ML20070U586

Forwards Pages to Be Appended to Chapter 5 of SAR Re Two Experimental facilities.Co-60 Irradiator Maintained in Reactor Tank.Subcritical Assembly,Separately Licensed from Reactor,Included for Completeness

ML20070U586
Person / Time
Site:	05000192
Issue date:	02/07/1983
From:	Bauer T TEXAS, UNIV. OF, AUSTIN, TX
To:	Bernard H Office of Nuclear Reactor Regulation
References
NUDOCS 8302100417
Download: ML20070U586 (4)

Text

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THE UNIVERSITY OF TEX AS COLLEGE OF ENGINEERING AUSTIN, TEX AS 78 712

!)epartment of AlechanicalEngineering Nudear Engineering Program 512 - 171 4 136 February 7,1983 Harold Bernard Standardization & Special' Projects Branch Division of Licensing Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Bernard:

Enclosed are copies of pages to be appended to Chapter 5 of The University of Texas Safety Analysis Report describing two ex-perimental facilities. The Co60 irradiator is maintained in the reactor tank. The subcritical assembly is se rntely licensed from the reactor but is included for completeness.

Sincerely yours, M

T. L. Bauer Reactor Supervisor S0P #3664 Enclosures (19)

TLB:mgm 8302100417 830207 PDR ADOOK 05000192 P PDR

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-from various positions of the rotary specimen rack. Based on these 8

cm3 results the concentration expected for a room volume of 6.8 x 10

is estimated to be less than 2.5% of the maximum permissible concentration for restricted areas. - The argon-41 produced in the pneumatic transfer tube and the rotary specimen rack that has been observed indicates that the amounts discharged from them is very small when averaged over time.

If these facilities are heavily used or used in such a way as to release large amounts of argon-41, this should be considered.

A modification of the pneumatic transfer system to a closed loop containing carbon dioxide allows for operation of the inlet / outlet .

terminal in a restricted room volume. Calculations indicate saturated i activities of 7.7 x 10- pCi/cm of nitrogen-16 and 0.2 x 10- pCi/cm 3 of oxygen-19 may be produced in the outer ring of the core matrix.

The total activity that could be produced in the pneumatic tube during steady-state operation is therefore, 12.6 pCi. Additional calculations show that the total activity induced in the CO2 during a $2.00 pulse is 60 pCi. An instantaneous release of this activity to a restricted room volume of 4.96 x 10 3 c ,3 would yield a concentration of 1.21 x-10-0 pCi/cm ,

which is less than 2.5% of the maximum permissible concentration for restricted areas.

5.5 SPECIAL EXPERIMENTAL FACILITIES 60 5.5.1 Co Irradiation Facility

.I 60 A Co irradiator consisting of 156 pencil sources of 0.5 inches diameter and 11.25 inches length is installed in the reactor coolant pool. Each source is doubly encapsulated with inner aluminum clad and outer stainless steel clad. The source pencils are arranged in a double staggered, circumferential array with an inside radius of 10.5 inches and outside radius of 12.5 inches (Figure 5.4a). The total source 5-23

a activity on April 18, 1967 was 9260 curies. A shelf suspended in the pool at the end opposite of the reactor position holds the Co irradia:i facility below 10 feet of water. Access to the facility is provided by water tight canisters or dry irradiation tubes. Two canisters with 0.625 inch canister wall thickness, 5.0 inch inside radius and 11.5 inch height and several 2 inch diameter vertical beam tubes determine routinely applied experiment exposure volumes.

5.5.2 Suberitical Assembly and Reflectors Cylindrical assemblies of graphite and polyethylene are utilized for student laboratory experiments with neutron sources and a subcritical uranium-235 reactor assembly. The plutonium beryllium neutron sources and uranium dioxide in polyethylene subcritical assembly may be stored and used in the room containing the reactor but are licensed separately from the reactor. The suberitical core and moderator assemblies are products of Lockheed Nuclear Products as presented in reports NR57 and NR58, March 1959 (Figure 5.4b) .

The subcritical polyethylene core is a cylinder 10 inches in diameter and 14 inches long. Reflector assemblies can be assembled with or without the fueled core. Dimensions of the cylindrical reflector assemblics are 30 inch diameter by 34 inch length for the graphite moderator and 22 inch diameter by 25 inch length for the polyethylene moderator. An additional graphite moderator cylinder 30.5 inches high by 24 inch diameter is available for neutron source moderation.

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