ML20031H144
| ML20031H144 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 09/29/1981 |
| From: | Gallagher J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Keimig R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20031H139 | List: |
| References | |
| NUDOCS 8110270183 | |
| Download: ML20031H144 (4) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A, PA.19101 (215384I 5003 JOSEPH W. G ALLAGHER stacinic encouct one espaaresteet September 29, 1981 Re: Docket Nos. 50-277 50-278 Report No. 50-277/81-16 50-278/81-17 Mr.
R.
R.
Keimig, Chief Projects Branch #2 Division of Resident and Project Inspection Region I U.S.
Nuclear Regulatory commission 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Keimig:
Your letter of September 1, 1981, forwarded combined Inspection Report Nos. 50-277/81-16 and 50-278/81-17.
Appendix A addresses one item which does not appear to be in full compliance with Nuclear Regulatory Commission requirements.
TF.13 item is categorized as a Severity Level IV Violation and is testated below with our response.
Technical specification 3.8.C.1 states, "The release rates of gross activity except for halogens and particulates with half lives longer than eight days shall not exceed:
Qiv MPC i1 Os E
+
g 0.24
- 2. 0 X 10s i
where:
Os = combined units 2 & 3 off gas stack release rate in Ci/sec E = average Y energy release in Mev.
8110270183 811021 gDRADOCK 05000277 PDR
Mr.
R.
R.
Kaimig Page 2 Qiv = combined units 2 & 3 release rate in Ci/sec from reactor building ventilation exhaust stack MPC
= as defined for radionuclide i in column 1, Table II of Appendix B 10 CFR 20 assuming a 10 minute old off gas mixture.
Contrary to the above, on June 22, 1981, the release rate of gross activity, excluding halogens and particulates with half lives longer than eight days, exceeded the Technical specification limit for about seven minutes, with the peak rate being 1.82 times the limit.
Response
On June 21, 1981, the recombiner mechanical compressors tripped due to high hydrogen gas levels downstream of the recombiner.
This resulted in the recombiner mechanical compressor suction header pressure increasing to a positive level.
When this happened, a release occurred through the Unit 3 reactor building vent, with activity levels within Technical Specification limits.
The sole cause of this occurrence was thought to be a leaking 2B recombiner mechanical compressor suction line snubber drain valve.
Pending repairs to the valve, suction pressure was controlled negative.
On June 22, 1981, before repairs could be made to the snubber drain valve, the release described in the Notice of Violation Tnd reported in Licensee Event Report 2-81-35 occurred shortly after Unit 2 had shutdown automatically due to loss of a plant load bus.
The plant load bus which was lost also caused the tripping of 2A recombiner mechanical compressor resulting in the compressor suction pressure sga', increasing to a positive value.
This again caused leakage to occur which resulted in the release which exceeded Technical Specification limits.
The line associated with the leaking 2B mechanical compressor suction valve was cut upstream of the valve and a pipe cap installed to preclude further leakage.
Subsequent to removal of the leaking valve and capping of the line, several more losses of recombiner system negative pressure resulted in releases well within Technical Specification limits.
Investigation revealed two additional leak paths.
A normally closed recombiner mechar.ical compressor suction line loop seal isolation valve was found cracked open.
(The loop seal was drained, since several other system drains had been added to the system after initial installation and this loop seal drain is no longer required).
This valve is in a location where it could be used as a foothold to gain access to other equipment in the area.
The valve was wired closed.
The second leak path was the recombiner condenser conductivity element drain valve, which I
.e Mr.
R.
R. Keimig Page 3 draine to the recombiner equipment drain sump.
The'recombiner equipment drain sump airborne activity levels were found to be abnormally high and it was determined that this valve was cracked open approximately one quarter turn.
The valve was closed.
Subsequent losses of recombiner negative pressure resulted in no appreciable increase in Unit 3 reactor building vent activity levels.
The release in excess of Technical Specifications, wt.;h occurred at 9:30 a.m. on June 22, 1981, caused the Unit 3 root vent monitor to spike for a seven minute period releasing 12 mci /sec.
(6.6 mci /sec. average) for a total release of 2.8 curies during the peak period (1.82 times the Technical Specification limit).
The peak tailed off above background for three hours releasing 0.760 mci /sec. average for a total release of 8.6 curies over the tailing off period.
The total release over the entire period is calculated to be 11.4 curies.
Analysis of roof vent iodine and particulate samples indicated no increase in the release rate during any of the gaseous activity spikes.
The release, which was of shcrt duration, resulted in maximum dose at site boundary of.08 mR.
Very truly yours, 1
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COMMONWEALTH OF PENNSYLVANIA :
ss.
COUNTY OF PHILADELPHIA J.
W. Gallagher, being first duly sworn, deposes and says:
That he is Manager of the Electric Production Department of Philadelphia Electric Company, the Applicant herein; that he has read the foregoing response to Inspection Report Nos. 50-277/81-16 and 50-278/81-17 and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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Subscribed and sworn to before me this
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