ML20003E717
| ML20003E717 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/01/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20003E711 | List: |
| References | |
| NUDOCS 8104100121 | |
| Download: ML20003E717 (4) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION I
.p WASHINGTON, D. C. 20555 o
%; v*....f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING Al1ENDMENT NO. 96 TO FACILITY OPERATING LICEflSE NO. DPR-38 AfiENDMENT NO.96 TO FACILITY OPERATING LICENSE NO. DPR-47 A11ENDMEllT N0.93 TO FACILITY OPERATING LICENSE fl0. DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS NOS. 1, 2 AND 3 DOCKETS NOS. 50-269, 50-270 AND 50-287 Introduction By letter dated May 1,1979, Duke Power Company (the licensee) proposed revisions to the Oconee Nuclear Station (0conee) Technical Specifications (TSs) which alter Sections 4.4.3, 4.5.3 and 4.14.
These changes are primarily administrative in nature, modifying the fonnat of the specifications. Changes to Sections 4.5.3.la and 4.14.la were subsequently made following telephone discussions with the licensee.
By letter dated Fcbruary 16, 1981, the licensee proposed revising various sur-veillance requirement intervals from annually to refueling cycle to coincide with the extended (18-month) refueling cycle. By letter dated March 6,1981, the licensee proposed requimments for the operability and testing of the anticipatory reactor trip system.
Evaluation I.
Filter Testing We have reviewed the proposed changes to Sections 4.4.3 (Hydrogen Purge System),
4.5.3.
(Penetration Poom Ventilation System) and 4.14 (Reactor Building Furge Filters and Spent Fuel Pool Ventilation Systems) of the Oconee TSs requested by letter dated 11ay 1,1979. These sections specify the limiting conditions for operation and surveillance requirements on three Engineering Safety Features (ESF) ventilation filter systems which ar6 used to mitigate the radiological consequences of accidents at Oconee. Most of the changes are only to modify the format of the three above sections in the ESF ventilation filter system and do not reduce any of the requirements in the present Oconee TSs on the Hydrogen Purge System, Penetration Room Ventilation System and Reactor Building Purge Filters and Spent Fuel Pool Ventilation System.
In addition to the proposed changes to mocify the present format of Sections 4.4.3, 4.5.3 and 4.14 of the Oconee TSs, the licensee requested changes to (1) delete the prefix " cold" from references to DOP tests in the Oconee TSs, (2) allow 31 days following removal of a carbon sample to verify that the sample has an acceptable methyl iodide removal efficiency, and (3) for only the Hydrogen Purg.e System, require removing a charcoal sample after every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation to test the sample's methyl iodide removal efficiency. The requested change to delete the prefix " cold" from refemnces to D0P tests is consistent with the in-place testing criteria of Regulatory Guide 1.52 (Revision 2), " Design Testing and Maintenance Criteria for Post-Accident Engineered-Safety-Feature Atmosphere Clean-up B104100{Q,\\
. System Air Filtration and Adsorption Units of Light-Water-Cooled Nuclear Power Plants". The proposed change to allow 31 days between removing the -
charcoal sample from the ventilation filter systems and verifying the methyl iodide removal efficiency of the charcoal sample is the standard time allowed for verification of the charcoal radiciodine removal efficiency.
If this efficiency is too low, the system would be declared inoperable until the charcoal in the system was replaced. The proposed change, to require removing a charcoal sample once every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of Hydrogen Purge System operation to test the sample's methyl iodide removal. efficiency, is in accordance with the requirement specified in footnote c. to Table 2 of Regulatory Guide 1.52.
Based on the considerations given above, we conclude that these.croposed' changes to Sections 4.4.3, 4.5.3 and 4.14 of the Oconee TSs are acceptable.
The licensee was asked to amend Sections 4.5.3.la 'and 4.14.la to require that monthly each train of the Penetration Rocm and Spent Fuel Pool Ventilation System be started from the. control room and verified operable at design flow within + 10%. Previous to the suggested alteration of the licensee's submittal, no operability requirement was stated in the Oconee TSs. These changes increase the assurances that these ventilation filter systems will be available at an acceptable flow rate when needed. The licensee has agreed to include this additional requirement.
The proposed changes discussed above to the Oconee ESF ventilation filter systems do not change any of the assumptions made to calculate the potential conse-quences of postulated design basis accidents-at Oconee. The potential conse-quences of these postulated accidents, which are not changed by)these proposed changes to the Oconee TSs, are given in Safety Evaluations (SEs dated Decemoer 1970 and July 1973 for Oconee.
Licensee Event Reports (LERs) relevant to ESF air filtration and adsorption-systems have also been reviewed. LER R0-287/78-19 discusses failure of the. pe.oe _ _,
tration filters due to moisture saturation caused bv. steam leakace on.
Oconee Unit 3.
LER 79-023/03L-9'and 79-030/03L-0 discuss declaring the pene-tration room ventilation system inoperable due to high humidity from steam leaks on Oconee Unit 1.
