ML20211N894
| ML20211N894 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 10/10/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20211N892 | List: |
| References | |
| NUDOCS 9710170160 | |
| Download: ML20211N894 (5) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDHENT NO.100 TO FACILITY OPERATING LICENSE NO. NPF-47 ENTERGY OPERATIONS. INC.
RIVER BEND STATION. UNIT 1 DOCKET NO. 5Q-118
1.0 INTRODUCTION
By letter dated August 29, 1996, Entergy Operations Inc. submitted a request for NRC review and ap?roval to amend the Technical Specifications (TSs) of RiverBendStation(RSS), Unit 1.
The TS changes proposed are in support of the Average Power Range Monitor (APRM) setpoint T-Factor elimination and reactivity anomaly calculation improvement.
By letter dated August 29, 1996, the licensee submitted the proprietary General Electric (GE) report to support the T-factor elimination; this letter contains proprietary information to su port the licensee's request and does not alter the staff's initial no si nificant hazards determination.
Also by letter dated Se >tember 5,1997, the licensee provided additional infomation regarding tie APRM setpoint T-factor elimination and identified two additional changes to the TS to delete reference to the APRM TS being deleted. By letter dated October 8, 1997, the licensee provided the details to support their T-factor elimination proposal; reincation of operating limits to the Core Operating Limits Report is to be accompanied by a reference in the TS to the methodology described in NEDC-32489P, 'T-factor Setdown Elimination Analysis for River Bend Station," dated April 1996, for development of the limits and to this amendment providing results of the NRC review of NEDC-32489P for application to River Bend Station. The September 5 and October 8, 1997, letters provided clarification and did not change the staff's initial no significant hazards determination.
2.0 BACKGROUND
Currently, Linear Heat Generation Rate (LHGR) protection for off-rated operations is provided by the APRM setpoint T-factor as defined in the licensee's August 29, 1996, letter.
For T-factors greater than 1.0, the APRM flow-biased scram and control block setpoints are setdown (reduced)d andby the factor T.
This setdown limits the initial power condition permitte therefore, the severity of events associated with power increases. The licensee is proposing to replace the APRM T-factor setdown (TS 3.2.4) with more meaningful power and flow dependent Maximum Critical Power Ratio (MCPR) and LHGR limits and to include these power and flow dependent curves in the Dk ObN 05000058 e
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t-Core Operating Limits Report (TS 5.6.5). This change will eliminate the need for manual setpoint adjustments and allows more direct thermal limit control.
The licensee states that the proposed change will increase plant operating efficiency and improve the human / machine interface by reducing the reed for manual adjustments.
The River Bend Technical Specification Bases define Reactivity Anomaly as "a measure of the predicted versus measured core reactivity during power operation.' Currently this Technical Specification Requirement 3.1.2, is met by comparing the actual control rod density to the predicted control rod density. The licensee is requesting to modify this TS to allow the use of an equivalent method for d6termining a reactivity anomaly. The k-effective would be calculated with the physics design code and compared with measured steady state (Keff=1) operating conditions.
3.0 EVALUATION APRM SETPOINT T-FACTOR ELIMINATION The RBS T-Factor Setdown Elimination program utilizes results of Anticipated Operational Occurrences (A00s) analyses to define initial condition operating limits which conservatively assure that all licensing criteria are satisfied without setdown of the flow-referenced APRM scram and rod block trips. In support of T-Factor elimination, the licensee submitted NEDC-32489P which describes the methodology used to develop the power-and flow-dependent MCPR and Linear Heat Generation Rate As a means to demonstrate the app (LHGR) ion of the methodology to River Bendlimits whi licat Station, NEDC-32489P also provides plant specific power-and flow-dependent thermal limits based on RBS Cycle 6 core configuration and plant operating parameters. The staff used these Cycle 6 analyses to evaluate the methodology for development of the power-and flow-dependent LHGR and MCPR limits (curves).
Transient analysas were performed at a variety of power and flow conditions during original BWR Maximum Extended Operating Domain (ME00) evaluations.
Plant-specific, power-and flow-dependent MCPR and LHGR limits were developed by the licensee for RBS. The licensee has implemented and will continue a program to verify the applicability of these limits for future application to include conservative margins to the limits calculated during-the initial MEOD application. Between 40% rated thermal power (RTP) and 25% RTP, RBS-specific evaluations were performed to establish the plant-unique limits in the low power range. These plant-specific limits include sufficient conservatism such that they will remain valid for future RBS reloads of GE fuel, utilizing the GEXL-PLUS correlation and the GEMINI analysis methods.
