ML20217K993

Safety Evaluation Supporting Amend 234 to License DPR-56

ML20217K993
Person / Time
Site:	Peach Bottom
Issue date:	10/14/1999
From:	NRC (Affiliation Not Assigned)
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ML20217K929	List: ML20217K924 ML20217K976 ML20217K993
References
NUDOCS 9910270043
Download: ML20217K993 (5)

Text

i 1 kQ Ctag e t UNITED STATES g .j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20665 4001 i

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i SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 234 TO FACILITY OPERATING 1 LICENSE NO. DPR-56 EECO ENERGY COMPANY PUBLIC SERVICE ELECTRIC AND GAS COMPANY DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY 1

PEACH BOTTOM ATOMIC POWER STATION. UNIT NO. 3 DOCKET NO. 50-278 l

1.0 INTRODUCTION

By letter dated March 2,1998 (Reference 1), in response to Generic Letter 94-02,"Long term Solutions and Upgrade of interim Operating Recommendations for Thermal Hydraulic Instabilities in Boiling Water Reactors (BWR)," PECO Energy Company (the licensee) proposed design modifications to the Power Range Neutron Monitoring (PRNM) system in the Peach Bottom Atomic Power Station, Units 2 and 3. Subsequently, by letters dated March 1,1999 (Reference 2), as supplemented June 14, October 1 (Reference 3), and October 6,1999 (Reference 4), the licensee proposed license amendments to revise the Technical Specifications (TSs) for both Peach Bottom Units. The proposed TS changes will enable the licensee to install the proposed design modification. This modification will upgrade the existing analog PRNM, excluding the associated detectors and cables, with a General Electric (GE)

Company digital PRNM called " Nuclear Measurement Analysis and Control (NUMAC)." This NUMAC FRNM will also include an Oscillating Power Range Monitor (OPRM) to detect and suppress reactor power instabilities and provide an automatic trip function. The OPRM_is called

" Option ill stability trip function" in the staff approved licensing Topical Report NEDO-31960, "BWR Owner's Group Long-Term Stability Solution Licensing Methodology" dated July 1993.

By ' letter dated September 5,1995 (Reference 5), the staff approved GE licensing Topical Report (LTR) NEDC-32410P, " Nuclear Measurement Analysis and Control Power Range Neutron Monitor (NUMAC-PRNM) Retrofit Plus Option ill Stability Trip Function." This Topical l Report addressed the full scope of the modification to replace the Power Range Monitoring i portion of an anSy Neutron Monitoring System in GE BWRs with GE NUMAC PRNM including OPRM. In th!s Topical Report, the staff approved proposed TS changes for Average Power Range Monitor (APRM) reactor trip and rod block protective fuiictions. By letter dated I

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- August 15,1997, the staff approved Supplement 1 to NEDC-32410P which includes TS 1 c requirements for_OPRM and provides clarification of issues related to the APRM.  !

The licensee's proposed TS changes reflect only the PRNM portion of the modification affecting 1 the Reactor Protection System (RPS) and Rod Block Monitoring (RBM) functions of the APRM j instrumentation and will be implemented following installation of NUMAC-PRNM. The licensee  !

will submit a separate license. amendment request for the proposed TS changes to reflect the n l OPRM portion of the modification after the first operating cycle following installation of NUMAC-PRNM in each Peach Bottom unit. During this period, the OPRM trip function will not be connected to plant RPS in order to evaluate the performance of the OPRM algorithms. Until implementation of the TS requirements for the OPRM operability, PECO Energy will continue to implement the Interim _ Corrective Actions specified in the NRC Bulletin 88-7 Supplement 1,

" Power Oscillations in Boiling Water Reactors (BWRs)", to detect and suppress power oscillations.

. The June'14, October 1, and October 6,1999, letters provided clarifying information that did not h change the staff's initial proposed no significant hazards consideration determination.

l l- 2.0 EVALUATION The staff safety evaluation report (SER) in Reference 5 states that those licensees who

- reference Topical Report NEDC-32410P for the installation of NUMAC-PRNM, should provide l

plant-specific r'evised TSs for the PRNM functions consistent with Appendix H of the Topical Report. The staff's SER also asked the licensees to provide clarification and reconciled differences between the specific plant design and the Topical Report design descriptions. In .

Reference 2, the licensee stated that the proposed TS changes are consistent with the NRC- l approved.GE Topical Report NEDC-32410P with some minor deviations. The licensee also provided plant specific response for the Required Utility Actions specified in the Topical Report. 1 The staff's review of the plant specific response and the licensee's justification for various

' deviations resulted in a request for additional information. The licensee responded to the staff's request in References 3 and 4 which included Control Rod Block Instrumentation (CRBI) revised Limiting Condition for Operation (LCO) TS Table 3.3.2.1-1.

