ML19347B247
| ML19347B247 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 08/20/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19347B240 | List: |
| References | |
| NUDOCS 8010140123 | |
| Download: ML19347B247 (5) | |
Text
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,o SAFETY EVALUATION BY THE OFFICE CF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 49 TO PROVISIONAL OPE 9ATING LICENSE NO. OPR-16 JERSEY CENTRAL POWER AND LIGHT COMPANY 0YSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-219
1.0 INTRODUCTION
By letter dated February 15, 1980, Jersey Central Power and Light Company (the licensee), submitted a request (Technical Specification Change Request No. 79) to change Apoendix A of its Provisional Operating License No. DPR-16 for Oyster Creek Nuclear Generating Station.
The proposed amendment would incorporate the 10 CFR Part 50, Appendix I design objectives for gaseous effluents into the Technical Specifications as Limiting Conditions of Operation.
2.0 JACKGROUND On June 4,1976, the licensee submitted the report " Evaluation to Demon-strate Compliance with 10 CFR 50 Apoendix I" for the Oyster Creek Nuclear Generating Station.
In Section 3 of the report, " Gaseous Radwaste System",
the licensee describes a system for the treatment and hoTdup of air ejector offgas prior to release to the atmosobere.
Based on the operation of this Augmented Offgas Treatment System (A0G), the licensee calculated the dose to the public in unrestricted areas and concluded that the gaseous releases from the Oyster Creek Station would meet all of the requirements of Para-graphs II B & C of Appendix I to 10 CFR 50. After reviewing this report the staff concluded that the systems, when installed and operated croperly, are capable of maintaining releases of radioactive materials in affluents to "as low as reasonably achievable" levels in conformance with the requirements of 10 CFR 50.34a and the design objectives of Aopendix I to 10 CFR 50.
However, the A0G described in the licensee's Appendix I recort has not been put into continuous operation.
The A0G at Oyster Creek utilizes an air recirculation loop to dilute the offgas from the steam jet air ejector prior to entering the recombination section of the system.
Figure 1* is a schematic description of the system.
The offgas, prior to the introduc-tion of the recycled dilution air, is explosive (50"; and 301, by volume of hydrogen and oxygen, respectively).
To prevent a hydrogen ignition at the pre-heater or reccmbiner sections of the A0G, the offgas must be diluted Copy attached
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. J to a hydrogen concentration of less than 4% by volume. This should be accomplished by the mixing with air recycled from the recombiner-condenser section of the A0G.
However, catalyst fines (palladium dust) from the recombiner could migrate and travel with the recirculation air to the region in front of the recombiner section of the system. Any incomplete mixing at the area where the dilution air is introduced could result in regions where the hydrogen concentration of the offgas remains high.
This coupled with the presence of catalyst fines has caused numerous instances of hydrogen ingnitions.
The A0G was originally scheduled for operation in September 1977.
During initial system testing in August 1977, offgas ignitions occurred.
The licensee modified the system drain lines.
Subsequent offgas ignitions (e.g., on March 17,1978) led the licensee and his contractors to modify the mixing tee region where the dilution air recirculation is introduced for better mixing.
Other problems which may have contributed to the causes of offgas ignitions were also uncovered, e.g., the mixing tee installed was found to be inverted. More recently, the licensee has installed a flame arrester (see Figure 1) upstream of the mixing tee.
This should prevent the offgas ignition from travelling to the delay-pipe region of the system.
l The continual reoccurrence of these operational problems of the A0G
- esulted with a special meeting between the NRC and the licensee on September 13, 1979.
The licensee was made aware of the necessity to.
maintain and operate the installed radwaste equipment (i.e., the A0G).
J Although the gaseous radioactivity releases, without the continuous operation of the A0G, has been kept within a small fraction of the tech-nical specification and 10 CFR 20 limits, the licensee ccmitted to meet the design objectives of Appendix I.
The licensee also expected the A0G to become operable after the January to July 1980 refueling outage when operational experience with the newly installed flame arrester will be tested.
Until the successful continuous operation of the A0G can be demonstrated, the licensee has comitted to the following interim actions.