In' the Oconee Unit i SE, 50% of all containment leakage is assumed to go through the penetration room filtration systen which is considered 90% efficient in iodine removal. Should the Unit 1 filtration system be inopera-tive, our calculated design basis Loss of Coolant Accident (LOCA) 2-hcur thyroid dose (refer to Regulatory Guide 1.4) would increase from 190 Rem to 345 Rem.
For Oconee Units 2 and 3, the iodine rencval efficiency for the 50% containment leckage to the penetration room filtration system is assumed in the SE to be 90% for elemental and particulate iodine and 70% for organic iodine. Should the Unit 2 or 3 filtration system be inoperative, our calculated design basis LOCA 2-hour thyroid dose would increase from 235 Rem to 424 Rem.
It is, therefore.
concluded that the penetration room filtration system must be operational to prevent the design basis LOCA 2-hour site exclusion boundary thyroid dose from exceeding the 300 Rem limit in 10 CFR Part _100. All three LERs conclude that the offsite release during a LOCA would be well within the guidelines of 10 CFR Part 100 without the penetration room ventilation system in operation since the licensee prest.cably did not use the design basis LOCA asstcptions that are
' defined in Regulatory Guide 1.4. We, therefore, determined that additional assurance of the operability of the penetration room filters was necessary.
The licensee investigated the possibility of including demisters and heaters or cooling coils designed to reduce the inlet stream relative humidity to less than 70% and found these modifications to be impractical. The licensee has, however, replaced the check valves in the main feedwater lines on Unit 3 (these valves are a major source of the humidity problem due to leakage) and has initiated engineering schedules for similar replacement of these valves on Units 1 and 2 at the next available unit outage. The licensee has also implemented procedures to monitor the humidity in tne penetration room and take prompt action to reduce the humidity to less than 70% whenever this value is exceeded. We find that these modifications and procedures provide sufficient additional assurance that the penetration room filter will remain operable and are acceptable.
II. Surveillance Testing Intervals By letter dated February 16, 1981, the licensee proposed to revise the sur-veillance interval for the presently required annual tests for the filter system in Section 4.5.3 to a refueling cycle interval. Discussions with the licansee disclosed that the same change was requested for the filter systems in Sections 4.4.3 and 4.14.
(A similar request to extend surveillance intervals was approved by Amendments Nos. 91, 91 and 88 which were issued on January 28, 1981, for the Oconee Units 1, 2 and 3, respectively). Since it is the NRC staff's intent that such tests be perfonned at least once per operating cycle and since the refueling cycle interval has been defined, by the previously mentioned Amendments, to be in accordance with the latest NRC guidance contained in NUREG-0103, Revision 4. " Standard Technical Specifications for B&W PWRs", we find these changes to be acceptable.
The licensee also included revisions to Sections 4.5.2 (Reactor Building Cooling Systems),4.5.4 (Low Pressure Injection System Leakage), 4.6 (Emergency Power Periodic Testing)), 4.7 (Reactor Control Rod System Tests), 4.12 (Control Room Filtering System and 4.19 (Fire Protection and Detection System)'to extend various surveillance tests from annually to at least once per refueling outage.
We have reviewed these changes and find them to be in accordance with the requirements given in NUREG-0103, Revision 4, and have concluded that they are acceptable.
It should be noted that the surveillance testing required to be performed "during each refueling outage" need not ce performed more frequently than once every 22-1/2 months, even though a special circumstance may arise which requires refueling operations at a shorter interval, and may be perfomed at times other than a refueling outage. This interpretation is consistent with the requirements of NUREG-0103.
An editorial change was also included in the licensee's February 16, 1981, request which revises the requirement to report Reactivity Anomalies (in Section 4.10) to the Nuclear Regulatory Comission inatead of the predecessor agency,-
the Atomic Energy Comission. This change is desirable and acceptable.
III. Anticipatory Reactor Trio System Reouirements By letter dated March 6,1981, the licensee proposed TSs to require the opera-bility and testing of the anticipatory reactor trip system. Approval of the system was provided by a letter to the licensee from the NRC dated December 4,
1980, which attached the NRC staff's SE and requested that TS requirements be submitted.
The licensee's March 6,1981, proposal was in response to the staff's Decerser 4,1980 request.
We have reviewed the licensee's submittal and find that it is in accordance with and responsive to our request. We further find that the proposed TSs contain the requirements which ane applicable to other similar systems in use at other nuclear plants and those contained in the Standard Technical Specifications for Babcock and Wilcox PWRs. We, therefore, conclude that these additional requirements are acceptable.
Environmental Consideration We have determined that the amendments do not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environniental impact.
Having made this determination, we have further concluded that the amendments involve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 151.5(d)(4),
that an environmental impact statenent, or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance of these amendments.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendments do not involve a significant increase in the probability or consequences of accidents previously considered and do not involve a signi-ficant decrease in a safety margin, the amendments do 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 Cocrnission's regulations and the issuance of these anendments will not be inimical to the common defense and security or to the health and safety of the public.
Dated: April 1,1981
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