ML20212C187

Requests Approval of Encl Procedure & Hazards Analysis Re Insertion of Detector in Reactor Tank to Make Spectral Analysis of Radiation.Experiment Part of Planning Process for Decommissioning

ML20212C187
Person / Time
Site:	05000148
Issue date:	02/27/1987
From:	Rosson H KANSAS, UNIV. OF, LAWRENCE, KS
To:	Dosa J NRC
References
NUDOCS 8703030730
Download: ML20212C187 (2)

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<a THE UNIVERSITY OF KANSAS LAWRENCE, KANSAS - 66045-2223 I

DEPARTMENT OF CHEMICAL AND PETROLEUM ENGINEERING s

) 4006 LEARNED j 913-8644965 f February 27, 1987 l

} Mr. John Dosa j U.S. Nuclear Regulatory Commission

( Washington, D.C. 20555

{ Re: License R-78, Docket 50-1118 -

\ '

Dear Mr. Dosa:

I l As the next step in our planning process for decommissioning, we would like j to obtain better information about the activation products within the reactor shielding. We propose to insert a detector in one or more beam port tubes and inside the reactor tank to make a spectral analysis of the

{ radiation therein. It is our hope that most of the residual activation is

{ concentrated within the pneumatic tube end station.

Enclosed is a written procedure and hazards analysis for the proposed experiments. We seek your approval.

~

} Since ely, l /A

{ Harold F. Rosson l Reactor Director i

i l

1 Enclosure Copy w/o encl: Nuclear Reactor Committee l

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y AppfevedbhtheNuclearReactorCommitteeonFebruary27, 1987.

i.

-e EXPERIMENT

,' Analysis of Activation Products in the Ceactor Structure,

, The purpose of the proposed experiment is to determine the types and A quantjties (if possible) of activation products in the shielding structure of

- the former reactor. The first approach will be to determine the spectrum and h energies of t'$c radiations emitted by means of a multi-channel analyzer u' sed

- with a NaI detector. The detector is to be placed in the beam port for the analysis. This will require removal of the beam port plug (or plugs) so that the. detector may be inserted.

Hazard Analysis and Procedurba It is alr'eady known that the maxim.um dose rates nside the tank a*re of the order of 30 st/hr, therefore it is not likely that higher dose rates would be encountered at'the outside of the shielding when the beam port is opened since the shortest accessible distance to tha former location of the core will be nine feet. However, calibrated survey meters will be used to determine the dose rate as each section of the plug is removed. If dose rates greater than 50 mR/hr were observed af ter the withdrawal of any-given segment of the plug (There are eight segments to each beam port plug), further removal would be terminated. (In that case the levels would too intense for the detection system in any case.) Analysis would be performed without further removal of the plugs.

Standard protective gear (lab coats, gloves, and drop cloths) will be used in handling the plugs. Wipe tests will be made of the plugs and-

, _ evaluated as.thay are removed. Plugs will be placed on drop cloths and will be directly _ nonitored for activity in addition to the wipe tests. Personnel will not stand in f ront of the beam port until surveys have verified the absence of excessive dose rates. Only personnel performing the experiments will be in the room.

No one wilI be allowed to position themselves in front of the beam port except for the insertion of the detectors and/or the plugs. If necessary time limits will be placed on .the time spent in front of the bebn port. ALARA will be considered to be achieved if total exposures are kept below 0.2 person-rems. Re-evaluation of procedures will be accomplished if this arbitrary i 1imit is approached. 5, elf reading dosimeters wi11 he woin in addition to fi1m l

badges.

! Drop clothes wi11 he monitored. If contrary to our expectaticns, contanination is found, they will be disposed of in our radioactive waste.

In addi tion, it is also proposed that: the NaI detector be lowered into the tank f rom the top and that the spectrum be deterimined inside the tank.

It will not be necessary to enter the tank to acco'mplish this task even though that could be done without appreciable exposure. The lid will be removed and the detector will be lowered into the tank. The power supplies, MCA, and timer will remain at tank top. The dose rate at the top of the tank is only of the order of a few uR/hr and presents no radiation hazard.

At the end of the experiment, the lid and the plugs will be ie-installed and secured. 'A record that both have been relocked will be made.