ML20083Q108
| ML20083Q108 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 02/08/1973 |
| From: | Ross D JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Kruesi F US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19289B251 | List: |
| References | |
| NUDOCS 8302230275 | |
| Download: ML20083Q108 (3) | |
Text
{{#Wiki_filter:% 77 o t i 'J Jersey Central Pbv/k & Light Company M ADISON AVENUE AT PUNCH BOWL RO AD e MORRISTOWN, N.J. 07960 e 539-6111 February 8, 1973 Mr. F. E. Kruesi Director of Regulatory Operations United States Atomic Energy Commission Washington, D. C. 20545
Dear Mr. Kruesi:
Subject:
Oyster Creek Station Docket No. 50-219 Personnel Radiation Overexposure 'Ihe attached report details the information surrounding the overexposure of three of our personnel at the Oyster Creek Nuclear Generating Station on January 1,1973 and is being submitted in accord-ance with the requirements of 10CFR20, paragraph 20.405(a)(1). According to the requirements in paragraph 20.405(c), each of the individuals noted in Enclosure 1 will be notified regarding the natum and extent of overexposure. Upon discovery of the condition, greater controls were immdiately instituted to prevent a recurrence of the situation and more stringent requiments will be instituted with regard to sampling frequency and access control for future maintenance activities. Very truly yours, 2C d 0--O<:7 Donald A. Ross Manager, Nuclear Generating Stations pk Attachments cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region 1 9 2 1940 fa'W i, ( C,pyo - 83Japgggpoj@@@@DR P COPY SENT REGION } e w
o 7 -[( e d~ t REPORT OF OVEREXPOSUIES. As a result of the reactor scram on December 29, 1972 and the atterxiant problems which were experienced, all five relief valves were ) beirs removed fran the main steam lines for inspection and ultimate modifi- ! cation. During -the initial stage of this maintenance period, three 'indi-viduals were exposed to concentrations of radioactive material in excess of the amounts specified in Appendix B,' Table 1, Column 1 of 10CFR20. 'A description of the incident follows: On December 31, 1972, samples taken of centainment airborne encentrations were such that access to the containment was unlimited (168-hours) for the maintenance activities involved. A routine containment air sample taken at 8:15 a.m., January 1, 1973, indicated an increased airborne-concentrationoverthepreviousdaywiththemgorcontributor,andinfact the only contributor of significance, being Xe 3 Access was pennitted to the ccntainment but with a reduced stay time of 15.7 hours.. Based upon this fact, an increased sartpling frequency was initiated and an investigation carmenced in an effort to determine the source of this activity. A second s le, taken nearly an hour later at,9:10 a.m., indicated the levels of. Xql 3 e had measurably' increased, reducing the stay ttne to 12.3 hours. It was decided at that tine to count still a third sample after being in service for a shorter time interval. Tentative plans were made'to stop- . all work in the contain:mnt if the. sample showed an increasing airborne level which would limit access to five hours or less. Forty minutes. later, at 9:50- a.m., the sample was counted and it was discovered that th icycl3 of Xc333 had again more than doubled; however, the subsequeni, access time was reduced to only 6.1 hours and maintenance activities were - pennitted to continue particularly in light of the fact that a work break was less than two hours away. By this time, the source of activity had been detennined to be - originating from the open relief valve flanges which were being cleaned up. by several mechanics. Preparations were made to start the condenser mechanical vacuum pump and to perform the valving required in the main steam system so that the gasses caning out of the reactor coolant could be eva'cuated to the condenser instead of diffusing into the primary containment atmosphere. Directions were given to tightly cover any of. the remaining open relief valve flanges and to insure that prior to proceeding to work on any more flanges airflow would be checked to be in the inward direction. In addition, the containment airlock interlock rechanism was made up requiring that at least one of'the two airlock doors be closed at all times and themby insuring that the containmnt. atmosphere was being evacuated via its normal path. However, the' fourth cample taken at 11:25 a.m. indicated a Xeisa concentration of 4.76 x 10* pc/ml which limited the allowable stay time to just less than one. hour. By the time the sample had been analyzed and calculated, all personnel in the containment had stopped work for their nonntl break. l-t i h g r a h A 8 jy m ?.,..
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.p. Q -V ~ 4-At that time, access to the contalment was restricted until'further samples could be taken and the airborne activity. fourd to have decreased to more acceptable levels. Pre 11. % calculations were made which indicated that three personnel were in the containment during the period of time involved so that the requirements of 10CFR20, paragraph 20.103(b) were not met. The extent of the occupancy time ranged frcm 37% to 51% above the allowable tine limits. Instructions were given to prevent.these affected personnel from gaining access to any area of the plant where airborne activity concentrations were of such a nature that access would not be unlimited. In addition, the increased containment air sampling frequency was maintained and a more strict criteria for access was instituted to insure that no additional personnel overexposures occurred as a result of abnonnal concentrations of airborne activity. This, coupled with the operation of the mechanical vacuum pump,'the covering of the relief valve flange openings, and the maintenance of the containment airlock interlock, prevented any-further exposure problems during the progress of maintenance-work in the contairrnent. lists the personnel involved, the average concentrations of Xel33 and Xe135 to which they were exposed, the permissible stay times based upon the average concentrations, the period of time actually within the contaiment, and the estimated extent of excessive exposure during this period. s. Measures will be taken dur$ng future maintenance activities to sample airborne concentrations at a greater frequency when open flanges to the reactor coolant system exist and to make provisions, if possible, to insure that activity cannot diffuse into the surrounding atmosphere. Additionally, more stringent limits will be imposed on access criteria i to areas of airborne radioactivity concentrations and plotting of any unanticipated changes in concentration will be initiated to permit basing access decisions on the anticipated future trend. IF 7 r. p - = -
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