The impact of the APRM setdown elimination on the LOCA and fuel thermal-mechanical integrity analyses was evaluated in GE report NEDC-32489P. The core wide Anticipated Operational Occurrences (A00s) were analyzed to support the generic GE Maximum Extended Load Line Limit Analysis (MELLLA) region w
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3-l during the original development of the analysis. For operation in the generic GE MELLLA region, the analyses include evaluations to determine the limiting i
MCPR requirement and the peak vessel ressures bo lesentatlon,th of which are evaluatedthe analyses i
based on Cycle 6 fuel. To support i j
off-rated power-and flow-dependent MCPR and LHGR curves associated with the j
removal of the APRM setpoint T-factor. The staff has reviewed the methodology for determining these power-and flow-dependent MCPR and LHGR limits and finds it acceptable for RBS.
i The licensee will perfom a cycle-specific validation for Cycle 7 prior to l
1 lesentation and the plant-specific limits for future reloads cores by i
in luding these limits in the Core Operatin Limits Report (COLR). The existing COLR will be revised to reflect th deletion of the T-factor limits i
and the addition of power nd flow-dependent limits for both MCPR and LHGR.
l Consistent with the regt sents of 10 CFR 50.36, the TSs re arding the COLR i
TS 5.6.5)t of the curves related to the relccated operatinmust include a reference l'
evelopmen limits (power-and flow-dependent curves). By letter dated October 8,199 the licensu l
pro >osed to include NEDC-32489P which, among other things, sets forth the i
motiodology for determining the Hwer-and flow-dependent limits) with the' notation that the methodology was acceptable only as evaluated and approved by this Safety Evaluation and license amendment in the COLR TS 5.6.5 list of references to satisfy this requirement. The licensee's posal and the notation that the COLR will document MCPR and LHGR (incl ng power-and flow-dependent limits) to -TS 5.6.5 are acceptable. The proposed revision to i
the Itst of approved methodologies will ensure that values for cycle-specific parameters are determined such that all applicable ' limits (e.g., nuclear
- limits, transient analysis limits, and accident limits) are met. Based on the i
above, the licensee proposal to eliminate APRM setdown and the deleting of i
TS 3.2.4 ("APRM Gain and Setpoints") in its entirety is acceptable.
The licensee's letter dated September 5,1997, also included changes to TS Surveillance Requirement 3.3.1.1.2 and to Administrative Controls 5.6.5 to i
- remove reference to the APRM Gain and Setpoints TS whicn is being eliminated.
l These changes were overlooked in the licensee's original submittal. With the elimination of APRM Setpoints TS 3.2.4, continued reference in other technical specifications would be in error. The staff finds the revisions to these sections to be acceptable.
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The licensee's October 8,1997, letter included proposed wording for the COLR (Administrative Controls 5.6.5) to address the staff's concerns on T-factor elimination. The proposed wording also included wording related to section 5.6.5.b.1)in the COLR". - The staff has not yet acted on this proposal, which-that wo specified was included in a earlier license amendment request and has not provided the 4
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requisite prior notice to the public.
In discussions with the licensee on October 10, 1997, the licensee agreed, the-staff will handle the licensee's request by separate action. Therefore, the proposed wording is not being authorized in this license amendment.
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?i REACT WITY ANOMALIES The licensee's proposed change to the method of :alcuiating the reactivity anomaly as specified in the TS 3.1.2 Limiting Cc idition of Operation and l
Surveillance Requirement 3.1.2.1 has been reviewed by the staff. The basic cewept of the TS has not been cht.nged by the licensee's proposal. There is still a comparison of a calculated and an observed reactor reactivity state.
This change will allow more dttailed anal.vtic methods to replace the relatively crude analysis of cor, trol rod reactivity status. This is an
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acceptable change. The Bases for TS 3.1.2 have been changed slightly to i
provide a clearer statement of the reason for the comparison addressed in the TS. The change is acceptable.
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REVIEW
SUMMARY
Based on the staff review of the T-factor elimination in conjunction with the licensee's proposed additions to TS 5.6.5 to reference the methodology used to develop the power and flow dependent limits included in the COLR and to reference this safety evaluation approving the olant-specific application of the methodology to River Bend Station, and on tie staff review of the reactivity anomal
- calculation improvement, the staff concludes that the L'
changes proposed by the licensee to the RBS TSs and bases are acceptable.
4.0 ETATE CONSULTATION In accordance with the Comission's regulations, the Louisiana State Official was notified of the proposed issuance of the amendment.
The State official had no coments.
5.0 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. The NRC staff has determined that the amendment involves no significant it. crease in the amounts, and no significant change in the types, of any effluent that may be released offsite, and that there is no significant increase in individual or cenulative occupational radiation exposure. The Comission has previously issui.d a proposed finding that the amendment involves no significant hazards consideration, and t';ere has been no public coment on such finding (61 FR 55032). The amendment also changes record E
keeping and reporting requirements. Accordingly, the amendment meets the elioibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9) and it-(10). Pursuant to 10 CFR 51.22(b) no environmental impact statement or enviv;1 mental assessment need be p.epared in connection with the issuance of the amendment.
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6.0 CONCLUSION
The Comission 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 Comission's regulations, Q
and (3) the issuance of the amendment will not be inimic:1 to the common Q9 defense and security or to the health and safety of the public.
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Principal Contributor:
G. Schwenk Date:
October 10, 1997
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