ML20070P692
| ML20070P692 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/19/1991 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20070P695 | List: |
| References | |
| TAC-79969, ULNRC-2381, NUDOCS 9103280032 | |
| Download: ML20070P692 (23) | |
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3 March 19, 1991 United States Nuclear Regulatory Commission ATTN -Document Control Desk Mail Station Pl-137 Washington, D.C.
20555 ULNRC-2381 Gentlement TAC No. 79969 DOCKET NUMBER 50-483 CALLAWAY PLANT
-ENGINEERED SAFETY-FEATURES ACTUATION SYSTEM i
Union Electric, Company herewith transmits an application.for amendment to Facility Operating License.
No. NPF-30 for-the Callaway Plant.=
This amendment application includes revisions to Technical Specification Tables 3.3-1, 4.3-1,-3.3-3, and 4.3-2-and associated Bases <to extend the allowable
-i out-of-service: times-(AOTs) and surveillance test
- 1
'intervalsL STIs),forcthe analog channels of the
- Engineered (Safety-Features Actuation ~ System (ESFAS).
Extended AOTs are also requested for'the ESFAS actuation.
logic-and:actuationtrelays of the Solid State Protection System;(SSPS.LThese changes are similar in-nature to those previou) sly reviewed and approvedcfor-the Reactor Trip SystemE(RTS) via: References 1 and'2.
Editorial changes to Table 3.3-6 are also requested.
Changes are included for~the STI and AOT associated with the analog-channels for Functional Unit-6.d of-Tables 3.3-3':and 4.3-2,. Steam Generator Water-Level Low-Low-(for auxiliary feedwater: actuation) and Functional-Unit 7.b of TablesL3.3-3 and-4.3-2, RWST--Level Low-Low' Coincident with Safety Injection l(for automatic-switchover. to the containment s stp). The generic Westinghouse-Owners Group'-Technical-Specification' L.
Optimization-Program (WOG TOP) did not. analyze for the effects'on unavailability and: core damageLfrequency-
- associated.with the Environmental Allowance' Modifier (EAM). and Trip Time Delay (TTD) added to the steam generator level analog channel circuitry, as discussed in E
' References-6-8, nor did that program evaluate the= effects L
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A 1 associated with the RWST Level / automatic switchover function. Reference 5 demonstrates that the effects of the analog channel AOT and STI changes have a minimal impact on overall reliability and risk, based on the small relative contribution of analog channels in general to RTS/ESFAS unavailability. Changes for these Functional Units are discussed further in the attached safety
-evaluation.
The Callaway Plant On-Site Review Committee and the Nuclear Safety Review Board have reviewed this amendment application. Attachments 1 through 3 provide the Safety Evaluation, Significant Hazards Evaluation, and draft Technical Specification mark-ups, respectively, in support of this amendment request. This amendment-application-may result in a slight increase in the probability of core damage accidents over and above that previously evaluated in the FSAR; however, this small potential increase in accident probability has been 4
. accepted by the Staff and is insignificant when compared to the uncertainties in defining the core damage frequency.
Implementation of these Technical Specification changes will not endanger the health or safety of the general
-public. It has been determined that this amendment application does not involve a significant hazard consideration as determined per 10CFR50.92.
The following is a list of references used in this cover letter and in Attachment 1, Safety Evaluation, of this amendment application:
- 1. ULNRC-1174 dated 10-16-85 2.
Amendment No. 17 to Facility Operating License NPF-30-dated 9-8-86
- 3. USNRC letter from C.E.
Rossi to R.A. Newton dated 2-22-89 (NRC Safety Evaluation for WCAP-10271 Supplement 2 and Supplement 2, Revision 1) l 4.
USNRC letter from C.E.
Rossi to G.T.
Goering dated 4-30-90 (NRC Supplemental Safety Evaluation for WCAP-10271 Supplement 2, Revision 1)
- 5. Westinghouse Owners Group letter to NRC OG-90-38 dated 7-20-90 (transmitting WCAP-l 10271, Supplement 2, Revision 1-P-A (updated),
" Evaluation of Surveillance Frequencies and Out of Service Times for the Engineered Safety Features Actuation System")
6.
ULNRC-1822 dated 8-30-88
- 7. ULNRC-1905 dated 2-7-89 8.
Amendment No. 43 to Facility Operating License NPF-30 dated 4-14-89
.=.
-3
- 9. ULNRC-2196 dated 4-12-90
- 10. Amendment No. 57 to Facility operating Licenso NPF-30 dated 9-20-90 application, you have any questions on this amendment If please contact us.
Very truly yours,
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Donald F. Schnell
./32" GGY/ dis Attachments: 1 - Safety Evaluation 2 - Significant Hazards Evaluation 3 - Draft Technical Specification Mark-ups I
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i STATE OF MISSOURI )
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Alan C, Passwater, of lawful age, being first duly sworn upon oath says that he is Manager, Licensing and Fuels (Nuclear) for Union Electric Company; that he has read the foregoing document and knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do so; and
'that the facts therein stated are true and correct to the best of his knowledge, information and belief.
/ / /
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'cE M u v*d W By_
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Alan C.
Passwater Manager, Licensing and Fuels Nuclear
/N N' --- _da y SUBSCRIBED and sworn to before me this of 7 A L t d / -- -
1991.
