ML16341F150
| ML16341F150 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 05/12/1989 |
| From: | Shiffer J Pacific Gas & Electric Co |
| To: | NRC/IRM |
| Shared Package | |
| ML16341F149 | List: |
| References | |
| NUDOCS 8905170256 | |
| Download: ML16341F150 (24) | |
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PGNEIE L
er No.:
DCL-89-129 ENCLOSURE UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
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PACIFIC GAS AND ELECTRIC COMPANY
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Diabl o Canyon Power Pl ant
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Units 1
and 2
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Docket No. 50-275 Facility Operating License No.
DPR-80 Docket No. 50-323 Facility Operating License No.
DPR-82 License Amendment Request No. 89-05 Pursuant to 10 CFR 50.90, Pacific, Gas and Electric Company (PGhE) hereby applies to 'amend its Diablo, Canyon Power Plant (DCPP) Facility Operating License Nos.
The proposed change amends the Units 1
and 2 Technical Specifications (Appendix A of the Licenses) regarding Technical Specification 3.8.1.1 to change the diesel generator allowed outage time to seven days.
I Information on the proposed change is provided in Attachments A and B.
This change has been reviewed and is considered not to involve a significant hazards consideration as defined in 10 CFR 50.92 or an unreviewed environmental question.
- Further, there is reasonable assurance that the health and safety of the public will not be endangered by the proposed change.
Subscribed to in San Francisco, California this 12th day of May 1989.
Respectfully submitted, Pacific Gas and El.ectric Company PU
Locke 2679S/0069K OFFICIAL SEAL t'HERESE TOLIVER ROTARYPUB UC. CAUFORNIA r
0IYANDCOtNITYOF SAN IRANQStm MyComm Expcres Doo. 2$. 1990 Howard V. Golub Richard F.
Locke Attorneys for Pacific Gas and Electric Company By J.
D. Sh'f er Vice Pres 'dent Nuclear Power Generation Subscribed and sworn to before me this 12th day of May 1989 Therese Toliver, No ary Public in and for the City and County of San Francisco, State of California My commission expires December 25, 1990.
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Attachment A
REVISION TO TECHNICAL SPECIFICATION 3.8.1 ELECTRICAL POHER SYSTEHS, A.C.
SOURCES AND ASSOCIATED BASES A.
DESCRIPTION OF AHENDHENT REQUEST This license amendment request (LAR) proposes to (l) revise the allowed outage time (AOT) requirement of Technical Specification 3.8.1.1 Action Statement
- b. to a 7-day AOT requirement for any one inoperable diesel generator (DG) and (2) revise the associated Bases to indicate the proposed AOT is an exception to the recommendations of Regulatory Guide 1.93.
The 7-day AOT would be applicable to the current five DG and future six DG configurations.
The proposed change to the Technical Specifications of Operating License Nos.
DPR-80 and DPR-82 is noted in the marked-up copy of the appl1cable Technical Spec1fication (Attachment B).
B.
BACKGROUND PGhE has been implementing activities to enhance diesel generator reliability at Diablo Canyon Power Plant (DCPP).
This effort consists of developing preventive maintenance procedures, providing personnel
- training, and 1mplementing reliability improvement recommendations.
The purpose of the preventive maintenance program is to min1mize the number of DG failures by maintaining the diesels 1n a mechanical and electrical condition that max1mizes DG reliability.
The preventive maintenance procedures were developed using Engine Division of Hhite Industrial Power Inc.
(ALCO) guidelines, "Engine Haintenance Schedule for Standby Engines (HI-ll272)," and DCPP operating experience.
Hhen a
diesel failure occurs, an investigation is conducted to determine and evaluate the cause of the failure. If it 1s determined that additional maintenance activities would help prevent recurrence, these maintenance activities are included 1n the procedure revisions.
Also, vendor information on preventive maintenance, surveillance
- programs, and procedures is rev1ewed
- and, where applicable, incorporated for use at DCPP.
The basis for not including vendor recommendations will be established and documented.
Another aspect of the diesel generator reliability improvement effort 1s personnel training.
Training has been provided by the diesel supplier and will now be supplemented by the purchase of our training diesel unit wh1ch will enhance the ons1te training program for PGSE maintenance personnel and eng1neers.
