ML20137D067
| ML20137D067 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/21/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20137D064 | List: |
| References | |
| NUDOCS 9703250250 | |
| Download: ML20137D067 (6) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION 2
WASHINGTON, D.C. 3066H001 t
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l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION j
RELATED TO AMENDMENT NO. 205 TO FACILITY OPERATING LICENSE DPR-57 1
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AND AMENDMENT NO.
146 TO FACILITY OPERATING LICENSE NPF-5 GEORGIA POWER COMPANY. ET AL.
EDWIN 1. HATCH NUCLEAR PLANT. UNITS 1 AND 2 i
DOCKET NOS. 50-321 AND 50-366 l
1.0 INTRODUCIION I
By letter dated October 29, 1996, as supplemented February 19, 1997, Georgia i
Power Company, et al. (the licensee), proposed license amendments to change l
the Technical Specifications (TS) for the Edwin I. Hatch Nuclear Plant, Units 1 and 2.
The proposed changes would reflect design changes that upgrade 4
the analog power monitoring system in the two Hatch plants with a General Electric (GE) Company Nuclear Measurement Analysis and Control Power Range Neutron Monitor System (NUMAC-PRNMS), including the Oscillation Power Range Monitor (OPRM) function. The February 19, 1997, letter provided clarifying l
information that did not change the initial proposed no significant hazards l
consideration detemination or expand the scope of the Federal Register j
notice.
1 By letter dated September 5,1995, the staff approved GE licensing topical report (LTR) NEDC-32410P, " Nuclear Measurement Analysis and Control Power Range Neutron Monitor (NUMAC-PRNM) Retrofit Plus Option III Stability Trip i
j Function." The staff review of this topical report determined that NEDC-32410P contains acceptable guidance for replacing the existing power range monitors in a boiling water reactor (BWR) with a digital NUMAC-PRNMS.
By l
1etter dated December 26, 1996, the staff approved Supplement I to i
NEDC-32410P, which provided clarification of issues related to the Average i
Power Range Monitor (APRM) and APRM technical specifications, and included proposed technical specifications for the OPRM.
j The licensee's proposed TS amendments applicable to the APRM portion of the Hatch TS are to be implemented following installation of the NUMAC-PRNMS.
The OPRM functions will not be connected to the Reactor Protection System (RPS) trip relays during the first 6 months of operation of the NUMAC-PRNMS modification. At the end of the 6-month period, following NRC staff review I
and approval of the operating data, setpoints and margins, the OPRM trip function will be connected to the RPS channels, and OPRM-specific TS i
amendments will be implemented. During this test period, the existing interim j
corrective actions for determining and mitigating power oscillations will i
remain in effect. The following safety evaluation addresses only the APRM TS i
changes for Hatch, Units 1 and 2.
A separate safety evaluation will address the OPRM TS changes.
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2.0 SYSTEM DESCRIPTION 1
i Using the existing local power range monitors (LPRMs) and the recirculation coolant loop flows, the NUMAC-PRNM system provides APRM and OPRM trip signals i
to the RPS. The APRM system averages LPRM signals, processes flow signals from the reactor core recirculation flow instrumentation, and then compares the results to RPS trip set points. The OPRM detects and suppresses reactor l
core power instabilities using_the Option III approach described in LTR j
NED0-31960, "BWR Owners' Group Long-Tern Stability Solutions Licensing Methodology," dated June 1991.
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The GE NUMAC-PRNMS consists of four APRM channels and four voter channels.
Trip signals from the each of the four APRM channels are sent to all four voter channels. One voter module is dedicated to each RPS trip relay. A reactor trip occurs when two or more of the four APRM functions calculate a trip condition.
i 3.0 EVALUATION As stated in the staff's safety evaluation of NEDC-32410P, to receive NRC approval of a NUMAC-PRNM system installation, the licensee must confirm:
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1.
The applicability of NEDC-32410P, including clarifications and reconciled differences between the specific plant design and the topical report design descriptions, 2.
The applicability of_ the BWR Owners' Group topical reports that address i
the NUMAC-PRNM system and associated instability functions, set points and margins, 3.
Plant-specific revised TSs for the NUMAC-PRNM system functions are consistent with NEDC-32410P, Appendix H, and Supplement 1, 4.
