ML20100M210

Responds to Re Carter Request for Smearable Surface Contamination in Disintegrations Per Minute Per 100 CM2 & Imbedded Contamination in Components of Agn 201 Measured in Ur/H at 1 Meter.Smearable Contamination Measurements Encl

ML20100M210
Person / Time
Site:	05000276
Issue date:	04/11/1985
From:	Karam R Neely Research Reactor, ATLANTA, GA
To:	Thomas C Office of Nuclear Reactor Regulation
References
NUDOCS 8504170357
Download: ML20100M210 (3)

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Georgia Institute of Technology Neely Nuclear Research Center Atlanta, Georgia 30332

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-(404) 894-3600 esonGIATECit 1886-1986 DESENDG TOMORROW Y April 11, 1985 Dr. Cecil 0. Thomas Standardization & Special Projects Branch Division of Licensing ,

U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Reference:

Docket No. 50-276

Dear Dr. Thomas:

This letter is being sent to you in response to a request from Dr. Robert E.

Carter of your staff concerning residual and smearable radioactivity in the defueled AGN 201. Dr. Carter wanted to know the smearable surface contamin-2 ation in disintegrations per minute per 100 cm and the imbedded contamina-tion in the components of the AGN measured in pR/hr at 1 meter.

By way of background, the room which houses the AGN 201 at the Emerson building also houses a suberitical facility containing about 2500 Kg of natural uranium metal slugs stored against the wall in a wood cabinet (see Fig. 1). As indicated in Fig.1, the dose rate at 1 meter from the wood cabinet is 3 mR/hr. The dose rate at a point approximately halfway between the AGN tank and the storage cabinet.is 300 ER/hr. The dose rate at the level of the " Glory" hole inside the AGN tank is 3 pR/hr. This location corresponds to the exact center of the core. The dose rate measured at the far side of the AGN tank away from the fuel storage cabinet is 4 pR/hr.

All these measurements are indicated in Figure 1.

These measurements were obtained with an Eberline PRM-7, serial No. 633 micrometer. This instrument was calibrated by the Georgia Tech Radiation Safety Officer with radiation standards referenced to the National Bureau of Standards.

The smearable contamination measurements are summarized in Table I. All the listed values are within the limits specified in Regulatory Guide 1.86, Table I.

I hope that you will find this information satisfactory. If you have any questions please let me know.

" '7' 417 [ hh -

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R.A. Karam e -

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Interim Director j i

An Equal Education and Employment Opportunity institution A Unit of the University System of Georgia

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.. e TABLE I Results of Smearable Surface Contamination on AGN 201 Components Smear # Location Disintegration per Minute per 100 cm 1 Outer surface aluminum tank 55 8 & Y; 10 a 2 Inner surface aluminum tank ,

25 8 & Y; 10 a 3 Graphite annulus (inside surface) (This 101 8 & Y; 11 0 graphite formed the reflector around the AGN core.)

4 Aluminum tube of Glory Hole 30 8 & Y; 0 a 5 Outside AGN tank 35 8 & Y; 10 a 6 Lead bricks (shield on top of core) 30 S & Y; 10 a 7 Console 40 8 & Y; O a 8 Floor 40 6 & Y; 0 a 38 9 Wood cabinet for U storage 90 8 & Y; 10 a 10 Inside aluminum tank inside ACN 85 8 & Y; O a These values were obtained with a gas proportional counter, Beckman sharp low S II. The efficiency of this machine is 20%. The background counts associated with this instrument are 30 dpm B Y and 0 a's.

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