ML20072S672
| ML20072S672 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 09/07/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20072S671 | List: |
| References | |
| NUDOCS 9409140193 | |
| Download: ML20072S672 (3) | |
Text
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UNITED STATES i
-I NUCLEAR REGULATORY COMMISSION i
(...../
WASHINGTON, D.C. 20555-0001 SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO AMENDMENT NOS.112 AND 105 TO FACILITY OPERATING LICENSE NOS. DPR-42 AND DRP-60 NORTHERN STATES POWER COMPANY l
PRAIRIE ISLAND NUCLEAR GENERATING PLANT. UNITS 1 AND 2 DOCKET NOS. 50-28? AND 50-306
1.0 INTRODUCTION
l By letter dated January 29, 1993, as revised June 15, 1994, the Northern
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States Power Company (NSP or the licensee) requested amendments to the Technical Specifications (TS) appended to Facility Operating License Nos.
DPR-42 and DPR-60 for the Prairie Island Nuclear Generating Plant, Unit Nos.1 and 2.
The proposed amendments would involve the core exit thermocouple action statements in TS 3.15.A.
2.0 EVALUATION l
The requested TS changes include:
(1)
Specification 3.15.A.2 "An exception to the requirements of 3.15.A.2 for the core exist i
thermocouples" is incorporated into the existing action statement.
i (2)
Specification 3.15.A.3 The new action statement 3.15.A.3 specifies the action to be taken if the l
number of core exit thermocouples is less than the required total number of channels specified in Table TS.3.15-1 (four per quadrant).
Continued operation would be allowed provided:
(a) Greater than or equal to four core exit thermocouples are operable in the center core region, (b) Greater than or equal to one core exit thermocouple is operable in each quadrant of the outside core region, (c) The minimum channels operable requirement (two thermocouples per quadrant) is met, and (d) The inoperable channels are returned to operable status within 30 days or a special report to the Commission is prepared and submitted pursuant to TS 6.7.B.2 within the next 14 days outlining the action l
9409140193 940907 PDR ADOCK 05000282 PDR p
4 taken, the cause of the inoperability, and the plans and schedule for restoring the system to OPERABLE status._ As a minimum, the required total number of channels will be restored prior to startup following the next refueling outage.
(3) Specification 3.15.A.4 With the number of OPERABLE channels for the core exit thermocouples less than the Required Total-Number of Channels shown on Table TS.3.15-1 and with either less than four core exit thermocouples OPERABLE in the center region or less than one core exit thermocouple OPERABLE in each quadrant of the outside core region, restore the Inoperable channels to OPERABLE status within 7 days, or be in at least HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
The Specifications (Item 1 through 3) are the requested changes to the action statements to be taken if the number of core exit thermocouples (CET) is less than the required total number of channels specified in -Table TS.3.15-1 (four per quadrant). These changes deviate from the TS requirements stated in Item II.F.2 of NUREG-0737 (Generic letter 83-37). However, the licensee has.
provided their justifications for these deviations as follows:
(a) Prairie Island is a two loop plant with a core exit thermocouple system consisting of 36 thermocouples which monitor 121 fuel assemblies in a core area of 52 ft.
In comparison, a Westinghouse four-loop plant has 51 core exit tpermocouples which monitor 193 fuel assemblies in a core area of 96 ft.
Even though the area of the Prairie Island reactor core is approximately half the size of the four-loop plant, the number of thermocouples per unit of core area is higher.
(b) Thermocouple failures occurred in 1992 on both units. While enough thermocouples remained operable to meet the Technical Specifications of four thermocouples per core quadrant, there was a high potential for additional failures which could have reduced the number of thermocouples below the required total number of channels limit in some quadrants.
During the November 1992 dual unit outage, ABB/CE (CET system designer) was contracted to assess the condition of the CET head connectors, troubleshoot the entire system (including the cables in containment) and replace the head connector if necessary.
The following repairs were made during this outage: eight head connectors replaced on Unit 1; four head lift rig cable assemblies replaced on Unit 1; and one head lift rig cable assembly replaced on Unit 2.
A modification was initiated in 1993 to replace all head connectors with a newer, sturdier model and to install a transition cable to reduce the chance of damaging the head connector.
This modification was completed on Unit 2 during the November 1993 refueling outage and was completed on Unit I during the May 1994 refueling outage.
The staff has reviewed the licensee's proposed TS changes to the action statements to be taken if the number of core exit thermocouples is less than the required total number of channels specified in Table TS.3.15-1 (four per
o l
. quadrant), and has found that the requested TS changes to the action statements are acceptable since the Prairie Island Plants have a higher density of thermocouples per unit of core area; the required total number of channels will be restored prior to startup following the next refueling i
outage; conditions for continued operation are established in TS 3.15.A.3; and a new HOT SHUTDOWN action statement TS 3.15. A.4 is established to deal with the operable requirement for four core exit thermocouples in the center core or one in each quadrant of the outside core region in addition to the old action statement for Specification 3.15. A.5 which is "With the number of OPERABLE event monitoring instrumentation channels less than the Minimum Channels Operable requirements of Table TS.3.15-1, either restore the minimum number of channels to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in at least HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />."
The staff has reviewed the request by Northern States Power Company to revise the TS of the Prairie Island Nuclear Generating Plant, Units 1 and 2.
Based on the review, the staff concludes that these revisions are acceptable.
5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Minnesota State official was notified of the proposed issuance of the amendments.
The State official had no comments.
4.0 fNVIRONMENTAL CONSIDERATION The amendments change a requirement with respect to installation or use of a tacility component located within the restricted area as defined in 10 CFR Part 20.
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 consideration and there has been no public comment on such finding (59 FR 39594). 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 assur,.ce that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such 4
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:
T. Huang Date: September 7, 1994
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