ML20116M169
| ML20116M169 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/19/1992 |
| From: | Beck G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20116M173 | List: |
| References | |
| NUDOCS 9211200095 | |
| Download: ML20116M169 (37) | |
Text
- _ - _ _ _ __
i PIllLADELPIIIA ELECTRIC COMPANY NUCLEAR GROUP llEADQUARTERS 955 65 CilESTERBROOK BLVD.
WAYNE, PA 19087-5691 (215) 640&vo PeUCLLAR SERVICLS DLPARTMENT October 19, 1992 Docket Nos. 50-277 50-2'/8 License Nos. DPR-44 DPR-56 U. S. Nuclear Regulatory Commission ATTN Document Control Desk Washington, DC 20555
SUBJECT:
Peach Bottom Atomic Power Station, Units 2 and 3 Technical Specifications Change Request (TSCR) 92-04
REFERENCE:
TSCR 92-03, G. J. Beck to USNRC, Sept. 28, 1992 Gentlemen:
Philadelphia Electric Company is submitting Technical Specifications Change Request (TSCR) No. 92-04, in accordance with 10 CFR 50.99, requesting an amendment to the Technical Specifications (TS) (Appendix A) of Operating License Nos. DPR-44 and DPR-56. Information supporting this Change Request is contained in Attachment 1 to this letter, and the proposed replacemant pages are contained in Attachment 2.
Tiis submittal requests changes to TS surveillance intervals to facilitate a change in the Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, refueling cycles from 18 months to 24 months. The 24 month refueling cycle will require a change from the current 18 month TS surveillance testing interval (i.e., a maximum of 22.5 months accounting for the allowable grace period) to a 24 month testing interval (i.e., a maximum of 30 months ,
accounting for the allowable grace period). These TS changes were evaluated in accer.:ance with the guidance provided in NRC Generic Letter 91-04, changes in fechnical Specification 18003'J gpagggg g68g;7
[g i t e
a
- . - . - - . . - - -~. - - - . ..-- - - - - _ . ~. -
, , l, U. S. Nuclear Regulatory Commission October 19, 1992 Document Control Desk Page 2 t
i Surveillance Intervals to Accommodate a 24-Month Fuel Cycle,"
dated April 2, 1991, and are being proposed accordingly.
As discussed in our letter dated rebruary 11, 1992, this is !
the third of three Change Requests being submitted to the NRC to support the current change to 24 month refueling cycles at PBAPS, Units 2 and 3. This Change Hoquest involves a proposed change to the TS surveillance intervals for instrument calibration TS line items and and a change to the definition of refuel cycle and operating cycle.
Certain of the evaluations included in this Change Request relate to specific items in the TS tables and text for which no change to the text is required. The TS surveillance interval for theso-items is delineated by " operating cycle" or " refuel outage" in the TS tables (i.e., at least once per 18 months as defined in the definition section of TS). The change to this definition is proposed in this Change Request. Accordingly, we request that the NRC review and issue the changes when the NRC has approved all of TS changes proposed in this and the previous Change Request. We request that all approved TS changes associated with j
the change to 24 month refueling cycles for PBAPS, Units 2 and 3, requested in the second and third Change Requests, be issued by February 28, 1993. Also, we request that the approved TS changes be effective 30 days after issuance of the Amendments.
If you have any questions regarding this matter, please contact us.
Very truly yours, G. J. Beck, Manager Licensing Section 1
Enclosures:
Affidavit, Attachment 1, Attachment 2 cc: T. T. Martin, Administrator, Region I, USNRC J. J. Lyash, USNRC Senior Resident Inspector, PBAPS W. P. Dornsife Commonwealth of Pennsylvania ,
9 n.,---,,n,-+-.-.-,,c,,-a,,_--.--,,.n-,,,,-,..., nn,,---..-~,-,,,~,.. --n--,-- .,,n.n,,--n.,n,-c,,., ann _ n-n a, m - , ,,m-we e,,,+.e,,,-,~-
i COMMONWEALTil OF PENNSYLVANIA:
! Ss.
COUNTY OF CHESTER G. R. Rainey, being first duly sworn, deposes and says:
That he is Vice President of Philadelphia Electric Cornpany; the Applicant herein; that he has read the attached Technical Specifications Change Request (Number 42-04) for Peach Bottom Facility Operating Licenses DPR-44 and DPR-56, and knows the contents thereof; and that the statements and matters set f orth therein are true and correct to the best of his-knowledge, information and belief.
/ cvs f s./. j Vice President Subscribed and sworn to before me this /['hL day 4 of 8 1992.
TM /
-fLG -
Notary Public tMarat Seal Ocives A. CWan.retary PJAc 7"t'iw.Twp-, CNMeer CcuW
. L*/Wd.smEures#i24 f095
l ATTACHMENT l' l PEACH DOTTOM ATOMIC POWER STATION '
UNITS-2 AND 3 Docket Nos. 50-277 50-278 License Hos. DPR-44 DPR-56 TFCHNICAL SPECIFICATION CHANGE REQUEST 92-04
" Change to the Frequency of Instrument Survo111ance Tests" Supporting Information for Changes-33 Pagee i
r 6
- , + y- . e - - . ..y .. , . . , - ,~ y,,..,,,....,...,,,._,.u,., .
-.,..gy,-, , yi...-. _, - ,. , y,-,-._.p.,. .7.,..
Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 Philadelphia Electric Company (PEco), Licensee under Facility Operating Licenses DPR-44 and DPR-56 for the Peach Bottom Atomic Power Station (PBAPS) Unit No. 2 and Unit No. 3, respectively, requests that the Technical Specifications contained in Appendix A to the Operating Licenses be amended. Proposed changes to the Technical Specifications are indicated by vertical bars in the margin of each page. The proposed revised pages for each unit are included in Attachment 2.
The proposed changes are being requested to support changing the fuel cycle at PBAPS from 18 to 24 months. This request is limited to changing the surveillance frequency only. The surveillance tests will continue to be performed as they always ,
have been in that no modifications to test methodologies or station equipment have been included in this request. Equipment required !
to mitigate the consequences of an accident will not be affected, except that the frequency of testing that equipment will be extended to accommodato a 24 month fuel cycle. In addition, the frequency of some TS line items currently required once every
" refuel outage" or " operating cycle" will not be changed; for these TS items a change in the text of the TS is being requested. The TS frequency for these items will be defined as once every "18 months". This will not change the effect of the TS; the requirement will still be performed once every 18 months, but the TS words for those line items must be changed.
This request in conjunction with the previous submittal proposes two types of changes: intent changes and text changes.
Intent changes are those TS line items that use " refuel cycle" or
" operating cycle" to define the surveillance frequency. As noted previously, these terms are currently defined to mean 18 months with a 25% grace period. No change to the text of the TS is being requested for these line items; however, a TS change request to change the definition of the " REFUEL OUTAGE" and " OPERATING CYCLE" to 24 months with a 25 percent grace period is included in this request. The request to change the definition of these terms is being submitted now because the evaluation of the instrument calibration surveillance frequency ic complete as well as the evaluation of all other TS line itt,ms that use the terms " REFUEL OUTAGE" or " OPERATING CYCLE". The other type of change in this submittal are text changes. In some TS line items, where sufficient justification to extend the surveillance period to 24 months could not be developed we are requesting that the interval remain the same. In some other TS line items the surveillance frequency was specifically designated as 18 months. For these items a change to the TS pago-is required. The revised pages are attached.
L
Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 !
l A Discussion on the Effect of Increased Survo111ance Intervals '
on Instrument Drift and safety Analysis Assumptions:
NRC Genoric Letter 91-04 (GL91-04), Enclosure 2 provided guidanco to licensees on the type of analysis and information :
that would be required to justify a change to the Survo111anco Interval for instrument recalibrations. Seven specific actions were delineated in GL91-04 and are repeated below along with our response. This discussion is meant as a generic discussion to provide insight into the methodology PECo used to evaluate the affects of an 1ncreased surveillance interval on instrument drift. A specific discussion on the affects of such a change are included in the description of changes and safety discussion section which follows.
- 1. Confirm that instrument drift as determined by_as-found and as-left calibration data from surveillance and maintenance records __has not, except-on rare occasions, exceeded acceptable limits for a calibration interval.
The effect of increased calibration intervals on the TS instrumentation for PBAPS Units 2 and 3 to accommodato 24 month refueling cycles has been determined. Two issues associated with the instrumentation have been evaluated: a) instrument availability based on consideration of historical instrumant test failures and b) instrument drift.
- a. Instrument Availability with Consideration to Historical Instrument Test Failures For the TS instrumentation at PBAPS Unita 2 and 3, a search was done of all surveillance tests (STs) that satisfy the instrument calibration requirement. The search identified all failed test since 1982 unless the testing requirement had boon established after that time.
Each of the failed tests were reviewed to determine the cause of the failure. The purpose of this ovaluation was to determine the impact an increase in_the surveillance interval has on instrument availability. This review identified that instrument failure ratos detected by the eighteen month surveillance requirement was significantly less than 1 percent. Locause of the very small percentage of failures which are detected only on an eighteen month basis and system redundancy the change in the surveillance-frequency will have a amall impact, if any, on system availability.
