ML20148S048

Annual Rept from Univ of Washington

ML20148S048
Person / Time
Site:	05000139
Issue date:	12/31/1987
From:	Robkin M WASHINGTON, UNIV. OF, SEATTLE, WA
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8802020331
Download: ML20148S048 (7)

Text

- B B

ANNUAL REPORT FROM THE UNIVERSITY OF WASHINGTON Facility License _R-73 Docket No. 50-139 i

A. A Narrative Summarv c1 Ooerating Exoerlence int 1987 The ~Un iversity of Washington Nuc l ear Reactor was operated for 158.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> (baseline to shutdown) and generated 7778 KWH of energy during 1987. The 142 experiment runs consisted of sample Irradiations for neutron activation analysis, Isotope production, class demonstrations and TLD trradiations. In addition there"were 23 runs for training and calibrations.

B. Unscheduled Shut Qq1ns Date Power Level Cause Mar 2 95 KW No indication, except rods dropped and dump va l ve opened. Probable cause is the photo diode isolation in the saf ety amp i l fler dropping Delow operational level as a result o f 110 AC no i se.

July 7 8 watts See above.

a July 1-6 to work on rod drive systems for Reg Rod and and Shlm # 3. Maintenance performed descr* bed below. This repair work was reviewed by a  :

Region V inspector on July 27-28, 1987.

July 13-23 Further work on Shlm 3 described in maintenance below and reviewed by Region V inspector on July 27-28, 1987.

C. Co r r ect l ya and Engre n t l yg Ma i nt en e nce Haying sa f et y significance ,

f

1. Routine calibrations and maintenance as scheduled. L

2. July 1 Worked on Shim 3 to determine reason f or s low drop times. Determined that the drive mechanism which is located outside the reactor was operating satisf actorily. Removed the hold down bracket from outer drive shaft bearing with rod dropping satisfactorily. Reassembled outer bearing bracket with drop time satisfactory. Checked drop times on 7/2 and [

7/6 which were satisfactory.

Jul y 2 and 6 investigation Indicated that the slow drop times f or the Reg Rod were being caused by bearings in the rod drive mechanism. Two bearings were replaced on the long shaft in the drive mechanism. Two springs were added to the release cl utch l to decrease the disengagemer.t time. After reassemb l y the drop

t ime f or the Reg Rod was 520 mil I lsec and has per f ormed I satisfactorilly on subsequent checks.

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- . University of Washington Dockol No. 50-139 1987 Annual Report J u I y 13 -22 Checks of drop time f or Shim 3 on Ju i y 7 and 8 were satisfactory. On Ju l y 13 the drop t ime was s l ow. To summarize the foi lowing items were performed to attempt to

-bring the drop time of Shim 3 Into specifications. The outer shaft bearing was cleaned, the position Indicator potentlo-meter was real Igned as was the drive mechanism on the support stand. A 0.019 inch shim was placed under outer bearing support on rod shaft. The result of these actions was to bring the drop time for shim 3 Into specifcation.

For some time we have been monitoring the drop time f or Shim 3 prior.to each days operation. After the Jul / Inspection by Region Y we agreed to monitor the drop time of Shim 3 prior to each reactor run and periodical l y measure the drop time foi lowing reactor operation. This monitoring of the drop time for Shim 3 Indicated satisfactory performance for the rest of the year. However on Jan 4, 1988 the drop time for Shim 3 exceeded the 1 second limit. Subsequent drops brought the drop time into specification. Region Y was noti fied by tel ephone on January 4, 1988 and a written report sent to NRR/NRC Headquarters and NRC Region V on January 14, 1988.

Since August the drop times f or Shlm 1 and Shim 2 have been monitored monthly with alI checks being satisf actory.

