ML20044B876
| ML20044B876 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom, Limerick  |
| Issue date: | 03/05/1993 |
| From: | Beck G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-90-001, IEB-90-1, NUDOCS 9303110232 | |
| Download: ML20044B876 (21) | |
Text
T 10CFR50.54(f) i gi NRCB No. 90-01, PIHLADTLPHIA ELECTRIC COMPANY Supplement 1 diUCLEAR GROUP rfEADQUARTERS 955-65 CHESTERBROOK BLVD.
WAYNE, PA 19087-5691 (215) 640-6000 NUCLEAR SERVICES DEPARTMENT Decket Nos. 50-352 50-353 50-277 50-278 License Nos. NPF-39 NPF-85 DPR-44 DPR-56 U.S.
Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
Limerick Generating Station, Units 1 and 2 Peach Bottom Atomic Power Station, Units 2 and 3 Response to NRC Bulletin No. 90-01, Supplement 1,
" Loss of Fill-Oil in Transmitters Manufactured By Rosemount" Gentlemen:
On March 9, 1990, the NRC issued Bulletin No. 90-01,
' Loss of Fill-Oil in Transmitters Manufactured by Roseraount," requesting that holders of operating licenses for nuclear power reactors promptly identify and take corrective actions for Rosemcunt Model 1153, Series B and D, and Model 1154 transmitters that may be or have the potential for leaking fill-oil.
Philadelphia Electric Company (PECo) responded to this NRC Bulletin (NRCB) by letters dated July 13, 19 f ', October 16, 1990, and April 30, 1993.
Subsequently, on December 22, 1992, the NRC issued NRCB No. 90-01, Supplement 1,
" Loss of Fill-Oil in Transmitters Manufactured by Rosemount," to inforst addressees of activities taken by the NRC and the industry in evaluating Rosemount transmitters, and to request licensees to take actions to resolve this issue.
The Supplement requested that
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Nuclear Regulatory Commission March 5, 1993 Document Control Desk Page 2 recipients review the information for applicability to their facilities and modify, as appropriate, their actions and enhanced monitoring programs as described in the Supplement.
In addition, the Supplement requested licensees to provide a response to the Reporting Requirements within 60 days after receipt.
PECo received NRCB No. 90-01, Supplement 1 on January 7, 1993.
r Attached is PECo's response to NRCB No. 90-01, Supplement 1, for Limerick Generating Station (LGS), Units 1 and 2,
and Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3.
As requested by the Supplement, this response is being submitted within 60 days from the date of receipt, and in accordance with 10CFR50.54(f).
The attached response addresses the Reporting Requirements t
identified in the Supplement for both the LGS and PBAPS facilities.
All of the Requested Actions have been completed,
'7d are specifically identified in Table 1 of the attachment.
The description of PECc's enhanced monitoring program, which has been modified as indicated in the attachment, is also included as Exhibit 1 to the attachment.
If you have any questions, or require additional information, please do not hesitate to contact us.
Very truly yours, j[
c-c G. J( Beck, Manager i
Licensing Section Attachment cc:
T.
T. hartin, Administrator, Region I, USNRC w/ attachment T.
J. Kenny, USNRC Senior Resident Inspector, LGS w/atte.chment I
J. J. Lyash, USNRC Senior Resident Inspector, PBAPS w/ attachment I
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COMMONWEALTH OF PENNSYLVANIA ss.
COUNTY OF CHESTER G.
R. Rainey, being first duly sworn, deposes and says:
i That he is Vice President of Philadelphia Electric Company, I
the Applicant herein; that he has read the foregoing response to l
NRC Bulletin No.
90-01, Supplement 1,
" Loss ol Fill-Oil in Transmitters Manuf actured by Rosemount," and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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Vice President Subscribed and sworn to beforemethislld t
day of 7 ; ' &
1993.
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f Limerick Generating Station, Units 1'and 2 Docket Nos. 50-352 50-353 Peach Bottom Atomic Power Station, Units.2 and 3 i
Docket Nos. 50-277 50-278 l
Response to NRC Bulletin No. 90-01, Supplement 1,." Loss of Fill-Oil in Transmitters Manufactured by Rosemount" t
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Page 1 of 5 1
i ATTACHMENT l
Limerick Generating Station, Units 1 and 2 i
Peach Bottom Atomic Power Station, Units 2 and 3 s
Response to NRC Bulletin No. 90-01, Supplement 1, " Loss of Fill-Oil in Transmitters Manufactured by Rosemount"
Background
On March 9,1990, the NRC issued Bulletin No. 90-01, " Loss of f
Fill-Oil in Transmitters Manufactured by Rosemount," requesting that holders of operating licenses for nuclear power _ reactors promptly identify and take corrective actions for Rosemount Model 1153, Series B and D, and Model 1154 transmitters that may be or have the potential for leaking fill-oil.