- b. Instrument 9 rift
l Docket Nos._50-277-50-278-l License Nos. DPR-44 ;
'DPR-56 :
For the TS instrumentation at PBAPS Units 2 and 3, all [
opplicable surveillance tests were reviewed, and i historical instrument drift related data was obtained.
j This data included as-left values, as-found values and required limits identified during each' instrument i calibration. Based on this data a drift analysis was !
performed. The failure history in combination with the =,
drift study demonstrates that except in rare occasions instrument drift has not exceeded the current allowable limits. l
- 2. Confirm that the values of drift for each instrument type (make, model, and rango) and application have been determined '
with a high probability and a high degree of confidence, Provide a summary of the methodology and assumptions-used to j determine the rate of instrument drift with time based upon historica1' plant-calibration data. ,
The following details the methodology used to perform the !
'?
PBAPS drift analysis:
General Electric (GE) developed a computer model for drift i determination as documented in NEDC-31336 "GE Instrument setpoint Methodology" to perform instrument setpoint ;
calculations. This document was submitted and is currently ;
under review by the NRC. The Boiling Water Reactor Owners' Group (BWROG) committee for Surveillance Test Extension determined that the drift module of the GE Instrument Setpoint i Methodology could be used to determine-instrument drift for periods longer than eighteen months based on actual instrument -
performance in plant environments. 3 General Electric under the direction of the BWROG Surveillance Test Extension committee developed the " General. Electric ;
Instrument Trending Analysis System (GEITAS). . This quality assured program is being used to determine the feasibility of 1 extending various surveillance tests to thirty-six months.'
A copy of the verified and validated GEITAS program was obtained from General Electric and was used to project the-thirty month drift number. The as-found and as-left data was taken from eighteen month / refueling _ cycle' instrument-.
calibration surveillance tests and analyzed. This analysis:
produced' values:at intervals from:one to thirty months.
However, for-conservatism,.(1) the various errors contained in ,
the as-found and'as-left values (e.g., temperature and :
L calibration errors) where not removed and-(2) the: Interval. ,
with the highest projected drift value was compared with the u precent eighteen month surveillance test acceptance criteria.
o-S h
- , . _ _ . - - . . . , .,,,_
- _.-.u _ - . .a.-.. . . _ . _ _ _ . . . . . _ . . - - _ _ _,-
Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 The results of the computer runs showed acceptable 30 month drift values that were within surveillance test drift allowances if (1) there were a sufficient amount of historical data to satisfy the computer algorithms and (2) the majority of the as-found and as-left values were within acceptable limits.
It should be noted that for certain caans a different methodology was utilized to demonstrate that the drift was acceptable. These cases included instruments that were recently installed, instruments that were tested more frequently because of other commitments or instruments that have 30 month drift numbers published. For each instrument where the GE Program was not utilized to evaluate the drift data e summary of the methodology is contained in the specific write up for the change.
- 3. Confirm that the magnitude of instrument drift has been determined with c high probability and a high degree of confidence for a boundirq calibration interval of 30 months for each instrument type (make, model number and range) and application that performs a safety function. Provide a list of the channels by TS section that identifies these instrument application.
The determination that thu magnitude of instrument drift has been determined with a high degree of probability and a high degree of confidence for a bounding calibra'..on interval of 30 months for each instrument type is included l'.. the description of char.es and the safety discussion section that follows. A list of channels by TS section is included.
- 4. Confirm that a comparison of the projected instrument drif t errors has been made with the values of drift used in the setpoint analysis. If this results in revised setpoints to accommodate larger drift errors, provide proposed TS changes to update trip setpoints. If the drift errors result in revised safety analysis to support existing setpoints, provide a summary of the updated analysis conclusions to confirm that safety limits and safety analysis assumptions are not exceeded.
The thirty month projected drift number was compared to the present allowance for the instrument application.- If the drift for an instrument type did not fall within the present bounds of the acceptance criteria the surveillance interval was either left at a eighteen month calibration surveillance interval or was extended to a 30 month calibration .
surveillance interval based on other justification, s mh as more frequent testing. If an instrument has not been in 4_
Docket Nos. 50-277 (
50-278 License Nos. DPR-44 DPR-56 service long enough to establish a thirty month projected drift value, the surveillance interval was either left at an eighteen month surveillance interval or extended to a 30 month surveillance interval. To extend to a 30 month surveillance interval, justification of either more frequent testing or justification from the instrument manufacturer was provided.
In no case was the actpoint of an instrument changed to accommodato a drift crror larger than previously evaluated.
- 5. Confirm that the projected instrument errors caused by drif t2 are acceptable for control __of plant parameters to effect a safe shutdown with associated instrumentation.
As discussed in response to number 4, the justification for extending the surveillance interval of an instrument was an instrument drift calculation within the existing design basis.
Additional factors included more frequent testing cr a manufacturer's recommendation. In no case was the existing safe shutdown analysis chinged to accommodate a large drift-orror.
- 6. Confirm that all conditions and assumptions of the setpoint and safety analyses have been checked and are appropriately reflected in the acceptance criteria of plant surveillance procedures for channel checks, channel functional tests, and channel calibrations.
PECo hab not changed any of the setpoint or acceptance criteria of the present eighteen month surveillance test, therefore, there is no cause to reverify the criteria used to establish the acceptance criteria in the surveillance test.
- 7. Provide a summary description of the program for monitoring and assessing the effects of increased calibration surveillance intervals on instrument drift and its effects on safety.
PECo's program will review each calibration surveillance that does not meet the leave alone criteria (i.e no recalibration or adjustment required) of the calibration surveillance test.
Based on the results of that review a decision on-the appropriate calibration interval will be made. Such a decision will consider such things as shortening the surveillance test (SP) interval, changing the setpoint of the instrument or leaving the surveillance interval-at thirty months. Review of the ST results will be performed until such time as we determine that further evaluation is no longer necessary.
B; Description of Changes and Safety Discussions
Docket Noc. 50-277 50-278 License Nos. DPF-44 DPR-56 Because of the volume of TS line items required to be evaluated, the specific changes were grouped and each group has been analyzed. Note that the name of each group is merely an administrative title and may not contain all of the items that could be logically connected to this group. Each group is described below with a list of the TS line items, a description of the requirement, and a safety discussion. Where a change to the TS is being proposed and text from the TS section is reproduced in the discussion section, the affected words or phrases will be highlighted with bold type. In performing these evaluations, the guidelines of Generic Letter 91-04 were followed.
(1) Isolation Instruments Table 4.2.A, item 2 page 80 Table 4.2.A, item 3 page 80 Table 4.2.A, item 4 page 80 Table 4.2.A, item 8 page 80 Table 4.2.A delineates the minimum test and calibration frequency for core standby cooling systems. The lastruments for the following Primary Containment Integrity System (PCIS) functions: Low-Low-Low Water Level (item 2), Main Steam High Temperature (item 3), Main Steam High Flow (item 4) and Reactor Pressure - Feedwater Flush Permissive (item 8) have a listed calibration frequency of "once/ operating cycle."
Safety Discussion: The subject TS line items currently require the calibration testing of the subject instrumentation to be performed once per operating cycle. The calibration surveillance is performed to ensure that at a previously evaluated setpoint actuation takes place to provide the required safety function. By increasing the refueling cycle, the time interval for calibration surveillance of the subject instrumentation will be increased. However, as currently required by PBAPS TS, functional tests are performed during the refueling cycle more frequently than the calibration surveillance. These functional tests detect failures of the instrumentation channels, except for field devices, such as transmitters, that are only tested once every 18 months.
Gross instrumentation failures are detected by alarms, by a comparison with redundant and independent indications.
Instrumentation purchased for these functions are highly reliable and meet the design criteria of safety related status. All isolation instrumentation is designed with redundant and independent channels which provide means to verify proper instrumentation performance during operation, and adequate redundancy to ensure a high confidence of system performance even with the fallere of a single component. Based on the above discussion, PEcc ~ ,ncluded that the impact on
Docket Nos. 50-377 50-278 License Nos. DPR-44 DPR-56 l
Instrumentation availability was small, if any as a result of this change.
To verify this conclusion, an historical search of the surveillance tests for each instrument was performed. The search identified all failed or partially failed tests, and then each failed or partially failed test was reviewed and evaluated. The purpose of this evaluation was to demonstrate that the increased calibration surveillance interval would not increase the period an instrument would be unavailable. The results of this search support the above conclusions that the impact on instrument availability, if any, is small as a result of the change in the surveillance interval.
f A second evaluation performed an instrument drift analysis for the increase in the calibration interval to a maximum of 30 months. The details of the drift analysis are included below.
j The GE methodology, previously described, was used to perform the drif t analysis on the Moduflash 652, Main Steam Line High Temperature instruments (TS 4.2.4, item 3). Based on this drift analysis, we conclude an increase in the surveillance interval to accommodate a 24 month-fuel cycle does not affect these instruments with respect to drift.
