ML20211B319

Informs That Bids for Docket 50-602 Project Opened on 861021 W/Award of General Contract on 861204.Dismantling Activities of Docket 50-192 License Projected to Commense in Aug or Sept 1988.Submits Info to Suppl 850503 Decommissioning Plan

ML20211B319
Person / Time
Site:	05000192, University of Texas at Austin
Issue date:	02/06/1987
From:	Bauer T TEXAS, UNIV. OF, AUSTIN, TX
To:	Berkow H Office of Nuclear Reactor Regulation
References
NUDOCS 8702190380
Download: ML20211B319 (2)

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'y February 6, 1987 Atten: Herb Berkow Special Projects U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Docket 50-602 Project schedule Docket 50-192 Maximum Potential Offsite Dose during Decommissioning

Dear Sir:

Bids for the docket 50-602 project were opened October 21, 1986 with award of general contract December 4,1986. A preconstruction conference held February 2, 1987 set the estimated project completion date in June of 1987. Dismantling activities of 50-192 license acti-vities are projected to commense in August or September of 1988 with a request for final termination of license R-92 submitted towards the end of the year, 1988. Additional schedule information will be sub-mitted as construction progresses to allow coordination of the status of the 50-602 and 50-192 dockets and the transfer of special nuclear materials and activities between these dockets.

In response to a question by NRC staff, the following informa-tion is provided to supplement the docket 50-192 Decommission Plan submitted May 3, 1985.

An estimate of the maximum public exposure is assumed to take place in an uncontrolled of fice area immediately north of the decom-missioning activities in the reactor room. Noting the exposure rates and locations of tasks presented in Table 1.3 of the plan, a typical continuous exposure rate is identified. If the minimum continuous dose of .2 mrem /hr is assumed to exist at the area at the top of the open reactor tank, then the dose at 10 feet would be .002 mrem /hr.

Over the 3 month period the exposed empty tank pit is being dismantled the total dose for a 40 hour4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> week occupancy is about 1 mrem. The minimum exposure rate should be appropriate since most exposures in excess of the minimum will occur in the tank pit and will be colli-mated upward or be more than 10 feet from any uncontrolled area.

The 10 foot distance to the uncontrolled area is conservative and allows for the possible storage of low level waste material at loca-tions near the adjacent of fice. Intervening shielding of brick and masonary will further decrease the total exposure. For a maximum occupancy of 5 persons the maximum estimated person-rem exposure is then .005 rem. At least one order of magnitude of conservatism is expected in the estimate.

0702190300 070206 o PDR ADOCK 050001?2 P UDR '

s February 6,1987 Page 2 The release of particulates or gases from the ventilation system are projected to be 10% of the MPC for unrestricted areas as noted on page 1-20 of the Decommissioning Plan. Assuming that one MPC represents an annual dose of 500 mrem, the estimated dose from airborne releases for a person at the exhaust point is estimated. If the con-centrations are released during concrete removal and packaging (8 hrs

• 60 days) then the total maximum dose from airborne material is 2.7 mr ((8*60/8750)*500). This estimate is conservative since it depends on the source term in the concrete (already estimated to be at least a factor of 10 above expected values), does not allow for dilution after release and assumes a person resides at the release point which will not be allowed.

Sincerely, A 4 Th~

Thomas L. Bauer Assistant Director Nuclear Engineering Teaching Laboratory TLB:dlw cc: G. Fonken H. Walls H. Marcus D. Klein i

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