ML17333A491
| ML17333A491 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/28/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17333A490 | List: |
| References | |
| NUDOCS 9607050041 | |
| Download: ML17333A491 (7) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-N01 SA Y
VALU TION BY THE OF ICE OF NUCLEAR REACTOR REGULATION R
L ED TO MENDHENT NO. 210 0 FACILITY OPERATING LICENSE NO.
DPR-58 ND AMENDMENT N0.195 TO FACILITY OPERATING LICENSE NO.
DPR-74 NDIANA IC IGAN OW COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NOS.
1 AND 2 DOCKET NOS. 50-315 AND 50-316
- 1. 0 INTRODUCTION By letter dated Hay 19,
- 1995, and supplemented October 20,
- 1995, and April 8, 1996, the Indiana Michigan Power Company (the licensee) requested amendments to the Technical Specifications (TS) appended to Facility Operating License Nos.
DPR-58 and DPR-74 for the Donald C.
Cook Nuclear Plant, Unit Nos.
1 and 2.
The proposed amendments would lower the high neutron flux reactor trip setpoints with main steam safety valves (HSSVs) inoperable.
The setpoints for the high neutron flux with inoperable MSSVs are contained in TS Table 3.7-1.
The new methodology used to derive these new setpoints is also being changed in the basis portion of TS 3/4.7. 1. 1.
I The action statement for TS 3.7. 1. 1. is being modified to allow continued operation with MSSVs inoperable with four reactor coolant loops in operation with the reactor trip breakers open in Mode 3.
The current TS allows continued Mode 3 operation with three loops in operation and the reactor trip breakers open but not with four loops in operation.
With four loops in operation the action statement now requires the reactor trip setpoints to be reduced according to TS Table 3.7-1.
The proposed TS would not allow continued Hode 3 operation (with three or four loops in operation) with the reactor trip breakers closed with inoperable MSSVs.
The proposed amendment would also now require that the reactor to be taken only to HOT SHUTDOWN rather than COLD SHUTDOWN if the action statement cannot be met.
Additionally, the licensee is modifying the safety valve surveillance requirements (SR 4.7.1.2) to state the provisions of TS 4.0.4 do not apply to SR 4.7.1.1 for entry into Hode 3.
The April 8, 1996, submittal provided information clarifying the location of the TS 4.0.4 exemption statement.
This information was within the scope of the original application and did not alter the staff's no significant hazards considerations determination.
Therefore renoticing was not warranted.
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2.0 lvALUATI N The MSSVs are designed to prevent the main steam lines and the secondary side of the steam generator from exceeding 110 percent of the design (1085 psi) pressure.
Each steam line is equipped with five safety valves with staggered setpoints.
A minimum of two operable safety valves is required on each steam line to be able to continue operation in Modes 1 and 2 in accordance with TS Table 3.7-1.
The full relieving capacity of the HSSVs is designed to protect the main steam lines for the anticipated transient requiring the maximum relieving capacity, which is a turbine trip from 100 percent rated thermal power with no condenser heat sink available.
Westinghouse has determined that the methodology used by Indiana Michigan Power Company for the D. C.
Cook plant to establish the maximum allowable power range neutron high flux setpoints may not provide a low enough setpoint to preclude an overpressurization of the main steam piping during some anticipated transients.
The old methodology assumed that the maximum allowable initial power should be a linear function of the available relief valve capacity.
The new methodology uses an algorithm to determine the maximum power allowable, and therefore the reactor trip setpoint, to assure the main steam lines are not overpressurized with inoperable HSSVs.
Westinghouse issued Nuclear Safety Advisory Letter (NSAL)94-001, dated January 20, 1994, with a new algorithm to determine the revised neutron flux high setpoints with inoperable HSSVs.
The Nuclear Regulatory Commission has not endorsed the new Westinghouse methodology.
However, the setpoints obtained using the methodology are lower, more conservative, and provide a
greater margin to safety than the current setpoints.
The setpoints with one, two, or three inoperable HSSVs would change from 87.2, 66.4, and 43.6 to 65. 1, 46.5, and 28.0 percent.
The bases in the TS are also being revised to include the new algorithm.
The staff finds that the new setpoints and the basis for the neutron flux high reactor trip setpoints are more conservative and provide a greater margin to safety than the existing setpoints and are therefore acceptable.
The licensee also requests two of the action statements for TS 4.7. 1.1 to be amended.
The action statements for this TS, as currently written, are confusing.
The current applicability for both statements is Modes 1,
2 and 3.
Action B allows continued operation in Mode 3 if there are three of four reactor coolant system loops in operation and the reactor trip breakers open.
Action B, as currently written, does not allow continued operation in Mode 3 with four reactor coolant system loops in operation and the reactor trip breakers open.
Having four loops in operation provides more cooling than having three loops in operation and continued operation should be allowed in Mode 3 with four loops in operation if the reactor trip breakers are open.
There is added conservatism provided by the amendments because the proposed TS will not allow Mode 3 operation with the reactor trip breakers closed with inoperable MSSVs.
The current TS do allow Hode 3 operation with inoperable HSSVs if the neutron high flux reactor trip setpoints are reduced.
Having the reactor trip breakers open provides greater assurance that there will not be a
transient requiring the HSSVs.
Another chaAge requires the reactor to be taken to HOT SHUTDOWN (Mode 4) rather than COLD SHUTDOWN (Mode 5) if the action statements for TS 3.7. 1. 1 cannot be met.
This change is acceptable for two reasons.
The applicability of TS 3.7. 1. 1 is Modes 1,
2 and 3.
Allowing the reactor to be taken to Mode 4,
a mode were the TS is not applicable, is acceptable.
The ultimate safe condition of the-plant with the new TS will be Mode 4.
In Mode 4 there are no credible accidents that require the use of the MSSVs.
Additionally, requiring the reactor to be taken to Mode 5 is unnecessary.
The staff concludes, therefore, that the proposed changes to the action statement of TS 3.7.1. 1 are
.cceptab';e.
The surveillance requirements (SR) for the HSSVs are also being modified to allow entry into Mode 3 without having the SR associated with the MSSVs having been performed in the stated surveillance interval.
TS SR 3.7. 1.2 is being added stating the provisions of TS 4.0.4 are not applicable for entry into Mode 3.
TS 4.0.4 does not allow entry into an operational mode without having the SR having been performed in the stated surveillance interval.
The change is acceptable because the SR cannot be performed prior to entering Hode 3.
To perform SR 3'.7. 1. 1, the secondary pressure must be above 800 psig and the reactor coolant system must be above 350'F to achieve this secondary pressure.
The transition temperature for Mode 3 to 4 is 350'F.
If the surveillance requirement is exceeded during an extended
- outage, the licensee would not be able to perform the SR prior to entering Mode 3.
The change is also consistent with the Westinghouse Standard Technical Specifications and other SR that cannot be performed without entering an operational mode where the SR is required.
The staff finds the proposed amendments acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Michigan State official was notified of the proposed issuance of the amendments.
The State official had no comments.
- 4. 0 ENVIRONMENTAL CONS IDERATION The amendments change the requirements 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 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 consideration and there has been no public comment on such finding (60 FR 65681).
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 staff 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 amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
C. Jackson Date:
June 28, 1996
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