The main steam temperature loops (item 3) use Burns RTD's for the temperature sensing elements. An RTD is a f actory calibrated device that does not exhibit drift because of the principle of operation of the temperature sensing mechanism.
Therefore, an ircrease in the surveillance interval to accommodate a 24 month fuel cycle does not af fect the Burns RTD with respect to drift.
Rosemount transmitters are used for the input to the following channels: Reactor Low - Low - Low Water Level (item.2), Main Steam Line High Flow (item 4), and Reactor Pressure (item 8).
Drift values for 30 months are published for Rosemount transmitters, Rosemount Report D8900126, and these published values are within the surveillance test drift allowances.
Therefore, an increase in the surveillance interval to accommodate a 24 month fuel cycle does not af fect the Rosemount transmitters with respect to drift.-
Rosemount trip unit; aro functionally checked and the setpoint verified, and recalibrated if necessary, on a more frequent basis than every 18 months. This more frequent functional check and setpoint verification requirement remains unchanged.
Therefore, an ine case in the surveillance interval to accommodate a 24 month fuel cycle' does not af fect the Rosemount trip units with respect to drift.
, - . ~ , . - -
Docket Nos.-50-277 50-278 License Nos. DPR-44 DPR-56 Based on the above evaluations, we have concluded that the -
impact on instrument availability, if any, is small as a !
result of this change to a 24 month surveillance interval. !
(2) Alternate Rod Insertation/ Recirculation Pump Trip Instruments Table 4.2.G Items 1 and 2 page 88 I Table 4.2.G definos the minimum test and calibration frequency for instruments that initiate a Alternate Rod Insertation (ARI) and a Recirculation Pump Trip (RPT). The plant conditions that initiate an ARI/RPT are Reactor High pressure and Reactor Low-Low Water level.
Safety Discussion: The subject TS line items currently require the calibration testing of the subject instrumentation to be performed once per operating cycle. The calibration surveillance is performed to ensure that the instrument is-properly aligned so that at a previously evaluated setpoint, actuation takes place to provide the required safety function.
By increasing the refueling cycle, the time interval for calibration surveillance of the subject instrumentation will ,
be increased. However, as currently required by PBAPS TS, functional tests are performed during the refueling cycle more :
frequently than the calibration survoillance. Thise functional tests detect failures of the instrumentation channels, except for field devices, such as transmitters, that-are only tested once overy 18 months. Gross instrumentation failures are detected by alarms and by a comparison with redundant and independent indications.
Instrumentation purchased for these functions are highly reliable and meet the design criteria of safety related status. Note the contact inputs for the ARI/RPT functions, which are not safety-related, are' electrically isolated from
- the safety related instrumentation. All ARI/RPT equipment '
power sources, logic and sensors are electrically independent from the RPS shutdown to ensure a high confidence in system performance. Based on the above discussion, PECo concluded that the impact on instrumentation availability was small, if any as a result of this change.
To verify this conclusion, an historical search of the surveillance tests for each-instrument was performed. The search identified all failed or partially failed tests, and then each failed or partially failed test was reviewed and evaluated. The purpose of this evaluation was to demonstrate that the increased calibration surveillance interval would-not increa7e the period an instrument would be unavailable. The results of this search support the above conclusions that the
. - .~ - . . .- . - . - -. .- - . - . _ , -
. - _ _ _ _.__ .---_ _ __ ___ ___ ___ ___m -
Docket Nos. 50-277 50-278 Licenso Nos. DPR-44 DPR-56 Impact on instrument availability, if any, is small as a result of the chango in the surveillance interval.
A second evaluation performed an instrument drift analysis for the increase in the calibration interval to a maximum of 30 months. The details of the drift analysis conducted for this section are . included below.
Rosemount Transmitters provide the signal for the Reactor High Pressure (Table 4.2.G., item 1) and the Reactor Low -Low Water Level (Table 4.2.G, item 2). These transmitters do not require a 30 month drift study because as previously discussed Rosemount has published a 30 month drift valuo that is within the existing surveillance test drift allowances. Therefore, an increase in the surveillance interval to accommodate a 24 month fuel cycle does not affect the Rosemount transmitters with respect to drift.
The signal from the Rosemounts is processed by a Foxboro micro-computer, which consists of, Foxboro I/E converters, Foxboro trip switches and E/I converters. A monthly surveillance test is performed to verify all ARI/RPT setpoints related to the Foxboro micro-computer. During the performance of this test switch sotpoints are recorded and ' unctions checked in the associated test logics strings. During the monthly performance of the test, control indication is not checked; however, this indication is checked on a daily basis by an ST performed to verify reactor level and pressuro indicators are within acceptable limits. With the more frequent testing provided by the monthly and daily tests, it in concluded that the calibration for the ARI/RPT compensated level may be extended to a 30 month interval.
(3) Containment Systems and Primary System Boundary Instrumentation TS 4.6.D.3 page 147 TS 4.7.A.3 page 170 TS 4.6.D.3 requires that the switches that monitor the integrity of the relief safety valve bellows be calibrated once por operating cycle.
T5 4.7.A.3.a requires: "The pressure suppression-chamoor-reactor building vacuum breakers including setpoint shall be checked for proper operation every refueling outage."
It is requested that this wording be changed as follows: "The pressure suppression chamber-reactor building vacuum breakers l shall be checked for proper operation every refueling outecc.
t
_g.
1 Docket Nos. 50-277 i 50-278 )
bicense Nos. DPR-44 l DPR-56 Associated instrumentation including setpoint shall be checked for proper operation every eighteen months." ,
Safety Discussion: The wording chango to Technical Specifications item 4.7 A.3.a is boing proposed to ensure that the present calibration uurvot11ance interval remaina unchanged when the definitjon of reineling cycle is changed.
Because the change maintains the calibration interval at the same frequency, this change can be considered administrativo in nature and therefore have no impact on the safety or operation of the plant.
Technical Specification lino item TS 4.6.D.3 requires the calibration testing of the subject instrumentation to be performed once por operating cycle. The calibration '
survoillance is performed to ensure that the instrument is properly aligned so that at a previously evaluated setpoint, actuation takes place to provide the required safety function.
By increasing the operating cycle longth, the time interval for calibration surveillance of the subject instrur.cntation will be increased. Tha ADS relief valve pressure switches are not safety related. Their function is to inform the operator oC a safety related bollows leak. Since the device is only
, for indication a onco per twenty-fotr month surveillance test frequency is acceptable. >
- To verify the conclusion, an historical-search of the surveillance tests for each instrument was performed. The search identified all failed or partially failed tests, and then each failed or partially failed test was reviewed and evaluated. The purpose of this evaluation was to demonstrate that the increased calibration surveillance interval would not increase the period an instrument would be unavailable, the-results of this search support the above corclusions that the impact on instrument- availability, if any, is small as a
. result of the chango in the surveillance interval.
I
( A second evaluation proformed an instrument drift analysis for i
the increase in the calibration interval to a maximum of 30-months. The details of the drift analysis ccnducted for this section are included below.
l The GE methodology, previously described, was used to perform
.the drift analysis on the following instruments: =ITT Barton, 580A-0, Torus to-Heactor Building pressure switches, (TS 4.7.A.3.a) and Pressure Control inc, A17-1, Torus Vacuum Relief Valvo switches, (TS 4.6.D.3). Based on this drift analysis, we conclude an increase in the surveillance interval L
o to accommodate a 24 month fuel cycle does not affect these instruments with respect to drift.
L
Dockot Nos. 50-277 50-278 j License Nos. DPR-44 DPR-56 .
-l t
(4) Emergoney Core Cooling System (ECCS) Instrumentation TS Table 4.2.D, items 1, 2, 3, 5, 10, 11, 16, and 10 page 81 TS 4.5.G.2 page 133 TS Table 4.2.8 defines the minimum test and calibration frequency for Coro Standby Cooling Systems (CSCS). The instrument channels with a calibration frequency of "once/ operating" cycle are as follows: Reactor Water Lavel(item 1), Drywell Pressure (item 2), Reactor Pressuro (item 3), Auto Sequencing Timers (item 5), Steam Line High Flow - HPCI & RCIC (item 10), Steam Line High Temperature -
HPCI & RCIC (item 11), ADS Relief Valves Bellows Pressure Switches (item 16) and Condensate Storago Tank Level - RCIC (item 18).
Safety Discussion: The subject Technical Specification line itnms currently require the calibration testing of the subject instrumentation to be performed onco per operating cycle. The calibration survoillance is performed to ensure that the instrument is proporly aligned so that at the previously evaluated setpoint, Engineering Safeguard Functions (ESP) t actuate to provide the required safety function. By increasing the operating cycle longth, the-time interval for calibration surveillance of the subject instrumentation will be it. creased. However, as currently required by PBAPS Technical Specifications, functional tests are performed during the operating cyclo more frequently than the calibration surveillance. These functional tests detect ,
failures of the instrumentation channels, except for field devices, such as transmitters, that are only tested once every .
