ML20085F542
| ML20085F542 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/09/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20085F538 | List: |
| References | |
| NUDOCS 9506190293 | |
| Download: ML20085F542 (5) | |
Text
ff UNITED STATES i
W/ I E NUCLEAR REGULATORY CCMT/ISSION 3 gCf f WASHINGTON, D.C. 20555400 $
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 98 TO FACILITY OPERATING LICENSE NO. DPR-80 AND AMENDMENT NO. 97 TO FACILITY OPERATING LICENSE NO. DPR-82 PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON NUCLEAR POWER PLANT. UNITS 1 AND 2 DOCKET NOS. 50-275 AND 50-323
1.0 INTRODUCTION
By letter of August 17, 1994, Pacific Gas and Electric Company (or the licensee) submitted a request for changes to the Technical Specifications (TS). The proposed amendments would relocate TS 3/4.4.2.1, " Safety Valves -
Shutdown," 3/4.4.7, " Chemistry," 3/4.4.9.2, " Pressurizer (Temperature Limits)," 3/4.4.10, " Structural Integrity," and 3/4.4.11, " Reactor Vessel Head Vents," in accordance with the Commission's Final Policy Statement for relocation of current TS that do not meet any of the screening criteria for retention.
These TS limiting conditions for operation would be relocated to Diablo Canyon Nuclear Power Plant Administrative Controls and the Updated Final Safety Analysis Report (UFSAR) by reference, such that future changes to these requirements would be made pursuant to 10 CFR 50.59.
As part of the relocation of TS 3/4.4.2.1, TS 3/4.4.2.2, " Safety Valves -
Operating," would be revised to require that the pressurizer safety valves be operable in Mode 4 with the reactor coolant system cold-leg temperature greater than the low-temperature overpressure protection (LTOP) system enable temperature, and TS 6.8, " Procedures and Programs," would be revised to t
include the reactor coolant pump flywheel inspection program.
2.0 EVALUATION Section 50.36 of Title 10 of the Code of Federal Regulations established the regulatory requirements related to the content of TS. The rule requires that TS include items in specific categories, including safety limits, limiting conditions for operation, and surveillance requirements; however, the rule does not specify the particular requirements to be included in a plant's TS.
The NRC developed criteria, as described in the " Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors" (58 FR 39132), to determine which design conditions and associated surveillances are "necessary to obviate the possibility of an abnormal situation or event giving rise to an immediate threat to the public health and safety" and need to be located in the TS.
Briefly, those criteria are (1) detection of abnormal degradation of the reactor coolant pressure boundary, (2) boundary conditions for design basis accidents and transients, (3) primary success paths to prevent or mitigate design basis accidents and 9506190293 950309 PDR ADOCK 05000275 p
transients, and (4) functions determined to be important to risk or operating experience.'
The Commission's Final Policy Statement acknowledged that its implementation may result in the relocation of existing TS requirements to licensee controlled documents and programs.
TS 3/4.4.2.1. " Safety Valves - Shutdown" The existing requirements in TS 3/4.4.2.1 and TS 3/4.4.2.2 specify limiting conditions for operation (LCOs) and surveillance requirements for reactor coolant system (RCS) safety valves in Modes 4 and 5.
The licensee has proposed to combine the requirements for Mode 4 with those for the operating modes by revising " Safety Valves - Operating" to include a requirement that the pressurizer safety valves be operable in Mode 4 with the reactor coolant system (RCS) cold-leg temperature greater than the LTOP system enable temperature. The requirements for RCS safety valve operability and surveillances in Mode 5 would be relocated to plant procedures.
1 The safety valves, together with the reactor protection system, protect the RCS from being pressurized above its safety limit of 2735 psig.
In the event that no safety valves are operable, an operating residual heat removal loop, connected to the RCS, provides overpressure relief capability and will prevent RCS overpressurization.
In addition, the overpressure protection system (relief valves) provides a diverse means of protection against RCS overpressurization at low temperature.
The proposed changes to the TS establish operability and surveillance requirements for the safety valves which are consistent with the RCS overpressure design basis.
The existing TS requirements for the safety valves in Mode 5, when the RCS is below the pressure and temperature conditions associated with overpressure transients, do not constitute initial conditions that challenge the RCS or a primary success path to mitigate a design basis accident or transient. Therefore, these requirements do not satisfy the criteria for TS and the licensee has proposed to relocate these provisions to the plant procedures and, because these functions are described in the FSAR, futura changes to these revirements would be subject to 10 CFR 50.59.
The staff has concluded that 10 CFR 50.36 does not require inclusion of the RCS safety valve operability and surveillance requirements in Mode 5.
Further, the changes to combine the LCOs and surveillance requirements for the safety valves in Modes 1, 2, 3, and 4 is purely administrative. The staff has, therefore, concluded that the proposed changes are acceptable.
The Commission recently pr:wastseted a proposed change to 10 CFR 50.36. pursuant to which the rule would be amerwied to codify and incorporate these criterie (59 FR 48180). fhe Comission's Final Policy statement specified that Reactor Core Isolation Cooling, Isolation Condenser, Residual Meet Removet. Stan@y Liquid Control. and Recirculation Pwp Trip are included in the TS under Criterion 4 In the proposed change to 550.36, the Comission specificetty req;ested public corrrients r+gerding application of Criterion 4
Until additional guidance has been developed. Criterion 4 will not been applied to add 15 restrictions other than those indicated above.