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DAntlARA J. PrAFF NOTARY PUBLIC STATE Or Mir400Rt M-( COMMISSION EXPIRES Af RIL N.193
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Shaw,-Pittman, Potts & Trowbridge 12300 N.
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Cormah CFA,-Inc-,
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Gaithersburg, MD.20879 R.-C.
Knop Chief, Reactor Project Branch I U.S. Nuclear Regulatory Comminnion Region III 799 Roosevelt Road Glen F.llyn, Illinoin 60137 Bruce Bartlett Cal 1away Resident Offico U.S.
Nuclear Regulatory.Commionion RRill Stoodman, Minnouri 65077 M. D.
Lynch (2)
Office of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Comminolon 1 Whi te Flint, North, Malt Stop 33E21 11555 Rockville-Pike Rockvillo,.MD 20852 l Manager,' Electric Department Misoouri Public 'Scrvico Commission P.O.
Box 360-Jefforson City, MO 65102
~Ron Kucera Department of Natural Rnnources
-P.O.: Box 176 Jefferson City, MO 65102 i
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SAFETY _ EVALUATION _
Background
In response to growing concerne over the impact of current testing-and maintenance requirements on plant operation, particularly as related to instrumentation oystems, the Westinghouse Owners Group (WOG) initiated a program to develop a justification to be used to revise generic and plant-specific instrumentation technical specifications. Operating plants have experienced many inadvertent reactor trips and safeguards actuations during performance of instrumentation surveillances, causing unnecessary transients and challenges to safety systems.
Significant time and effort on the part of operating staffs have been devoted to performing, reviewing, documenting, and tracking the various surveillance activities, which in many-instances seemed unwarranted based on the high reliability of the equipment. Therefore, significant benefits for operating plants appeared to be achievable through revision of instrumentation test and maintenance requirements.
On February 3, 1983, the WOG submitted WCAP-10271, " Evaluation of Surveillance Frequencies and Out-of Service Times for the Reactor Protection. Instrumentation System" to the NRC as the first step in gaining approval of the Instrumentation Program, WCAP-10271 justifies revisions to plant-specific technical specifjcations.
The justification consists of the deterministic and numerical evaluation of-the effects of particular technical specification changes with consideration given to such things as safety,
_ equipment requirements, human factors, and operational impact.
The objective was to reach a balance in which safety and operability are ensured. The technical specification revisions.
evaluated were increased test and maintenance times, less frequent-surveillance, and testing in bypass.
'In July _1983, the NRC requested additional _ information from the WOG (letter from C.O.
Thomas to J.J.
Sheppard dated July 28, 1983). The WOG responded in October 1983 with Supplement 1 to WCAP-10271, which contained the additional information requested.
Specifically, Supplement _1 demonstrates the applicability of the justification contained in WCAP-10271 to the Reactor Trip System (RTS) for two, three, and four loop plants with either relay or solid state logic.' Additionally, this supplement extends the
_ evaluation to topics - not addressed in the original WCAP, such as
-the interdependence of surveillance intervals and hardware L
failure rates.
l References 1 and 2 revised the Callaway RTS Instrumentation Technical Specification Tables 3.3-1 and 4.3-1 to increase the l
allowable out-of' service time (AOT) for the RTS analog channels and to extend the surveillance test interval (STI) for the analog channel operational tests ( AcoTs). These changes were in accordance with WCAP-10271 and its Supplement 3, as per the MRC l
L
l Safety Evaluation Report (SER) dated February 21, 1985 which approved the following for RTS analog channels only:
a) Quarterly STIs on a staggered test basis b) 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to place an inoperable channel in a tripped mode c)11ncreased AOTs for test (4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) and maintenance
-(12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />), and d) testing in bypass This SER specifically stated that for analog channels shared by the RTS and Engineered' Safety Features Actuation System (ESPAS),
the -approved relaxations applied only to the RTS function.
In a letter dated July 24, 1985, from the NRC to h.D.
Butterfield, Chai rman of the WOG, comments were provided on the draft
" Guidelines for Preparing Submittals Requesting Revision of Reactor Protection System Technical Specifications." Enclosure 3 of that letter provided a broader relaxation of-the surveillance
-for' shared components, subject to proper annotation of the eurveillance requirements.
4
- On March.20, 1986, the WOG submitted WCAP-10271, supplement 2,
" Evaluation of Surveillance Frequencies and Out of Service Timen for the Engineered Safety Features Actuation System." On May 12, 1987,'the WOG submitted WCAP-10271, supplement 2, Revision.1.
L Supplement 2 and Supplement.2,- Revision.1 specifically demonstrate the applicability of the justification contained in WCAP-10271 to the ESFAS for two, three, and four loop plants-with either: relay or solid state systems.
In Appendix D of WCAP-10271, Supplement.2, Revision 1, the results for extending the A0Ts for testing and maintenance on the reactor--trip breakers and the logic cabinets-were presented.
On1 February 22, 1989, the NRC. issued their SER for WCAP-10271, Supplement 2 and Supplement 2, Revinion 1 (Reference 3). This.SER approved the above changes a) -Ed) for the ESFAS analog channels.
