ML20215J853
| ML20215J853 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 06/15/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20215J836 | List: |
| References | |
| NUDOCS 8706250131 | |
| Download: ML20215J853 (5) | |
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- UNITED STATES L D's[ s' 3
NUCLEAR REGULATORY COMMISSION
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P SAFETY EVALUATION BY THE OFFICE OF' NUCLEAR REACTOR REGULATION 6
SUPPORTING' AMENDMENT NO. 19 TO FACILITY OPERATING-LICENSE NO. NPF-38 e
q LOUISIANA POWER AND LIGHT COMPANY-j
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WATERFORD STEAM ELECTRIC STATION, UNIT 3 DOCKET NO. 50-382
1.0 INTRODUCTION
6y applications dated February 23, 1987, Louisiane Power and Light Company i
(LP&L or the licensee) requested changes to the Technical--Specifications.
(Anpencix A to Facility Operating License No. NPF-38) for the Waterford h
Stear Electric Station, Unit 3.
The proposed changes would:
- 1) raise ~the emergency feedwater initiation:setpoint from'30% to.36.3% of wide range j
m i; 2) reise the required refueling water storage pool' level from 82%
to 83%; and 3) raise:the' required safety-injection tank level from 60% to C 14..
2.0.D_J5CUSSION I
The proposed changes to the Technical Specifications requested by the' jJ Mcensee are in three areas, as described below.
b 2'1 Eeergency Feedwater Initiation Setpoint' (NFP-38-53)-
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Tabre 4 3-4' identifies tripivalues for the Emergency Feedwater (EFW)-
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Contrdi Valve Logic Lo Level.
Two levels are given for this parameter; p
36.6% wide range with a safety. injection. actuation, signal (SIAS) or 30 A% vithout a SIAS signal.
The operability forlthis system is 9 required;for. Modes 1'through 3 as protection against' design basis
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,. events-such as a Small. Break Loss of Coolant Accident'(LOCA), Steam x
' Generator. Tube Rupture or a' Steam Line or Feedwater Line Break...(The
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36.6% setpoint is nece,sary only~'for the large.Feedwater i.ine' Break eytot). ' The proposed change will. redefine the 30.0% wide range set -
i pt nt-to 36.6%, removing.the-dependence,upon the SIAS and resulting in one Lo Levet setpoint, thereby simplifying the Technical Specifica-s t
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2.2 Minimum Required Water Level for RWSP (NPF-38-55)
The proposed change would revise Technical Specifications _3.1.2.8b.1,
" Borated Water Sources - Operating" and 3.5.4a, " Refueling Water Storage Pool".
Currently, the Technical Specifications require that the Refueling Water Storage Pool (RWSP) contain a minimum water volume of 475,000 gallons.
The Technical Specifications refer to 82% as being equal to'the required. volume; however, calculations have shown that,.in order to maintain the-required 475,000 gallons in the RWSP, the indicated level must be; equal to 82.4%.
The proposed change, would conservatively "round-up" the required level to 83% instead of rounding-off" to 82%.
2.3 Minimum Required Water Level for SIT (NPF-38-56)
The proposed change would revise the note to Technical Specifica--
tion 3.5.1, " Safety Injection Tanks".
As' presently written, the a
note is applicable in Modes 3 and.4 and currently allows the safety injection tank.(SIT) level to be decreased to between 60%
and 83.8% level when. pressurizer pressure has been decrea ud to less than 1750 psia and only three SITS are operable.
This lower level of 60% corresponds to the minimum required water volume of 1332 cubic feet that must be maintained in.each of the three operable SITS; however, calculations have shown that, in order to maintain the' required water volume of 1332' cubic feet,
.I the SIT level must be 60.23%.
The proposed change, therefore,
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would conservatively "round-up" the required level..to 61%
instead of "round-off" to 60%.
3.0 EVALUATION The proposed changes to the technical-specifications requested by the licensee and described in three areas above, are evaluated below.
3.1 Emergency Feedwater Initiation Setpoint (NPF-38-53)-
Currently, under automatic control in.the absence'of SIAS, the-EFW control valve. positions are determined based on steam genera-
. tor level and EFW flow.' However, with a SIAS, the control valves i
are no' longer controlled by flow, but rather by steam generator level only. The' rate at which.the valves.open and close'is a.
function of the difference between the setpoint-and the actual level, and the length of time that difference exists.
Currently,
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when the steam generator level drops to' the'"Lo-Lo" Level'(30.0%.
without a SIAS, 36.3% with a SIAS), a priority open signal'is l
sent'to the valves which overrides al1~ automatic or manual controls.
Once.the level raises above the applicable value, the control j
returns. to' its previous mode; either." automatic" or " manual" under 1
operator. control.
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r Because the setpoint increase.is in the conservative direction, additional safety margin will be provided for the design basis events of concern with the exception of the Large Feedwater Line o
Break, which will be unaffected by the change.
Raising the EFW.
control valve logic Lo Level setpoint has no effect on the probability of occurrence of the initiating event itself.
The setpoint comes into play only when an analyzed event progresses to.the point of reducing the steam generator level to the setpoint value.
