ML20247N648
| ML20247N648 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 07/27/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247N637 | List: |
| References | |
| NUDOCS 8908030094 | |
| Download: ML20247N648 (6) | |
Text
-
e 8
'h
(.
UNITED STATES c.
'l
- 3.
- ;, c NUCLEAR REGULATORY COMMISSION T,
J wAsumarow.o. c.rosss N..../
l i
_ SATETY EVALUATION BY THE '0FFICE OF WUCLEAR REACTOR REGU' ATION RELATED TO AMENDMENT NO. 143 TO FACILITY OPERATING LICENSE NO. DPR-6_6 DUQUESNE LIGHT COMPANY OHID EDISDN COMPANY PENN5YLVANIA POWER COMPANY BEAVER VALLEY POWER STATION, UNIT NO. 1 DOCKET NO. 50-334 INTRODUCTION Dy letter dated June 22, 1989 Duquesne Light Company (the licensee, acting as agent for the above utilities) submitted a recuest to amend the Technical Specifications for. Beaver Valley Unit 3.
The amendment would increase the maximum river water temperature limit (the ultimate tieSt sink temperature), and revise several related specifications. By letter dated July 24, 1989 the licensee requested issuance of an amendment under emergency conditions. We have reviewed the licensee's submittals and our review results follow.
DISCUSSION AND EVALUATION The ultimate heat sink (i.e. the Ohio River) provides a source of cooling water for normal operation, and to dissipate the heat of an accident to achieve and maintain the unit in a safe shutdown condition. The current design inlet l
temperature of the service water system (from river water) for Unit 1 is 86*F.
The inpan of increasing the river water temperature limit from 86*F to 90*F was evaluated by the licensee for its effects on safety-related equipment during normal operation, effects on post-accident containment depressurization/
cooling, and effects on reactor safe shutdown. The increase in the allowable river water temperature will provide additional margin to prevent a plant s5utdown should abnormally hot weather conditions, as experienced in the summer of 1988, reoccur.
(1) Specifications 3.1.2.7.b.3. 3.1.2.8.b.3, 4.1.2.7.b, 4.1.2.8.b, and 4.8.2.1.b TheminimumRefuelingWaterStorageTank(RW$T)temperatureischangedfrom 43*F to 45'F.
This change is required to make the limit consistent with the assumptions used in the analysis to support this amendment. A minimum RWST temperature of 45'F is used for analysis of inadvertent operation of the Quench Spray System. This analysis establishes the mir.imum allowable containment air partial pressure. In addition, a maximum allowable RWST temperature of 55'F is now imposed in specification 3.1.2.8.
This limit is consistent with the maximum T.WST temperature also assumed in the revised containment depressuri-
- ation analysis. Surveillance requirement 4.6.2.1.a.2 is revised to refer tr the allowable RWST temperature range given in Specification 3.1.2.8.
8908030094 890727 PDR ADOCK 05000334 p
j j
. (
i These danges are results of a veanalysis (see dange (4) below), and are acceptable on the basis that change (4) is acceptable.
(2) Table 3.5-5, Engineered Safety Features Response Times The Quench Spray respotse time listed in Table 3.3-5 is increased to B5 seconds from 77 secor.ds. This change is a result of the observations made from the licensee's recent Safety System Functional Evaluation (SSFE) review of the Quench Spray System, and is required to maintain consistency between the overall system response time and the individual component requirements. The 85 second limit is the sum of 10 seconds for diesel generator startup and loading and 75 seconds for stroke time of the Quench Spray containment isolation valves. These values have been assumed in calculating the Quench Spray delay I
time for the containment analyses depressurization analysis.
On the basis that the change is a mfinement of a calculational model, and has been factored in change (4) below, we find it acceptable.
(3) Specifications 3.6.1.2, 4.6.1.2, 3.6.1.3 and 4.6.1.3 The previously calculated peak containment pressure for a DBA-LOCA is changed from 38.3 psig to 40.0 psig. This change is the result of using a more conservative value for containment free volume in the containment depressuri-2ation reanalysis. Specifically, the licensee factored uncertainty values into the previously used licensing basis value for the new calculation: minimum volumes were thus used for perA pressure and depressurization calculations, and naximum volumes were used for NpSH (net positive suction head) calculations.
The methodology of the oomputer odes used for these analyses have been previously reviewed end found acceptable by the staff.
