 00n.the morning of 2 March 1990,.the power calorimetric procedure was-completed ; satisfactory. -

On Tuesday, 6 March - 1990, the night crew observed : a

[

s Esatisfactory Compensating: Voltage Check of the linear channel.

The_. channel performedL correctly through all required checks, and,is currently working as L well ins.-it did prior. to.this ' incident.

It is obvious to the NSC. staff that the only 1

.cause of the Linear Power.ChannelcFailure was-the corroded connector,'and that the4 L NSC-operations staff can' expect reliable operation from this measuring channel.

M

c

.f 5

i i

[

i

?

J