By raising the setpoint, feedwater will be-available. earlier than previously analyzed for most events, thus l
mitigating the consequences of.the event.
Raising the EFW trip set point in a conservative. direction does i
not create any new failure or accident path.
Therefore, the proposed change does not create the possibility of occurrence of any new or different kind of accident from any accident previously evaluated.
By raising the EFW setpoint,.feedwater flow will be provided earlier than assumed in the analysis.for most events, resulting -
i in an additional margin of safety'for'those events.
The staff concludes, therefore, that the proposed change is-acceptable.
3.2 Minimum Required Level for RWSP (NPF-38-55)
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This change.is being proposed 'to correct a potential nonconser-'
I vatism in.the percent indicated level that corresponds to the minimum required volume'that must be maintained.in the RWSP.
The reason for maintaining a minimum volume of borated water -in q
the RWSP is to ensure that the available supply of water to the Emergency Core Cooling System (ECCS) is consistent with the.
1 assumptions used in the~ 1arge break loss-of-coolant accident-(LOCA) presented in the FSAR.
1 Since the proposed change increases the required. level:that'must be maintained in'the RWSP (and hence increases the: required j
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volume), there will'be no affect on the LOCA analyses as de' scribed in Chapters 6 and 15 of the'FSAR.
Therefore, the proposed change will not involve a significant' increase in the probability or consequences of any accident.
~ r The proposed change will ensure that the indicated level of the RWSP is consistent with the volume 'equirement that was. determined r
,z by.the FSAR.
There has been'no physical-change to. plant systems, structures or components.
The only change to plant procedures will.betto require an increased RWSP level when performing routine survei.11ance tests..Therefore, the proposed change will not' create the' possibility of.a new or different kind of ace.ident from any. accident-previously evaluated.1
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7-The intent of these specifications is to ensure that a 3
sufficient supply of borated water is available for injection by the ECCS in the event of.a LOCA'. -The minimum RWSP volume requirement ensures that sufficient water will be available' inside the containment to permit recirculation through the.
safety injection pumps and back into the core.
This minimum 1
volume requirement also includes an allowance.for water not usable because of RWSP discharge line location and other physical characteristics.
Since'the proposed change simply updates the RWSP level that corresponds to this minimum volume
- l requirement, it will not involve a significant reduction in the margin of safety.
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The staff concludes, therefore, that the proposed change is acceptable.
3.3 Minimum Required Water Level for SIT (NPF-38-56)
This change is being proposed to correct a potential non-conser-vatism in the percent level that corresponds.to the minimum'-
required volume that must be maintained in'the SITS. ~The reason for maintaining a minimum-volume is to ensure that,'in the event.
of a large break loss-of-coolant accident (LOCA),.the amount of water injected into the RCS from the SITS is consistent with the amount of water assumed in'the large. break LOCA analysis presented in the FSAR.
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Since the proposed change increases the. required levt.1-that must-be maintained in the' SIT (and hence increases the' required volume) there will be no effect on the LOCA analyses described a
in Chapters 6 and 15 of the FSAR.
Therefore,:the proposed.
change will not involve a significant: increase in.the proba-bility or consequences of any' accident.
i The proposed change will ensure'that.the level.of.the SITS'is consistent with the volume requirement that was' determined by the Safety Analysis.
There has been no physical change to. plant-systems, structures or components.
The only change to' plant procedures will be to require an increased SIT level _ when per-forming routine surveillance tests.
Therefore,'the proposed change will not create the possibility of a new or.different-kind of accident'from any accident previously evaluated.
The intent of these specifications is to ensure that a sufficient
'i volume of borated water ~will belimmediately forced into the' l
reactor core through each of the four. cold legs in the. event that the RCS pressure falls below the pressure of the safety.
injection tanks. This initial surge ofl water into the core a
provides. the initial cooling mechanism during the large break -
LOCA analysis. The minimum SIT. volume requirement ensures there is sufficient' water in each of the SITS'to perform the function-a
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, - assumed in the safety analysis.
Since the proposed change simply updates the SIT level that corresponds to the minimum volume requirement, it will not. involve a significant reduction in the margin of safety.
The staff concludes, therefore, that the proposed change is acceptable.
4.0 CONTACT WITH STATE OFFICIAL The NRC staff has advised the Administ.rator, Nuclear Energy Division, Office of Environmental Affairs, State of Louisiana of the proposed determination of no significant hazards consideration.
No comments were received.
5.0 ENVIRONMENTAL CONSIDERATION
This amendment involves changes in installation or use of facility components located within the restricted area.
The staff has determined that the amendment involves 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.
Accordingly, the amendment meets the 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 this amendment.
6.0 CONCLUSION
Based upon its evaluation of the proposed changes.to the Waterford 3 Technical Specifications, the staff has concluded that:..there is-
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reasonable assurance that the health and safety of'the public will not be endangered by operation in the proposed manner, and such activities will be conducted in compliance with the Commission's regulations and the issuance of the amendment willinot be' inimical to-the common defense and security or to the health and safety of the public.
The staff, therefore, concludes that the proposed changes are acceptable, and are hereby incorporated into the Waterford 3 Technical Specifications.
Dated:
June 15,1987 Principal Contributor:
S. Sun
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