The new calculated peak pressure is still within the containment design pressure of 45 psig, and the leakage criteria imposed by these specifications are not relaxed. Furthermore, the containment leakage test pressure is changed from 38.3 psig to 40.0 psig which is more conservative. We find this j
change acceptable.
l (4) Figure 3.6-1 and Specifications 3.6.1.4, 3.6.1.5 and 3.7.5.1 I
Figure 3.6-1, the maximum allowable Primary Containment Air Pressure versus River Water Temperature curve, has been revised to reflect the revised containment depressurization analysis based on a single RWST temperature limit and the increased river water temperature limit. The revised figure includes additional containment average air temperature restrictions when operating with river water temperature above 88'F as required to support the assumptions of the revised analysis. Technical Specification 3.6.1.4 and 3.6.1.5 for j
containment maximum air partial pressure and containment minimum temperature 1
are revised to be consistent with the new Figure 3.6-1.
l The licensee used the LOCTIC computer code to perform the reanalysis. The reanalysis took into account the following changes:
)
f a.
Use of a single maximum RWST temperature (55*F) j New RWST setpoints for sp(ray recirculation and quench b.
spray cutback were used see change (6) below).
i J
r
.1
. f E,
.]
'l -
1
- 3'-
I L
i c.
.Use of reduced containment net free volume-(see change.(3) above).
d.
Assumption of.10% degradation of rated head for the' quench spray and-i recirculation spray pumps, in accordance with ASME Section XI, and j
addressing the licensee's SSFE concerns.
-i e.
Containment. quench spray themal efficiency is assumed to be 99%-(95%
, was assumed in the licensing basis) and recirculating spray themal efficiency is assumed to range between 99% and 95% (a constant 90%
was assumed in the licensing basis). These are currently acceptable j
values.;
i i
f.
Use of ANS 5.1-1979 model for decay heat generation (previously, ANS
-l 5.1-1971 was used).
g.
Reactor thermal power of 2733 ET, i.e. licensed rating plus 2%
uncertainty (previously, the ESF rating of 2766 MWT was used).
h.
Cmdit for steam condensation by safety injection during reflooding was assumed (previously not allowed).
The results of the licensee's analyses show that the Containment Depressurization System is capable of reducing the containment pressure to subatmospheric within j
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> for river water temperature up to 88'F. Depressurization will still i
be attair,ed in an heur if river water temperature was at 90'F or less and
~
initial containment temperature at greater than 95'F. Thus no revisions need i
~ be made to accident evaluations in the unit's licensing basis. Furthermore.
l
. the reanalysis showed that KPSH requirements will continue to be satisfied for i
' the low head safety injection pumps and recirculation spray pumps.
The licensee evaluated the effen' of elevated service water temperature on other plant systems, such as the emergency diesel generators cooling system, control room air conditioning units, safeguards area air conditioning units, etc. All of these evaluations lead to the conclusion that the system are
- capable of accepting the increased river water temperature while continuing to perform their intended design functions.
I The licensee evaluated the effect of the increased service water temperature on the reactor coolant system's cooldown capability using the residual heat removal systems. At the elevated temperatures, Unit I would require 28 hours3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br /> (instead of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) to cool down from 350*F to 140*F. There is thus a time increase of about 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, but the longer cooling time is still within acceptable limits.
l l
_-__-m-_____m__
m 4
2 i
r 4-i Based on satisfactory resolution of all the above considerations, we find the increase of service water temperature limits and the associated _ revised depressurization analysis acceptable.
'(5) Section 4.6.2.1.b and 4.6.2.2.d I
The surveillance requirements of the Quench and Recirculation Pumps are revised
.to reflect the allowable margins for pump degradation assumed in the revised containment depressurization analysis (see item d. of change (4)). This change is acceptable on the basis that the revised depressurizatien analysis is acceptab1e.
(6) Table 3.3-4 1
The RWST level-auto quench spray flow reduction setpoir,t is revised from 11'0" i
to 8'6"; the allowable value is also reduced by 2 1/2'. Similarly, the RWST level low set point is changed from 19' 2-i"to 18' 8-1"; the new allowable value is set at 6".
These setpoint changes are required to include revised instrument channel uncertainties into the analysis. New reactor trip and ESF instrumeat channel inaccuracies were recently calculated for Beaver Valley Unit I using an updated methodology described in Westinghouse topical report WCAP-11419. Changes to the reactor trip and ESF setpoints and allowable values based on this' revised methodology were submitted to the NRC in Technical Specification Change Request No. 156 (No significant hazards notice published in Federal Register, 54 FR 15B28). These proposed RWST level setpoint changes were used in the revistd containment depressurization analysis.