4 Staggered-testing was not required -for 'ESFAS analog. channels and
-the requirement was removed from the RTS analog _ channels. In L
addition, the-following changes were approved for the ESFAS I
- automatic actuation logic and actuation relays:
e) increasedEACT for.teeting (4-houroffor Solid State Protection System (SSPS) plants) f) increased ACT for maintenance (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> for both SSPS'and relay _ system plants) l The ESFAS functions approved in the Reference 3 SER were those presented in-Appendix Al of Reference 5. These functions are included in the Westinghouse Standard Technical Specifications
.(STS).
on-April 30, 1990, the NRC issued a Supplemental SER (SSER) on WCAP-10271, Supplement-2, Revision 1 (Reference-4). This SSER
. approved the=AOT and STI extensions for the non-STS ESFAS functions that were included in Appendix A2 of Reference 5. The SSER also approved the above changes e) and () for the RTS-actuation logic. No changes were approved for the test-and maintenance A0Ts for the reactor trip breakers.
With the issuance of References 3 and 4, the relaxations for thn analog channels of the'RTS and ESFAS are now the same. The A0Ts
=for test and maintenance of RTS and ESFAS actuation logic are also now the same.
PEOPosed ShAn_gea This amendment application and Amendment No. 43 to the Callaway
~ Facility operating hicense (Reference-8) add new action statements to tables in Section 3/4.3 of the Technical Specifications.
In order to avoid confusion, the action statement numbering is being revised to el-iminate the duplicate use of action statement numbers (e.g.,
Action Statement 27(a) becomes Action Statement 35).
The matrix below provides-a listing of the new action statements, the changes from the nun,Lering used in Amendment No. 43, and a change to avoid the duplicate use of number 27 in Tables 3.3-3 and 3.3-6.
The action statement references given in the Technical Specifications have been changed to correspond to the following action statement numbers:
Table 3.3-1 Action Statement 31 - new number Table _3_,3,3 Action-Statement 32 - new number l
Action Statement 33 - new number Action Statement 34 - new number Action Statement 35 - Revised from number 27(a) in Amendment No. 43 Action Statement 36 - Revised from number 27(b) in Amendment No. 43 Action Statement 37 - Revised-from number 27(c) in Amendment No. 43 T1ble.3.3-6 Action Statement 38 - Revised from number 27 to avoid - duplication wi th Table 3.3-3
... t These numbering changes are purely administrative in nature and do.not represent any technical change to the manner in which the Technical Specifications are applied.
They are intended to make the Technical Specifications more user-friendly, Given'the above background, this amendment application proposes to revise Technical Specification Tables 3.3-1, 4.3-1, 3.3-3, 4.3-2, and 3.3-6 as follows:
1.
Tables 3.3-1 and 4.3-1, Functional Unit 14 Notes 1 and 15 are deleted from Tables 3.3-1 and 4.3-1, re spec tivel y.,
for Functional Unit 14. These notes deal with channels that are shared by both the RTS and ESFAS; however, Functional Unit 14 of Tables 3.3-1 and 4.3-1 (RCP Undervoltage Reactor Trip) is unrelated to Functional Units 6.f erl 8 of Tables 3.3-3 and 4.3-2 (Loss of Offsite Power-Start Turbine Driven Auxiliary Feedwater Pump and Loss of Power). The former deals with'13.8'kV power supplies (buses PA01 and PA02) whereas the latter deal with 4.16 kV power supplica (buses NB01 and NB02). These notes were inadvertently added to Functional Unit 14 via References 1 and 2.
It is noted that Table 3.6-9 of Reference 5 analyzed for
. unavailability effects on auxiliary feedwater pump start associated with RCP bus undervoltage and that this functional relationship is included in the standard Technical Specifications; however, this design does not apply to Callaway.
2.
Table 3.3-1, Functional Units 17 and 20 Per Reference 4 and-Appendix D to Reference 5, test and maintenance AOTs for SSPS logic cabinets are extended.
'New Action Statement 31 provides for'these test and
. maintenance AOT extensions. The extended test AOT.-for
-the RTS logic surveillance includes-bypassing the associated reactor trip breaker (1.'o.,
racking in the bypass breaker) for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Since Functional Unit 17 is, implemented in the SSPS logic, given that the action statement. changes on page D-7 of Reference 5 were approved infReference 4, this-new Action Statement 31 applies to both the RTS safety injection input from ESF as well_as the automatic trip and interlock logic.
_ Current Action Statement 9 will _ apply only _ to the reactor trip-breakers, Functional Uni t 19, and has been clarified as such.
3.
Tables 3.3-1 and 4.3-1 With the approval of the ESFAS changes discussed in References 3-5, the AOT and STI for RTS and ESFAS analog channels are now the same. Note 1 of Table 3.3-1 and Note 15 of Table 4.3-1 have been revised appropriately.
l
--5 4.
Table 4.3-1 Per References 3 and 5, staggered testing is no longer required for RTS analog channels.
Note 14 has been deleted appropriately.
5.
