ML19269D493
| ML19269D493 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/22/1979 |
| From: | Banks H CAROLINA POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| GD-79-1330, NUDOCS 7906040153 | |
| Download: ML19269D493 (4) | |
Text
- F]AM21 Cp&L G
o Carolina Power & Ught Company Raleegn. N. C. 27602 May N,1979 FILE: NG-3513 (B)
SERIAL: GD-79-1330 Mr. James P. O'Reilly, Director U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, GA 30303 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 LICENSE NOS. DPR-71 AND DPR-62 DOCKET NOS. 50-325 AND 50-324 14-DAY RADIOLOGICAL ENVIRONMENTAL EVENT REPORT
Dear Mr. O'Reilly:
On May 8-9, 1979, BSEP Environmental Technical Specification 2.5.2.a(2) was exceeded for a period of approximately 5 1/2 hours due to an airborne release from the Unit No. I reactor building. This report is submitted in accordance with Environmental Technical Specification 5.4.2b.
Incident Description At 1936 hours0.0224 days <br />0.538 hours <br />0.0032 weeks <br />7.36648e-4 months <br /> on May 8,1979, the Unit No. I reactor water clean-up (RWCU) backwash receiving tank was transferred to the radwaste building. By procedure, an air mixing valve is opened to mix the contents of the tank prior to transfer. This valve was inadvertently left open after the transfer was complete. A portion of the residue in the tank apparently dried and became airborne inside the tank.
Airborne activity was released into the reactor building through a loose access cover on the tank vent filter, and exhausted via the building ventilation system.
At approximately 2100, the reactor building exhaust monitor showed a significant increase in activity.
At this time, EI-23.2 (high airborne activity in the reactor building) was implemented and a search for the source was begun. Air sampling,-
analysis, and investigation of the source continued until 0222 on May 9,1979, when the normal reactor building ventilation system was secured and the standby gas treatment system was placed into service by operator action, based on an MPC ratio of two on the 50-foot elevation. The reactor building roof vent monitor was not at its alarm setpoint. This r.cion terminated airborne releases from the reactor building.
Terrestrial environmental sampling was conducted inside the site exclusion boundary and at approximately one-half mile off site in the downwind direction (see attachment for sampling results). After the results became available on May 10, 1979, the NRC Region II office was D' i 2259 126 7906040 / 9 3
Mr. James P. O'Reilly May 22, 1979 notified of the incident and of the fact that an environmental event report would be submitted within 14 days. The head of the Radiation Protection Branch of the N.C. Department of Human Resources was also notified on May 10, 1979. On May 11,1979, the Brunswick County Civil Preparedness Coordinator and the Mayor of the city of Southport were notified for information.
Corrective Action 1.
The tank transfer procedure has been revised. Emphasis has been placed on assuring that the air mixing valve is closed prior to tank transfer.
2.
A caution tag has been hung on the valve stating the precautions to be taken.
3.
The incident has been reviewed with all operating personnel by a memorandum submitted by the Operating Supervisor.
4.
This event will be discussed during the next shift safety meeting for all operations shifts.
5.
The reason for the filter access cover being loose and the action required to prevent future occurrence is now being evaluated.
6.
The individuals involved have been counselled on the potentially serious consequences of events of this type.
Yours very truly, Original Signed BF RAROLD R. 3 AXES H. R. Banks Manager Nuclear Generation JLK/RMR/DCS/jpw*
Enclosure 2259 127
,. cc:
Mr. Harold R. Denton bec: Messrs. D. L. Bensinger C. S. Bohanan J. M. Johnson W. B. Kincaid S. McManus A. C. Tollison C. W. Woods
SUMMARY
OF AIRBORNE REI. EASE 1.
The air sample obtained from the Unit No. I reactor building exhaust vent (counting room No. 79-3198) indicated a release rate of 6.34 E-7 Ci/sec during the incident. This exceeds the instantaneous release limit (E.T.S. 2.5.2a(2) by a factor of 3.7, and resulted in a total release of 12 mci. The percentage breakdown of the isotopes released is as follows:
Isotopes
% of Total 51 Cr 27.0 5
Mn 32.0 9
Fe 12.8 S7 Co 0.08 S8 Co 6.5 60 Co 18.0 0
Zn 2.2 95 Zr 0.1 III Sn 0.08 Sb 0.33 Sb 0.13 Using this as a source term with the existing meteorological conditions, a projected off site whole body dose of 8% of the 10CFR20 Appendix B limits (based on x =
Q
) was obtained.
na a U 2.
Ten vegetation samples were obtained on May 9,1979, five inside the site boundary (NC) and five at approximately'one-half mile outside the site boundary (BC).
Concentration Sample Point Isotopes *
(pCi/gm dry)
NC-1 Mn '
2.49 E-1 5
0 C
1.69 E-1 137 Cs 2.00 E-1 54 NC-2 Mn 2.11 E-1 60 Co 2.51 E-1 13 Cs 6.63 E-2 4
NC-3 Mn 3.08 E-1 137 Cs 2.34 E-1 NC-4 Nog
< MDA NC-5 Cr 4.28 E+0 54 Mn 4.95 E-1 S
Co 1.51 E-1 6
C 2.16 E l 137 Cs
< MDA BC-1 Cs 4.98 E-1 137 BC-2 Cs 4.83 E-1 2259 128
54 BC-3 Mn 1.14 E-1 137 Cs 2.44 E+0 BC-4 Mn 5.13 E-1 Co 2.85 E-1 7
Cs 1.82 E+0 BC-5 Mn 5.55 E-1 60 Co 2.38 E-1 C.[
2.09 E+0 137
- Cs was not. detected in the release, though it was a major constituent of the off-site samples. This isot. ope had previously been attributed to Chinese nuclear testing.
3.
In addition, an air sample (CR No. 79-3208) was obtained beyond the site boundary.
Concentration Air Sample Isotopes (pCi/cc)
BC-3 Cr 3.58 E-13 Mn 5.17 E-13 58 C
5.74 E-14 60 Co 6.46 E-13 When summed, this equals 0.22% of the 10CFR20 Appendix B limits for unrestricted areas.
4.
Sample BC-4 was analyzed in terms of projected adult dose commitments.
Using the assumptions of Regulatory Guide 1.109 (assuming no decay),
the following values were obtained:
Projected Dose Rate Pathway mrem / day External - khole Body
.0012 Produce - Whole Body
.0025 Produce - Liver
.0042 Produce - GI and LLI
.027 Leafy Vegetation - htole Body
.0003 Leafy Vegetation - Liver
.0005 Leafy Vegatation - GI and LLI
.0033 2259 129
.