The revised values provide corrections to the previous values. On the basis 1
that the revised depressurization analysis is acceptable, changes to Table l
3.3-4 are also acceptable.
i i
(7) Bases Sections 3.6.1.4, 3.6.1.5 and 3.6.1.G
)
The bases sections are revised to reflect change (4) above, and are thus au.eptable.
EMERGENCY CIRCUMSTANCES The licensee's July 24, 1989 letter presents the following with regard to justification of the emergency consideration of the June 22, 1989 application:
During the evaluation process to support this license change, it was determined that the current Unit I technical specifications for river water temperature [3.7.5.1], RWST temperature '3.1.2.8] and contaiment air partial pressure [3.6.1.4] provided ambiguous information during periods when the river water temperature exceeded 80*F. With the minimum RWST temperature attainable at this time of approximately 53*F and our current maximum allowable containment air partial pressure oprating be requ[ Figure 3.6-1] of specification 3.6.1.4, a Unit 1 plant shutdown may curve ired below the 86*F maximum temperature limit of specification 3.6.5.1.
Due to the recent abnormally h'gh ambient temperatures and forecast for additional hot weather, our river water.emperature has increased such that a plant shutdoe coJ1d be required within the next few days if the proposed technical spec 1Twation change is not approved.
n
~
.g
- a _
f, y
P l
~
- i..
- )
The revised analyses, at submitted in our proposed technical specification change request were substantial. This submittal was not provided in a more timely manner due to the significant amount of plant re-analysis and n yiews required to support this change. These analyses included multiple LOCTIC input changes for the evaluation of the containment depressurization capability, NPSH evaluation of the containment depressurization pumps, River Water System components operation at the increased temperature limit and plant cooldown duration.
We conclude that failure to grant the emergency license amendment would require shutdown of Unit 1.
Based upon the above, we conclude that the licensee has adequately addressed the standards of 10 CFR 50.91(a)(5) with regard to demonstrating the need for an emergency license amendment. We further conclude, based on our frequent monitoring of the licensee's activities leading to the requested amendment, that the. licensee has not abused the emergency provision by failing to make timely application for the amendment.
TINAL NO SIGNIFICANT HA21.PDS CONSIDERATION DETERMINATION The Commission's regulations in 10 CFR 50.92 state that the. Commission way make a final determination that a license amendment involves no significant hazards considerations, if operation of the facility, in accordance with the amendment would not:
(1) Involve a significant increase in the probability nr consequences of any accident previously evaluated; or (2) Create the ipssibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.
This amendment has been evaluated against the standards in 10 CFR 50.92. It does not involve a significant hazards consideration because the answers to the three criteria are all negative as follows:
We have re-evaluated previously analyzed accidents and determined that no accidents ~ were caused by high river water temperature. Furthermore, we determined that despite the proposed changes to the technical specifications, the original design requirement of the containment depressurization system will continue to be met, and safety-related systems which require river water cooling will be capable of performing their original design functions at the l
increased service water temperature limit. Hence the probability and consequences previously analyzed accidents will not be increased.
There is no hardware, software or operational procedure changes as a result of the proposed amendment, and hence no new failure modes are introduced.
G i
e V
'a
- t,.
The anendment does involve a slight nlaxation of the river water temperature.
Hwever, the above evaluation shows that the safety systems and non-safety systems will continue to meet their original design criteria. fience we conclude that the relaxation in safety margin is insignificant.
STATE CONSULTATION in accordance with the Commission's regulations, efforts wer.: made to contact the Commonwealth of Pennsylvania representatives. The state (Mr. Richard Janati) representative was contacted and had no connents.
ENVIRONMENT 1. CONSIDERATION This amendment changes requirements with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. We have determined that the amendment involves no significant increase in the amounts, and no signifi-cant change in the types, of any effluent > that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. We have previously irsued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding. We have also made a final no significant hazards consideration finding with respect to this amendment. Accordingly, this 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.
CONCLUSION We have evaluated the effects of increasing the allowable river water temperature on the system and components to perform their safety function, and j
found the effects to be minor and thus acceptable.
We have 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, and (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the comon defense and security or to the health and safety of the public, Dated: July 27,1989 Principal Contributor: Jin Guo and Peter S. Tam j
{
l J