(1)
Efforts to make the A0G operable, including system design and equipment modifications, will be expedited if necessary.
Should major and exte ded system modifications become necessary, the licensee would infonn the staff on the schedule and progress of those changes.
(2) The existing technical soecifications on radioactivity of Aopendix I would become limiting conditions of operation which would not be exceeded.
The plant would operate under these interim technical specifications until the A0G can be centinuously operated without hydrogen ignition problems.
At that time, these interim technical soecifications would be replaced by the revised Radiological Effluent Technical Specifi-cations (RETS) for Oyster Creek.
The RETS would include the requirement to maintain and operate the installed radwaste systems.
. 3.0 EVALUATION The proposed technical specification 3.6.F.1 would limit the annual average releases of noble gases such that the calculated gamma and beta air doses at the unrestricted areas are less than 10 mrads and 20 mrads, respectively.
The NRC staff generated X/Q value used in this specifica-tion is for the site boundary location (569m, SE) which results in the highest calculated dose.
The methodology of the beta air dose calcula-tion assumes a semi-infinite plane model as described in equation B-4 of Regulatory Guide 1.109, Rev. 1.
Almost all of the noble gases releases from Oyster Creek are from the 100 meter stack.
The methodlogy of the gamma air dose calculation uses the finite plume model as described in equation B-1 of Regulatory Guide 1.109, Rev. 1.
The NRC RABFIN computer code which utilizes this model was used to calculate the gamma air dose factors in Table 3.6-1.
Proposed technical specification 3.6.F.2 would limit the calculated annual average dose by all pathways resulting from gaseous effluents of radio-iodines and radioactive materials in particul3te form to less than 15 mrem.
The X/Q and D/Q values used in this soecification are for a dis-tance of 890 m in the SE direction which is the location of highest potential thyroid dose based on the Oyster Creek Appendix I analysis.
The dose conversion factors for iodine isotopes by ingestion through the vegetation consumption pathway were reduced by a factor of two based on the assumption that one-half of the iodine released is non-elemental.
Over 90% of the iodine releases in gaseous effluents at Oyster Creek are from the main condenser Steam Jet Air Ejector System (SJAE).
Iodine releases from this source, in contrast to other sources (e.g., building ventilations) have been demonstrated to consist almost entirely of the non-elemental form. Assuming 50% of the iodine to be in the inorganic form, in this case, should be conservative and, therefore, acceptable.
However, when the ACG beccmes operational, and when these interim technical specifications are to be replaced by the RETS, the iodine releases can no longer be assumed to be largely from the SJAE. Consequently, the assumption that 50% - f the iodine exists in the non-elemental form would no longer be apolicable.
The licensee originally prooosed to use semi-infinite model gamma air dose factors. We replaced those dose factors with factors based on the finite plume model because Oyster Creek has a tall (100m) stack. We also replaced the meteorological parameter at the site boundary with the NRC staff generator parameter. We have discussed these changes with the licensee's representative and have mutually agreed upon them.
4.0
SUMMARY
Sasad on the discussion above, we have concluded that the procosed change in technical specifications, would limit the radioactivity releases in gaseous effluents from the Oyster Creek station to within the design objectives of Appendix I to 10 CFR 50. A review of the reported releases from the station from January 1977 to December 1979 indicates that there
..ere periods (e.g., from January to December 1979) when the design objec-tives were exceeded.
Some improvements in the releases may be realized baring the initial periods following the January 1980 refueling outage
. (i.e., by replacement of some of the old fuel that may be defective).
Other actions by the licensee, especially expediting the repair and opera-tion of the A0G, may be necessary with the implementation of the croposed technical specifications. We, therefore, find the proposed changes, as modified, acceptable.
5.0 ENVIBQNMENTAL CONSIDERATION We tr,e determined that the amendment does not authorize a change in effl ent types or total amounts nor an increase in power level and will not esult in any significant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 951.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
6.0 _ CONCLUSION We have concluded, based on the considerations discussed above, that:
(1) because the amendaent does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment 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 manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Attachment:
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