ML13330A131
| ML13330A131 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/01/1980 |
| From: | Papay L SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| 10CFR-020.405, 10CFR-20.405, NUDOCS 8010150279 | |
| Download: ML13330A131 (2) | |
Text
Southern California Edison Company U'C P. 0. BOX 800 2244 WALNUT GROVE AVENUE LT. PAPAY ROSEMEAD, CALIFORNIA 91770 VICE PRESIDENT 213-572-474 October 1, 1980 CP I
c U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Reoion V 1990 North California Boulevard Suite 202, Walnut Creek Plaza Walnut Creek, California 94596 Attention: Mr. R. H. Engelken, Director DOCKET No. 50-206 SAN ONOFRE -
UNIT 1
Dear Sir:
By letter dated September 3, 1980, we reportec seventy-three (73) persons as possibly exposed in excess of 10 CFR 20.101 limits during the thiro calendar quarter of 1980. That report resulted from a preliminary evaluation of top of head vs. chest exposures during steam generator test and repair work.
This report is submitted in accordance with the requirements of Title 10, Chapter 1, Code of Federal Regulations, Part 20, paragraph 20.405. Based on a further review of the exposure data, it has been concluded that eleven (11) individuals during the second calendar quarter of 1980 and four (4) individuals during the third quarter of 1980 may have exceeded the quarterly limits specified in 10 CFR 20.101 while working at San Onofre Unit 1. None of these individuals could have exceeded his 5(N-18) lifetime limit and no individual could have exceeded 5 rem during either calendar quarter.
An extensive investigation of this incident was performed to determine whether or not the initially reported exposures actually occurred and whether or not there were additional possible exposures in excess of 10 CFR 20.101 limits during the second quarter of 1980. This investigation included consideration and evaluation of the following items:
o Film badge response vs. orientation in the steam generator channel head o
Average gamma energy in the steam generator channel head o
.Radiation surveys of the steam generator channel head o
Minimum probable exposure for one steam generator channel head entry o
Measured exposures to the head, trunk and extremities of steam generator channel head entrants 8o1015097?.
U.S. Nuclear Regulatory Commission October 1, 1980 o
Energy of the-beta radiation present o
Protection from beta exposure by protective clothing o
Examination of the Radiation Exposure Permits for steam generator work o
Examination of the high radiation area log for steam generator work o
Examination of the Westinghouse maintained daily work log o
Personal ano telephone interviews with involved personnel o
Computerized search of the entire controlled area entry log for potential steam generator channel head entries during the second and third calendar quarters of,1980 Resultant calculations from the above investigation indicate that the personnel shown on Attachment 1 may have received exposure to whole body in excess of the 10 CFR 20.101 limit during the second and third calendar quarters of 1980.
These calculated.exposures in excess of the 10 CFR 20.101 limit result from an inadequate assessment of the placement of personnel monitoring devices during a unique work function. Personnel were originally provided with one film badge which was located on the upper part of the chest. The results of the investigation described above demonstrated that the exposure at the top of the head exceeded the chest exposure by an average factor of 1.62.
To prevent a recurrence of this type incident, all steam generator channel head entrants are now badged with film on the top of the head, on the forehead and on the chest and with a TLD ring on each hand.
Whole body exposure is taken to be the highest of the three film badges.
Self-reading dosimeters are used to provide an immediate indication of top of head and chest exposure during channel head work. The practice of wearing several film badges will be continued for future station activities as appropriate.
The data supporting the conclusions stated within this report will be on file at the San Onofre station. If you have any questions or if we can provide additional information, please let me know.
Sincerely, cc:
Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555