ML20210U834

Safety Evaluation Supporting Amends 179 & 171 to Licenses NPF-35 & NPF-52,respectively

ML20210U834
Person / Time
Site:	Catawba
Issue date:	08/13/1999
From:	NRC (Affiliation Not Assigned)
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ML20210U821	List: ML20210U817 ML20210U834
References
NUDOCS 9908200221
Download: ML20210U834 (4)

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lt UNITEte STATES NUCLEAR REGULATORY COMMISSION If WASHINGTON. D.C. 20555-0001

\\ ** *,+s[AFETY EVALUATION BY THE OFFICE OF NUCLEAR REA

_RELATED TO AMENDMENT NO.179 TO FACILITY OPERATING LICENSE NPF-35 AND AMENDMENT NO.171 TO FACILITY OPERATING LICENSE NPF-52 DUKE ENERGY CORPORATION. ET AL.

CATAWBA NUCLEAR STATION. UNITS 1 AND 2 DOCKET NOS,50-413 AND 50-414 e

1.0 INTRODUCTION

By letter dated March 25,1999, Duke Energy Corporation (the licensee) submitted a request to mend the facility operating licenses NPF-35 and NPF-52 for Catawba Nuclear Station, Units 1 a

and 2. The proposed amendments would revise those parts of the station's Technical Specifications (TS) regarding reactor trip system (RTS) and engineered safety features actuation system (ESFAS) instrumentation trip setpoints (TSP) as follows:

' Remove the inequality signs applied to the TRIP SETPOINT column of TS Tables 3.3.1-1, " Reactor Trip System Instrumentation," and 3.3.2-1, " Engineered Safety Feature Actuation System Instrumentation," and revise the TRIP SETPOINT column heading to read " NOMINAL TRIP SETPOINT." Also change Notes 1 and 2 of this table to replace

" TRIP SETPOINT" with " NOMINAL TRIP SETPOINT."

Add the definition of NOMINAL TRIP SETPOINT to Section 1.1.

Change the column' heading " TRIP SETPOINT" in Table 3.3.6-1, " Containment Purge and Exhaust isolation Instrumentation," to " NOMINAL TRIP SETPOINT."

Delete inequality signs in Surveillance Requirement (SR) 3.3.5.2 and change " TRIP SETPOINT" to " NOMINAL TRIP SETPOINT."

Revise Limiting Condition for Operation (LCO) 3.4.12, " Low Temperature Overpressure Protection (LTOP) System," to remove inequality signs from the lift setting value (400 psig) and change " LIFT SETTING" to " NOMINAL LIFT SETTING."

- Delete the response time associated with Functions 11 and 12 in TS Table 3.3.1-1.

Change the TS Bases to correspond with the TS revisions.

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2.0 BACKGROUND

The staff identified a generic concern during inspections at the Watts Bar and Sequoyah plants.

The concem deals with the nominal values associated with tolerar.ces beyond maximum and minimum TSPs (inequalities) shown in the TS. The staff concluded that the existing practice of 9908200221 990813 PDR ADOCK 050(X)4 3 y

e.. s setting the TSP in a manner inconsistent with the improved Technical Specifications (ITS) TSP inequalities would render the instrument inoperable on toe basis of the ITS surveillance requirements, LCOs, and Actions / Conditions. The inequalities were being interpreted as limits that would require entry into the appropriate LCO remedial action when exceeded.

The staff has identified a similar concern at the Vogtle plant. The licensee for Vogtle chose to revise the Vogtle TS to adopt the term " NOMINAL TRIP SETPOINT" and to allow calibration tolerance bands (lower and upper bands) around the TSP value. This approach was consistent with the licensee's setpoint methodology and previous revisions to the ITS, and was found acceptable by the staff. The licensee for Catawba has taken a similar approach to resolve the concern.

3.0 EVALUATION The proposed changes by the licensee and the staff's evaluation of the changes are discussed below:

3.1 Tables 3.3.3-1 and 3.3.2-1 The licensee proposed to delete the inequality signs as applied to the TSP column of Tables 3.3.1-1 and 3.3.2-1. The licensee also proposed to revise the TSP column to read " NOMINAL TRIP SETPOINT." In addition the licensee proposes to add the definition of NOMINAL TRIP

' SETPOINT to Section 1.1.

The licensee has defined the limiting safety system setting (LSSS) to be the allowable value, and the nominal TSP is the value set into the instrument. In accordance with the setpoint methodology used at Catawba, no action is required as long as the LSSS value is not exceeded, and it is acceptable for the applicable safety-related instrumentation as-left TSP to be exceeded by the instrumentation calibration setting tolerances.