Also, personnel have been 1nvolved in industry DG rel1ab111ty improvement meetings, such as the EPRI Seminar in August 1987 on diesel generator operations, ma1ntenance, and test1ng.
These activities to enhance diesel generator reliability also include
- industry, NRC", and vendor DG reliab111ty improvement recommendations.
For example, PGhE's review of NUREG/CR-0660, "Enhancement of Onsite 2679S/0069K
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l Emergency Diesel Generator Reliability," indicated that of the recommendations included in this report, many were already implemented at
- DCPP, such as prelubing of the diesels and appropriate training of personnel.
To further enhance reliability, PGhE has implemented the recommendations of Generic Letter 84-15.
Two of the concerns raised in Generic Letter 84-15 were cold fast starting of the DGs and excessive testing.
The DCPP Technical Specifications were revised to allow the gradual acceleration and/or gradual loading of the DGs and to minimize the number of DG starts (License Amendments 15 and 14 for Units 1
and 2, respectively, issued July 24, 1987).
PGLE has also modified the DGs to improve reliability.
Two examples of these modifications are the fuel oil priming system and the compressed air filtration and dehumidification system.
The fuel oil priming system
, was added to enhance the starting reliability of the DGs.
The compressed air filtration and dehumidification system was added to improve reliabi lity of the solenoid valves and air motors by reducing corrosion.
These air system modifications also improve DG starting reliability.
As mentioned
It is planned that the sixth diesel will also be a
commercial grade ALCO DG similar to the five existing DGs.
Hith the sixth DG installed and operable, DCPP will have three dedicated diesels for each unit, rather than the current five diesel configuration with a swing DG as discussed below.
This arrangement will simplify the operation of the system and provide the net benefit of increased maintenance schedule efficiency.
Overall, this will provide greater flexibilityof plant operation.
As part of this effort to enhance the onsite power system, PGhE has also performed detailed risk and reliability analyses to determine an appropriate AOT for the DGs.
These studies and their results were documented in PGhE letter DCL-89-126 dated Hay ll, 1989.
These studies demonstrated that a 7-day AOT is acceptable for DCPP.
Therefore, this LAR requests that a 7-day AOT be specified for Technical Specification 3.8.1.1 Action Statement b.
f ffi n
n wr The DCPP electrical power system consists of an offsite system and an onsite system.
The offsite power system is comprised of a 230 kV transmission system and a 500 kV transmission system.
The onsite power system consists of a distribution system normally supplied by the offsite power system.
In the event of a loss of offsite power, the onsite power system is supplied by five emergency DGs.
A description and discussion of reliability for the offsite and onsite power systems follow.
l.
DCPP Offsite Power System Description DCPP is connected to the 230 kV transmission system for startup and standby power.
The two incoming 230 kV transmission
- lines, one from 2679S/0069K
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the nearby Horro Bay Power Plant,-and the other from the Hesa Substation, feed a 230 kV switchyard having three 230 kV circuit
- breakers, one for each line and one for the standby startup transformers.
The single line diagram of the 230 kV system to Units 1 and 2 is shown on Figure 8.2-1 of the FSAR Update.
Figure 8.2-2 of the FSAR Update shows the offsite interconnections.
Figure 8.2-3 of the FSAR Update shows the general arrangement of the 230 kV and 500 kV switchyards.
The 230 kV switchyard of the Horro Bay Power Plant is a reliable source of power with four generating units and two 230 kY double circuit tower lines from Hidway and Gates substations connected to the 230 kV switchyard buses.
The switchyard contains a 230 kV double bus arrangement and has bus paralleling and sectionalizing facilities to obtain a high degree of service continuity.
In addition to the 230 kV offsite power source, the 500 kV transmission system can be used as an alternate source.
The main generator can be disconnected from the main and auxiliary transformers after the two 500 kV breakers are opened.
The main and auxiliary transformers can then be restored to service as a source of power to the plant.
Offsite power to the plant can also be provided from the 500 kV transmission system when the main generator is not in operation.
The 500 kV line is a backup for the 230 kV plant power supply via the main transformer to the unit auxiliary transformer.
Figure 8.1-1 of the FSAR Update (Plant Single Line Diagram) shows the three 500 kV line terminals and the interconnections to the plant auxiliaries.
Figure 8.2-5 of the FSAR Update shows the arrangement of the 500 kV switchgear.
In addition to the highly reliable transmission
- system, the weather conditions are not severe in the vicinity of Diablo Canyon.