Plant-specific environmental conditions are enveloped by the NUMAC-PRNM system equipment environmental qualification values, and 5.
Administrative controls are provided for manually bypassing APRM/0PRM channels or protective functions, and for controlling access to the APRM/0PRM panel and channel bypass switch.
The licensee's actions with regard to the above conditions are discussed in the following sections.
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a o s 3.1 Anolicability of the NUMAC-PRNM System Desian to the Hatch Plant Desian The staff compared the applicable Hatch design. features with the corresponding design features in NEDC-32410P. The NUMAC-PRNMS design modification proposed for Hatch Units 1 and 2 conforms to the NUMAC-PRNM system design description in NEDC-32410P and is compatible with the existing plant neutron monitoring system and RPS. Therefore, the staff finds that the NUMAC-PRNM system design is applicable to the Hatch plants.
i 3.2 PRIMS Instability Functions. Set Points. and Marains The licensee will test the PRNMS instability function (OPRM), including the adequacy of the setpoint values and margins during the initial 6 months of OPRM operation. At the end of the 6-month period, following NRC staff review and approval of the operating data, the OPRM trip functirn will be connected to the RPS channels, and an OPRM-specific TS amendment w;11 be implemented.
The staff approved the 6-month period for OPRM confirmatory testing in the safety evaluation of NEDC-32410P, and therefore, finds the licensee approach acceptable. The TS amendment will be approved in a separate safety evaluation.
3.3 Plant-Soecific Revised Technical Specifications The staff reviewed the APRM TS amendments. The Hatch Unit I and Hatch Unit 2 1
TS and TS Bases conform to the staff-approved model TS in NED0-32410P-A, Appendix H, and Supplement 1.
In the following discussion, the staff addresses only those TS changes that are different from the reference LTR TS.
Differences between the licensee submittal and the LTR are as follows.
3.3.1 Page EIA-6, Proposed Change 5.
Table 3.3.1.1-1 (page 2 of 3), APRM Downscale Function (currently 2.d) is deleted. The Hatch accident analyses do not credit the APRM Downscale interlock for enabling the j
intermediate range monitor (IRM) Flux or Inop trip in the Run Mode.
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Plant Hatch TSs require the APRMs to be OPERABLE and available when i
the Mode switch is placed in the Run Mode. The NUMAC APRMs include automatic self-test features that are interlocked with an Inop trip.
Plant Hatch operating procedures require confirmation that the APRMs are on scale prior to switching to the Run Mode. These features and procedures provide acceptable assurance that APRM trip functions will be available without the APRM Downscale interlock with coincident trip from the associated IRM. The staff, therefore, finds this change acceptable.
3.3.2 Page EIA-10, Proposed Change 12. Table 3.3.1.1-1 Voter Function 2.e is discussed in the proposed Hatch TS Bases, and is referenced in Hatch Limiting Condition for Operation 3.10.8 and SR 3.10.8.1.
In the existing Hatch TS, Function 2.e is the APRM Inoperability function.
This function was changed to Function 2.d by deletion of the previous Hatch TS Function 2.d (APRM Downscale Function) in Proposed Change 5 (above) and insertion of the Voter Function 2.e, which adds in the
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requirement that the Voters be operable, which is appropriate. This proposed change, therefore, is acceptable.
3.3.3 Page B 3.3-7, the LTR states, "...In addition, to provide adequate coverage of the entire core, consistent with the design bases for the APRM Functions 2.a, 2.b, and 2.c, at least [20] LPRM inputs, with at i
i least [three) LPRM inputs from each of the four axial levels at which l
the LPRMs are located, must be operable for each APRM channel.
For I
the OPRM Upscale, Function 2.f, LPRMs are assigned to " cells" of [4]
l detectors. A minimum of [later) cells, each with a minimum of [2]
l LPRMs, must be OPERABLE for the OPRM Upscale Function 2.f to be OPERABLE."
l The proposed Hatch Bases state, "...In addition, to provide adequate j
coverage of the entire core, consistent with the design bases for the l
APRM Functions 2.a, 2.b, and 2.c, at least 17 LPRM inputs, with at least three LPRM inputs from each of the four axial levels at which i
the LPRMs are located, must be operable for each APRM channel." The lesser number of LPRM inputs into each APRM channel (17 vs. 20) in the Hatch TS is consistent with the Hatch core design, which is smaller
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l than the core design referenced in the LTR. The staff, therefore, j
concurs with the proposed changes.
