ML20137E249

Informs That Defueled Components of AGN-201 Training Reactor Moved from Emerson Bldg to Neely Nuclear Research Ctr,Per .Listed Radiological Surveys Conducted.Survey Results Encl

ML20137E249
Person / Time
Site:	05000276
Issue date:	08/15/1985
From:	Karam R Neely Research Reactor, ATLANTA, GA
To:	Thomas C Office of Nuclear Reactor Regulation
References
NUDOCS 8508230183
Download: ML20137E249 (7)

Text

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• . Georgia institute of Technology' f' Neely Nuclear Research Center Atlanta, Georgia 30332 &

(404) 894-3600 anaara'a Tucu sees.19e6 DESIGNING TOMORROW TODAY August 15, 1985 Dr. Cecil O. Thomas Standardization and Special Projects Branch Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Reference:

Docket No. 50-276 License #111 for AGN-201

Dear'Dr. Thomas:

In accordance with your letter, dated July 10, 1985, we have moved the defueled components of the AGN-201 training reactor from the Emerson Building to the Neely Nuclear Research Center. The small parts and console of the AGN are stored in Room Gil4 of the NNRC and the big tank is placed within the fence near the cooling tower of the GTRR. The following radio-logical surveys were made:

1. Survey of the yard at NNRC to determine background before AGN-201 tank is moved. The survey is repeated after the tank is moved.

2. Survey of AGN-201 area at Emerson Building af ter AGN components were moved out but before the subcritical facility and. associated 2500 Kg of natural uranium were relocated. In this survey the radiation level due to the 2500 KG of natural uranium and background in the AGN area was determined.

3. Smearable surface contamination of AGN-201 components after transfer to NNRC.

4. Survey of AGN area at Emerson Building after AGN-201 and sub-critical facility and associated fuel were moved out.

The surveys were conducted using 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 surface contamination counting was obtained with a gas propor-tional counter, Beckman Sharp Low 6 II. This counter is also calibrated with NBS Standards.

Figure 1 shows background measurements in pR's/ hour in the yard of the NNRC within the fence before the AGN-201 tank and the aluminum subcritical g 8508230183 850815

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PDR i i

ADOCK 05000276 P py An Equal Education and Employment Opportunity Institution A Unit of the University System of Georgia

Dr. Cecil 0. Thomas Page 2 August 19, 1985 tank were moved in place near the water cooling tower of the GTRR. Figure 2 shows results obtained after the AGN tank and the aluminum tank of the subcritical facility have been moved in place. Comparison of the results shows that the placement of AGN tank near the water cooling tower did not change the background, 20 pR/hr. Additionally the micrometer reading inside the AGN tank at the level of the glory hole is 1 pR/hr. The reason for this low reading is due to the presence of the original 10 cm thick lead shield inside the ACN tank. The readings in the middle circle (See figure 2) of 4 and 5 UR/hr. are inside the steel shell of the ACN but above the lead shield. The readings in the outer circle correspond to the top of the steel shell. Note that these values are slightly lower than the background of 20 pR/hr. The difference is due to the fact that background was measured at waist level whereas the values measured on to. of the tank correspond to an elevation of more than 10 feet. The smear results shown in figure 2 j are virtually all background.

1 I

Figure 3 shows results of the survey at the AGN-201 area af ter the AGN components were moved from Emerson to NNRC. Note that readings at locations where ACN tank was, are significantly higher now than was reported in my April 11, 1985 letter to you.

l Results of smearable surface contaminations on AGN-201 components after move to NNRC are given in Table I. Results are comparable to those reported

[ earlier.

l.

r Finally a survey of the AGN area at Emerson was made after both the AGN-201

and the suberitical facilities were moved out to the NNRC. The results are

given in figure 4.

l I hope that you will find this information satisfactory. If you have any question, please let us know.

Sincerely,

.h. W -_ _

R.A. Karam Interim Director RAK/jlr l

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TABLE I Results of Smecrable Surface contamination on n 201 C1mponents Smear # Iocation Disintegration per Minute per 100 cm Before nove as reported After move to NNRC April 10, 1985 1 -- Outer surface aluminum tank 55 Sy ; 10 a*' 50 By ; 4 a**

2- Inner surface alminum tank 25 By ; 10 a 18 Sy;6a 3 Graphite annulus (inside surface) 101 By ; 11 a 61 By ; 0'a

'1his graphite formed the reflector around the NN core.)

4 Almine tube of Glory Hole 30 By ; O a 16 By ; 1 a 5 Outside NE tank 35 By ; 10 a 36 By;Oa 6 . Lead bricks (shield on top of core) 30 By ; 10 a 26 By;0a 7 Console 40 Sy ; 0 a 55 By ; 0 a 8 floor 40 By ; 0 a 37 By;2a 8 66 By;1a

.9 hood cabinet for U storage 90 By ; 10 a 10 Inside almine tank inside NN 85 By ; O- a 26 By;Oa

• '1hese values were obtained with a gas proportional counter, Beckman sharp low B II.

'Ibe efficiency of this machine.is 20%. 'Ihe background counts associated with this instrment are 30 dpn Sy and O a's.

'** Background measured 8/12/85: By =- 50 dpn; a = 3 dpn

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a= 3 DPM Sy = 30 DPM Figurn 2 . Micro R/hr. measurements and Smear Pesults: pure numbers are in UR/hr. units and '

r numbers preceded by the symbol # refer to locations of smears. (values are given in side table) .

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Fig.'3 Survey of AGN-201 Area After AGN Components Ware. Moved.to NNRC I

FENCE e 110 ER/hr measured at same level as measured before AGN tank was moved.

I e'120 pR/hr. at 1 meter above tank's previous location e 190 pR/hr. at the level of Glory' Hole's previous Stairs location e 300 UR/hr 6

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Figure 4. NN area survey after ACN-201 and subcritical facilities were moved. .1he numbers '

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