ML20058K665
| ML20058K665 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/01/1978 |
| From: | Wachter L NORTHERN STATES POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-78-08, IEB-78-8, NUDOCS 9102130428 | |
| Download: ML20058K665 (2) | |
Text
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August 1, 1978 i
r Mr. James G. Keppler l
Director - Region III I
Office of Inspection and Enforcement United States Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 The Monticello Nuclear Plant, a GE B'a'R, does not have a fuel transfer tube as described in IE Bulletin 78-08. However, it does have a fuel transfer slot between the reactor well and the fuel pool. This slot is directly above the drywell, such that the bottom of a fuel assembly passes ~8' over an accessible area of the drywell. For a section of the fuel transfer slot - 6' long, only 1"-2" of steel it, present for shielding between it and the area of concern in the drywell. Prior to beginning refueling operations, a fuel transfer shield is installed which provides suf ficient shielding to personnel in the drywell. A review of surveys indicates that exposure rates of 2.5 R/hr are present in the affected area of the drywell during fuel transfer. This exposure rate exists for s-10 seconds and occurs typically 200-400 times for a 10-20 day refueling operation.
The drywell as a whole is treated as a high radiation area and is controlled as such when work is being perfor=ed in it.
Therefore, positive control of access exists to the area near the fuel transf er shield since it is in the drywell. The drywell entrance is conspicuously posted in accordance with 10 CFR 20 203 (c). Also, the top of the drywell in the area where the exposure rate increases due to fuel transf er is provided with additional posting in order to further control access. Each refueling outage an Area Radiation Monitor, with alar =, has been installed on the upper levels of j
l the drywell so that any abnormally high exposure rates will be detected and appropriate action taken.
The only other possibility for high transient exposure rates to accessible areas during fuel tratisfer is that caused by removing fuel from the edge of the core and creating high exposure rates in various areas of the drywell.
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AUG 3 1978 9102130428 780801 CF ADOCK 05000263 CF SC'
NO. e*HERN OTATE3 POWER C.- MPANY Mr. James G. Keppler August 1, 1978 Page 2 In this instance, at least 2.5 f eet of water and 6 inches of steel are for shielding which is roughly equivalent to the 6 inches of lead present in the fuel transf er shield. Surveys made during the cost recent refueling outage indicate that no exposure rates in excess of 1 R/hr should be created by these fuel movements.
Although this investigation does not reveal any potential for excessive radiation streaming and associated high exposure rates during fuel transfer, in radution surveys will continue to be made in this area, as appropriate, order to insure that personnel exposures will be maintained as low as l
reasonably achievable.
l Yours very truly, V
n GP A /
l L.
. k'achter Vice President - Power Production and System Operation f
ec:
Mr. G. Charnoff