Philadelphia Electric Company (PECo) responded to this NRC Bulletin (NRCB) by letters dated July 13, 1990, October 16, 1990, and April 30, 1991.
'su..equently, on December 22, 1992, the NRC issued NRCB No.
90-01, rupplement 1, " Loss of Fill-Oil in Transmitters Manuf actured by Rosemount," to inform addressees of activities taken by the NRC and the industry in evaluating Rosamount transmitters, and to
-t request licensees to take actions to resolve this issue.
The i
Supplement requested that recipients reviow the inf wq. tion for applicability to their facilities and modify, as appropriace, their i
actions and enhanced monitoring programs as described in the Supplement.
In addition, the Supplement requested licensees to r
provide a response to the Reporting Requirements within 60 days after receipt.
PECo received NRCB No. 90-01, Supplement 1,
on l
January 7, 1993.
The Reporting Requirements delineated in the Supplement have been restated below followed by our response for Limerick l
Generating Station (LGS), Units 1 and 2, and Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3.
r REPORTING REQUIREMENTS l
Operating Reactors Provide within 60 days after receipt of this bulletin, a response that includes the following-1.
A statement whether the licensee will take the actions requested above.
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Response to NRCB No. 90-01, Supplement 1 Attachment l
Page 2 of 5 i
2.
With regard to the actions requested above that the licensee is taking:
a.
A list of the specific actions that the licensee will complete to meet Item 1 of Requested Actions for Operating Roactors provided in this supplement, including justifications as appropriate.
b.
The schedule for completing licensee actions to meet Item 1 of Requested Actions provided in this supplement.
c.
When completed, a statement confirming that Items 1 and 2 of Requested Actions for Operating Reactors provided in this supplement have been completed.
3.
A statement identifying those actions requested by the NRC that the licensee is not taking and an evaluation which provides the bases for not taking the requested actions.
RESPONSE
Response to Reporting Requirement 1.
PECO has taken the actions reques'.ed in NRCB No.
90-01, Supplement 1, for LGS, Units 1 and 2, and PBAPS, Units 2 and 3.
Response to Reporting Requirement 2.a.
The specific actions to meet Item 1 of the Requested Actions in the Supplement Tre identified in the attached Table 1, and are further explained below. These actions supersede the actions taken in response to the original Bulletin.
Requested Action Items 1.a and l.b of the Supplement are not applicable since there are no transmitters within the scope of NRCB No. 90-01, supplement 1, that meet the criteria of these Action Items installed at LGS or PBAPS (see attached Table 1).
The transmitters installed at LGS and PBAPS that meet the criteria of Requested Action Items 1.c and 1.d of'the Supplement, as appropriate, are included in the enhanced monitoring program implemented at LGS and PBAPS (see attached Table 1).,The enhanced monitoring program provides a means to:
- 1) promptly identify transmitters exhibiting symptoms indicative of loss of fill-oil,- 2' confirm operability of these transmitters, and 3) initiate the appropriate corrective action for those transmitters determined to l
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Response to NRCB No. 90-01, Supplement 1 Attachment Page 3 of 5 be inoperable.
Although previously provided in our July 13, 1990 response to NRCB No.
90-01, a description of PECo's enhanced monitoring program is provided as Exhibit 1 to this attachment.
The program has been modified based on the guidance provided in the Supplement.
Specifically, Item C.2 (i.e.,
Data Collection Methods) of i
Exhibit 1 to our July 13, 1990 response stated that instrument panel meters would be used for data collection whenever - the transmitter drift limit, based on Rosemount Technical Bulletin No.
4, is equal to or greater than 1% of the calibrated span.
Our July 13, 1990 response also stated that data would be collected using the panel meters on a bi-weekly basis.
Requested Action Item 1.c of NRCB No. 90-01, Supplement 1, states that transmitters that meet t
the criteria of this Action Item should be monitored on a monthly basis.
The accuracy of the panel meters is consistent with that needed for comparison with manufacturer drift data criterion when the drift criterion is equal to or greater than 1% of the calibrated span.
Accordingly, we have modified the enhanced monitoring program, as indicated in Item C.2 of Exhibit 1 to this attachment, to require collecting the data using panel meters on a monthly basis.
In addition, Exhibit 1 also incorporates the change to the enhanced monitoring program previously described in our October 16, 1990 response to NRCB No. 90-01.
Specifically, our October 16, l
1990 response indicated
- that, based on our experience of implementation of the enhanced monitoring program, the extended span response checks at approximately 130% of calibrated span could not be performed for transmitters, in particular, those tnat provide indication only, where a transmitter output greater than 100% can not be indicated.
Accordingly, we have changed the i
description of the enhanced monitoring program, as indicated in Item E (i.e., Extended Span Response Checks) of Exhibit 1 to this attachment, to reflect this previous change to the program.
