ML20072K256
| ML20072K256 | |
| Person / Time | |
|---|---|
| Site: | Aerotest |
| Issue date: | 08/08/1994 |
| From: | Tsukimura R AEROTEST OPERATIONS, INC. |
| To: | NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| References | |
| NUDOCS 9408290428 | |
| Download: ML20072K256 (3) | |
Text
{{#Wiki_filter:- t ,J;M& N'A AEROTEST OPERATIONS, INC. Ogg 3455 FOSTORIA WAY. SAN RAMON. CALIFORNIA 94583.(415)866-1212 lih (& 8 August 1994 Executive Director for Operation-U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Ret Docket No. 50-228
Dear Sir:
This informational letter is to keep the cognizant NRC personnel informed on our program to meet the requirements of 10 CFR 20.1301. We are currently using calculations as specified in 10 CFR 20.1302 (b) (1) to demonstrate that we are not exceed-ing the annual dose limit. In anticipation of the required lower limits in the newly implemented 20.1301 requirements, we increased our fenced area and added significant shielding to our largest source of environ-mental radiation, the demineralizer column. The additional shielding consists of 2 inches of lead, 7.5 inches of concrete and an additional 24 inches of concrete about 3 feet away from the new shields. These changes were all made in early 1994. The overall dose reduction factor from these changes is calculated to be a factor of about 100. The dosimetric monitoring period was reduced to monthly from quarterly in order to evaluate our dose reduction techniques in a timely fashion. And, indeed, the doses at our fences dropped as expected in March, 1994. See Table I. However, the doses from succeeding months have begun increasing in spite of reduced reactor operating hours. To counteract any forseeable problems, a letter was request-ed and received from our neighbor on three sides Pacific Gas and Electric Company (PG & E) concerning their limited occupancy of the area next to our east fence. Administrative controls were added to the north and west fences in the form of periodic sur-veillance (approximately 1 hour intervals) of the area whenever l ( the reactor is operational. As an additional safeguard, we have l made and are continuing to refine fence surveys using collimated i detectors under shutdown and 180 Kw power conditions in order to l re-identify our source of radiation. kLe goo - 010394 9408290429 94o909 hgi PDR ADOCK 05000229 i P PDR A $UBSIDI ARY OF
Page 2 s We are investigating also the components of our peripheral doses in terms of procedure and accuracy. To bolster our envi-ronmental data, we have added calcium sulfate chips at our fence line, are going back to quarterly monitoring based on recommenda-tions from our dosimetry supplier, Radiation Detection Company, and placed albedo dosimeters at the two closest PG & E work sites. A special session of our Reactor Safeguards Committee (RSC) was convened to discuss the accumulated data to date. The RSC has suggested various actions which should help in our efforts to meet the requirements of 20.1301 without having to rely on occu-pancy rates and administrative controls. Aerotest will pursue these actions in a timely fashion in an effort to confirm the adequacy of our changes to meet the new requirements and will provide updates on our progress to the NRC. Very truly yours, b. Ray R. Tsukimura Vice President, General Manager i cc Marvin Mendonca, USNRC Samuel Collins, USNRC, Region IV G. Ben Huber, AO Roy Leway, OEA i i l I I
3 i TABLE I PERIMETER DOSIMETRY vs N-RAY ROOM QUARTERLY FENCE Doses
- N-Ray Reference Rx Op.
Period East West North South Room Badge hours ending 6/91 55/40 60/40 10/0 30/0 750/500 75/40 787 9/91 55/35 50/0 20/0 30/0 600/100 65/0 706 12/91 25/0 70/0 20/0 '30/0 500/85 70/0 790 Annual 210 220 50 90 1425 250 2978 3/92 90/30 75/0 40/0 55/0 960/200 130/0 640 6/92 80/0 70/0 35/0 30/0 700/350 80/0 569 9/92** 95/0 100/0 50/0 60/0 800/190 180/0 550 12/92 30/0 2S/0 0/0 0/0 270/130 30/0 506 Annual 325 270 125 145 3590 420 2265 3/93 85/0 45/0 0/0 0/0 550/260 55/0 492 6/93 45/0 45/0 0/0 25/0 85/40 50/0 490 9/93 45/230 30/0 20/0 20/170 500/160 50/0 473 12/93 65/0 50/0 15/0 25/0 350/110 70/0 472 Annual 470 170 35 240 2055 225 1972 1+2/94 35/0 15/0 20/0 10/0 490/50 30/0 284 3/94 10/0 10/0 ND ND 290/40 25/0 199 4/94 20/0 15/0 10/0 ND 250/50 15/0 162 5/94 30/0 30/0 20/0 20/0 230/0 35/0 145
- Note Doses reported for neutron / gamma in millirem since change to Radiation Detection Company.
- Note:
ARRR operating power level dropped from 250 to 180 Kw f 4 4 3 ,4 4 -r .y- ~ .-,.--w v r-r =}}