Table 3.3-3 Per Reference 3 (which approved-changes for ESFAS functions in the Westinghouse Standard Technical Specifications (STS), as given in Appendix Al of Reference 5, i.e.,
Callaway Functional Units 1.c, 1.d, 2.c, and 3.b.3) ) and Reference 4 (which approved changes for non-STS ESFAS functions, as given in Appendix A2 of Reference 5, i.e.,
Callaway Functional Units 1.e, 4.c, 4.d, 4.e, 5.b, and 6.d), AOTs for ESFAS analog. channels are extended. Revieed Ac tion Statement
~16 provides for an extended AOT (from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to A hours) for surveillance testing of analog channels of Functional Units 2.c and 3 b.3). New Action Statement 33 provides for 6. hours to place an inoperable channel in the tripped mode as well. as an extended AOT ( f rom 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />s-to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) for surveillance testing of analog channels of; Functional. Units 1.c, 1.d, 1.e, 4.c, 4.d, 4.e, 5.b, and 6.d (see item Il below). New Action Statement 32_provides similar AOT extensions for Functional Unit 7.b, as further discussed in item 12 below._ Current Action Statement 19 remains applicable to Functional Units 6.g, 8.a and 8..b-which are associated with the Balance-of-Plant ESFAS (BOP-ESEAS) and the Load Shedding and Emergency Load Sequencing (LSELS) systems. These systems were not included in the Reference 5 ana'.yses (see the discussion on ESFAS SER item 11.a-below).
6.
Table 3.3-3 Per Reference 3,-AOTs for the ESFAS automatic actuation
-logic and actuation relays in the SSPS are extended.
Revised Action Statement 14 provides for these test and maintenance'AOT extensions for Functional Units 1.b, 2.b, 3.a.2),-_3.b'.2), and_7 a. New Action Statement 34 provides the same. tent and maintenance AOT e ' 9nsions -for Functional Units 4.b and 6 b.
Current
.A.
on Statement 21-remains applicable to Functional Un__ 6.c which is associated with the BOP-ESFAS, not included in the Reference 5 analyses (see the discussion
-on ESFAS SER-item 1.a below). Revised. Action Statement-27, applicable only to Functional' Unit 5.a, also provides-for-the above test and maintenance AOT
-extensions.
The' requirement to be in at least HOT STANDBY within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> in revised Action Statements 14 and 27 as well as in new Action Statements 31 and 34 reflects the approved 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> maintenance AOT.
7.
Table 3.3-3, Functional Unit 6.g The de-energination of one train of BOP-ESFAS actuation logic and actuation relays will render two of the four main feedwater pump pressure switches inoperable. This situation impacts both Functional Units 6.c and 6.g.
Action Statement 21 for Functional Unit 6.c provides for operation with an AOT with one BOP-ESFAS logic train de-energized.
However, operation is not permitted under current Action Statement 19 for Functional Uni t 6.g with two pressure switches inoperable.
As such, Specification 3.0.3 would be entered.
Therefore, for clarification, a new ***
footnote has been added that states that Action Statement 21 applies to both Functional Units 6.c and 6.g in thi s situation (i.e., applies to both the BOP-ESFAS logic and to the AFW start on trip of both main feedwater pumps if one train of BOP-ESFAS logic is de-energized).
8.
Table 3.3-3, Action Statement 22 Action Statement 22 is clarified regarding the sequence of actions in a manner similar to Action Statements 1, 10, and 18, 9.
Table 3.3-3, Action Stntement 35 Action Statement 35 (previously 27(a) in Reference 8) is grammatically corrected such that the plurality of the object of_a_ prepositional phrase matches that of the subject being described (i.e.,
"... channels ir the affected protection sets..
").
This is consistent with Action Statements 7 and 36 (previously 27(b) in Reference 8) and represents the changes as requested in Reference 7.
10.
Table 4.3-2
-As discussed in the background for item 5 above, quarterly STis for analog channel operational testing (ACOT) were approved in References 3-5. Therefore, the STI for Functional Units 1.c, 1.d, 1.e, 2.c, 3.b.3),
4.c, 4.d, 4.e, 5 b, 6.d and 7.b (see item 11 below),
and 11.a is changed from monthly to quarterly.
11.
Tables 3.3-3 and 4.3-2, Functional Units 6.d and 7.b nOT extensions for surveillance testing and STI extensions for the ACOT of analog channels of Functional Unit 7.b, RWST Level Low-Low Coincident with Safety Injection (for Automatic Switchover to Containment Sump), were not approved as a part of the generic Technical Specification Optimization Program (TOP) discuased in References 3-5 nor did the generic l
program consider the effects of the Environmental Allowance Modifier (EAM) and Trip Time Delay (TTD) added to the steam generator level analog channel circuitry as discussed in References 6-8.
A separate evaluation was petformed that demountraten that the unavailability and risk results presented in Reference 5 for the AOT and STI increases analyzed therein are indicative of, or conservative with roepect to, the results expected for increasing the AOT and STI of the analog channels of Functional Unit 7 b.
Reference 5 demonstrates that the effects of the analog channel changes have a minimal impact on overall reliability and risk, based on the small relative contribution of analog channels in general to RTS/ESFAS unavailability.
The unavailability of the RWST low-low-1 (2 out of 4) signal would be expected to be on the same order of magnitude as that for the OT-Delta T,
OP-Delta T, and liigh Pressurizer Pressure reactor trip signals due to similarities in logic coincidence and circuit cards in the instrument loops.
Table 4.4-3 of WCAP-10271-P-A establishes this value as IE-4.
Thin approximate unavailability for the RWST low-low-l signal is generally an order of magnitude lean than the Case 1 S1 signal unavailabilities given om Table 3.6-6 of Reference S.