> TS 3/4.4.7. " Chemistry" The reactor coolant chemistry program provides limits on particular chemical properties of the primary coolant, and surveillance practices to monitor those properties, to ensure that degradation of the reactor coolant pressure boundary is not exacerbated by poor chemistry conditions. However, degradation of the reactor coolant pressure boundary is a long-term process, and there are other, direct means to monitor and correct the degradation of the reactor coolant pressure boundary which are controlled by regulations and TS (e.g., in-service inspection and primary coolant leakage limits).
Therefore, requirements related to the chemistry program do not constitute initial conditions that are assumed in any design basis accident or transient related to the RCS integrity, nor does the reactor coolant chemistry program constitute a primary success path or risk-significant safety function warranting TS requirements under the criteria in the Final Policy Statement described above.
The reactor coolant chemistry requirements are maintained in the licensee's Chemistry Program, which is described in the updated Final Safety Analysis Report. Any changes to these chemistry requirements would be evaluated under the licensee's Chemistry Program and, if the changes are determined to involve an unreviewed safety question, the licensee must submit a license amendment to obtain prior NRC review and approval in accordance with 10 CFR 50.59, in accordance with the criteria in the NRC's policy on technical specification improvements.
The staff has concluded, therefore, that requirements for RCS chemistry limits (a) are not specifically required by 10 CFR 50.36 or other regulations, (b) are not required to avert an immediate threat to the public health and safety,
)
and (c) are not necessary because changes that are deemed to involve an unreviewed safety question will require prior NRC approval by a license i
amendment as provided by 10 CFR 50.59(c).
TS 3/4.4.9.2. " Pressurizer (Temperature limits)"
Pressure and temperature limits are placed on the pressurizer to be consistent with the requirements of the American Society of Mechanical Engineers (ASME)
Code. As described in the Bases for the existing TS requirements, the pressurizer operates in temperature ranges above those for which there is reason for concern of non-ductile failure, and operational limits are provided to assure compatibility of operation with the fatigue analysis performed in accordance with the ASME Code requirements.
Pressurizer integrity is a design capability maintained by ASME Code design and component cyclic / transient limit requirements under 10 CFR 50.55a.
Further, these limits are associated with long-term effects on the material properties of the pressurizer; therefore, these operational limits are not necessary to ensure immediate protection of the public health and safety.
On this basis, the staff has concluded that the pressurizer pressure and temperature limits need not be controlled by TS because they (a) are adequately controlled by 650.55a and 650.59, (b) are not specifically required
4 by 10 CFR 50.36, and (c) are not required to avert an immediate threat to the public health and safety. Therefore, the proposed changes to the TS are acceptable.
TS 3/4.4.10. " Structural Intecrity" This specification provides inspection requirements for the ASME Code Class 1, 2, and 3 components to ensure that the structural integrity and operational capability of these components will be maintained at an acceptable level throughout the life of the plant. To the extent applicable, the inspection program for these components is in compliance with Section XI of the ASME
'911er and Pressure Vessel Code, in accordance with 10 CFR 50.55a. As part of the relocation of TS 3/4.4.10, TS 6.8 would be revised to include the reactor coolant pump flywheel inspection program, in accordance with the Westinghouse Standard TS (NUREG-1431), which is not covered under 650.55a.
The inspection program associated with the existing TS requirements is performed on systems required to function to mitigate a design basis accident.
However, the TS include separate operability and surveillance requirements for these systems.
The requirements in TS 3/4.4.10 relate to long-term maintenance of the structural design margins which are not relied on to avert an immediate threat to public health and safety.
Structural integrity is a design capability maintained by ASME Code under 10 CFR 50.55a.
Further, these limits and surveillance requirements are associated with long-term effects on the material properties; therefore, these operational limits are not necessary l
to ensure immediate protection of the public health and safety.
On this basis, the staff has concluded that these structural integrity requirements need not be controlled by TS because they (a) are adequately controlled by 550.55a and 550.59, (b) are not specifically required by 10 CFR 50.36, and (c) are not required to avert an immediate threat to the public health and safety. Therefore, the proposed changes to the TS are acceptable.
l TS 3/4.4.11. " Reactor Vessel Head Vents" The RCS vents are provided to exhaust noncondensible gases and/or steam from the RCS that could inhibit natural circulation core cooling following any event involving a loss of offsite power and requiring long-term cooling, such as a loss-of-coolant accident. The valve redundancy of the RCS vent paths serves to minimize the probability of inadvertent or irreversible actuation while ensuring that a single failure of the vent valve power supply or control system does not prevent isolation of the vent path. Their function, capabilities, and testing requirements are consistent with the severe core damage assumptions of item II.B.1 of NUREG-0737, " Clarification of Three Mile Island Action Plan Requirements" (November 1980). As such, this capability is not part of a primary success path to mitigate a design basis accident or transient, nor is it relied on to avert an immediate threat to public health and safety.
Therefore, the reactor vessel head vents do not satisfy any of the Final Policy Statement criteria and need not be included in the TS.
l l
, The staff has concluded, therefore, that requirements for reactor vessel head 1
vents need not be controlled by TS because they (a) are not specifically required by 10 CFR 50.36, (b) are not required to avert an immediate threat to the public health and safety, and (c) are not necessary because changes that are deemed to involve an unreviewed safety question will require prior NRC approval by a license amendment as provided by 10 CFR 50.59(c).
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the California State official was notified of the proposed issuance of tne amendments. The State official
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had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
These amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no 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 Commission has previously issued a proposed finding that the amendments involve no significant hazards considera-tion, and there has been no public comment on such finding (59 FR 51621).
Accordingly, the amendments meet 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 amendments.
5.0 CONCLUSION
The Commission 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 Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
C. Grimes Date:
March 9, 1995
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