Section 2.3.1.3 of the FSAR Update states that the annual mean number of days with severe weather conditions, such as tornados and ice storms, is zero at Hest Coast sites.
Because of the number of offsite circuits to DCPP and the lack of severe weather conditions, the DCPP offsite power system is highly reliable.
DCPP has never experienced a grid-related loss of offsite power.
2.
Onsite Diesel Generator Power System The onsite DG power system, the DCPP DG reliability, and station blackout coping durations are described below:
a.
Description The DCPP onsite power system consists of five DGs.
Two DGs are dedicated to Unit 1 and two DGs are dedicated to Unit 2, with 2679S/0069K
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the fifth DG (swing) shared by both units.
Each DG consists of a self-contained diesel engine directly connected to an alternating current generator.
The DG units were supplied by ALCO.
Each DG supplies a vital bus, with the swing DG supplying either a Unit 1 or 2 vital bus.
Additional information on the DGs can be found in Section 8.3.1 of the FSAR Update.
b.
Diesel Generator Reliability Record Based on the results of the DCPP diesel generator reliability improvement activities described
The reliability history of each DCPP DG was reviewed to determine the number of valid demands and failures in accordance with the recommendations of Regulatory Guide (RG) 1.108.
As indicated in Generic Letter (GL) 84-15, the median value of DG reliability at operating nuclear plants is 0.98/demand, with about 75 percent of the DGs currently in service having a reliability of 0.95/demand or greater.
The DCPP reliability history indicates that DCPP DGs have an average reliability of greater than 0.99/demand.
This is higher than the average DG reliability.
This conclusion is also consistent with Electric Power Research Institute report NP-4264, Volume 2, September 1985, "Failures Related to Surveillance Testing of Standby Equipment."
NP-4264 concludes from a comparison between manufacturers that the surveillance-related failures for the ALCO units are an order of magnitude less than for other manufacturers.
c.
Station Blackout Considerations NRC regulation 10 CFR 50.63 requires that each light-water-cooled nuclear power plant be able to withstand and recover from a station blackout (SBO) of a specified duration.
For the SBO
- duration, the plant must be capable of maintai ning core cooling and containment integrity.
PGhE has evaluated the ability of DCPP Units 1
and 2 for the current five diesel configuration to cope with a SBO event.
this assessment conforms with guidance from NUMARC 87-00 and Regulatory Guide 1.155.
Based on the determination as an Extremely Severe Heather (ESH) Group of 1, Severe Heather (SH)
Group of 1, Independence Group I 1/2, Design Characteristic P
Group of Pl, Emergency AC Power Configuration Classification (EAC) Group of C, and an allowed DG target reliability of 0.950, the DCPP units were assigned a required coping duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Since the units attain a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> coping duration, no actions including hardware modifications are required to reduce the site contribution to the overall risk of station blackout.
The SBO analyses are documented in PGLE Letter DCL-89-097, dated April 17, 1989.
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C.
JUSTIFICATION Presently, Technical Specification 3.8.1.1 allows a DCPP unit to operate for only 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> if one of the associated DGs is inoperable.
Increasing the AOT from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days will provide operational flexibilityand improved scheduling of maintenance and post-maintenance testing through the elimination or reduction of the problems associated. with completing the work in a shorter time interval.
Also, the longer AOT will provide additional time for implementation of equipment enhancements as they are identified.
The AOT limit allowed for safety equipment in the Technical Specifications is typically 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Exceptions are the 7 day limit for systems such as ventilation systems and containment cooling systems.
These AOTs are generally based on past experience, equipment accessibility, unique equipment design features, and engineering judgment.
- Recently, due to the use of risk and reliability analyses, increased AOTs have been approved based upon the required system availability (e.g., recently NRC-approved technical specification changes for the Brunswick plant, dated Harch 27,
- 1987, and the La Salle plant, dated February 7, 1989, and as recommended in NUREG/CR-3082).
The 7-day AOT would provide the plant staff with increased flexibilityin the performance of maintenance activities.
Under the current Technical Specification requirements, this maintenance can only be scheduled during periods of extended plant shutdowns, such as a refueling outage.
Additionally, an increase in the AOT will provide more flexibilityin performing repairs and would, in turn, increase the thoroughness and quality of the maintenance process.