Therefore, this separate evaluation concludes that the AOT and K'I extensions for Functional Unit 7.b should be acceptable since the safety injection signal (SIS) unavai labili ty, increases to which were reviewed and accepted by the Staff, would be expected to dominate the automatic switchover signal unavailability (i.e.,
slight increases in RWST level signal unavailability would be outweighed by the SIS unavailability whose coincidence is necessary for automatic swltchever)
In addition to the generic conclusions regarding the relative insignificance of the analog channels to ESFAS unavailability, the AOT and STI extensions for Functional Unit 6.d are supported by the following considerations:
1)
An discussed in Section 3.4.2 of WCAP-11883, submitted via Reference 6 for the EAM/TTD modification, and as described in Sec tion 5. 5 < >f the RTD Bypass hicensing Report attached to Reference 9 (re: Delta-T input to TTD), the mean time between failure (MTBF) values for the 7300 printed circuit cards used in these modifications are sufficiently high that the reliability of the protection systems is not degraded.
11)
Although the TTD timer modulen are unique to Functional Unit 6.d (see also Functional Uni t 13. c of Table 3.3-3),
they are disabled above 20% rated thermal power as dincunned in Reference 6.
~
. 111) Extended AOTs and STIs were approved for RTS Functional Unit 13 of Tables 3.3-1 and 4.3-1, Steam Generator Water Level Low-Low, in References 2 and 8.
Since these level channels are common to both RTS and ESFAS, consistent AOTs and STIs are desirable. See the discussion of RTS SER item-2.d below.
32.
Table 3.3-3, Functional Uni t 7.b New Action Statement 32 provides for 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to place an inoperable channel in the-tripped modo as well as an extended AOT (from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) for surveillance testing of analog channels of Functional Unit 7.b, if the channel is inoperable for any reason other than i:
surveillance testing. The inoperable channel must be restored to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or the plant must be shut down. If the channel is inoperable because it is being tested, - the channel may be tripoed
- for up_to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for the surveillance testing. Current Action Statement 16 does not_ apply to Functional Unit 7~.b since testing or operation-in bypass, other than as discussed-in response to RTS SER item 2.c below, is not applicable to the RWST level channels due to the absence of bypass indication in the control room. Prior surveillance testing of these normally de-energized, energize-to-actuate channels has been performed with the tested channel's bistable in the tripped condition.
This new Action Statement would limit the duration that an RWST level channel-could be tripped, due to its being inoperable or for testing, in order to' limit the probability for automatic _switchover to an empty containment cump upon receipt of an inadvertent safety injection signal (SIS) coincident with a single f ailure
-of another iUST level channel. This sequence of events, as'shown in FSAR F.igure 7.6-3, would start.the RHR pumps, open the containment sump RHR suction valves and, after meeting the. sump suction valve open position interlock-the RWST RHR: suction valves would close. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> restoration-time for an inoperable channel is
-consistent with that given in other Technical Specifications affecting RHR operability, e.g.,
3.5.2 for one ECCS train inoperable and 3.8.l.1 for one diesel generator inoperable.
13.
BASES 13/4.3.1 and 3/4.3.2 References 3-5 were added to the BASES with regard to ESFAS surveillance intervals and allowod outage _ times.
A discussion of analog channel bypass-testing was also added for clarification, consistent with the discussion of RTS SER item 2.c below.
I
--9 14~
Table 3.3-6 7
Action Stater.ent 27 is renumbered to 38 an discussed above.
RTS and ESFAS SER Conditions The proposed changes above are consis,ent with the NRC Staff letters cited as References 3 and 4. The Staff..has stated that approval of these changes is contingent upon confirmation that certain conditions are met. Although WCAP-102?1 Supplement 2 and Supplement 2, Revision 1 apply to the ESFAS instrumentation, it is:our-' interpretation that conditions imposed in tho SER for RTS instrumentation (WCAP-10271 and its Supplement 1) ahall *190 be applied to the ESFAS where appropriate. Our responses to these SER conditions are provided below.
a._SER Condition - Confirm the applicability of the veneric-analyses to the plant.
Response - The methodo_ logy of WCAP-10271 and its supp-lements was applied to specific RTS ar.d ESFAS functions implemented via the Westinghouse Solid State Protection _ System (SSPS).
At Callaway Plant, selected ESFAS functions are imple-mented via plant-specific features, such as the BOP
-ESFAS or-the Load Shedding _and;2mergency Load Sequencing (LSELS)-system. These syntoms are included on Technical' Specification: Tables 3.3-3 and f.3-2.
A review was performed _to assure that the functions used ' in the generic-analysis' auri the empicyment of the SSPS to perform ESFAS' functions, as _ described in the generic analysis, are applicable = to - the Callaway de-t sign _ Based-on'this review, Action Statemence and -STIs for the following _ Functional ~ Units in Tables 3.3 und 4.3-2 have not been changed:
(1) _ Functional -Unit-3.c- (Containment Purge I_so-lation) - Implemented via th9 BOP ESFAS, (2)' Functional' Unit 6.(Auxiliary-Feedwater) -
. Most of these sub-functions are implemented
.via the BOP ESFAS. Therefore, no changee are requested to Functionar Units 6.c, 6.f, 6.q, and 6.h. Manual functions are not affected by the WOG program, tnus Functional Unit 6.a is unchanged. Functionni Units 6.b and 6.d are changed an described above-. Functional Unit l'
l
l 10 -
6.e, Saf-ty injection, in changed by virtuo of its Functional Uni ta 1 c, 1.d, and 1.n being changed.
