ML20086Q802
| ML20086Q802 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 07/26/1995 |
| From: | Barkhurst R ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20086Q805 | List: |
| References | |
| W3F1-95-0087, W3F1-95-87, NUDOCS 9507280199 | |
| Download: ML20086Q802 (8) | |
Text
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KJhna L A MO66-07M Tel 50J 739 %61 Ross P. Barkhurst 4# Dew rq CFulv v m WMhwf. cf 3 '
A4.05 PR-LJuly 26, 1995 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.
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Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 Technical Specification Change Request NPF-38-168 Gentlemen:
The attached description and safety analysis supports a change to the Waterford 3 Technical Specifications (TS). The proposed change modifies specification 3.5.2 to allow up to seven days to restore low pressure safety' injection (LPSI) pump operability. This proposed change is a collaborative effort of participating Combustion Engineering Owners Group members based on an integrated review and assessment of plant operations, deterministic / design basis factors and plant risk.
Joint Application Report CE NPSD-995, referenced herein in support of.this change, has been submitted to the staff for review and approval under separate htter CE0G-95-344 dated July 10, 1995.
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 this
'l change involves no significant hazards considerations. The bases for that determination is included in the attached submittal.
Waterford 3 requests that the implementation _date for this change be within 60 days of NRC issuance of the amendment to allow for distribution and procedural revisions necessary to implement this change. Although this request is neither exigent nor emergency, your prompt review is
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requested.
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9507280199 950726 PDR ADOCK 05000382 P
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Technical Specification Change Request NPF-38-168 W3F1-95-0087 Page 2 July 26, 1995 Should you have any questions or comments concerning this request, please contact Paul Carepino at (504)739-6692.
Very truly yours,
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R.P. Bar hurst Vice President, Operations Waterford 3 RPB/PLC/ssf
Attachment:
Affidavit NPF-38-168 cc:
L.J. Callan, NRC Region IV C.P. Patel, NRC-NRR R.B. McGehee N.S. Reynolds NRC Resident Inspectors Office Administrator Radiation Protection Division (State of Louisiana) gg American Nuclear Insurers
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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MFIDAVIT 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-38-168; 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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Subscribed and sworn to before me, a Notary Public in and for the Parish and State above named this 2,6" day of J ULT
, 1995.
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Notary Public My Commission expires W'*
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l DESCRIPTION AND SAFETY ANALYSIS 0F PROPOSED CHANGE NPF-38-168 The allowed outage time (A0T) for a single low pressure safety injection (LPSI) subsystem is being extended from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.to seven days (168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br />).
Existino Specification i
See Attachment A Proposed Specification See Attachment B Backaround The LPSI subsystems in combination with the high pressure safety injection (HPSI) subsystems form two redundant Emergency Core Cooling System (ECCS) subsystems. The two LPSI pumps are high volume, low head centrifugal pumps designed to supplement the safety injection tank (SIT) inventory in reflooding the reactor vessel to insure core cooling during the early stages of a large loss of coolant accident (LOCA).
The LPSI pumps take suction from the refueling water storage pool (RWSP),
during the injection phase of a LOCA event, and pump the water through a common _ discharge header.
Prior to penetrating containment, the LPSI header I
splits into four injection paths, with individual injection valves.
Once inside containment, the LPSI headers combine with HPSI and SIT discharge piping and direct the flow through-a common injection header into each of the four reactor coolant system cold legs and into the reactor vessel. The LPSI system pumps start and valves open upon receipt; of a safety injection actuation signal. When RWSP level is drawn down by inventory transfer during the injection phase, a low-low RWSP level actuates recirculation actuation signal (RAS) which stops the LPSI pumps and opens the _ SIS sump isolation valves. This is necessary to ensure adequate net positive suction head remains available for the HPSI pumps and containment spray pumps which remain running for long term core cooling.
The LPSI system is also used in conjunction with a portion of the containment i
spray system for decay heat removal in the shutdown cooling alignment.
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< Description The current Waterford 3 TS address the LPSI system as a portion of the ECCS subsystem. TS 3.5.2 requires two independent ECCS subsystems be operable.
With one ECCS_ subsystem inoperable, based upon any component inoperability, the subsystem must be returned operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or transition to hot shutdown within the following 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The proposed change will allow up to seven (7) days to restore operability to a LPSI system should that be the cause of ECCS subsystem inoperability. The Combustion Engineering Owners Group (CE0G) report CE NPSD-995, " Joint Applications Report for Low Pressure Safety Injection System A0T Extension," explores the proposed change utilizing current probabilistic safety analysis (PSA) methodologies to address the changes in risk when compared with current TS time limitations.
This study of the risk factors that are impacted by extending the A0T for a single LPSI train from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to seven (7) days demonstrates a negligible increase in risk (<1%).
In order to perform a more complete assessment of the overall change in risk, an accounting for avoided risks associated with reducing power and going to hot or cold shutdown must be considered.
This
" transition risk" is important in understanding the trade-off between shutting down the plant compared with restoring the LPSI train to operability while at power.
Also of interest in assessing overall plant risk is the risk avoided based on LPSI system maintenance while in cold shutdown.
Every time the plant is placed in cold shutdown the LPSI system is required for decay heat removal when in the shutdown cooling mode of operation. Any maintenance performed on the LPSI system during shutdown cooling operations adds to the risk of a loss of shutdown cooling event. Therefore, performing LPSI system maintenance with the unit on-line, when the LPSI system is not normally in demand, represents a decrease in shutdown risk.
The results of this study concluded that the change in core damage frequency due to increasing the LPSI A0T from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to seven (7) days is insignificant (<1%).
Additionally, when the reduction in transition and shutdown risks are considered, it can be shown that there is an overall reduction in plant risk.
Thus, it is the conclusion of the study that the overall plant impact will be either risk beneficial, or at the very least, risk neutral.
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l aSafetv Analysis
.'The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive finding in any of the following
,j 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 The Low Pressure Safety Injection system (LPSI) is part of the Emergency Core Cooling System subsystem.
Inoperable LPSI components are not accident initiators in any accident previously evaluated.
Therefore, this change does not involve an increase in the probability of an accident previously evaluated.
The LPSI system is primarily designed to mitigate the consequences of.a large Loss of Coolant Accident (LOCA).
These proposed changes do not affect any of the assumptions used in the deterministic LOCA analysis.
l Hence the consequences of accidents previously evaluated do not change.
In order to fully evaluate the LPSI A0T extension, probabilistic safety analysis (PSA) methods were utilized. The results of these analyses j
show no significant increase in the core damage frequency. As a result,-
l there would be no significant increase in the consequences of an accident previously' evaluated. These analyses are detailed in CE NPSD-i 995, Combustion Engineering Owners Group " Joint Applications Report for low Pressure Safety Injection System A0T Extension."
Therefore, the proposed change will not involve a'significant increase in the probability or consequences of any accident previously evaluated.
i 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?
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Response
No.
j This proposed change does not change the design,' configuration, or l
method of operation of the plant.
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' 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 The proposed changes do not affect the limiting conditions for operation or their bases used in the deterministic analyses to establish the margin of safety.
PSA evaluations were used to evaluate these changes.
These evaluations demonstrate that the changes are either risk neutral or risk beneficial. These evaluations are detailed in CE NPSD-995.
Therefore, the proposed change will not involve a significant reduction in a margin of safety.
Safety and Sianificant 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 10CFR50.92; nnd (2) there is 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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NPF-38-168 ATTACHMENT A 1
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