ML20135F930
| ML20135F930 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 03/12/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20135F929 | List: |
| References | |
| NUDOCS 9703170190 | |
| Download: ML20135F930 (6) | |
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UNITED STATES g
j NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D.C. 2066dk.0001 SAFETY EVALUATION BY.THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 50 TO FACILITY OPERATING LICENSE NO. NPF-86 NORTH ATLANTIC ENERGY SERVICE CORPORATION 3.EL
- TATION. UNIT NO. I h ;KET NO. 50-443
1.0 INTRODUCTION
j By application dated October 17, 1996, North Atlantic Energy Service Corporation (North Atlantic /the licensee) proposed an amendment to the Appendix A Technical Specifications (TSs) for the Seabrook Station, Unit 1 (Seabrook). The proposed amendment would relocate certain instrumentation requirements stated in TS 3/4.3, Instrumentation in accordance with the guidance in Generic Letter 95-10, " Relocation of Selected Technical Specifications Requirements Related to Instrumentation." North Atlantic has committed to relocate the deleted requirements to the Seabrook Station Technical Requirements Manual (SSTR) which is incorporated into the FSAR such 4
that future changes could be nade under 10 CFR 50.59. The associated bases for the deleted TS requirements would be deleted also, but they would not be incorporated into the SSTR. The following Limiting Conditions for Operation (LCOs) and associated Surveillance Requirements (SRs) would be relocated to the SSTR:
Technical Soecification Title LC0 - 3.3.3.2 Incore Detector System SRs & Tables LCO - 3.3.3.4 and associated Meteorological Instrumentation SRs & Tables LCO - 3.3.4 and associated SRs Turbine Overspeed Protection The proposed amendment also would delete (without relocating to the SSTR) the reference to the location of the meteorological tower from Technical Specification 5.5.
9703170190 970312 PDR ADOCK 05000443 P
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2.0 BACKGROUND
l Section 182a of the Atomic Energy Act of 1954,' as amended (the Act) requires i
applicants for nuclear power plant operating licenses to include technical l-specifications as part of the license. The Commission's regulatory i
requirements related to the content of technical specifications are set forth in 10 CFR 50.36.
That regulation requires that the technical specifications include items in five specific categories, including (1) safety limits, limiting safety system settings and limiting control settings; (2) limiting conditions for operation; (3) surveillance requirements; (4) design features; i
and (5) administrative controls. The regulation does not specify the j
particular requirements to be included in the technical specifications.
l The Commission, however, provided guidance for technical specification contents in its " Final Policy Statement on Technical Specification Improvements for Nuclear Power Reactors," which was published in the Federal l
N ister at 58 FR 39132 (July 22, 1993). The Commission indicated therein i
that compliance with its Final Policy Statement satisfies Section 182a of the Act. Criteria for the content of technical specifications were subsequently incorporated into 10 CFR 50.36, cf. 60 FR 36953 (July 19, 1995).
In particular, the Commission indicated that certain items could be relocated from the technical specifications to licensee-controlled documents, consistent with the standard enunciated in Portland General Electric Co. (Trojan Nuclear Plant), ALAB-531, 9 NRC 263, 273 (1979).
In that case, the Atomic Safety and Licensing Appeal Board indicated that " technical specifications are to be
-reserved for those matters as to which the imposition of rigid conditions or limitations upon reactor operation is deemed necessary to obviate the possibility of an abnormal situation or event giving rise to an immediate threat to the public health and safety."
J The four criteria defined by 10 CFR 50.36 for determining whether a particular matter is required to be included in the technical specification limiting conditions for operations, are as follows:
(1)
Installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor
-coolant pressure boundary; -
(2) a process variable, design feature, or operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; (3) a structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier; (4) a structure, system, or component which operating experience or probabilistic risk assessment has shown to be significant to public health and safety.
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j l Existing technical specification requirements which fall within or satisfy any of the above criteria must be retained in the Technical Specifications; those i
requirements which do not fall within or satisfy these criteria may be relocated to other licensee-controlled documents.