(3) Functional Unit 8 (1,onn of Power)
Not eval-unted in Reference 5.
(4) Functional Unit 9 (Control Room Isolation)
Implemented via the BOP ESFAS.
(5) Functionn! Unit 10 (Solid State Load Sequon-cer) - Hot evaluated in Reference 5.
A review was performed of the impact of extending the AOTs for thoso SSPS functions (i.e.,
steam generntor level low-low, phaue A containmer.t inolation, anfety injection, and SSPS logic) which nrovide input to plant-specific design feat.tres ruch an BOP ESFAS'. Imp-lementation of the following plant-npocilic functiann ic affected by any ch4nge in nignal availability to or from the BOP ESFAS:
(a) containment purge laolation (Fuactional Unit 3.c)
(b) auxiliary foodwater initiation (Functional Unit 6.d)
(c) control room ventilation inoltation (Functional Unit 9)
No changen are proposed to the Technical Speci fi c a tion requirements for the BOP ESFAS actuation logic and relaya (i.e.,
no changes are proposed for Functional Unite 3.c.3),
6.c, or 9.c) and the unavailabi'ity of the BOP ESFAS itself remaina unchanged. For the above functione (a) through (c), overal1 function unavaila-bility in made up of two neparate componento repro-senting SSPS unavailability and BOP ESFAS unavailabil-ity, the latter remaining unchanged. An reported in Tables 3,6-6 and 3.6-9 of Reference 5, typical unavailabilities for safety injection and auxiliary feedwater pump start increased by a factor of 3 to 6 Given that the BOP ESFAr unavailability doen not change, the overall. function unava31 ability increase would be bounded by the factor of 3 to 6 increase in SSPS unavailability, regardless of what value in as-nigned to the BOP ESEAS unavailability (typical value is 5E-04). Similar conclusions can also be drawn for Functional Unita 4 and 5 which are implemented via the Main Steam / Main Feedwater Inolation Actuation System.
Therefore, the overall impact of the changen in SSPS unavailabili ty resulting from the generic technicnl specification changes on the affected plant-npecific ESFAS functions remainn within the boundn of the generic anal yr> l n.
l l
1
- b. M 1Lb sti_ tion - Confi cu that any increase in instru-ent dt. ct due to the eMonded STIn is properly 4
a :cl oitar, for in the sotpoint cal..ilation methodology.
Benponse - J.R.
implemcated a program to evaluate set-poinc drift if RTS channels in accordance with the commituart in Reference 1.
Hased on this program, the values acod in the setpoint methodology properly account for RTS channel drift associated with the ex-tended STIs. For those ESEAS channels with extended STIs herein, a review of "as found" and "as left" data for each affected channel will be collected over a one yes" period after quarterly testing as begun. If nec-escary, estpoints and allowable values will be chanered if this data indicates r. need to do so. Pased on our experience to date, we do not foresee thi s beinct the case.
2 RTS SER Conditions (February 23, 1985)-
a, SER_Conditio11 - The NRC Staff stated in the RTS SED,.
datrd Febrtinry 21, 1985, that appi "4 of an increase in STI for tao analog channel operatdw al tests from once per not th to once per quarter 10 continq' nt upr n performance of the testing on 9 staggers 0 tba; basi:
Response - In the ESFAS SER, this provision was not required for ESFAS channels and the requirement was ro.noved f rom the RTS channels. The propoaei changes remove the ti caggered teshing requirement from the RTS analog channel operational tests.
b.
GEjLCondj tion - The S taf f ented in the RTS SER that al; proval of items rolated to extending STIs in contin-gent upon procedures being in placn to require evalua-t.on of RTS channel failures for ccnmon cause and to re. qui re additional testing if necessary.
Regponse - As stated in Reference 1, U. E., has imple-mented procedures to evaluate failures of RTS channels wi th qua r te r t y ACOTs for cammon cause. If common cause failuree are found, ndditional testing is required.
These procedures wil.1 now be npplied to both the RTS and RSFAS - cha.nnele vi th qt s rtei1y ACOTs.
c.
EjER_Condit;.1pfA - The NAC Staff stated in the RTS SER that approval of routinc channel testing in a bypassed ocndition is contingnat upon the capabi]ity of the RTS design to allos such t asting wi thout lifting leads or inst alli ng temporary jumpers.
Response - With the exception of the containment p r e ssu re (High-3) enannels (see Actica Statement 16)
.for conte.inment spiay actuation and phase B contain-ment loolation, Cn11away does not hav>e the capability to perfortt survelilance te s ti ng on a routine basis
12 -
with an analog instrumentation channel in a bypacned condition. Thorofore, the proponed changen to the ESFAS Technical Specificationn do not provide for the routine testing of channelt
'n bypass when the une of jumpero or lifted lesds is requiren. Uew Actic:'
Statementn 32 and 33 have been added t.0 Table J.3-3 to allow up to a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> bypass of an inoperable channel in order to perform nutveillance tenting of other channelo in the enmo functional unit. With regntd to existiry Action Statement 19 and to new Action Statements 32 nnd 33 for ESEAS, as well as to Action Statementn 2 and 6 for RTS, the testisq. in bypann allowance in based on an interpretation that this applien to cases where the b panned condition in the ntate when a failed channel enn 3
be taken out of the test mode (in which a channel trip was forced on the protection nyntem) nnd returned to operntion.