Similarly, a 7-day AOT would allow more efficient use of manpower for maintenance.
Critical activities could be performed on day shift when a
greater number of skilled support personnel are available.
This would also allow the same maintenance personnel to perform all of the repair work, thus providing continuity of work by minimizing turnovers.
- Also, the increased AOT would provide more time to perform post-maintenance testing.
PGLE is requesting that this LAR be approved by mid-September 1989 in order to support the Unit 1 third refueling outage, at which time maintenance work is scheduled for the swing DG.
PGLE has determined that the preventive maintenance, inspection, and acceptance testing required by Surveillance Requirement 4.8.1.1.2b cannot be completed in one 72-hour period; rather, it may take up to 7 days to complete this work on DG 1-3 for the Unit 1 third and fourth refueling outages.
Therefore, approval of this LAR to allow a 7-day AOT is necessary prior to the next scheduled refueling outage.
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Surveillance Requirement 4.8.1.1.2b for the Unit 1 third and fourth refueling outages could be scheduled for performance in several 72-hour periods in accordance with the present Technical Specification 3.8.1.1 AOT.
However, it is more effective when the maintenance is performed 1n one 7-day period.
Performing the maintenance in one 7-day period results in less total out-of-service t1me than if performed in several 72-hour per1ods.
In addition, performing the maintenance 1n several 72-hour per1ods requires more DG testing than in one 7-day period.
This reduction in testing is consistent with GL 84-15 and NRC letter dated October 26, 1988 (SECY-88-304),
from V. Stello to the Commission regarding Staff recommendat1ons to reduce testing at power operation.
D.
SAFETY EVALUATION In determining the safety, aspects of the proposed 7-day AOT, the reliability of the systems and components were evaluated.
Additionally, an AOT study was performed to assess the safety aspects of changing the AOT period.
This study used two different r1sk methodologies to evaluate the benefits and impacts of the 7-day AOT for planned and unplanned maintenance activities.
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As described in the Background section, the Diablo Canyon offsite and onsite power systems are highly reliable.
The 230 kV and 500 kV systems have been shown to provide rel1able offsite power sources for both units.
Regulatory Guide 1.155, Station Blackout, requires a
DG reliab1lity rate of 0.95 per demand.
As a result of many PGLE act1vities, the Diablo Canyon DGs have a reliability rate of greater than 99 percent.
This rate meets the guidance of Regulatory Guide 1.155 and 1s higher,than the average DG reliability.
k PGhE has evaluated the effects of 1ncreasing the AOT for the DGs using accepted risk and reliability analysis methods.
The study demonstrated that a 7-day AOT is both acceptable and practical for DCPP.
The study focused on an assessment of two issues:
(1) the appropriateness of a 7-day AOT for the purposes of unplanned ma1ntenance for the current five DG and future six DG configurations, and (2) the impact of a 7-day AOT for preplanned maintenance activities required by Technical Spec1fications.
PGhE was assisted in the evaluation by Hestinghouse Electric Corporation and Pickard, Lowe, and Garrick, Inc.
Th1s allowed outage time study was previously provided to the NRC in PGhE letter DCL-89-126, dated Hay ll, 1989.
Two probabi listic evaluation methods were used to assess the benefits and impacts of the proposed AOT revision.
Since PG&E had recently completed development of its plant spec1f1c PRA, it was used to assess absolute and 2679S/0069K
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relative r1sk values for the two 1ssues.
However, since the PRA calculates, time-average r1sk values, a second method was used, a
reliab1lity analys1s, to assess time-dependent r1sk involved in an AOT for unplanned maintenance which requ1res testing of the remaining DGs.
Such time-dependent effects are important in the evaluation of the affect of test1ng on the availability and reliability of the remaining DGs.
Such a time-dependent methodology has been recently reviewed and accepted by the NRC (Amendments 104 and 134 to the Brunswick Units 1 and 2
- licenses, March 27, 1989).
Both of these methods were used to evaluate a relative risk criter1on which was developed by Brookhaven National Laboratory (NUREG/CR-3082, "Probabi 11stic Approaches to LCO's and Surveillance Requirements for Standby Safety Systems,"
November 1982) and has been previously reviewed and accepted by the NRC for Brunswick.
This criterion defines a relative risk ratio that should be less than unity, that 1s, the risk level during the AOT 1s less than the risk level during the non-AOT period where all DGs are 1n their normal standby condition while the plant is in Modes 1
to 4.
