ML20107M371

Annual Rept of Operations,1984

ML20107M371
Person / Time
Site:	05000433
Issue date:	12/31/1984
From:	Kroes R CALIFORNIA, UNIV. OF, SANTA BARBARA, CA
To:	NRC COMMISSION (OCM)
References
NUDOCS 8503010247
Download: ML20107M371 (4)

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'/ e UllIVERSITY OF CALIFORNIA, SAflTA BARBARA L-77 TRAIfilflG REACTOR ANf4UAL REPORT OF OPERATI0f1S January 1, 1984 through December 31, 1984 License R-124 Docket tio. 50-433 A.E. Proffo, Reactor Director February 14, 1985 n .

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/ ;c i Operating Experience, Changes and Tests This is the tenth annual report for the 10 watt, L-77 training reactor at the University of California, Santa Barbara. The reactor is operated mainly for instruction in nuclear engineering.

The L-77 reactor is the principal facility for the HE125 Ileutronics Laboratory course. The course is required for all B.S. degree majors in.

nuclear engineering, and may be taken as an elective by graduate students or majors in other fields. In 1984,.six students took the course for credit.

Experiments include power calibration by flux plotting, control rod reactivity calibrations by subcritical multiplication and super critical period measure-ments, reactivity worth (importance) of neutron absorbing and scattering samples at different positions within the through-core tube, and approach :to critical.

The students operate the reactor under_ supervision of a licensed operator.

The lab is offered in the Spring Quarter, once a week for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Senior Operator is Professor A.E. Profio. An operator trainee (Stuart Scheffel) performs

.the weekly alarm checks as well as maintenance of the reactor and instruments, with the help of other department employees.

.There were no significant changes in the facility in 1984, except for improved security precautions during the Olympic Games, with some measures remaining after the games.

Tests and Calibrations Performed:

Annual

. Power calibration 5-16-84 ok Control rod worth 5-2-84 ok .

Control inspection 2-8-84 ok

.Radmon/ cam cal. 2-16-84 ok Seismic calib. 'l-23-84 ok MA . Tank / console maint.' 2-29-84 .ok "l JSamiannual' _. ,

' l:f Rod drop times '5-24-84 (1-16-85) ok xjsnm Pressure ~scraWeal. 'l-5-84 10-17-84 ok

-W% Shield water scram 1-5-84 10-17-84 ok W

. Flux instr / rec. cal. 7-20-84 due 1985 ok Rad / cont. survey 4-17-84 12-17-84 ok Radiation and security alarms were checked weekly.

Unscheduled Shutdowns and Scrams 2-21-84: Spurious period scram from electrical transient on switching rod drive.

3-16-84: Spurious period scram on moving rod down to level at 8.3 watts.

3-26-84: Spurious period scram on raising reg. rod, still subcritical.

• Note:. maintenance 4-8-84 greatly reduced tendency to scram from rod switching.

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12-17-84:._ Scram on improper range switching on picoameter.

Preventive and Corrective flaintenance Operations Spurious period scram problem was solved when shunt resistor in picoameter, inadvertently left out when last calibration was made, was replaced.

Normal preventivemaintenance was carried out.

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There were a number of false security and radiation alarms, some of which were related to momentary power outages:

1-30-84: False radiation alarm, probable electrical power transient.

- 4-16-84: False security (motion detector) alarm, cause not determined.

4-17=84: False motion detector alam. Sensitivity may be too high, reduced.

4-29-84: False air monitor radiation alarm: trip point set too low.

6-9-84 : .~alse security alarm. No signs of entry. Cause not determined.

9-11-84: False area radiation alarm: power outage.

10-14-84: False security alarm. No sign of entry. Cause unknown.

10-15-84: False security alarm. No sign of entry. flay be faulty sensor.

Changes Under 10 CFR 50.59 None.

Radioactive Effluents Discharged Liquid wastes: none.

Solid wastes: Very low level contaminated gloves and similar items dosposed to radwaste container for pickup and off-site disposal by contractor, through Environ-mental Health and Safety Office on campus.

Gaseous Wastes: Not discharged during operation as core-recombiner vessel is sealed and under vacuum. The core-recombiner vacuum (pressure) gage is recalib-

, rated,a nd the loss-of-vacuum alam and trip are tested semiannually,- by admitting air and then reevacuating into aholdup tank, for decay over the 6-8 months between tests. Short lived activities in the vessel gas space decay between tests.

Long lived hetivity, in particular 10.4-year half-life krypton-85, is discharged to the atmosphere (mixed with room exhaust air) when the holdup tank is evacuated.

3 QCalculations based on watt-hours of operation, fission yield of krypton-85, and

.:gQ conservatively neglecting radioactive decay, give for activity discharged in M;fA1984:;0.13; microcurie, negligible heelth effect.

w;nte  ; a W -Environmental-Surveys Done Outside Facility -

ep "I semiannaul Radiation levels are measured immediately outside the facility as part of the nf ~

radiation-contamination surveys. All were background level or lowest measureable (less than 0.1 mR/hr).

Significant Radiation Exposure

. None.

Energy Output in 1984

. 15.7 watt-hours-Hours Critical in 1984 16.2 Energy Output Since Initial Criticality 343.1 watt-hours (14.3 watt-days).

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• , UNIVERSITY OF CALIFORNIA. SANTA BARBARA omu. . .. . . m . . . . . . . . . . . . . . . . . . . . .

David Piergx>nt Gardner UFFICE OF Tile CHANCEL!DR

/Yrnidrat of fAc Unirersity SANTA IIARHARA. CALIFORNIA 9.1hm1 Rolert A. liuttenback

> canarruor at santa nar6 ara February 21, 1985 U.S. Nuclear Regulatory Commission

! Washington, D.C. 20555 i

j Commission Members; 3 Please find enclosed the University of

{ California at Santa Barbara L-77 training i reactor annual report of operations for 1 1984, reference License R-124, docket no.

l 50-433.

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If further information is required, please contact Dr. A.E. Proflo, Nuclear and Chemical Engineering, UC Santa Barbara (805) 961-3788.

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1 Robert J. Kroes l Vice Chancellor l Administrative Services i

cc: A.E. Profio i

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