3. No maintenance performed. The reactor has had a slow loss of core oxcess reactivity due to water being adsorbed by the graphite moderator. We believe that the gaskets at the bottom of the f uel boxes are al lowing water to come in contact with the graphite moderator. We know f rom the smal l amounts of water col l ected from the drain iIne in the process pit from the core region ihat there is a smal I l eak in the primary system in the core region. The enclosed graph shows our record of the excess reactivity of the core at cold clean critical. The change In core excess reactivity has been slow with t ime. The data show that, during periods of no operation, the recovery of react i v ity is a l so v ery s l ow. Thus, it is not possib l e f or the water in the graphite to be removed suddeniy. From our experience in December 1979 when a spil I of water on top of the reactor al lowed water to run over the graphite moderator we f ound that it took months f or the core excess react iv Ity to return to the l evel it was prior to the spil 1. A rev lew of the data from thermal cal ibrations of the reactor Ind icates that the water In the graphite is not affecting the nuclear instrumentation. We wilI continue to monitor the cors excess react i v ity. The loss of core excess reactivity was reported to Reglon Y by tel ephone on January 5,1988 and by I etter to NRR/NRC Headquarters and NRC Region Y on January 14, 1988.

D. Discussions ni Changes Carried Qui Pursuant in la CEE 50.59

1. None

, University of Washington- Docket'No. 50-139 1987 Annual Report E. Radioactive Heleases in tha Environs

1. During 1987, the Argon-41 released from the facility was measured to be 19.3 Curles. 9 The average concentration for the year wou l d be 3.1 x 10- microcuries/ml which includes ~ a dilution f actor of 45 al lowed by the technical speelfications.

2. One retention tank containing approximatel y 700 gal lons was dumped to the sanitary sewer on December 23. Total activity was l ess than 0.007 microcurles of beta activ ity and less than 0.0006 microcuries of alpha activity in the volume released to the sanitary sewer.

F. Environmental Surveys Outside thg Facility

< TLD monitoring data was col lected outside the reactor building at locations shown on the enclosed drawing. Results are tabulated In the attached table.

G.'Significant~ Exposures (over 1AR mrem int year).

For the year 1987 there were no significant exposures, i.e.,

over 500 mrem for the year.(January through November: December data not ava ll eb l e at report t ime. No incidents occurred.in Dece mber wh ich would lead to excess personnel exposure.)

i V

- University of Washington Dockot No. 50-139 1987 Annual Repor.

ENVIRONMENTAL DOSIMETER DATA - 1987 Values reported are in millirem with M being minimum.

See f oi lowing page f or a diagram of the p l acement location of the dosimeters around the facility.

The dosimeters each contain two TLD chips that are suppl led by R. S. Landauer,Jr & Co, Glenwood, lllInols 60425.

Exposure Period 10/1/86 to 1/1/87 to 4/1/87 to 7/1/87 to 12/31/86 3/31/87 6/30/87 9/30/87 Location 1 M M M M 2 20 20 20 M 3 20 M 20 M 4 20 20 20 M 5 10 20 10 M 6 M M 10 M 7 M 10 10 M 8 M M M M The data for the exposure period of 10/1/87 to 12/31/87 were not avail ab l e at the time the report was prepared.

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3 University of Washington Nuclear Reactor Clean Core Excess Reactivity 1.20

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4 UNIVERSITY OF WASHINGTON -

' SEATTLE, WASWNGTON 98105 '

College of Engineering Nuclear Reactor Laboratories Nuclear Reactor Building January 28,1988 U.S. Nuclear ^ Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Docket No. 50-139

Dear Str:

Enclosed is the routine Annual Report for the period January 1, l 1987 to December 31, 1987 in accordance wIth SectIon VIIl.K.3 of Appendix A, Technical Specif ications for Facil ity License No. R-73.

Please let me know if additional Inf ormation is needed rel ative to this report.

Since ly yours, ,

daMCC Mau r ice A. Robk i n, Ph. D., P.E.

Director Nuclear Engineering Laboratories M/S FD-10 206-543-4170 MAR:

Enclosure cc J.R. Bowen, Dean, College of Engineering K.L. Garlid, Chairman, Nuclear Engineering A.L. Babb, Chairman, Reactor Advisory Committee W.P. Miller, Assoc. Dir., UWNR NRC Reglon V i