18 months. Except for the Automatic Depressurization (ADS) relief valvo bellow pressure switches,. gross instrumentation f ailures are detected by alarms, and deviations or inconsistencius are detected by a comparison with redundant and/or independent indications.
Instrumentation purchased for these functions are highly; reliable and moet the design criteria of the system in which they are installed. ECCS Group initiation instrumentation is designed with redundant and independent channels which provido means to verify proper instrumentaticn performance during plant operation. Adequate redundancy is provided for other ECCS group instrumentation to ensure a high confidence of system performanco even with the fallare of a single component. Based on the above'disce.31on, the conclusion is made that the impact, if any,-is small on instrumentation
l Dock 9t Nos. 50-277 1 50-270 !
l Licenso Nos. DPR-44 l DPR-56 i
availability from the change to 24 month survoillanco intervals.
The ADS relief valve pressure switches are not safety related.
Their function is to inform the operator of a safety related-bollows Acak. Loss of the bellows will not prevent the relief valvo from performing its ADS function. Since the device is only for indication and loss of the safety related bellows would not prevent the ADS system from operating, a once per 24 month survoillance test frequency is acceptable.
To verify these conclusions, an historical search of the surveillance tests for each instrument was performed. The search identified all failed or partially failed tests, and then each failed or partially failed test was reviewed and evaluated. The purpose of this ovaluation was to demonstrate that the increased calibration surveillanco interval would not increase the period an instrument would be unavailable. The results support the above conclusion that the impact on instrument availability, if any, is small as a result of the change to the subject survoillanco interval.
A second ovaluation performed an instrument drift to analyze the increaso in the calibration interval to a maximum of 30 months. The details of the drift analysis are included below.
The GE methodology, previously describod, was used to perform the drift analysis on the following instrument: Pressure Control Inc, A17-1, pressure switches, (TS 4.2.B, item 16),
i Moduflash 652, temperaturo switches (TS 4.2.B, item 11),
Agastat ETR14D3BC200200, timers, (TS 4.2.B, item 10), Agastat "TR," ETR14D3BC, timers, (TS4.2.D, item 5). Based on this drift analysis, we conclude an increase in the surveillance interval to accommodate a 24 month fuel cycle does not affect those instruments with respect to drift.
Rosemount transmitters are used for the input to the following channels: Reactor Water Level (item 1), Drywell Pressure (item 2), Reactor Pressure (item 3) and Condensate Storage Tank Level (item 18). Drift values for 30 months are published for Rosemount transmitters, Rosemount Report DB900126, and those published values are within the surveillance tost drift allowancos. Rosemount trip units are functionally checked and the sotpoint verified, and recalibrated if necessary, on a more frequent basis than esery 18 months. This more frequent functional check and setpoint verification requirement remains unchanged. Therefore, an increase in the surveillanco interval to accommodatr a 24 month fuel cycle does not affect the Rosemount trip unir" with respect to drift.
Docket Nos. 50-277 50-278 License Nos. DPR-44 '
DPR-56 The signal from the Rosemounts is processed by a Foxboro micro-computer, which consists of, Foxboro I/E converters, Foxboro trip switches and E/I converters which provide main control room indication. A monthly surveillance test is .
performed to verify all setpoints related to the Foxboro '
micro-computur. During the performance of this test switch setpoints are recorded and functions checked in the associated test logic strings. During the monthly performance of the test, control indication is not checked; however, this :
Indication is checked on a daily basis by an ST performed to verify reactor level and pressure indicators are within acceptable limits.
The steam line temperature loops (item 11) use Burns RTD's for >
the temperature sensing elements. An RTD is a factory.
calibrated device that does not exhibit drift because of the principle of operation of the temperature sensing mechanism.
Based on the above eyaluations, it is concluded that the impact on instrument availability, if any, is small as a result of the 24 month surveillance interval changes.
(5) Electrical Protection Group Instrumentation TS 4.1.D.1 page 36 TS 4.1.D.2 page 36a TS Table 4.2.B, item 19 page 81a 4
TS 4.1.D.1 requires the Reactor Protection System (RPS) power supply (MG Set) protective devices listed below be functionally tested at least once every six r nths and calibrated once each refueling outage. -TS 4.1.D.2 requires the RPS alternate power supply protective devices listed below be functionally-tested at least once every-six months and calibrated once each refueling outage. The following setpoints shall be verified:
Device Acceptable Setting Undervoltage 113 + or - 2 volts >
overvoltage 131 + or - 2 volts Underfrequency 57 Hz + or .2 Hz Underfrequency Time Delay 6 seconds + or -1 second <
Safety Discussion: The electrical power system is designed-to provide a diversity of dependable power-sources which are
-physically isolated so that any failure.affecting one source of supply does not af fect the other source. The auxiliary.
electrical power systems are designed to provide-electrical-and physical independence, and to supply the necessary power for start-up, operation, shutdown and other station
Docket Nos. 50-377 50-278 License Nos. DPR-44 DPR-56 requirements. The auxiliary power system is tested and ,
inspected as required during the life of the plant tc Jemonstrate the capability of the system to pro.loe sufficient power to the essential loads. The RPS MG Set overvcitage, undervoltage and underfrequency relays are periodically tested to verify settings, operability and functional performance in accordance with surveillance test procedure.. These tests will provide assurance that the electrical protection system will operate at the required voltages, frequencies and times, and perform the intended functions when called upon to operate. Based on designed redundancy and reltability, it is concluded that the impact, if any, on component availability is small from the change to the subject surveillance interval.
A review of the ST history was not performed since the tests '
have been and will continue to be conducted on a six month basis. Further, a drift analysis was not performed on the relays associated with the STs because these tests functionally check the set point every six months.
TS Table 4.2.B, Item 19 requires the 4KV Emergency Power Source Degraded Voltage Relays have a minimum test and calibration frequency of "once per operating cycle." The wording in the table will be changed to "once per eighteen months."
t Safety Discussion: The wording change to Table 4.2.B, item 19 is being made to ensure that this requirement remains at its current specified frequency when the definition of operating cycle is enanged. Because the change maintains the surveillance test interval at the same frequency, this change l can be considered an administrative change which has no impact
! on the availability of the relays.
(6) Monitoring Group Instruments TS Table 4.2.F Items 1, 2, 3, 4, 6, 7, 9, 11, 14, 16 page 86 TS Table 4.15 Items IA - 1D, 2A - 2C, 3A page 240v TS Table 4.2 F delineates the minimum tast and calibration frequency for surveillance instruments. The calibration frequency of once per operating cycle is required for the following instruments: Reactor Water Level (narrow range, item 1), Reactor Water Level (wide range, item 2), Reactor Water Level (fuel zone, item 3), Reactor Pressure (item 4), Wide Range Drywell Pressure (item 6), Subatmospheric Drywell Pressure (item 7), Suppression Chamber Water Temperature (item 9), Wide Range Suppression Chamber Water Level (item 11),
9afety/ Relief Valve Position Indicator (acoustics, item 14),
"afety Valve Position Indicator (acoustics, item 16).
l l
.- -. _ . . - . _~ .. - , - - ~ - _ .
Docket Nos. 50-877 50-278 License Nos. DPR-44 DPR-56 Safety Discussion: An evaluation of the subject changes demonstrated that the overall impact, if any, on the instrument availability is small. The subject Technical Specification line items currently require the calibration testing of the subject instrumentation to be performed "once/ operating cycle". The accident monitoring calibration surveillance is performed to ensure reliable information is provided to the operator to monitor transient reactor plant behavior and to verify proper safety system performance following an accident. By increasing the operating cycle length, the time interval for calibration surveillance of the subject instrumentation will be increased. However, as currently required by PBAPS TS, functional tests are performed during the operating cycle more frequently than the calibration surveillance. These functional tests detect failures of the instrumentation channels, except for field devices, such as transmitters, that are only tested nominally once overy 18 months. Instrumentation purchased for those-functions are highly reliable. The monitoring instrumentation is classified as safety related and meets the associated design criteria. This criteria includes redundancy and independent channels which ensures a high confidence of system performance even with the failure of a single component.
Based on the above discussion, the conclusion is made that the impact, if any, on instrumentation availability is small which permits the change to 24 month surveillance intervals.
To verify this conclusion, an nistorical search of the surveillance tests for each instrument was performed. The search identified all failed or partially failed tests, and then each failed or partially failed test was reviewed and evaluated. The purpose of this evaluation was to demonstrate ,
that the increased calibration surveillance interval would not increase the period an instrument would be unavailable. The results support the. conclusion that the impact on instrument availability, if any, is small for the change to the subject surveillance interval.
A second evaluation performed an instrument drift analysis for the increase in the calibration interval to a maximum of.30 months.
The GE methodology, previously described, was used to perform the drift analysis on the following instruments: ITT Barton 764, water level, (TS 4.2.F, item 11),-Foxboro 2A-AIM, 227S-2R6, 2AP-AIM-PR, N-E11GM, pressure switchee,.(TS 4.2.F, item 6), Simmonds <recision, 10701F11060, temperature switches, (TS 4.2.F, item 9), Foxboro, 227S-2R6, pressure switches, (TS 4.2.F, item 7). Based on this drift analysis, we conclude an increase in the survefilance interval to
i Docket Nos. 50-277 50-278 License Nos. DPR-44
- DPR-56 i
accommodate a 24 month fuel cycle does not affect these instruments with respect to drift.