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3.0 EVALUATION 1
3.1 In-core detector system i
North Atlantic has proposed to remove LCO 3.3.3.2, "In-core Detector System",
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from the Technical Specifications and relocate corresponding requirements for the system in the SSTR.
In-core instrumentation is used periodically to calculate reactor core power peaking factors to verify nuclear design predictions, ensure operation within established fuel performance limits, and 4
calibrate other nuclear instrumentation.
The measurements are used in a confirmatory manner and do not provide direct input to reactor protection system or engineered safety features actuation system functions.
These instruments are not used for and are not capable of detecting a i
significant abnormal degradation of the reactor coolant pressure boundary before a design basis accident.
These instruments do not function as a primary success path to mitigate events which assume a failure of or a challenge to the integrity of fission product barriers. Core power distributions (measured by the in-core detectors) constitute an important initial condition to design basis accidents and therefore need to be addressed by technical specifications. However, the detectors themselves are not an active design feature needed to preclude analyzed accidents or transients.
Therefore, the staff finds that the in-core detector requirements do not meet the criteria of 10 CFR 50.36 for inclusion in technical specifications.
Therefore, removal of the in-core instrumentation requirements from the Technical Specifications and relocation of corresponding requirements to the SSTR is acceptable. Any subsequent changes to the provisions may be controlled pursuant to 10 CFR 50.59.
3.2 Seismic Instrumentation North Atlantic has proposed to remove LCO 3.3.3.3, " Seismic Instrumentation",
and associated SRs and tables from the Technical Specifications; corresponding requirements would be relocated in the SSTR.Section VI(a)(3) of Appendix A to 10 CFR Part 100 requires that seismic monitoring instrumentation be provided to determine promptly the response of those nuclear power plant features important to safety in the event of an earthquake.
This capability is required to allow for a comparison of the measured response to that used in the design basis for the unit.
Comparison of such data is needed to (1) determine whether the plant can continue to be operated safely and (2) permit such tiniely action as may be appropriate. However, the seismic instrumentation does not actuate any protective equipment or serve any direct role in the mitigation of an accident.
, The capability of the plant to withstand a seismic event or oliher design basis accident is determined by the initial design and construction of systems, structures, and components.
The instrumentation is used to alert operators to the seismic event and evaluate the plant response. The Final Policy Statement explained that instrumentation to detect precursors to reactor coolant pressure boundary leakage, such as seismic instrumentation, is not included in the first criterion. As discussed above, the seismic instrumentation is not a protective design feature or part of a primary success path for events that challenge fission product barriers. The staff has concluded that the seismic monitoring instrumentation does not satisfy the criteria stated in 10 CFR 50.36. Therefore, removal of seismic monitoring instrumentation requirements from the Technical Specifications and relocation of corresponding requirements to the SSTR is acceptable. Any subsequent changes to the provisions may be controlled pursuant to 10 CFR 50.59.
3.3 Meteorological Instrumentation North Atlantic has proposed to remove 1.C0 3.3.3.4, " Meteorological Instrumentation," and associated SRs and tables from the Technical Specifications; corresponding requirements would be relocated in the SSTR.
In 10 CFR 50.47, " Emergency Plans," and 10 CFR Part 50, Appendix E, " Emergency
% nning and Preparedness for Production and Utilization Facilities," the Commission requires power plant licensees to provide reasonable assurance that adequate protective measures can and will be taken in the event of a radiological emergency. Timely access to accurate local meteorological data is important for estimating potential radiation doses to the public and for determining appropriate protective measures.
In 10 CFR 50.36a(a)(2), the Commission requires nuclear power plant licensees to submit annual reports specifying the quantity of each of the principal radionuclides released to unrestricted areas in liquid and airborne effluents and such other information as may be required by the NRC to estimate maximum potential annual radiation doses to the public. A knowledge of meteorological conditions in the vicinity of the reactor is important in providing a basis for estimating annual radiation doses resulting from radioactive materials released in airborne effluents.
Accordingly, the meteorological instrumentation serves a useful function in estimating radiation doses to the public from either routine or accidental releases of radioactive materials to the atmosphere.
