ML20112E456

Safety Evaluation Supporting Amends 146 & 140 to Licenses NPF-35 & NPF-52,respectively

ML20112E456
Person / Time
Site:	Catawba
Issue date:	05/31/1996
From:	NRC (Affiliation Not Assigned)
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ML20112E453	List: ML20112E451 ML20112E456
References
NUDOCS 9606060092
Download: ML20112E456 (3)

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• 4 UNITED STATES j

j NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 20086 0001 d

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.146 TO FACILITY OPERATING LICENSE NPF-35 4

AND AMENDMENT NO. 140 TO FACILITY OPERATING LICENSE NPF-52 DUKE POWER COMPANY. ET AL.

CATAWBA NUCLEAR STATION. UNITS 1 AND 2 DOCKET NOS. 50-413 AND 50-414 l.0 INTRODUCTION By letter dated November 15,-1995, as supplemented March 15, and April 10, 1996, Duke Power Company, et al. (the licensee), submitted a request for changes to the Catawba Nuclear Station, Units 1 and 2, Technical 1

Specifications (TS). The requested changes would revise the TS and the associated Bases to increase the setpoint tolerance of the main steam safety valves (MSSVs) from i 1% to i 3%, to incorporate a requirement to reset the i

as-left MSSV lift settings to within i 1% following surveillance testing, and i

to delete two obsolete footnotes. The March 15, and April 10, 1996, letters provided clarifying information that did not change the scope of the November 15, 1995, application and the initial proposed no significant hazards consideration determination.

l 2.0 EVALUATION To support the proposed TS for MSSV setpoint tolerances, the licensee has performed an evaluation to determine the impact on the design basis transients and accidents for Catawba Nuclear Station, Units 1 and 2.

Based on its evaluation, the licensee states in its April 10, 1996, letter that with the exception of the steam generator tube rupture (SGTR) event, all of the transients and accidents, which could potentially challenge the MSSVs, were previously analyzed in the Updated Final Safety Analysis Report (UFSAR) with the increased setpoint tolerance of i 3%. The affected transients and accidents include turbine trip, loss of AC power, partial loss of ficw, complete loss of flow, locked rotor, feedwater line break, uncontrolled bank withdrawal at power, single uncontrolled rod withdrawal, inadvertent opening of a pressurizer safety or relief valve and small-break loss of coolant accident. The results of these analyses demonstrate that the acceptance 4

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i. criteria for each event are met. The licensee stated that the methodology usedinitsanalysesisconsisteptwiththeNRC-app [ovedmethodologydescribed 4

in topical reports DPC-NE-3000-A and DPC-NE-3002-A, which were previously approved by the staff. The staff reviewed the licensee's analyses, and found them acceptable on the basis that approved methodology was used. The subject of the revised modeling for the opening of the safety valves as discussed in the licensee's arch 15, 1996, submittal was addressed by separate l

correspondence l

The licensee states that the NRC-approved methodology for the SGTR in DPC-NE-3002-A specifies that the MSSVs are modeled with lift, accumulation, and blowdown assumptions, which maximize secondary pressure. These assumptions conservatively delay the operator actions to isolate a failed open atmospheric steam dump valve which causes increased radiological consequences following a i

steam generator tube rupture event. The licensee has reanalyzed this event i

with the increased MSSV setpoint tolerance of i 3%. The results of its reanalysis show that the radiological consequences are within acceptance criteria.

The staff finds the licensee's analysis acceptable on the basis i

that approved methodology was used.

The licensee-proposed changes include the addition of a statement to TS Surveillance Requirement 4.7.1.1 to require that during surveillance testing, i

as-left lift settings shall be within i 1%. This will prevent excessive setpoint drift (i.e., beyond i 3%) which could cause the peak system pressures i

to exceed the allowable limits.

The added statement supports.the tolerance of 1

i 3% the staff found acceptable in the two paragraphs above.

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3.0 STATE CONSULTATION

In accordance with the Commission's regulations, the South Carolina State official was notified of the proposed issuance of the amendments. The State l

official had no comments.

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As approved by letter from R. E. Martin (NRC) to M. S. Tuckman (DPC) dated December 27, 1995, transmitting safety evaluation for DPC-NE-3000-P,

" Thermal-Hydraulic Transient Analysis Methodology," Revision 1.

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As approved by letter from R. E. Martin (NRC) to M. S. Tuckman (DPC) dated December. 28, 1995, transmitting safety evaluation.for DPC-NE-3002, "FSAR Chapter 15 System Transient Analysis Methodology," Revision 1.

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Letter from H. N. Berkow (NRC) to M. S. Tuckman (DPC) dated April 26.

j 1996, " Safety Evaluation on Change to Topical Report DPC-NE-3002-A On Opening Characteristics of Safety Valves."

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4.0 ENVIR0000 ENTAL CONSIDERATION i

The amendments change requirements with respect to installation or use of a l

facility component located within the restricted area as defined in 10 CFR 4

Part 20 and change surveillance requirements. The NRC staff has determined I

that the amendments involve no significant increase in the amounts, and no l

significant change in the types, of any effluents that may be released 4

and that there is no significant increase in individual or cumulative l

occupational radiation exposure. The Commission has previously issued a f

proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (60 FR j

65676 dated Deceniber 20,1995). Accordingly, the amendments meet the e

eligibility criteria for categorical exclusion set forth in 10 CFR i

51.22(c)(9).

Pursuant to 10 CFR 51.22(b, no environmental impact statement I

or environmental assessment need be prepa) red in connection with the issuance of the amendments.

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5.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, I

that:

(1) there is reasonable assurance that the health and safety of the i

public will not be endangered by operation in the proposed manner, (2) such 1

activities will be conducted in compliance with the Commission's regulations, i

and (3) the issuance of the amendments will not be inimical to the common j

j defense and security or to the health and safety of the public.

i Principal Contributors:

P. Campbell C. Liang j

Date: May 31, 1996 i

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