ML19345E448
| ML19345E448 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 12/22/1967 |
| From: | Haueter R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Low L US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19345E447 | List: |
| References | |
| NUDOCS 8101190345 | |
| Download: ML19345E448 (3) | |
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. CompEny General Offices: 212 West Michigan Avenue, Jackson, Michigan 49201. Area Code 517 788-05 J December 22, 1967 Mr. Lawrence D. Lov, Director Division of Compliance United States Atomic Energy Cartsission Washington, D. C.
20545
Dear Mr. Lov:
Please refer to your letter of November 28, 1967, received by us on December 4, concerning a compliance inspection conducted at the Big Rock Point Nuclear Plant on October 4, 1967 In your letter you stated that "your operating and admin-istrative procedures are not complete in that they do not contain adequate instructions relative to your evaluation of radiation hazards in high radiation areas prior to the performance of operations in those areas."
This statement was prompted by a suspected overexposure of one of our employees to external beta radiation during the temporary repair of a leak in the ruptured diaphragm in the air ejector off-gas system on September 12, 1967 We reported suspected overexposure to Mr. Eber R.
Price of the AEC by letter of September 25, 1967 As our report indicated, a Radiation Protection Technician made a special survey of the leak area prior to the repair, obtaining readings of 15 r/hr at the leak and 5 r/hr 18 inches frcn the leak. The readings included open beta vindow readings. Nevertheless, the exposed individual's film badge indicated that he should be credited with expo-sure to 14 rem beta and 2 rem gamma in 1-1/2 minutes. Since the survey failed to disclose a possibility of exposures of this magnitude, one could conclude that our evaluation procedures were inadequate in this instance.
It should be emphasized, however, that this particular case appears to have been exceptional. The factors contributing to the suspected overexposure were:
1.
The appearance for the first time in our process steam of an inordinately high beta-to-ga=ma dose ratio; the ratio in this case was 7 to 1, whereas normal beta-gam::n dose ratios are fram 2 to 1 to 3 to 1.
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Mr. Iavrenca T ; Icv, Director December 22, 1>Jl 2
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2.
The sporadic, puffing nature of the radioactive off-gas leak; one would nomally expect a plant process steam leak to have a continuous flow.
3 The use of a radiation monitoring survey instra-ment which aprerently did not detect the large beta component of the radiation field, if in fact such a component was present.
4.
The unexplained out-of-calibration condition of the radiation monitoring survey instrument which had been calibrated earlier in the day.
5 Plant mmgement's decision to make the temporary repair without reducing plant load to reduce work-ing levels of radiation, since the survey indicated that the radiation exposure to personnel during the repair would be well within applicable Part 20 limits.
Our procedures manual contains Radiation Protection Procedures, the effect of which is to require every job perfomed in a high radiation area, especially in areas where the general field is above 1000 mrem /hr, to be individually evaluated and monitored by a qualified member of the plant's Radiation Protection Department.
In over five years of radiation work, some of it extremely difficult, this suspected overexposure was the first incident of its kind to occur. The
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survey which was made in this instance was apparently made in accordance with the applicable plant procedures. Its ineffectiveness in this case is probably largely attributable to the first two of the foregoing five factors. Since it is certainly conceivalle that such an incident could occur a6ain, we are instituting certain changes in our procedures.
1.
Corrective Steps Taken and Results Achieved The details of the suspected overexposure incident have been reviewed at length with the plant staff. Emphasis was placed on using. properly calibrated survey iristruments. Special briefing sessions have been held with the plant eupervision and radiation protection staff to better prepare them to identify similar troublesome circumstances.
As a result, the plant str2ff is more aware of similar potential problem j
areas.
In addition, a section has been added to the plant operat-ing procedures manual describing the proper methods of making surveys and what to do when certain radiation levels are reached. It covers both routine and special survey situations. Two screening levels for radiation exposures connected with nonroutine jobs have been established.
If someone could exceed a weekly screening level of 0 3 rem, the job vill be reviewed
4 Mr. Iavrznce D. Iov, Director 3
December 22, 1967 1.
Corrective Steos Taken and Results Achieved (Contd) by at least the supervisor in charge and the Chemical and Nadiation
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Protection Engineer. Special attention vill be given to detecting unexpected leak behavior. If someone could exceed a weekly screening level of 1.25 rem, his job assignments will also be reviewed by the Plant Superintendent or his designee. As a result of these changes in procedure, more high level technical and plant management attention /
vill be focused on all work performed in high radiation areas.
2.
Corrective Steps Which Will Be Taken Improvements vill also be made in our surveying techniques, calibration methods and instrument sensitivity. We plan to purchase additional raidation monitoring survey instrumentation more sensitive to measuring beta radiation in the presence of high gamm background than-the instrumentation we are presently using. We vill also purchase a lar60 beta radiation source for calibration purposes. When these two items become available for use, a complete plant survey vill be made to redeter-mine existing beta-gamma dose ratios in all hi6h radiation areas. Plant operating procedures vil.1 be modified, if necessary, as a result of this study.
In any event, the plant operating procedures will be modified to require that two radiation monitoring survey instruments, one of which must be a beta detecting instrument, be used on all work perfomed in a general radiation field greater than 1000 mrem /hr. This requirement will eliminate any problems which might arise frcan single instrument failure or miscalibration.
3 The Date When Full Co=pliance Will Be Achieved The plant operatiD6 procedures manual has already been modified to supplement the instructions concernin6 evaluation of radia-tion hazards in high radiation areas prior to the performance of operations in such areas. Further modifications vill be made early in the second quarter of 1968 after the new survey instrumentation and calibration source are delivered to the plant and the aforementioned study is completed.
Yours very truly, eA A L&
cds Robert L. Haueter Assistant Electric Production Superintendent-Nuclear 1
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