The first method, referred to in this study as the probabilistic risk
- analys1s, made extensive use of the Diablo Canyon Probabilistic Risk Assessment (DCPRA) models developed for the DCPP Long Term Seismic Program (PG&E Letter DCL-88-260, dated October 28, 1988).
The DCPRA is a full scope Level 1 risk assessment which includes both internal and external initiating events.
In the study, use is made of the dom1nant accident sequence model to compute the impact of DG AOT changes on plant risk; risk is presented in terms of core damage frequency, and also relative risk.
The probabi listic risk analysis provided a means to assess the relative risk and absolute risk (core damage frequency) associated with a 3-day AOT and a 7-day AOT while accounting for both planned and unplanned maintenance.
Acceptability was demonstrated by obtaining small changes in absolute risk and maintaining a relative risk ratio less than unity.
Additionally, the PRA results trended consistently with the reliability analysis results.
The second method is referred to as the reliability analysis.
This reliab1lity analysis is compatible with the probabilistic risk analysis by basing the reliability analysis on the DCPRA DG fault tree models and plant specific data.
The DG fault trees 1n the reliability analysis have been extended beyond that typically modeled in PRA DG system fault trees to 1nclude diesel subsystems as well as support systems.
Thus, th1s reliability model with its DG fault trees is designed to be a stand-alone model.
In addition, the m1ssion times were representative of current regulatory requirements such as those included in the Station Blackout Rule.
The reliab111ty analys1s 1s similar to the Carolina Power
& L1ght Company's (CP&L's) Brunswick time dependent, phased-miss1on approach (CP&L Letter NLS-85-516, dated June 28, 1985).
Th1s approach has been previously approved by the NRC for Brunswick (License Amendments 104 and 134) and is based on NURfG/CR-3082.
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Both the PRA and reliab111ty approaches evaluated three cases for their impact on plant risk and reliability.
The three cases consider the current and future DG system configuration with five and six DGs, respectively, and the effect of d1fferent AOTs for planned and unplanned maintenance act1vities.
The base case considers the existing plant conf1guration with a 72-hour AOT on all DGs to perform unplanned maintenance.
Once every 18 months, dur1ng the refueling outage of one unit, planned maintenance on the swing DG occurs with the other unit at power.
The 10 day duration of the planned scheduled maintenance for the swing DG corresponds to recent operational experience at Diablo Canyon, where four outages of approximately 3-days each were required.
The second case is similar to the first except that the DGs are sub)ect to a 7-day AOT for unplanned maintenance.
Planned maintenance on the swing DG is also performed;
- however, since the AOT is longer, all the maintenance can now be performed within the 7-day AOT 1nstead of four 72-hour AOTs.
The third case considers the planned plant configuration with six DGs and a 7-day AOT.
Planned maintenance during power operation 1s no longer applicable since this maintenance can now be performed without affecting the other unit.
Results for these cases using both methods are shown in Table l.
Using a
relat1ve risk criterion, both of these methods confirm the acceptability of a 7-day AOT for the purposes of performing unplanned maintenance for both the five and s1x DG configurations (see Table l).
In particular, the relative risk ratios for all cases were determined to be significantly less than unity, that is, the risk level during the DG AOT was found to be significantly less than the risk level during the non-AOT period where all DGs are in a normal standby condition while the plant is in Hodes l to 4.
- Further, the PRA also demonstrated that there is negl1gible change in risk associated with a 7-day AOT to that of a 3-day AOT, and that there are slight quantitat1ve benefits in performing Technical Specification requ1red maintenance with a 7-day AOT.
The PRA analysis also determined that addition of the sixth diesel will have a reduction 1n risk over the life of the plant (see Table l).
In total, quantitative and qualitat1ve analyses confirm that the 7-day AOT, along w1th add1tion of the s1xth diesel by the fourth refueling outage of Unit 2, should improve overall DG system reliability and will provide both short term and long term quant1tative and qualitative benefits to the safe operation of the plant.
Based on the above evaluation, there is reasonable assurance that the health and safety of the public will not be adversely affected by the proposed 7-day AOT for both the current five DG and future six DG configurations.
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E.