The proposed TS' changes revise the RPS and RBM function LCOs of the APRM instrumentation. Additionally, the TS Bases associated with the RPS and the RBM LCOs are updated.to reflect these revisions. Also, editorial changes are incorporated in Reactor Coolant System LCO 3.4.1 and Special Operations LCO 3.10.8. The staff finds all changes to be consistent with the Topical Report except for two changes in the RBM LCO and one change in

- the RPS LCO. The staff finds these three changes to be acceptable as described below:

2.1 RBM LCO'

- In the revised CRBI LCO table, the licensee changed thermal power limits on specified conditions for the operability of the RBM trip functions from the current "two-sided" to a "one-sided" configuration to reduce the risk 'of non-compliance with the TS required surveillance of the RBM instrumentation.' The proposed changes to thermal power limits are conservative with

- respect to the current TS requirements and, therefore, are acceptable.

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The licensee also deleted the RBM "Downscale" trip function from the CRBI LCO table which is neither addressed nor proposed to be deleted in the Topical Report. The licensee stated that this trip fails to meet any of the four criteria of 10 CFR 50.36(c)(2)(ii) for an LCO to be included

- in the plant TS for safe operation of the facility. Also, no credit was taken for the downscale function in any ARPM RBM TS (ARTS) analyses by GE. With the current analog neutron monitoring system, inclusion of the RBM downscale function in the plant TS, in addition to RBM Inop function, has some merit because there are some failure modes that could result in a

reduction of signal (downscale RBM signal), but not a full failure (inop RBM signal). The NUMAC RBM has a built-in self-test capability to detect abnormal operating conditions, and provides an RBM Inop alarm and the associated rod block signal. No failure modes have been

. identified which would result in the RBM flux value being reduced to near zero without other

' alarms.' This feature reduces the value.of the RBM downscale function to that of a " diagnostic aid" in troubleshooting certain Inop conditions which have already been indicated by self test.

As such, the RBM "Downscale" function becomes part of the overall RBM inop function, which is retained in the plant TSs. Therefore, the staff finds the licensee's proposed deletion of RBM downscale function from the plant TSs to be acceptable.

2.2 RPS LCO -

-In the proposed changes to the RPS instrumentation LCO TS Table 3.3.1.1-1, the licensee l changed the instrument setpoint allowable values (AVs) for Si'.1ulated Thermal Power-High and Neutron Flux High reactor trip functions of the APRM instrumentation. These changes are non-conservative with respect to the current TS AVo because the Neutron Flux-High instrument setpoint Analytical Limit (not included in the plant TSs and defined as the measured or calculated limit established by the safety analysis to encure that the safety limit is not exceeded) was not changed (increased) as stated in Reference 2. In response to the staff's request for additional information dated September 27,1999, the licensee stated in Reference 4, that the revised AV for Neutron Flux-High instrument setpoint was calculated based on an analyticallimit of 122 percent RTP instead of 120 percent RTP value used for the current TS Setpoint AV. This change of analytical limit is based on the analysis performed by GE. The licensee stated that the proposed changes to the AVs were calculated using the staff approved instrumentation setpoint methodology documented in NEDC-31336," General Electric

' Instrumentation Setpoint Methodology" and the 122 percent RTP analyticallimit. The staff finds the licensee's justification for the proposed setpoint AV changes to be acceptable.

2.3 ' Summary

Based on the above review and justifications for TS changes, the staff concludes that the licensee's proposed TS changes are acceptable.

3.0 STATE CONSULTATION

In_ accordance with the Commission's recul*=, N Pennsylvania State official was notified of the proposed issuance of the amendments. The State official had no comments.

4.0 ENVIRONMENTAL' CONSIDERATION The amendment changes a requirement with respect to installation or use of a facility

component located within the restricted area as defined in 10 CFR Part 20 and changes

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-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 consideration, and there has been no ,

. public comment on such finding (64 FR 29711). Accordingly, the amendments meet the I 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

4 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 nealth and safety of the publ ..

Principal Contributor: 1.Ahmed Date: 0:tober 14,1999 j i

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6.0 REFERENCES

1. Letter from Garret D. Edwards (PECO Energy) to NRC dated March 2,1998, " Selection of Option lit for Long-Term Solution _"

- 2. Letter from Garret D. Edwards (PECO Energy) to NRC dated March 1,1999, " Proposed Changes To Peach Bottom Units 2&3 Technical Specifications"

3. Letter from James A. Hutton, Jr. (PECO Energy) to NRC dated October 1,1999,

" Response to Request for Additional Information"

4. Letter from James A. Hutton, Jr. (PECO Energy) dated October 6,1999," Supplemental Information"

5. Letter from NRC to David W. Reigel (GE NUMAC Project) dated September 5,1995,

" Acceptance of Licensing Topical Report NEDC-32410P" i

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