Rosemount transmitters provide the input for the following instrument channels: Reactor Water Level (narrow range, item 1), Reactor Water Level (wide range, item 2), Reactor Water Level (fuel zone, item 3), Reactor Pressure (item 4), Wide Rat.go Drywell Pressure (item 6)and Subatmospheric Drywell Pressure (item 7). Drift values for 30 months are publ.!shed for Rosemount transmitters, Rosemount Report D8900126, and these published values are within the surveillance test drift allowances. Therefore, an increase in the surveillance interval to accommodate a 24 month fuel cycle does not affect Rosemount transmitters with respect to drift.
The signal from the Rosemounts is processed by a Foxboro micro-computer, which consists of, Foxboro 1/E converters, Foxboro trip switches and E/I converters. A monthly surveillance test is performed to verify all setpoints related to the Foxboro micro-computer. During the performance of this test switch setpoints are recorded and functions checked in the associated test logic strings. During the monthly performance of the test, control indication is not checked; however, this indication is checked on a daily basis of the ST performed to verify reactor level and pressure indicators are within acceptable limits. With the more frequent testing provided by the monthly and daily tests, it is concluded that ,
the calibration interval may be extended to 30 months.
The Safety Relief Valve (SRV) position indicating instrument loops (Table 4.2.F, items 14, 16) were reviewed. A review of l data from existing surveillance tests indicates that the-historical as-found and as-left values could not support a 30 month drift value. However, a review of the data shows that f ailures of the instruments during calibration (i.e. , as-found values greater than acceptable limits) were in the conservativo direction with respect to the detection of flow.
Pased on the fact that the instrumentation' fails in the conservativa direction, the calibration interval can be extended to support a 24 month fuel cycle. Further, this instrumentation will continue to be monitored for drift using the trending program being established for instrument drif t.
Reactor water (narrow range) level (TS 4.2.F item 1) and reactor pressure instrumentation (TS 4.2.F, item 4): These instrument loops have been upgraded for Unit 3 in 1991 by Modification 1843. The modification replaced the existing.
transmitters with Rosemount transmitters and replaced the-existing analog signal processors with new digital processing instruments. For Unit 2, the same changes will be made by
Docket NoO. 50-377 50-278 License Nos. DPR-44 DPR-56 Modification 1043. These changes for Unit 2 are scheduled to .
be implemented during the refueling outage in September 1992, I prior to the start of the first 24 month fuel cycle. For the l digital processing instruments installed for Unit 3 in 1991, j there has not been sufficient operating time to generate <
historical as-found and as-left data for determining 30 month 1 drift values. Of the digital processing instruments, only the analog-to-digital (A/D) converters could show drift. The A/D converters that could show drift are only a portion of the analog processing instrumentation that was replaced by Modification 1843. The drift for the A/D converters is an order of magnitude less than the drift for signal conditioning instruments that were replaced. The remaining digital processing portions of the loops will not drift due to the fact that digital conversions have no mechanisms for drift (i.e., voltage levels corresponding to "0's" and "l's" or "off" and "on" conditions, not varying analog signal conditions). In addition to the reduction in total instrument drift, an increase in the surveillance interval is justified because the digital feedwater instrumentation includes self-diagnostic software programs. These self-diagnostic programs and associated hardware check the operation of the instrumentation and identify with an alarm those signals that are out of tolerance. The diagnostics monitor the instrumentation from the input to the A/D converters to the output circuits of the digital processors. Instrumentation is monitored at a frequency commensurate with the reliability of each instrument. Based on the above discussion, the conclusion is made that the surveillance interval for the digital feedwater instrumentation for Unit 3 can be extended to accommodato a 24 fuel cycle. This conclusion would also be applicable for Unit 2 when the digital feodwater changes are made by Modification 1843.
Reactor Compensated Level Loops for Monitoring: The reactor level loops used for monitoring at PBAPS are currently tested on a monthly basis and daily indication checks for instrument operability are also performed. The level instrumentation used for monitoring is comprised of Rosemount level and pressure transmitters and a Foxboro micro-computer consisting of, Foxboro I/E converters, Foxboro trip switches, and E/I converters which provide Main Control Room indication. In addition, a monthly surveillance is performed to verify all setpoints related to the Foxt co micro-computer. During the performance of this test, a calibrated current source is input into the I/E's which tests the micro-computer and the output of the electronic switche- Also, switch setpoints are recorded and functions ere checked in the associated logic strings. During e monthly performance of the test, the indication in the Control Room is not checked. This 17 -
Docket Nos. 50-277 50-278 ;
License Nos. DPR-44 DPR-56 l l
l Indication, hownver, is checked on a daily basis to verify that reactor level and pressure indications are within i acceptable Jimits. With the mot i frequent testing provided by the monthly tests and the daily tests, the conclusion is made that the calibration for the reactor level instrumentation may be extended to a 30 month interval.
Note, as previously discussed, the transmitters which are Rosemount transmitters, do not require a 30 month drift evaluation. Published drif t values from Rosemount document that 30 month drift for the transmitters is within the existing surveillance test drift allowances.
Pyco Thermocouples are used to measure suppression chamber water temperature (Technical Specification, Table 4.2.F, Item 9). These thermocouples provide input to the Simmond Precision instrumentation. The thermocouples are factory calibrated devices that do not exhibit drift due to the operation of the temperature sensing mechanism. Therefore, an increase in the surveillance interval to accommodato a 24 month fuel cycle does not affect the operation of the Pyco Thermocouples.
Differential Pressure Switches in the Drywell Pressure Instrument Loops (Table 4.2.F, item 6):
Foxboro differential pressure switches are used in the Drywell pressure instrument loops. A review of the surveillarice vats s
, used to calibrate these switches shows that since the restart of Peach Bottom Atomic Power station, the method used to test and calibrate the switches has changed. The change to the tests results in different numerical data being obtained. Due to different sets of numerical data for the same switches, the GE drift analysis program was used to evaluate a drift value using data-from tests using the newer test method only. The results indicate that the drift value is within acceptable limits, liowever, due to a limited amount of data, the-drif t value represents an eighteen month period only. A review of the data from tests using the earlier test method indicates that the switches have not needed recalibration. Therefore, since historical data shows that instrument drift has been within acceptable limits for a period of time that is greater than thirty months, the calibration surveillance interval can be extended to accommodate a twenty-four month fuel cycle.
Further, these switches will continue to be monitored for drift using the trending program being established for instrument drift.
Based on the above evaluations, it is concluded that the impact en teatrument availability, if any, is small as a result of the 24 month surveillance interval changes.
Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 TS Table 4.15 delineates the seismic monitoring instrumentation surveillance requirements. The surveillance frequency for this table is defined as 18 months and a change ,
to the text of Table 4.15 is required. The specific instruments with a surveillance frequency of 18 months are as follows: Triaxial Time-History Accolorographs (item 1),
located at the following plant locations: Containment Foundation (item la), Refueling Floor (item Ib), Reactor Core ,
Isolation Cooling (RCIC, item ic) Pump and the "C" Diesel Generator (item id), the Triaxial Peak Accelerographs (item 2) located at the following plant locations: Reactor Piping (Drywell, item 2a), Refueling Floor (item 2b), and the "C" Diesel Generator (item 2c) and the Triaxial Response-spectrum Recorder located in the Cabic Spreading Room (item 3a).
Safety Discussion: The seismic monito.'ing calibration surveillances are performed to ensure that the operator is provided with information on the effects of an earthquake on the structures, systems and components of the plant that are necessary for continued operation without undue ri.sk to the health and safety of the public. The seismic m;nitoring instrumentation is not required and does not have redundancy with independent indications. However, functional test and monthly instrument checks are performed during the operating cycle more frequently than the calibration surveillance.
These functional test detect failures of the instrument channels. Portions of the monitoring instrumentation that are classified as non-safety related have been designed to the criteria of NRC Regulatory Guide 1.97, category 2.
Requirements for non-safety related instrumentation.that is classified as Category 2 instruments per NRC Regulatory Guide 1.97 for Post-Acc3 dent monitoring include the following a) Environmental qualification b) Highly reliable and/or battery backed power sourCo.
c) QA requirements consistent with the importance to safety of the instrumentation, d) Diverse or backup instrument channel.
Other non-safety related instrumentation is inherently designed to perform its intended function. For example, seismic instrumentation is designed to operate during a seismic event and the seismic instrumentation panel is powered from a non-safeguard distribution panel that is fed from safeguard power. A backup power supply is located in the seismic instrumentation panel and is capable of supplying the seismic system for a minimum of 25 minutes following a loss of power. Based on the above discussion,.the conclusion-is madt 19 -
- .- -.a .- = -
1 Docket Nos. 50-277 50-278 l
License Nos. DPR-44 ,
DPR-56 that the impact; if any, is small on instrument availability from the change to 24 month surveillance intervals.
