ML20058A421
| ML20058A421 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 11/16/1993 |
| From: | Barkhurst R ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20058A424 | List: |
| References | |
| W3F1-93-0309, W3F1-93-309, NUDOCS 9312010080 | |
| Download: ML20058A421 (8) | |
Text
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W ENTERGY-l T 1 " ",6-0 W h wu i A 70m Tj ';N 739 RM Ross P. Darkhurst a,: i n :Cp,w Vc !m 3 W3F1-93-0309 A4.05 PR November 16, 1993 l
Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.
20555 i
Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 Technical Specification Change Request NPF-38-144 Gentlemen:
The attached description and safety analysis support a change to the Waterford 3 Technical Specification " Power Distribution Limits, DNBR Margin."
The proposed change has been evaluated in accordance with 10CFR50.91(a)(1) using criteria in 10CFR50.92(c) and it has been determined that the i
proposed change involves no significant hazards considerations. The Plant Operating Review and Safety Review Committees have reviewed and accepted the proposed change based on the foregoing evaluation.
This change is being submitted to prevent restrictions on base operating margin (Core Operating Limit Supervisory System [COLSS] / Core Protection Calculators [CPCs] margin) due to thermal margin event requirements when both CEA Calculators are inoperable or when COLSS is Out of Service during Fuel Cycle 7.
Waterford 3 plans to shutdown for refueling in March of.
l 1994 and startup in May.
In order to avoid restriction of base operating margin, we would prefer to implement thi.s proposed change prior to startup following refuel and respectfully request the staff to consider this schedule during its review / approval process.
9312010080 931116 PDR ADOCK 05000382 P
PDR p oo t Ig g
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Technical Specification Change Request NPF-38-144 W3F1-93-0309 Page 2 i
November 16, 1993 1
Should you have any questions or comments concerning this request, please
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contact Paul Caropino at (504)739-6692.
Very truly yours, f
t y
t R.P. Barkhurst Vice President, Operations Waterford 3 i
RPB/PLC/dc
Attachment:
NPF-38-144 cc:
J.L. Milhoan, NRC Region IV D.L. Wigginton, NRC-NRR R.B. McGehee N.S. Reynolds NRC Resident Inspectors Office Administrator Radiation Protection Division (State of Louisiana) j American Nuclear Insurers i
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l UNITED STATES OF' AMERICA NUCLEAR REGULATORY COMMISSION In the matter of
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Entergy Operations, Incorporated
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Docket No. 50-382 Waterford 3 Steam Electric Station
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AFFIDAVIT R.P. Barkhurst, being duly sworn, hereby deposes and says that he is Vice President Operations - Waterford 3 of Entergy Operations, Incorporated; that he is duly authorized to sign and file with the Nuclear Regulatory Commission the attached Technical Specification Change Request NPF-38-144; that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.
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R.P. Barkhurst Vice President Operations - Waterford 3 STATE OF LOUISIANA
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) ss PARISH OF ST. CHARLES
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Subscribed and sworn to before me, a Notary Public in and for 'he Parish and-State above named this
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day of A/o r o m G r t
, 1993.
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m Notary Public N'"
My Commission expires 1
CESCRIPTION AND SAFETY ANALYSIS 0F PROPOSED CHANGE NPF-38-144 This is a request to revise Technical Specification (TS) 3.2.4, "Pcwer Distribution Limits, DNBR Margin."
Existina Soecificatios See Attachment A Procosed Specification j
See Attachment B Description This proposed TS change modifies the DNBR Margin, limiting Condition For Operation (LCO) 3.2.4b & c to prevent restrictions on base operating margin during Cycle 7 operation. The purpose of the TS LC0 is to limit the core power distribution to the initial value assumed in the accident analyses.
Specifically, operation within this LC0 either limits or prevents potential fuel cladding failures in the event of a postulated accident. This LC0 limits the amount of damage to the fuel cladding during an accident by ensuring that the plant is operating within acceptable conditions at the onset of a transient. The limiting safety system settings and this LCO are based on the accident analysis, so that specified acceptable fuel design limits (SAFDLs) are not exceeded as a result of anticipated operational occurrences (A00s) and the limits of acceptable consequences are not exceeded for other postulated accidents.
The proposed change revises TS 3.2.4b (when COLSS is in service, and neither Control Element Assembly Calculator (CEAC] is operable) and TS 3.2.4c (when COLSS is out of service, and either one or both CEACs are operable)..These i
changes are proposed to prevent restriction on base operating margin (COLSS/CPCs margin) due to thermal margin event requirements when COLSS is in service and both CEACs are inoperable or when COLSS is out of service and at least one CEAC is operable.
