ML20206A864

Ro:On 860527,after Reactor Startup Following 10-day Programmed Shutdown,Readings of Certain Thermionics Data Showed Slightly Higher Secondary Pressure than Desired. Fused Light Circuit Not Operating.Right Fuse Installed

ML20206A864
Person / Time
Site:	General Atomics
Issue date:	06/05/1986
From:	Asmussen K GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER
To:	Harold Denton Office of Nuclear Reactor Regulation
References
67-9012, NUDOCS 8606180381
Download: ML20206A864 (3)

Text

r s

@ In Reply G A Technologies Inc.

Refer To: 67/9012 PO. BOX 85608 SAN DIEGo. CAUFORNI A 92138 5 June 1986 (619) 455-3000 Mr. Harold R. Denton Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Docket No. 50-163: Reactor Facility License R Possible Reportable Occurrence.

Dear Mr. Denton:

On Wednesday, May 28, 1986, the NRC office of Region V was notified by telephone of a possible reportable occurrence concerning the TRIGA Mark F Reactor (R-67). Upon a careful rereading of the pertinent section of the Technical Specifications, i.e., Section 10.2.6(g), it may be that this is not a reportable occurrence. However, upon further investigation of the event, another aspect of the related thermionics operation may be report-able. Both aspects are reported herein.

At 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> on May 27,1986, about 3-1/2 hours after completing a reac-tor startup following a 10-day programmed shutdown, the on duty senior re-actor operator (SRO) was taking hourly readings of certain thermionics data when he discovered a slightly higher secondary pressure than desired in the in-core number 4 thermionic device. The latter is a non-fueled thermionic test and an alarm is not required by the Technical Specifica-tion. Taking all the correct steps in the notification procedure, he con-tacted, among others, the thermionic test engineer for guidance. At this juncture he found that the fused light alarm circuit at the reactor con-sole was not operating and that the associated reactor room audible alarm could not function. The SRO then instituted control of personnel entry into the reactor room. This extra control was continued on the following shift and lasted until the fuse in the light alarm circuit was replaced with a slightly larger fuse by an electronic technician (about 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on May 28). These facts were reported to Region V on May 28.

The confusion as to whether this is a reportable occurrence arises from the interpretation of the intent of 10.2.6(g). Section 10.2.6(g) re-quires a pressure sensing device capable of indicating a leak in the purgeable secondary contaiment be operable. We believe that the routine prompt notification of the reactor console operator by the computer print-er (at the same console) with or without the console alarm light and aud-ible alarm within the reactor room is sufficient under 10.2.6(g) because the reactor operator has complete control of entry to the reactor room 8606180381 860603 DR ADOCK 0500 1 3 gg 10955 JOHN JAY HoPKINS DR , SAN DIEGO CAUFoRNIA 92121

t 1 H. R. Denton 67/9012 '

and, for anyone in the reactor room, he can order immediate personnel evacuation from the reactor room. While we-normally provide an audible

~ alarm in. the reactor. room, it appears that the intent of 10.2.6(g) is met without such a' reactor room alarm.

A further review of the events surrounding the failure of-the light alarm

- on the reactor console revealed the following additional information.

The repeater printer located at the reactor console which immediately identifies all thermionic alarms was not functioning when the inspection was conducted at 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> on May 27, 1986. It had, in fact, not been activated, as it is normally,' when full power was reached at the end of-the reactor startup, i.e., at 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> on May 27, 1986. The regular hourly data taken at the main thermionic computer assured that no alarms of any sort had in fact occurred since 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> until the slightly high pressure in device number 4. (It may be .noted that this pressure reached

- the alarm point only a couple of minutes prior to 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />.) Failure to activate the repeater printer was traced to the thermionic staff. whose job it is to activate this printer ' arter completion of all thermionics diagnosis and reactor. startups. In this instance, the thermionic engi-neer instructed the SRO on how to put it on line. Thus from about 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> on, the repeater printer performed its function as usual.

The . normal function of ,the repeater printer. is to alert the reactor op-erators to the several thermionic operating parameters that may. be out--

side desired limits. Except for the secondary containment pressure

[10.2.6(g)(1)] none of the other alarms is related to actions required under 'the Technical Specifications. -The alarm- on the computer printer for the secondary. containment pr' essure has been used as the means to meet the intent of 10.2.6(g)(1).

1he following actions have been- taken in' response to and as a' result of

~

our investigations of the event occurring on May 27:

1. A slightly larger fuse (0.5a instead of'0.25a)' was inserted in the console light alarm circuitry on May 28, 1986. Subsequently, on June 3,1986, the DC Sonalert circuit which was part of the console light '

alarm circuitry has been replaced by an AC Sonalert, a change intended to improve reliability. The fuses are now 2 amps.

2. The thermionic staff has been reminded of the important function that the repeater printer on the reactor console plays in meeting a lic-ense required specification (10.2.6(g)(1)). To this end a specific item is being added to their thermionic startup and thermionic diag-nostic checklist to require specifically that the repeater printer be activated and functioning.

s-. . ,

j.

l-l H. R. Denton 67/9012

3. A purchase order has been placed to provid; additional instrur:enta-tion.for the thermionic equipment that will provide indication of excessive secondary pressure directly to the reactor console rather than through the thermionic computer. When this modification is installed, the operation as regards the licensed required alarm

, [10.2.6(g)(1)] will parallel that presently used for the license required scrams [10.2.6(f)(1)].

.If you have questions concerning the above, you may call me at (619) 455-2823 or Dr. W. L. Whittemore at (619) 455-3277.

Very truly yours,

~

Keith E. Asmussen Manager, Licensing &

, Nuclear Compliance KEA:he cc: Mr. John B. Martin, NRC. Region V.

5 1

' N y.

l s:

0 i...,, . .. _, ., .