To verify his conclusion, an historical search of the surveillance tests for each instrument was performed. The search j<fontified all failed or partially failed tests, and then eac< failed or partially failed test was reviewed and evaluate.. The purpose of this evaluation was to demonstrate that tF increased calibration surveillance interval would not incro' as the period an instrument would be unavailable. The results support the conclusion that the impact on instrument availability, if any, is small for the change to the subject surveillance interval.
A second evaluation performed an instrument drift analysis for the increase in the calibration interval to a maximum of 30 months. The details of this analysis are below.
Seismic monitoring instrumentation manufactured by Kinemetrics will provide the input for TS Table 15, items lA, IB, 1C, 1D, 3A. This instrument is new equipment that will be installed during the refueling outage scheduled for Spring of 1993.
Note, the existing instrumentation will operate to the expiration of the current 10 month fuel cycle until the new Kinometrics instrumentation is installed. An evaluation of drift for 30 months for the new Kinemetrics instrumentation cannot be done because there is no historical data to determine a 30 month drift valuo using the GE drift computer program. 11owever, Kinemetrics has determined that tne calibration interval for this instrumentation can be increased to 30 months. Based on the information provided by Kinometrics the calibration interval can be increased to accommodate a 24-month fuel cycle.
Solsmic monitoring instrumentation manufactured by Engdahl are triaxial accelerographs (Table 4.15, items 2A, 2B, 2C). An evaluation of drift for thirty months for the Engdahl triaxial accelerographs cannot be done because of cb.anging testing methods. Ilowever, Engdahl Enterprises has determined that the calibration jnterval for this instrumentation can be increased to twenty-four month with a grace period of six months.
Based on the above evaluations, it is concluded that the impact on instrument availability, if any, is small as a result of the 24 month surveillance interval changes.
(7) Reactor Protection System (RPS) Instrumentation TS Table 4.1.2 items 4 - 9, 12, 13 and nots 3 for item 9 and 13 page 44 i
l
.. .-.-- - . - ---.- ---~--- . - - -
Dockot Nos. 50-277 50-278 License Nos. DPR-44 '
DPR-56 TS Table 4.1.2 item 2 page 44 ms Table 4.1.2 defines the Reactor Protection System (RPS) instrument calfbration frequencies for reactor protection instrument channels. For the following items, PECo is requesting that the frequency of calibration be extended to ,
accommodate the 24 month fuel cycle: High Reactor Pressure (item 4), High Drywell Pressure (item 5), Reactor Low Water Level (item 6), High Water Level in the Scram 01scharoc Volume (item 7), Turbine Low Condenser Vacuum (item 8), Main ~Lteam Line Isolation Valve Closure (item 9), Turbine Control Valve Fast Closure (item 12), and Turbine Stop Valve Closure (item 13). For items 9 and 13 note 5 is referenced. Note 5 requires " Physical inspection and actuation of these position switches will be performed during the refueling outage" (page 46). Item 2 of Table 4.1.2; the cari.bration requirement for the APRM High Flux - Flow Bias Signal is an exception. PECo is requesting the calibration frequency of this item not be extended but rather the frequency be changed from "every refueling outage" to "once per eighteen anths".
Safety Discussion:
Tho subject Technical Specification line items currently require the calibration testing of the subject instrumentation to be performed once per operating cycle. The calibration surveillance is performed to ensure that the instrument is properly aligned so that at the previously evaluated setpoint, actuation takes place to provide the required safety function.
By increasing the operating cycle .ongth, the time interval for surveillance of the subject instrumentation will be increased. However. as currently required by the PBAPS Technical Specifications, functional tests are performed during tho operating cycle more frequently than the calibration surveillance. These fur.ctional tests detect failures of the instrumentation channels, except for field devices, such as transmitters, that are only tested once every 18 months. Gross instrumentation failures are detected by alarms, and deviations or inconsistencies are detected b'/ a comparisoa with redundant and independent indications.
Instrumentation purchased for these functions are highly reliable and meet the design criteria of safety related status. All RPS instrumentation is designed with redundant and independent channels which provide means to verify proper instrumentation performance during operation, and adequate redundancy to ensure a high confidence of system performance even with the failure of a single component. Based on the above discussion, t!.e conclusion is made that the negligible
- . - - - . _ - . _ ~ _ . - - - . . ~ - - _ - - - - - . . .
Dockot Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 impact on instrumentation availability permits the change to 24 month surveillance intervals.
To verify this conclusion, an historical search of the surveillance tests for each instrument was performed. The search identified all failed or partially failed tests, and ;
then each la11ed or partially failed test was reviewed and !
evaluated. The purpose of this evaluation was to demonstrate that the increased calibration surveillance interval would not 1 increase the period an instrument would be unavailable. The results of thi+ review support the above conclusions that the impact on instrument availability, if any, is small as a result of the change in the surveillance intarval.
A second evaluation performed an instrument drift analysis for the increase in the calibration interval to a maximum of 30 months.
The following RPS inputs used Rosemount transmitters:
Table 4.1.2, item 4 - High Reactor Pressure Table 4.1.2, item 5 - High Drywell Pressure Table 4.1.2, item 6 - Reactor Low Water Level item 9 - Turbine Condenser Low Vacuum Table 4.1.2, Drift values for 30 months are published for Rosemount transmitters, Rosemount Report D8900126, and these published values are within the surveillance test drift allowances.
The Rosemount tilp units are functionally checked and the setpoint verified, and re-calibrated if necessary, on a more frequent basis than overy 18 months. This more frequent functional check and setpoint verification requirement remains unchanged. Thornfore, an increase in the surveillance interval to accommodate a 24 month fuel cycle does not affect the Rosemount trip units with respect to drift.
Limit switches; The limit switches associated with the Main Steam Isolation valves (MSIV's) provide input to reactor scram logic and also provide valve position indication. Functional testing-on the i MSIV's is provided on a more frequent basis tha.. every 18 months. This functional testing consists of cycling one of the MSIV's from the open position to a specified percent closed position, and back to the open position. A different valve is cycled each time the functional test is run.
Confirmation that the switch is operating properly is done by observing the position Indicating lights when the valve' opens and closes. Since functional testing to confirm proper valve and limit switch operation is performed more frequently than l
L .. -
_ ._ _ . . . ~ _ _
Docket Nos. 50-277 50-278 License Nos. DPR DPR-56 every 18 months, an increase in the surveillance interval to a commodate a 24 month fuel cycle does not affect the limit switches with respect to drift. Note, fo he limit switches which are mechanical Jevices, misalignmen, is a more applicable term than drift.
Main Turbine Control Velve (MTCV) Fast Closure Pressure Switches. The pressure switch for the MTCV Electro-Hydraulic Control (EHC) oil pressure has been r luated using the GE drift Computer Program. This evalua* showed tuat these instruments (Baiksdale pressure swl: , experienced significant drift. This dr'tt was tound to be 88 psi for the Barksdale pressure switches which exceeds the current allowable drift of 60 psi identified in the original GE Setpoint Methodology (NEDC 31336). Note, the GE Setrsint Methodology (NEDC-31336) utilized historical data frota Peach Bottom and other plants to develop the 60 psi allowable value; therefore, the allowable drift of 60 psi would be applicable for this evaluation. The function of this pressure input is to provide an anticipatory scram in the event of the fast closure of the MTCVs which cauld result in a significant pressure transient following a generator load reject. After reviewing the accident scenario and considering the potential impact to the analysis performed for this event, it was concluded that the only impact from drift in the non-conservative direction would be to the respe.se time of the scram signal. As identified in the General Electric Instrument Setpoint Methodology NEDC-31336 dated October 1986, upon initiation of the event (Load Reject), the fast acting
,olenoid valve will energize allowing the trip oil to drain.
The GE document identified that the pressure will decrease frr. 1 ominal 1600 psi to O psi within 8-10 milliseconds. At apicoxP itely 400 psig, it is identified that the disk dump va l *,e 111 open to allow the MTCV to start to fast close.
Since it takes approximately 10 milliseconds for press.ro to reach zorn, it can be reasonably concluded that the approximate 100 psi of drif t would in the worst case cause an additional time delay of no areater that 2 - 3 milliseconds.
This 2 ' millisecond time delay would be added to the overall response time of the trip. Licensing document OPL-3 identifies that the time between when the MTCV starts to fast close and the pressure switch actuates will be no greater than 30 mil': seconds. OPL- tlso identifies an additional 250
. millis .onds allowance Ior the RPS and Control Rods to start to ins et. Historically, the response times for these funct. is has been in the order of 150 milliseconds, allowing signif. : ant margin to the input allowed for in OPL-3. In aoditic . to the impact of drif t on the response time, it should also be understood that the logic for these trips provides redundancy which would make it highly unlikely that
._. . - - - - . . -- - . - . ~ .. . --~
Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 all instruments composing a channel would drift to the same degree and in the same direction. Considering any potential drift in the conservative direction, it has been determined that this is not a concern since the coincident logic for these trips should prevent any spurious scrams, and any excessive drift will be identified during the operating cycle and require corrective action. When evaluating the maximum drifu projected by the BWROG's program and determining the potential impact on the plant's safety analysis, it can be concluded that this potential drift has a neg'*gible impact.
arther, based on our experience at Limerick Generating Stat 111 (LGS), we have p?stulated t.iat this drift could be i caused by the EHC System vibrations and pressure oscillations.