There are two systems that monitor core power distribution online: the Core Operating Limits Supervisory System (COLSS) and the Core Protection Calculators (CPCs). The COLSS and CPCs that monitor the core power distribution are capable of verifying that the linear heat rate (LHR) and DNBR do not exceed their limits. The COLSS performs this function by continuously
monitoring the core power distribution and calculating core power operating limits corresponding to the allowable peak LHR and DNBR. The CPCs perform this function by continuously calculating an actual value of DNBR and LHR for comparison with the respective trip setpoints.
Control element assembly calculators (CEAC) monitor CEA position. Should a CEA deviate from its subgroup position, the CEACs will monitor the event, sound an annunciator, and transmit an appropriate " penalty" factor to the CPCs.
COLSS is normally used to monitor DNBR margin. When at least one CEAC is operable, Specification 3.2.4a provides enough margin to DNB to accommodate the limiting A00 without failing the fuel. When neither CEAC is operable, the CPCs lack the CEA position information necessary to ensure a reactor trip when necessary.
In this case, Specification 3.2.4b requires the COLSS calculated core power to be reduced to ensure that the limiting A00 will not result in fuel failure.
Currently, Specification 3.2.4b requires that the COLSS calculated power be maintained at 13% below the COLSS calculated power operating limit to compensate for the potential error in the CPC DNBR calculation. This was based on the Cycle 2 safety analyses (Technical Specification Change Request, NPF-38-44, dated October 1, 1986) which revised a 19% margin to the current 13%. As a result of the reevaluation of the limiting A00s for Cycle 7, the proposed revision would increase this required adjustment to 16% which is more restrictive than the present value.
In instances when the COLSS is out of service but at least one or both CEACs are operable, Specification 3.2.4c applies.
It states that the DNBR operating margin shall bg maintained by comparing the DNBR indicated on any operable CPC channel with the allowable value from Figure 3.2-2.
Whenever COLSS is out-of-service, the CPCs are used to perform the same monitoring function. However, the extra conservatisms built into the CPC for transient protection are not all required when the CPCs are being used for monitoring. In order not to affect the CPC transient protection, these conservatisms are not taken from the CPC but are credited in the COLSS out-of-service limits in figure 3.2-2.
A reevaluation of the limiting A00s performed as part of the Cycle 7 safety analyses has verified that by maintaining the margin in the proposed figure 3.2-2, sufficient margin exists to ensure that the limiting Cycle 7 A00 will not result in fuel failure.
Safety Analysis The proposed change described wave shall be deemed to involve a significant hazards consideration if there is a positive finding in any cf the following areas:
1.
Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response
No For the case when neither CEAC is operable but COLSS is in service, the CPCs assume a preset CEA configuration and can not obtain the required CEA position information to ensure the SAFDL on DNBR will not be violated during an A00. Thus, as a result of limiting A00s for Cycle 7, Specification 3.2.4b requires that core power be reduced to a value 16%
less than the current COLSS calculated power operating limit. This ensures the limiting A00 will not result in a violation of SAFDLs. The i
proposed revision to Figure 3.2-2 accounts for the situation when COLSS is out of service but at least one CEAC is operable.
In this case, the Cycle 7 safety analysis has shown that by maintaining the CPC calculated DNBR above the value shown in the figure, the limiting A00 will not result in a violation of the SAFDLs. Therefore, the proposed change will not significantly increase the probability or consequences of any accident previously evaluated.
2.
Will operation of the facility in accordance with this proposed change create the possibility of a new or different type of accident from any accident previously evaluated?
Response
No.
The proposed changes are primarily a result of changes in Cycle 7 core parameters. These changes do not involve any change to any equipment or the manner in which the plant will be operated. These changes further restrict the plant operation when either COLSS or both CEACs are out of service. Therefore, the proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.
3.
Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?
Response
No i
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The intent of this Specification is to ensure that there is always sufficient margin to DNS such that the CPCs can mitigate the consequences of the most limiting A00 prior to a violation of the SAFDLs. Generally, this margin is continuously monitored by COLSS; however, if COLSS is out of service, but at least one CEAC is operable, the limitation on CPC calculated DNBR (as a function of ASI) shown in Figure 3.2-2 represents a conservative envelope of operating conditions consistent with the Cycle 7 safety analysis assumptions. This band of operating conditions has been analytically demonstrated to maintain an acceptable minimum DNBR throughout all A00s. On the other hand, for the case when COLSS is in service, but neither CEAC is operable, the proposed change will ensure that the limiting A00 will' not result in a violation of SAFDLs. Therefore, the proposed changes will not result in a significant reduction in the margin of safety.
Safety and Sionificant Hazards Determination Based on the above safety analysis, it is concluded that:
(1) the proposed change does not constitute a significant hazards consideration as defined by 10 CFR 50.92; and (2) there is a reasonable assurance that the health and safety of the public will not be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact of the station on the environment as described in the NRC final environmental statement.
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i NPF-38-144 ATTACHMENT A i
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