ML19329F874
| ML19329F874 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/24/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19329F862 | List: |
| References | |
| NUDOCS 8007110286 | |
| Download: ML19329F874 (4) | |
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SAFETY EVALUATION BY THE OFFICE OF MUCLEAR REACTOR REGULATION ETROPOLITAM EDISCN COWANY JERSEY CEMTRAL POWER AND LIGHT COW ANY r
PEMMSYLVANIA ELECTRIC COMPANY DOCKET NO. 50-320 THREE MILE ISLN G NUCLEAR STATION, UNIT NO. 2 Introduction By letter dated June 23,1980, (Reference 1), the Metrcpolitan Edison Cogany (l'icensee) proposed a change to the Appendix B Technical Specification dealing with the reactor building purge exhaust flow radiation monitors HP-R-225 and HP-R-226 and the associated interlock function for the purge exhaust dagers 05129 A/D and 05129 B/C. The proposed change would pennit bypassing the interlock function which would cause these dagers to autoestically shift position from the 00EN position to the RECIRCULATE positten on a high radiation signal during " rapid" purging of the TMI-2 reactor building at:nosphere pursuant to the Commission Order for Temporary Modifica-tion of License dated June 12, 1980.
Evaluation Radiation monitors HP-R-225 and HP-R-225 are provided to monitor the concentra-tions of radioactive materials in the exhaust flow of the two trains of the reactor building purge system. One monitor is provided for each train of the reactor build-ing purge system; these monitors are entirely separate from and have no affect on the hydrogen purge systas. These monitors are equipped with actuation circuitry to provide an interlodt function for the purge exhaust daspers D5129 A/D and 05129 9/C. This interlock causes the dagers to autoestically shift position from the OPEM position to the RECIRCULATE position on a high radiatica signal. The set point for these monitors is based upon the instantaneous release rate limit provided in n.,pendix B Techn,fsaypec1fication 2.1.2a which is in turn based upon the annual average i/0 for smaue >.
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the site. Since the reactor building purge operation will be performed using real-r time meteorological parameters and measured concentrations of Kr-85 in the purge affluent to limit the offsite doses to within the design objectives of 10 CFR Part 50, Appendix I, bypassing of this interlock will not cause a decrease in the margins provided by these set points. However, for the period of the purge of the TMI-2 reactor building atmosphere, the Coeurission's Order for Tegorary Modification of License dated June 12, 1980, supersedes this Technical Specification with limita-tions based upon doses to the maxime'ly exposed individual. Consequently, the basis for the monitors' set point and the operability requirements for the associated inter-lock function no longer exists; in fact, at the present set point, the system would not permit purging to continue if the concentration exceeded the set point even thoigh such operation is permitted by the Cossaission's Memorandum and Order and the Order for Tegorary Mou1fication of License. Furthermore, during this purging operation, the indication range of these monitors may be exceeded. Therefore, the detailed operating procedares fer purging han been modified to require periodic sagling of the gases in the reactor building purge system. These operating procedures require NRC staff approval pursuant to proposed Appendix A Tecnnical Sp=cification 6.8.2' prior to implementation. Based upon the foregoing consideraticas, we we find the licensee's preposal to bypass this interlock function during the period of the purge of the TMI-2 reactor building atmosphere acceptable.
Environmental Considerations The environmental considerations of releasing the krypton-85 from the TMI-2 reactor building atmosphere by controlled purging were evaluated in the " Final Environmental Assessment for Decentamination of the Three Mile Island Unit 2 "UC-0062, Liu= 1, May H60, (Refun:nce 2) anci
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3-in the Comission's Meerandum and Order dated June 12, 1980.
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it was concluded that there is reasonable assurance that the health and safety of the public will not be endangered by controlled purging of the TMI-2 reactor building atmosphere to the environment and that this action is insignificant from the standpoint of environmental igact. Thus, pursuant to 10 CFR Section 51.5 (d) (4),
an environmental igact statement or negative declaration and environmer*al igact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion Based upon our review, as discussed above, we find the licensee's prt sal to bypass the radiatica monitors' interlock function the purge exhaust &gers during purging of the reactor butiding atmosphere acceptable and grant the requested Appendix B Technical Specifications change. The measures authori::ed in connection with this evaluation will permit controlled purging of the reactor building atmos-phere to the environment in accordance with the Comission's Order for Temporary Modification of License dated June 12, 1980. Based on these considerations, we have concluded that: (1) because the amendment does not involve a significant j
increase in the probability or consequences of accidents previously considered or a significant reduction of a mergin of safety and thus, does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed menner, ano (3) such activities will be conducted in coeliance with the Commis-sion's regulations and the issuance of this asundment will not be inimical to the cosmon defense and security or to the health and safety of the public.
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References:
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Letter to Bernard J. Snyder, NRC, from R. C. Arnold, Metropolitan Edison Cogany,
" Technical Specification Change Request No. 25", June 23,1980.
2.
" Final Environmental Assessment foe Dec'ontamination of the Three Mile Island Unit 2 Reactor Building Atmosphere", NURES-0662, Volume I, May 1980. -
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