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The removal of the inequality signs from the TSPs as assigned to Tables 3.3.1-1 and 3.3.2-1 is consistent with the licensee's setpoint methodology and the ITS as revised by the staff (Watts Bar ITS). The removal of the inequality signs from the TSP value will allow the licensee to set the TSP value consistent with the two-sided calibration tolerance defined in the setpoint methodology.

The Bases associated with these TS sections provide clarifying information related to the as-left setpoints for the RTS and ESFAS instrumentation. The Bases allow for a channel to be considered operable with a nominal TSP found outside its calibration tolerance band, provided the TSP value is conservative with respect to its allowable value and is readjusted to within the j

established tolerance band of the nominal TSP. The Bases section also clarifies that if the plant condition warrants, the TSP may be set outside the NOMINAL TRIP SETPOINT calibration tolerance band as long as the TSP is conservative with respect to the NOMINAL TRIP SETPOINT.

The licensee has added the definition of NOMINAL TRIP SETPOINT in TS Section 1.1 to incorporate the details previously discussed herein and reads as follows:

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..s The NOMINAL TRIP SETPOINT shall be the design value of a setpoint. The TSP implemented in plant hardware may be less or more conservative than the NOMINAL TRIP SETPOINT by a calibration tolerance. If plant conditions warrant, the TSP implemented in plant hardware may be set outside the NOMINAL TRIP SETPOINT calibration tolerance band as long as the TSP is conservative with respect to the NOMINAL TRIP SETPOINT.

The staff finds the proposed changes acceptable as thece changes are consistent with the licensee's setpoint methodology.

3.2 Table 3.3.6-1 The licensee proposed to revise the column heading " TRIP SETPOINT" in Table 3.3.6-1 to read

" NOMINAL TRIP SETPOINT."

Table 3.3.6-1 contains the requirements for containment purge and exhaust isolation instrumentation and identifies no additional setpoint requirements beyond those already specified in Table 3.3.2-1 for ESFAS instrumentation. The licensee proposed this administrative change solely to ensure consistency with Table 3.3.2-1. The staff finds this change acceptable.

3.3 SR 3.3.5.2 The licensee proposed to change TRIP SETPOINT to NOMINAL TRIP SETPOINT and to delete the inequality sign. The licensee also proposed to revise the Bases section to incorporate these changes.

This chanDe has been discussed above in Section 3.1 and is, therefore, acceptable to the staff.

3.4 Section 3.4.12 The licensee proposed to revise the LCO to change " LIFT SETTING" to " NOMINAL LIFT SETTING" and to remove the inequality sign from the NOMINAL LIFT SETTING value.

The licensee proposed this change because its review of the safety analyses associated with the power-operated relief valve in the LTOP mode of operation has indicated that the as-left lift setting is indeed a nominal value. The proposed change will thus more accurately describe the nature of the lift setpoint,i.e. as nominal. The staff finds this change acceptable.

3.5 Functions 11 and 12 of Table 3.3.1-1 The licensee proposed to delete the response time associated with Functions 11 and 12 in Table 3.3.1-1.

Functions 11 and 12 pertain to the undervoltage and the underfrequency condition for the reactor coolant pumps. These functions identify a 0.7-and a 0.2-second response time, respectively. The term " response time" is misleading as these values are, in reality, time delays incorporated into the trip circuits to prevent spurious trips. The licensee's justification for removing these time delays from the TS is based on the fact that overall reactor trip response

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• .o times (1.5 seconds and 0.6 seconds, respectively) must be met for these functions, which will account for the time delays. Also, the Westinghouse Standard TS (NUREG-1431) do not specify inclusion of these time delays in the TS. On the basis of this information, the staff finds the proposed change acceptable.

3.6 Summary of Staff Evaluation The staff finds the licensee's proposed TS changes to be acceptable. The proposed changes are consistent with the licensee's setpoint methodology regarding nominal TSP, the Westinghouse Standard TS, NUREG-1431 (two-column format) and the guidance of Regulatory Guide 1.105, Revision 2. The removal of the setpoint column inequalities.is consistent with the use of a nominal TSP by the licensee. As delineated above, the staff found the proposed TS changes for RTS and ESFAS acceptable.

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4.0 STATE CONSULTATION

In accordance with the Commission's regulations, South Carolina State official Mr. Virgil Autrey was notified of the proposed issuance of the amendments to Catawba. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendments change requirements with respect to 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 staff has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (64 FR 24195 dated May 5,1999). 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.

6.0 CONCLUSION

i 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 amendments will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: Hukam C. Garg Date:

August 13, 1999