NO SIGNIFICANT HAZARDS EVALUATION PGhE has evaluated the hazard considerat1ons involved w1th the proposed amendment focusing on the three standards set forth 1n 10 CFR 50.92(c) as quoted below:
"The Commission may make final determination, pursuant to the procedures 1n 50.91, that a proposed amendment to an operating license for a facility licensed under 50.21(b) or 50.22 or for a testing fac11ity involves no significant hazards consideration, if operation of the facility in accordance with the proposed amendment would not:
l.
Involve a sign1ficant 1ncrease in the probability or consequences of an accident previously evaluated; or 2.
Create the possibil1ty of a new or different kind of acc1dent from any accident previously evaluated; or 3.
Involve a sign1ficant reduction 1n a margin of safety."
The following evaluation is provided for the three categor1es of the no significant hazards consideration standards.
l.
Does the change involve a sign1ficant increase in the probability or consequences of an accident previously evaluated?
The D1ablo Canyon offsite and onsite power systems are highly reliable.
The 230 kV and 500 kV systems have been demonstrated to provide reliable offsite power sources for both units.
The DCPP DG reliability history 1ndicates that average reliability 1s higher than the requirements in Regulatory Guide l.l55, Station Blackout, and is higher than the industry average.
The risk and reliability evaluation determined that the probability of an accident previously evaluated does not significantly change by increasing the DG AOT from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days.
The relative risk evaluation demonstrated that the relat1ve r1sk rema1ned low with an increased AOT from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days because of the improved maintenance possible with the 7-day AOT and the avoidance of multiple 72-hour AOTs.
Increasing the DG AOT does not involve physical alteration of any plant equ1pment and does not affect analysis assumptions regarding functioning of required equ1pment des1gned to mitigate the consequences of accidents.
- Further, the severity of postulated acc1dents and resulting rad1ological effluent releases will not be affected by the 1ncreased AOT.
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Therefore, the proposed change does not involve a sign1ficant increase in the probability or consequences of an accident previously evaluated.
2.
Does the change create the possibility of a new or different kind of accident from any accident previously evaluated?
Extending the DG AOT from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days does not necessitate physical alterat1on of the plant or changes in parameters governing normal plant operat1on.
Thus, this change does not create the possibility of a new or different kind of accident from any accident previously evaluated for Diablo Canyon.
3.
Does the change 1nvolve a sign1ficant reduct1on 1n a margin of safety?
As discussed
- above, the risk and reliability evaluations determined that the change in core melt frequency for a 7-day AOT compared with a 72-hour AOT 1s 1nsignificant.
Therefore, this change does not result 1n a significant reduction in a margin of safety.
F.
NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION In conclus1on, based on the above evaluation, PGhE submits that the activities associated with this license amendment request sat1sfy the no significant hazards consideration standards of 10 CFR 50.92(C)
- and, accordingly, a no sign1fi cant hazards cons1deration find1ng is )ustified.
G.
ENVIRONMENTAL EVALUATION PGhE has evaluated the proposed change and determined that the change does not involve (1) a significant hazards consideration, (11) a significant change in the types or s1gnificant increase in the amounts of any effluents that may be released offsite, or (111) a significant increase in individual or cumulative occupational radiation exposure.
Accordingly, the proposed changes meet the el1gibility criter1on for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Therefore, pursuant to 10 CFR 51.22(b),
an environmental assessment of the proposed change is, not required.
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TABLE 1
ANALYTICALRESULTS FOR UNPLANNED AND PLANNED HAINTENANCE ACTIVITIES(i) n nn PRA n
1 (2) n 1
nn R
i i An i
n 1
nn
~rien Relative
~Ri"'r~n Relative
~)(3)
~A~'A~',
3-Day AOT/5 DGs 2.12E-04 (10 day Outage)(2) 2.08E-04 0.05 LOOP
7-Day AOT/5 DGs (7 day Outage)(2) 2.15E-04 2.12E-04 0.08 LOOP 2.35E-04 LOOP/ 1.10E-09 LOCA 0.08 0.10
/ATE 7-Day AOT/6 DGs (0 day)(>>
2.02E-04 2.02E-04 0.08 LOOP 2.00E-04 LOOP/ 7.43E-10 LOCA 0.05 0.13 (1)
The DCPRA analysis was performed for Unit 1
and the reliability analysis was performed for both Units.
(2)
Duration of outage for planned maintenance.
(3)
AOT Risk Level + Non-AOT Risk Level 2689S
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