After modifications on LGS Unit 1 to eliminate the vibration and pressure oscillations, the MTCV Fast Closure Pressul Switches drift was reduced to within the allowable surveillance test values. PEco will monitor the results of the LGS drift and apply those lessons learned to improving the PBAPS E!!C system.
The Magnetrol, Robertshaw and FCI switches are associated with the Scram Discharge Volume (SDV) reactor scram (Technical Specification Table 4.1.2, item 7.). A review of the tests for these switches indicates the following: the acceptance criteria of a test for the switch is that the switch. contacts change state and indicate an alarm when a rising water level ,
corresponding to 50 gallons is reached. This acceptance i criteria it observed with a marked sight glass. The alarm is confirmed to actuate when the observed lev 4 1 is at or below 50 gallons. Based on this method of testing, there are no ,
as-found and as-left values. Therefore, a 30-month drift value is not determined by the GE drift computer program.
The Robertshaw and RCI switches are replacements for the Magnetrol Switches and were installed to provide diversity. A review of the calibration check surveillance test showed that since 1983 there has been no failed tests. In addition, the same mode' Magnetrol switches were evaluated for LGS and found to have a 30 month drift of approximately the same as calibration allowance. Based on these reviews and the diverse switches, it is concluded that the surveillance interval can be extended to a maximum 30 months.
Based on the above evaluations, it is concluded that the impact on instrument availability, if any, is small as a result of the subject surveillance interval changes.
The wording change to Technical Specifications Teble 4.1.2, item 2, is being made to ensure that the present calibration
-Docket Nos. 50'-277 50-278; License-Nos. DPR-44
-DPR surveillance interval remains at-the specified frequency when:
the definition of refueling cycle is changed. .Because_the:
change maintains the calibration interval at the same-frequency, this change can be considered'an administrative--
change.
(8) Radiation / Effluent Monitoring Instrumentation TS Table 4.1.2, item 10 'page 44 TS Tahle 4.2.F, Jtem 18 page 16a TS Table 4.9.F, items 19 and 20 page 86a _
TS 4.8.C.4d page 211 TS Table 4.1.2, item 10 requires a calibration check using a E radiation source be made each refueling outage for the Main 1(
Steam Line High Radiation RPS instrument channel.
TS Table 4.2.F, item 18 requires the instrument channel for the Drywell High Range Radiation Monitors be calibrated:
"once/ operating cycle".
~
TS Table 4.2.F, item 19 and item 20 requires-the instrument channel for the Main Stack High Range Radiation Monitor ~and the Reactor Building Roof Vent High Ranqe Radiation Monitor be calibrated "once/ operating cycle".- A cadnge to Table'4.2.F is -
requested to nahe the calibration frequency for these two instrument channels be "once per 18 months" t TS item 4.8.C.4d requires the main _ stack sample flow line Hi/Lo pressure switches be_ calibrated.every 18 months. A- - -
change to TS 4.8.C.4d is requusted to make the calibration frequency every 24 months.
Safety Discussion: The subject Technical Specification line items currently require the calibration testing of the; subject:
instrumentation-to be performed once every 18 months and/or=
.once per operating cycle. .The calibration surveillance is-performed to ensure that the instrument'ic1 properly aligned so that at _ the previously evaluated setpoint, actuation takest .
place to' provide _the reqaired safety function and=to provide-sufficient'information for control of radioactive material release from the site. By increasing the operating cycle
-length, the time interval for calibration surveillance for the subject' instrumentation-(except TS 4.2.F 19 and120) will be '"
increased. However, as currently required by'PBAPS Technical.
' Specifications, functional tests _are performed-during the operating cycle more frequently than the calibration surveillance. These functional tests can' detect failures =of-the-instrumentation channels more frequently than once.every 18 months. The drywell.high range radiation ~ monitoring-instrument loops-(Zechnical Specification Table 4.2.F, item l
Docket Nos. 50-277 50-278 3
License Nos. DPR-44 DPR-56
- 18) are highly reliable. This monitoring instrumentation is classified as safety related and meets the design criteria of safety related status. This includes redundency and independent channels which ensures a nigh confidence of system performance even with the failure of a single component. The other monitoring instrumentation (except the drywell high range radiation monitoring loops) is classified as non-safety related. This instrumentation also has been designed to criteria that provides reliability with multiple instrument channels to provide backup information in the event of a single channel failure. Note, an exception to multiple channels for backup are the common main stack sample flow switches. The main stack sample flow switches do not backup one another. A review of the Technical Specifications indicates that these switches are functionally tested every six months. Since the switches provide only a' gross high/ low flow alarm, the six month functional tests are adequate to detect failures. Based on the above discussion, the conclusion is made that the negligible impact on instrumentation availability permits the change to 24 month surveillance intervals.
To verify this conclusion, an historical search of the surveillance tests for each instrument was performed. The search identified all failed or partially failed tests, and then each failed or partially failed test was reviewed and evaluated. The purpose cf this evaluation was to demonstrate that the increased calibration surveillance interval would not increase the period an instrument would be unavailable. The results of this review supports the above conclusion that the impact on safety, if any, is small as a result of the change in the subject surveillance interval.
A second evaluation performed an instrument drift analysis for the increase in the calibration interval to a maximum of 30 months. The summary of the drift analysis is below:
The GE methodology, previously described, was used to perform the drift analysis on the Mercold D7400, Main Stack Gau Sample Pressure Switch, (TS 4.8.C.4d). Based on this drift aralysis, we conv)rde an increase in the surveillance interval to accomradcce a 24 month fuel cycle does not affect thesa ,
instr.ments with respect to drift.
RPS MSL Radiation Monitors: The current radiation m nit
- s e installed for Unit 2 and Unit 3 are being replaced by -G ieral Electric's NUMAC microprocessor based instrumentation. This instrumentation is scheduled to be replaced on Unit 2 during the next refueling outage which ste_ted in September 1992, and on Unit 3 during the next refueling outage currently
. - - - - - . -- - . ~-. . - - - . . .
Docket Nos. 50-277 50-278 i License Nos. DPR-44 DPR-56 scheduled for September 1993. Since the NUMAC instrumentation has not been installed at PBAPS, no drift study is-possible.
However, GE has published data that supports the conclusion that the 30 month drift values do not exceed existing surveillance test drift allowances. Since for Unic 2, the NUMAC instrumentation will be replaced prior to-commencing a 24 Month Cycle, the GE provided justification is sufficient for changing the surveillance interval to 24 months with a maximum of 30 months. On Unit 3, the NUMAC instrumentation will not be installed until the next refueling outage currently scheduled for September 1993. Since Unit 3 is currently on a 24 Month operating Cycle, this will result in the existing instrumentatica being subjected to a surveillance incerval of greater than the current evaluated interval of 22.5 month (18 months plus grace). For this additional period the instrument may drift. This is not considered to be a problem because this instrument (except the detector) is calibrated quarterly and the setpoint is checked by a weekly functional test. These tests will idenLify any potential drift of these instruments (except for the detector and cable) during this period of time. Furthermore, the readout of these instruments are monitored by station personnel and any deviation greater than +100 mR/hr/-200 mR/hr will require further action by plant staff. The quarterly and weekly surveillance tests, monitoring by plant staff, and the fact that the ion chamber detectors and cable are not considered susceptible to drift ensure that there is no potential impact on the subject instrument availability by allowing the additional time interval of source calibration of the existing radiation monitors. If Unit 2 NUMAC instrumentation is not installed during the current refuel outage a similiar justification would still apply for extending the surveillance frequency to 24 months.
General b".omics Rad Monitors: The drywell high range radiation monitors are nzanufactured by General Atomics (Table 4.2.F, item 18). A review of the surveillance tests indicates that a sufficient amount of historical data does not exist to satisfy the statistical algorithms of the GE drift computer program. A closer examination of the data from the surveillance tests identifies that, except for equipment that malfunctioned and had to be replaced, the monitors did not require recalibration for a period of time from 1988 to 1991.
Based on the above dir^ussion that historical data for the radiation monitors shows that recalibration was not required for a period of time greater than 24 months, the conclusion is made that the recalibration interval can be extended.
Further, the instrumwNation will continue to be monitored for drift using the trend'ag program being established for instrument drift.
Docket Nos. 50-277 50-278 i
License Nos. DPR-44 DPR-56 l l
l Based on the above evaluations, it is concluded that the impact on instrument availability, if any, is small as a i result of the 24 month surveillance interval changes.
The wording change to Technical Specification. Table 4.2.F, items 19 and 20, are being made to ensure that the present calibration surveillance interval remains at the specified frequency when the definition of operating cycle is changed.
Because the change maintains the calibration interval at the same frequency, this change can be considered an administra-tive change.