The meteorological instrumentation does not serve a primary protective function so as to warrant inclusion in the technical specifications in accordance with the 10 CFR 50.36 criteria. The instrumentation does not serve-to ensure that the plant is operated within the bounds of initial conditions assumed in design basis accident and transient analyses or that the plant will be operated to preclude transients or accidents. The meteorological instrumentation does not serve as part of the primary success path of a safety sequence analysis used to demonstrate that the consequences of these events are within the appropriate acceptance criteria. Accordingly, the staff has concluded that the meteorological instrumentation does not meet the 10 CFR 50.36 criteria and need not be included in technical specifications.
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Therefore, removal of the meteorological instrumentation requirements from the Technical Specifications and relocation of corresponding requirements to the SSTR is acceptable. Any subsequent changes to the provisions may be controlled pursuent to 10 CFR 50.59.
1 3.4 Turbine Overspeed Protection l
North Atlantic has proposed to remove LCO 3.3.4, " Turbine Overspeed Protection," and associated SRs from the Technical Specifications; corresponding requirements would be relocated in the SSTR. The turbine is equipped with control valves and stop valves which control turbine s)eed during normal plant operation and protect it from overspeed during a) normal conditions. The turbine overspeed protection system consists of separate mechanical and electrical sensing mechanisms which are capable of initiating fast closure of the control and stop valves.
General Design Criterion 4 of Appendix A to 10 CFR Part 50 requires that i
structures, systems, and components important to safety be appropriately protected from the effects of missiles that may result from equipment failures. Application of the design criteria to turbine missiles is described in SRP Section 10.2 and in subsequent safety evaluations related to probabilities of turbine failures, turbine orientations, and surveillance requirements for turbine overspeed protection systems.
In NUREG-1366,
" Improvements to Technical Specification Surveillance Requirements," the staff discusses the benefits, resultant costs, and the safety impact of performing turbine overspeed protection surveillances.
Although the design basis accidents and transients include a variety of system failures and conditions which might result from turbine overspeed events and potential missiles striking various plant systems and equipment, the system failures and plant conditions are much more likely to be caused by events other than turbine failures.
In view of the low likelihood of turbine missiles, assumptions related to the turbine overspeed protection system are not part of an initial condition of a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier. The turbine overspeed protection system is not relied upon in the design basis accident or transient analyses as a primary success path to mitigate such events.
Probabilistic safety assessments and operating experience have demonstrated that proper maintenance of the turbine overspeed control valves is important to minimize the potential for overspeed events and turbine damage; however, that experience las also demonstrated that there is low likelihood of significant risk to public health and safety because of turbine overspeed events.
Further, the potential for and consequences of turbine overspeed events are diminished by factors such as the orientation of the turbine relative to plant structures and equipment, licensee inservice testing programs, which must comply with 10 CFR 50.55(a), and surveillance programs for the turbine control and stop valves derived from the manufacturer's recommendations.
Accordingly, the staff finds that the turbine overspeed protection system does not meet the 10 CFR 50.36 criteria. Therefore, removal of the turbine overspeed protection instrumentation requirements from the Technical Specifications and relocation of corresponding requirements to the SSTR is acceptable. Any subsequent changes to the provisions may be controlled pursuant to 10 CFR 50.59.
3.5 Implementation In its application, North Atlantic comitted to insert the relocated requirements in the SSTR, but did not indicate the date by which this will be accomplished. North Atlantic's comitment is incorporated in new paragraph 2.(J), which incorporates new Appendix C to the license.
North Atlantic's comitment to relocate these items to the SSTR is required to be accomplished within 60 days of issuance of this amendment, as set forth in Appendix C to the license.
4.0 STATE CONSULTATION
In accordance with the Comission's regulations, the New Hampshire and Massachusetts State officials were notified of the proposed issuance of the amendment. The State officials had no coments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes a surveillance requirement. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no 1
significant change in the types of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Comission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public coment on such finding j
(61 FR 66713). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Comission has concluded, based 'on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with' the Comission's regulations, and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contribator: Albert W. De Agazio Date: March 12,1997
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