ML20107F924

Forwards Info Re Disassembly of Reactors as Followup to Author ,Per Request.Univ Will Not Submit Dismantlement Plan Until Contractor Proposal for Work Plan Reviewed

ML20107F924
Person / Time
Site:	05000142
Issue date:	02/15/1985
From:	Wegst W CALIFORNIA, UNIV. OF, LOS ANGELES, CA
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8502260234
Download: ML20107F924 (3)

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UNIVERSITY OF CALIFORNIA, LOS ANGELES UCLA p.

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COMMUNTTY SAFETY DEPARTMENT OFFICE OF RESEARCH & OCCUPA110NAL SAFETY LOS ANCELES, CAUFORNIA 90094 February 15, 1985 Mr. Harold Denton, Director Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: SSPB Docket No.

50-142 License No.

R-71

Dear Mr. Denton:

This will follow up on my letter of 16 January,1985, regarding disassembly of the UCLA reactor. The attachment herewith resporids to a verbal request from the NRC technical staff for more information concerning UCLA plans. The attachment derives in part from a " Request for Proposal" that UCLA is preparing, to solicit bids for the work there described.

As described in the attachment, the Work Plan is to be a contractors task and UCLA does not intend to submit a dismantlement plan until contractor proposals have been received and reviewed.

In the interim, the reactor staff is proceeding with the selective sampling of reactor constituents to gain a better perspective of realistic decomissioning alternatives. We believe it is in the best interests of-the University and the public to utilize the collective knowledge of the present staff to the fullest extent while that staff still exists.

At the present time, approximately 0.6 cubic feet (420 lbs.) of lead and 12 cubic feet (1200 lbs.)- of graphite have been. removed from the central region

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of the core. After sampling these materials to' determine the principle radio-nuclides present, some of these materials will be packaged for transport and burial. The information gained in this program will contribute materially to our understanding of decommissioning procedures. We hope you will. concur.

Srincerely, Walter F. Wegst Director, Office of Research &.0ccupational? Safety.

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PREPARATIONS FOR DECOMISSIONING THE UCLA REACTOR l.0 OBJECTIVE:

To evaluate deconsnissioning alternatives for the UCLA argonaut research reactor located on the UCLA campus _ in the School of Engineering and Applied Science.

2.0 THE WORK PLAN:

2.1 Conduct a radiation survey of the core constituents, the concrete biological shield,.and such other facilities as must be assayed to define the decommissioning requirements and costs. -The survey

.is-to be in sufficient detail. to provide:

a.

A shipper's description of radioactive materials.

b.

A prognosis ~ of the future radioactivity of major -

materials (principally graphite, lead, concrete and '

embeddedcomponents).

c.

Data for predicting man-rem ' doses 'for -various' decom--

missioning alternatives.

2.2

.To' accomplish the ~ radiation survey, the' reactor core is to be-disassembled and sorted into major categories: Graphite, lead, other metals.

The' metallic parts (non-lead) are.to be surveyed only.to the.

extent necessary to satisfy 2.1.a.; Those materials are to beicut c

- as.necessary, packaged for transport and burial. and shipped to

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Ja burial-site. ~

The removal' of metallic parts Lis to include..the protruding ~ portions -

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of-partially embedded parts, but excludes the embedded portions' of' those parts.:

The graphite.and lead are.to.be palletized in.such a way;asi o, t

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2 conveniently permit:

a. < Their packaging for-transport. and burial',

b.

Their restacking'in the empty; core space /forJsh'ipment.

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The concretecis to be sampled'and ' assayed to the extent!necessary; '

Lto distinguish between: radioactive ^ material tand exempt material,=

'and<to identify thesprincipal nuclides'. responsible;for-the radio -

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Dactivity.

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.The process pit is regarded as a potential decontamination site, and is to be cleared of extraneous equipment and piping. The heat exchanger, primary water piping, related' flow meters and valves are to be removed.. The holding tanks, primary water pumps, and sump pump are to be retained for use in holding, diluting, or otherwise purifying any contaminated water produced by dismantlement-decontamination work.

2.5 Based upon the results of the1 radiation survey 'and.the volumes.and masses of the principal contituents, cost ' estimates are to be prepared' for both prompt and-deferred decommissioning.

2.6 Deferred. decommissioning.is not yet defined in. detail, but in

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. general <a viable plan would hinge upon-certain key transitions such' as the passage of a material into a " low specific activity" or

" exempt" status. Radiation worker exposure and cost can be expected to decline with time.

3.0

-PRESENT STATUS:

3.1 The reactor fuel-has been removed from the site. The control' blade drive shafts have.been severed at the exterior surface of the biological shield and the~ external drive systems removed. All primary water and shield tank water have been drained 'and removed.

3.2 The reactor core has been uncovered and fifteen graphite stringers have 'been ' removed from the central region of the core. - The stringers are 'to be sampled for Wignerg energy and specific activity measurements.

3.'32 Removal;cf the central graphite created a void 12 inches by 20 inches-

- by five _ feet deep which extends from_ the core top to the concrete pedestal. The' radiation field in the void has a fairly uniform valuet i of one; rem per hour.

E3.4 The staff and others are _ assembling ~ a Request for Proposal to. solicit; 4

? bids for the continuation toward decommissioning.-

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3.5 -

The reactor operating staff remains-at nearlyjfull jlevel,sa Ievel.

.which will not-be sustained very much longer.; Meanwhile, thelstaff:is?-

acquiring some of.the.information essential ~ to?an. informed

decisioni

. regarding decommi ssioni ng L al ternati ves..

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-All concrete shielding remains on;the sitefandicould'be~ readilyc

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L restored to its - usual; geometry :to fcreate a :SAFSTOR or ENT0ps mode-2 2

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