Due to the failed nature of the channel, the channni cannot be assumed to be operable and 18, therefore, connic'ered to be in a state of bypans when the channel failure 13 such that itn bietable in not tripped.
d.
SER,Condi_. tion - The Staff stated in the RTS SER that for channela which provide dual inputs to other safety-related systems, such as ESFAS, the approval of items that extend STIn and ACTS applien only to the RTS function.
Response - The extenniono now approved for the ESFAS analog channels are the name an for RTS. Therefore, Tablem 3.3-1 and 4.3-1 have been revised accordingly, ne discuened above.
- e. SER_ Condition - Same nn ESEAS SER Condition 1.b above.
Respojjne - Same renponne nn provided for ESFAS SER Condition 1.b above.
3.
SSER Conditions (April 30, 1990):
n-.SSb Condi. tion - Same as ESFAS SER Condition 1.n above.
Response - Same responne nn provided for ESFAS SER Condition 1.n above.
Responae - Same reepont-na ptuvided for ESFAS SER Condition 1.b above.
Ev_n lu_n tion The extension of AOTs and STIs for the ESFAS analog channels and AOTs for the actuation logic and relnyn may result in a oljght i
inerenne in the probability of core damnge accidento over and above that previously evalunted in the FSAR.
Implementation of the proposed changes may result in a r.nnli increase in ESFAS unavailabili ty which could manifest j tnelf in
- slight increase in core damage frequency (CDF).
This small potential increaso in accident probability has boon accepted by the Staff (References 3 and 4) when compared to the range of uncertainty in the CDF nnd to the net bonofits to be gained by these changes.
I In WCAP-10271 and its supplomonte, the WOG evalunted the impact 1
of the proposed STI and AOT changes on CDF and public rink. The l
NRC Staff concluded in i ts evaluntion of the WOG analynes that nn overall upper bound of the CDF increase due to the proposed ST1/A0T changes is lose than 6 percent for Westingnouse l'WRs. The Staff also concluded that actual CDF increases for individuni plants are expected to be substantially lene than 6 percent. The Staff considered this CDF incree,se to be small when compared to the range of uncertainty in the CDF anntyses and, therefore, acceptable.
Additiona:
the Staff concluded that a staggered test strategy need not be implemented for ESFAS analog chnnnel tenting and in no longer required for RTS analog channel tenting. This conclusion was baned upon the small relativo contribution of tho j
analog channels'to RTS/ESFAS unavailability, process paramotor signal diversity, and normal operationni testing sequencing. 11.
addition, the commitmont to evaluato channel failuren for common cause will address this issue.
The change to add new Action Statement 32 to Functional Unit 7.b of Table 3.3-3 will reduce the probability _for an automatic j
switchover to an empty containment pump in the event that, while an RWST levol_ channel were inoperable or were being tested with its bistable tripped, an inadvertent safety injection nignal occurred along with a single-failure of a second_RWST level-j channel. ~ These channels do not have the design for operation or testina'in bypass needed for Action Statement 16 to be' applicable.
These channels do not have a bypass switch position-nor would control room indiention be given for any temporary bypass (e.g.,
by pulling cards)..
In changing to new Action Statement 32, there-is now a limit on the duration that a channel could be
-inoperable or be in test with its bistable tripped.
L The possibility of an accident or mallunction of a -different type than any previously evaluate ( in Uin FSLR-l' not created.
i The proposed changes ao not involve any design changes or hardwaro' modifications. Increannd STIs and A0Tn and allowed testing in the bypass mode will be accomp1!nhed with the prosent plant configuration. With the exception of the containment prensure_High-3 channeln, Callaway doon not have the capability
- to porform survn111ance testing. on a routine basis with an analog instrumentation channel.in a bypassed condition. In the future, should we elect to provido additional bypass testing capabilities, plant modifications will be required. Any future bypass testing modification would be accomplished without I
relianco upon lifted lends or jumporn and ntatus indication would l
be provided_to plant operators in the control room.
. j There will be no reduction in the margin of safety as defined in the basis vf any technical specification. The proposed changes do
- not alter the manner.in which safety limits, limiting safety system eettings, or limiting conditions for operation are determined. The impact of reduced testing, other than as described above, is to allow a longer time interval over which instrument uncertainties (e.g., drif t) may act. The commitment to monitor the effects of drif t addresses this concern, as discu'ssed in WCAP-10271, increasing the STI for the ESFAS instrumentation minimizes the potential number of inadvertent ESFAS actuations and reactor trips during surveillance testing.
Less frequent surveillance testing has been estimated by Westinghouse to result in 0.5 fewer inadvertent reactor trips, por unit, per year. Also, increasing the surveillance interval enhances the operational effectiveness of plant personnel. The amount of time plant personnel spend performing surveillance testing will be. reduced. This allows manpower to be used for 1
other tasks, such as preventive maintenance. The increased AOTs have been shown to result in fewer human factor errors, since more time is allowed to perform the needed actions.
In conclusion, there may be a slight increase jn the probability of core damage accidents over and above that previously evaluated in.the FSAR; however, any potential increase would be minimal when compared to the uncertainty ranges involved and has been accepted by the Staff.-The possibility for an accident or malfunction of a different type than any previously evaluated in the FSAR is not created. There will be no reduction in the margin of safety as defined in the basis of any technical specification.