3.3.4 Page B 3.3-11.
The LTR Bases state, in Function 2.d, Average Power Range Monitor - Inop, three of the four APRM channels are required to i
be OPERABLE for each of the APRM Functions. The Hatch Bases state, "Three of the four APRM channels and all four voter channels are i
required to be OPERABLE for each of the APRM Functions." The additional requirement of Voter operability is consistent with the APRM Power Range Monitor operability requirements discussion in the 4
LTR Bases and is, therefore, acceptable.
3.4 Plant-Soecific Environmental Conditions The staff reviewed the licensee's evaluation of environmental conditions in the Hatch plants and concludes that the Hatch environmental conditions are enveloped by the GE equipment qualification parameters established for the j
NUMAC-PRNMS modification.
In addition, the LTR restricts ARC welding j
practices, particularly during times when the potentially sensitive NUMAC-PRNMS equipment is required to be operational for plant safety. The i
licensee stated that reasonable ARC welding control and shielding practices l
will be used. The licensee clarified this statement in a letter dated February 19, 1997, by stating that arc welding will be restricted in the main 4
control room where the NUMAC-PRNMS equipment is located, shielding will be 4
evaluated, and the plant operating status will be considered prior to conducting arc welding. This approach conforms to the LTR recommendations approved by the staff concerning control of the electro-magnetic interference i
i (EMI) environment in conformance to 10 CFR 50, Appendix A, General Design 4
Criterion (GDC) 4, " Environmental and Dynamic Effects Design Bases," and is, therefore, acceptable.
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1 The LTR also states that new equipment and plant modifications not produce unacceptable levels of noise emissions that could adversely affect NUMAC equi unent, or the licensee is to take action to prevent these emissions from
'1 reacting potentially sensitive equipment. These measures apply for both noise susceptibility and emissions. The licensee indicated that Hatch design procedures state that all digital equipment systems to be installed or used within the plant shall be evaluated for susceptibility and emissions of EMI in accordance with EPRI Guideline TR-102323. The staff finds this approach acceptable for ensuring the EMI environment conforms to the requirements of GDC 4.
As described in the LTR, the PRWiS uses the same panel interfaces as the existing power range monitor equipment. High frequency filters will be installed on the ac power supply, and shielded cables for all signal leads will be used in lieu of testing nonsafety equipment noise effects on the i
PRNMS. Although more sensitive to EMI effects than the PRNMS, the licensee stated that the existing power range monitoring system has not been affected i
by the EMI environment resulting from the PRNMS modification. The staff finds the licensee's evaluation of the EMI environment and the measures taken to i
reduce adverse EMI affects to be an acceptable approach for ensuring the EMI environment conforms to the requirements of GDC 4.
3.5 Administrative controls In the safety evaluation of NEDC-32410P, the staff found acceptable the design features that control access to setpoint adjustments, calibrations, and test points. Since the licensee has not proposed design changes that would override these controls, the staff finds that the licensee has acceptable controls for controlling access to the PRNMS panel and the APRM/0PRM channel bypass switch.
4.0 STAFF CONCLUSION Based on the above review and justifications for the TS changes, the staff concludes that the licensee's proposed APRM TS changes for Hatch Units 1 and 2 for the NUMAC-PRNM system are consistent with the staff-approved guidance in NEDC-32410P and its supplement', which are incorporated by reference herein.
The staff further concludes that the licensee has properly addressed the plant-specific conditions described in the staff's safety evaluation for NEDC-32410P, and therefore, finds the NUMAC-PRNM system modification and associated APRM TS changes to be acceptable.
5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendments. The State official had no comments.
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6.0 ENVIRONMENTAL CONSIDERATION
i The amendments change a requirement with respect to the installation or use of facility components located withih 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 i
occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards i
consideration, and there has been no public comment on such finding (62 FR 130 dated January 2, 1997). Accordingly, the amendments meet the i
eligibility criteria for categorical exclusion set forth in 10 CFR l
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 j
the amendments.
7.0 CONCLUSION
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.
i Principal Contributor:
M. Waterman Date:
March 21, 1997