ML20235F936

Application for Amend to License R-66,supplementing & Clarifying Authorization for Possession,Storage & Use of 70,000 Ci Co-60 in UVAR Reactor Pool to Avoid Possible Misunderstanding from Use of Cobalt Rods

ML20235F936
Person / Time
Site:	University of Virginia
Issue date:	07/02/1987
From:	Mulder R VIRGINIA, UNIV. OF, CHARLOTTESVILLE, VA
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20235F939	List: ML20235F936 ML20235F964 ML20235F974 ML20235G007
References
NUDOCS 8707140045
Download: ML20235F936 (4)

Text

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UNIVERSITY OF VIRGINIA r DEPARTMENT OF NUCLEAR ENGINEERING AND ENGINEERING PIIYSICS

'A' 1 NUCLEAR REACTOR TACILITY SCIIOOL OF ENGINEERING AND APPLIED SCIENCE J CHARLOTTESVILLE, VA 22901

' F t a July 2, 1987 Telephone: 801-924-7136 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Subject:

Application for amendment of license Gentlemen, A modification to Amendment 8 of Facility License No. R-66, Docket 50-62 (for the University of Virginia Reactor or "UVAR")

is hereby requested. Amendment No. 8 was issued on August 4, 1971. It authorizes the possession, storage and use in the UVAR reactor pool of 70,000 Curies of cobalt-60, in the form of rods.

The purpose of the present request is to supplement and clarify the wording in that authorization, and thus avoid a possible source of misunderstanding originating from the use of the cobalt rods.

Amendment 8 replaced the then-existing Paragraph 3C of the license with the following; (c) Pursuant to the Act and 10 CFR Chapter I, Part 30,

" Rules of General Applicability to Licensing of Byproduct Material", to receive, possess, store and use in the reactor pool 70,000 curies of cobalt-60 as described in the application dated July 21, 1971, and supplements thereto dated July 23 and July 29, 1971, and to possess, but not to separate, such byproduct materials as may be produced by operation of the reactor.

We here wish to add the following paragraphs to the existing Amendment 8:

The individual cobalt rods may be used or stored at locations within the pool which meet the following criteria:

1. The cobalt rods shall not be stored or used at distances less than 5 feet from any face of the operating reactor.

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2. The cobalt rods shall be used and stored in the pool, at locations sufficiently well shielded,.such that the radiation dose rate at the pool surface, due only to the cobalt-60 rods located in a permanent arrangement, is less than 1.0 mR/hr.

3. The-cobalt rods shall-be used and stored in secure configurations designed to minimine the likolihood of their impact or damage.

4. UVAR pool water will be sampled and analyzed for cobalt-60 contamination at.

intervals not to exceed 40' days. If the Co-60 activity reaches 5 x 10-5 pCi/ml, a search for leaking cobalt rods will be made. Leaking rods will be isolated to preclude further contamination of the pool water."-

Discussion:

The original application for Amendment 8 (see Attachment.1) indicated that the cobalt-60 rods would be stored under at least 20 feet of water. Over the years we have interpreted Amendment 8 to allow the temporary use of small numbers of the cobalt-60 rods at underwater distances less than 20 feet, as long as the resulting dose rates at the pool surface were within the limits of 10 CFR Part 20, and ALARA considerations. Long-term storage of the material has always been in a rack resting on the pool bottom, at a depth of about 26 feet..

We have recently embarked upon a research program in which a substantial numbers of the cobalt rods will be used for extended periods (up to 5 years), to irradiate materials under conditions

- requiring frequent insertion and removal of samples and sample holders, and the control of sample temperature and atmosphere.

To facilitate the handling of these samples and enhance the safety of these. operations, we plan to place the cobalt rods in an irradiation rack supported upon a platform, placed in a fashion such that the irradiation rack containing cobalt rods will be 10 or 11 feet below the pool surface. At such depths the dose rate at the pool surface due to Co-60 is about 0.3 mR/hr. It should be noted that the pool surface dose rate when the reactor is operating is in the range of 10 mR/hr, due to Na-24 and N-16 radiation in the pool water.

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The requested supplement to Amendment 8 codifies two of the commitments we previously made in letters supporting the original amendment request, and clarifies conditions under which the rods may be used for extended periods. Under the existing amendment, and the wording of the supporting letter cf July 21, 1971, the prolonged use of the material at depths of less than 20 feet could be construed as storage at such depths, and therefore not in compliance with the provisions of Amendment 8.

The irradiation experiments now in the design stage are being performed for the nuclear power industry, under a fixed time contract. We would therefore appreciate action upon our modification request at your earliest convenience.

Yours sincerely,

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h Robert U. Mulder, Director U. of Virginia Reactor Facility Sworn to cad ttr: b:) ttfar: ma t:t _ '

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My Comnission Spir 93 G/17/09.

cc: USNRC Region II Administrator, Atlanta, Georgia Project Manager Mr. Al Adams, USNRC, Washington D.C.

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ATTACHMENT 1 Letters from J.L. Meem and L. R. Quarles, to Division of !

Reactor Licensing, USAEC, dated:

(a) July 21, 1971 (b) July 23, 1971 (c) July 28, 1971