The proposed revisions will reduce the number of ESFAS ac%ations and reactor trips and will allow better management of resou;ces to maintain the plant. Additional changes of an editorial or clarification nature have been proposed as discussed-in the f.X9E9. sed C_hanges section above (i.e.,
changen 1, 7, 0,~9. and 14).
i Based on the NRC evaluations of WCAP-10271 and its supplements
=and-the discussion of'the various SER conditions above, there is
, reasonable assurance that the proposed changes will not adversely affect or endanger the health or safety of the-general public.
J ULNRC-2381 ATTACilMENT 2 SIGNIFICANT !!AZARDS EVALUATION FOR ESPAS OPTIMIZATION
'ilG!11 FICA!1T. IIAZARDS EVAhUATIO!1 This amendment application includen revinionn to Technical Specification Tablen 3,3-1, 4.3-1, 3.3-3, 4.3-2, and 3.3-6 to extend the allowabin out-of-norvice timen (AUTn) and nurveillance tent intervals (STIn) for the annlog channeln of the Engineered Safety Featuren Actuntion System (ESFAS). Extended AOTn for the ESFAS actuation logic and actuation telnyn in the Solid State Protection System (SSPS) are also requented. In addition, changen of an editorial or cinrifiention nature have also been proponed.
Union Electric han reviewed the requirementn of 10CER50.92 nn they relate to the proponed Reactor Trip Syntom (RTS) nnd ESFAS technical rpecification changen for Callawny Plant. nnd hes determined that no significant hazard connideration in involved.
The proponed changen do not involve n nignificant haznrdn consideration becnune opnration of Callawny Plant in accotd9nce with thene chnngen would nott (1)
Involve n nignificant inerenne in the probabi11t.y or consequencen of an accident previounly evtlunted. The determination that the renuito of the proposed changen are acceptable wns establinhed in the 14RC Saf ety Evnlu-ntion Report (SER) and Supplemental SER (SSER) prepared for WCAP-10271 Supplement 2 and WCAI-10271 Supplement 2, Movision 1 (innued by lettern dated Febtuary 22, 1989 and April 30, 1990)
Implementntion of the proponed chnngen in expected to renult in an innignificant isnpnet on total ESFAS unnvnilability. Thin impact, which in primnrily due to lens frequent nurveillance, mny tenult in a nmall increnne (lenn than 6 percent) in core damage frequency (CDF).
The valuen determined by the Wentinghoune Ownern Group (WOG) nnd presented in the above WCAP for the increnne in CDF were verified by Brookhaven 11ntional haboratory na part of an audit and nennitivity annlynen for the 14RC Staff.
Bnned on the omnlI value of the pot.ential increnne compared to the range of uncertainty in the CDF, the impact van connidered to be acceptable.
Applicability of these conclunions to Callawny has been verified through n pinnt-npecific review and implementation of the generic analysin resultn in accordnnce with the 11RC SER nnd SSER conditione.
Additionally, the 11RC Staf f concluded that a staggeted tent strategy need not be implemented for ESFAS annlog channel testing and in no longer required for RTS nnnlog channel tenting. This conclunion was based upon the emn11 relative contribution of the annjog channeln to RTS/ESFAS unnvailnbility, procens parameter nignal di-versity, and normn1 operational tent sequencing. In add-iLion, a commitment made to evnlunto channel failuren for common enure will addrenn thin innue.
2-1 4
The new Action Stateinent 32 for Functional Unit 7.b of Table 3.3-3, Automatic Switchover to Cont.ainment Sump on RWST j
Level Low-Low Coincident with Safety Injection, reflects current' plant design and testing practice. It alno limits
- the probability for an automatic switchover transient to an empty containment sump for a scenario involving a tripped RWST level channel, duo to its being inoperable or being tested with its bistable tripped, followed by an inadvertent safety injection signal and a single f ailure of a seccad RWST level channel.
(2)
Create the possibility of a new or different kind of accident from any previously analyzed. The proposed changes will not result in physical alteration to any plant system nor will thoro be a change in th3 method by which any safety-related plant system performs its safety function.
(3)
Involve a significant reduction in a margin of safety. The proposed changes do not alter the manner in which safety limits, limiting safety system settings, or 11miting conditions for operation are determined. The impact of reduced testing, other than as_ addressed above, is to allow a longer time interval over which instrument uncertainties (e.g., drift) may act. The commitment to monitor the offects
--of drift will address this concern. Impicmentation of the proposed changes is expected to result in an overall improvement in.sofety, as follows:
- a. Reduced testing will result i n fewer inadvert-ent reactor trips, loss frequent actuation of ESFAS con.,)onents, and less frequent distraction of operations personnel.
b.
Improvements in the.offectivonosa of the opor-ating staff in monitoring and controlling plant operation will be realized..This is due to loss frequent distraction of the operators and shift-supervisor to attend to instrumentation
- testino,
- c. Longer repair timos asnociated with increased 1
AOTs will lead to higher quality repairs and
' improved reliability.
l' Based on the above discussions, it has been determined that the proposed Technical Specification revisions do not involvo a significant increase in the probability or consequences of an
= accident previously evaluated; or create-the possibility of a-now or different kind of accident; or involve a significant reduction in a margin of safety. Therefore, thfs amendment application doen not' involve a significant hazards consideration.
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