(9) Control Rod Block TS Table 4.2.C, item 10 page 83 TS Table 4.2.C, item 10 defines the minimum test and calibration frequency for Control Rod Blocks Actuation. The calibration frequency for the Scram Discharge Instrument Volume High Level, instrument channel is delineated as "once/ operating cycle".
Safety Discussion: The subject Technical Specification line item currently requires the calibration testing of the subject instrumentation to be performed once per operating cycle. The calibration surveillance is performed to ensure that the instrument is properly aligned so that at a previously evaluated setpoint, actuation takes place to provide the required safety function. By-increasing the operating cycle length, the time interval for calibration surveillance of the subject instrumentation will be increased. However, as currently required by PBAPS Technical Specifications, functional tests are performed during the operating cycle more frequently than the calibration surveillance.
The control Rod Block instrumentation is classified as safety related (for pressure boundary only). Instrumentation purchased for this function is highly reliable and meets the design criteria of safety related status. Based on the above discussion, the conclusion is made that the negligible impact on instrumentation availability permits the change to 24 month surveillance intervals.
To verify this conclusion, an historical search of the surveillance tests for each instrument was performed. The search identified all failed or partially failed tests, and then each failed or partially failed test was reviewed and evaluated. The purpose of this evaluation was to demonstrate that the increased calibration surveillance interval would not increase the period an instrument would be unavailable. The 2
a Docket Nos.-50-277 50-278 License Nos. DPR-44 DPR-56 results support the above conclusion that the impact on instrument availability, if any, is small as a result of the change in the subject surveillance interval.
A second evaluation performed an instrument drift analysis for the increase in the calibration interval to a maximum of 30 months. The purpose-of this evaluation was to support the conclusion that the impact due to drift on the subject instruments would have a small, if any,-impact on the instrument availability. The following summarizes the arguments that the impact from drift for the increased surveillance interval will have a small, if any, impact on instrument availability. Magnetrol Switches provide the input for the Scram Discharge Volume (SDV) for a Control Rod Block, Table 4.2.c, item 10. The acceptance criteria of a test for the switch is that the switch contacts change state and indicate an alarm, when a rising water level corresponding to 25 gallons is reached. This acceptance criteria is observed with a marked sight glass. The alarm is confirmed to actuate when the observed level is at or below 25 gallons. Based on this method of testing, there are no as-found and as-left values. Therefore, a 30 month drift.value-cannot be determined. A review of the results of existing surveillance tests indicates that, except for tests with defective switches that had to be replaced, the tests were satisfactory. This indicates that the switches actuated at or below a level corresponding to 25 gallons unless a switch was defective.
Further, the Magnetrol level switches have the same trip mechanism as the SDV Switches used at the Limerick Generating Station (LGS). For LGS, the Magnetrol-SDV Switches have been evaluated sat.Jfactorily for 30 month drift. Based on the above discussion, the Magnetrol Switches have operated satisfactorily without recalibration and have been identified to be similar switches that have been satisfactorily evaluated for drift at LGS. Therefore, it is concluded that the surveillance interval for these switches can be increased-to l accommodate a 24 month fuel cycle.
L l Other Changes to the PBAPS Technical Specifications to support 24 i
Fuel Cycle Operation:
In addition to the proposed changes to the instrumentation TS line items, the following is a discussion of other changes PECo is requesting to support a change to a 24 month fuel cycle. The overall impact of these changes has been shown to be minimal based on the combination of the evaluations provided for the individual TS line items changes proposed in the submittal and the earlier submittal.
~. .
Dockst.Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 (1) The following changes to the Definition Section (page 8) are being proposed:
the definition of "Once per Cycle" will be_ changed from "At least once per 550 days" to "At least once per 732" days.
the definition of " Refuel" will be changed from "At least once per 550 days" to "At least once per 732 days".
the definition of "(N) Refuel Cycle" will be changed from "At least once per (550xN) days" to "At least once per (732xN) days".
A new definition for 24 months will be added: "At least once per 732 days".
(2) In the bases of PBAPS TS sections 3/4.6.D, page 157 the following change is proposed: change "50 percent of the valves per year..." to "50 per cent of the valves per cycle....".
This change to the bases will correct an omission that occurrad when PECo converted from a 12 month fuel cycle to an 18 month fuel cycle. PEco changed the TS but did not reflect-the change in the bases. The change will maintain consistency between the TS and the current operating practices, and the TS bases.
(3) In the bases of PBAPS TS section 3/4.7.A, page 193, the following change is proposed: delete "approximately oncc per year" from the "Drywell Interior Paragraph". This change to the bases will correct an omission that occurred when PECo converted from a 12 month fuel cycle to an 18 month fuel cycle. PECo changed the TS but did not reflect the change in the bases. The change will maintain consistency between the TS, the current operating practices, and the TS Bases.
(4) Technical Specification Table 4.15 (page 240v): change the definition of "R" from "every 18 months" to "every 24 months".
Safety Assessment Summary The proposed TS changes involve a change in the surveillance testing intervals from 18 months to 24 months to facilitate the current change in the PBAPS Unit 2 and Unit 3 refueling cycles from 18 months to 24 months. The proposed _ changes are to the surveillance frequencies only, and do not involve a change to the TS surveillance requirements themselves or the way in which the surveillances are performed. Additionally, the impact of the proposed TS changes on the availability of equipment or systems required to mitigate the consequences of an accident, if any, is small based on other, more frequent testing or the availability of Dockst Noc. 50-277 50-278 License Nos. DPR-44 DPR-56 redundant systems or equipment. A review of surveillance test history demonstrated that there was no evidence _of any failures that would invalidate the above conclusions.
Information Supporting a Finding of No Significant Hazards Consideration We have concluded that the proposed changes to the PBAPS TS, to facilitate a change from 18 month to 24 month refueling cycles, do not involve a Significant Hazards Consideration. In support of this determination, an evaluation of each of the three standards set forth in 10CFR50.92 is provided below.
- 1. The proposed TS changes do not involve a significant increase in the probability or consequences of an-accident previously evaluated.
The proposed TS changes jnvolve a change in the surveillance testing intervals to facilitate the current change in the PBAPS Unit 2 and Unit I, refueling cycles from 18 months to 24 months. The prcposed TS changes do not physically impact the plant nor de they' impact;any design or functional requirements of the associated systems. That is, the proposed TS changes do not degrade the performance or increase the challenges of any safety _
systems assumed to function in.the accident. analysis below the design basis. The proposed TS changes tio not impact the TS surveillance requirements themselves nor the way in which the surveillances are performed. In addition, the proposed TS changes do not introduce any new accident initiators since no accidents previously evaluated have as their initiators anything related_to the change in the frequency of surveillance testing.
Also, the proposed TS changes do not affect the availability of equipment or systems required to mitigate the consequences of an accident because of other, more frequent testing or the availability of redundant systems or equipment. Furthermore, an historical review of surveillance test results indicated that there was no evidence of any failures that would invalidate the above conclusions. Therefore, the proposed TS changes do not increase the probability ut consequences of an accident previously evaluated.
2
- 2. The proposed TS changes do-not create the possibility of a new or different kind of accident from any accident-previously evaluated.
m Dockst Nos. 50-277 50-278 License Nos. DPR-44 DPR-56' The proposed TS changes involve a change in the surveillance testing intervals to facilitate the current change in the PBAPS Unit 2 and Unit 3 refueling cycles from 18 months to 24 months. The proposed TS changed do not introduce any failure mechanisms of a different type than those previously evaluated since there-are no
, physical changes being made to the facility. In addition, the surveillance test requirements themselves and the way surveillance-tests are performed will remain unchanged. Furthermore, an historical review of surveillance test results indicated there was no evidence of any failures what would invalidate the above conclusions. Therefore, the proposed TS changes do not create the possibility of a new or different kind of accident from any previously evaluated.
- 3. The proposed TS changes do not involve a significant reduction in a margin of safety.
Although the proposed TS changes will result in an increase in the interval between surveillance tests, the impact on system availability is small based on other, taore frequent testing or redundant systems or equipment, and there is no evidence of any failures that would impact, if any, the availability of the systems.
Therefore, the assumptions in the licensing basis are not impacted, and the proposed TS changes do not reduce a margin of safety.
Information Supporting an Environmental Assessment An environmental assessment is not required for the changes proposed by this Change Reques*, because the requested changes conform to the .:riterja for " actions eligible for categorical exclusion," as specified in-10C7R51.22(c)(9). The requested changes will have no impact on the environment. - The requested changes do not involve a significant hazards consideration'as discussed in the preceding section. The requested changes do not involve a significant change in the types or significant increase in the amounts of any effluents that may.be released offsite. In addition, the proposed changes do not involve a significant-increase in individual or cumulative occupational radiation exposure.
Dockst Nos. 50-277-50-278 License Nos. DPR-44 DPR-56 Conclusion The Plant Operations Review Committee and the Nuclear Review Board have reviewed these proposed changes to the TS and have concluded that they do not involve an unreviewed safety question, or a significant hazards consideration, and will not endanger the health and safety of the public.
t