Requested Action Item 1.c of the Supplement also stated that on a case-by-case basis, except for transmitters that initiate reactor protection or Anticipated Transient Without Scram (ATWS) trips on high pressure or low reactor water level, licensees may monitor using an enhanced surveillance program at least once every refueling cycJe, but not to exceed 24 months, transmitters that meet the criteria of this Action Item if sufficient justification is provided based upon transmitter performance in service and specific safety function. This Action Item also requested that the NRC be-provided a copy of the justification to extend the enhanced j
surveillance program beyond the monthly test interval, At the current time, PECo will continue to monitor the process operating data of these transmitters on a monthly basis at LGS and PBAPS as l
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I Response to NRCB No. 90-01, Supplement 1 Attachment Page 4 of 5 indicated in the attached Table 1 and Exhibit 1.
However, if in the future we determine to extend the monitoring of these transmitters beyond the monthly interval, we will provide the NRC with a copy of the appropriate justification at that time.
Requested Action Items 1.e and 1.f of the Supplement specify the criteria (see attached Table 1) for excluding transmitters from the enhanced monitoring program (i.e.,
at the licensee'"
i discretion) based on a high degree of confidence for detecting failure of the transmitters caused by a loss of fill-oil and a high degree of reliability for the function of the transnitters consistent with their safety significance.
Transmitters installed at LGS that meet the criteria of both of these Action Items have been excluded from the enhanced monitoring program.
Transmitters installed at PBAPS that meet the criteria of Action Item 1.f have been excluded from the enhanced monitoring program.
Currently, there are no transmitters installed at PBAPS that meet the criteria of Action Item 1.e.
With respect to transmitters excluded from the enhanced monitoring program at LGS and PBAPS, we have a high degree of j
confidence for detecting the failure of such transmitters, and we will maintain the reliability of the function of such transmitters, based on the demonstrated performance of the transmitters and the following reasons.
As stated in our July 13, 1990 response: 1) l transmitter calibration procedures have been revised to include statements that remind the Instrumentation and Controls (I&C) technicians to look for symptoms indicative of loss of fill-oil (i.e.,
sluggish response, inability to calibrate to full span, reduced or one-sided response to signal
- noise, etc.)
while performing routine calibrations, 2) operations personnel at both LGS and PBAPS have been advised of the potential problems associated with Rosemount transmitters and the symptoms associated with these problems, and 3) I&C technicians at both LGS and PBAPS i
have been trained to observe for symptoms indicative of loss of fill-oil in transmitters during their performance of routine calibration and testing activities.
In addition, we will continue to: 1) perform the extended span response check (i.e.,
Item E of the attached Exhibit 1) as a part of the regularly scheduled surveilknce testing of such transmitters, and 2) perform an operabilicy acceptance test (i.e.,
Item D of the attached Exhibit
- 1) to screen any transmitters identified as exhibiting symptoms indicative of loss of fill-oil.
With respect to Requested Action Item 1.e, we will continue to evaluate transmitters installed at both LGS and PBAPS that meet the criteria of this Action Item for exclusion from the enhanced monitoring program in the future as they exceed the Rosemount recommended psi-month threshold criteria.
j Response to NRCB No. 90-01, Supplement 1 Attachment Page 5 of 5 t
Response to Reporting Requirement 2.b.
PECo has completed the actions to meet Item 1 of the Requested
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Actions at both LGS and PBAPS as indicated in the response to l
Reporting Requirement 2.a. above, i
Response to Reporting Requirement 2.c.
Items 1 and 2 of the Requested Actions have been completed at both LGS and PBAPS.
Item I has been completed as indicated in the i
response to Reporting Requirement 2.a. above.
In addition, we have evaluated our enhanced monitoring program as requested by Item 2, i
and have determined that our program provides measurement data with an accuracy range consistent with that needed for comparison with i
manufacturer drift data criterion for determining degradation.of Rosemount transmitters within the scope of NRCB No.
90-01, Supplemont 1, caused by a loss of fill-oil.
The data collection i
methods and the criteria used are discussed. in Item C of the attached Exhibit 1.
Response to Reporting Requirement 3.
As indicated in response to Reporting Requirement 1.,
and-described in responso to Reporting Requirement 2.a. above, PECo has taken the actions requested in NRCB No. 90-01, Supplement 1, for
_l LGS, Units 1 and 2, and PBAPS, Units 2 and 3.
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TABLE 1 Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 50-353 Peach Bottom Atomic Power Station, Units 2 and 3 Docket Nos. 50-277 50-278 Response to'NRC Bulletin No. 90-01, Supplement 1, " Loss of Fill-Oil in Transmitters Manufactured by'Rosemount" i
Requested Actions for Rosemount Transmitters Manufactured
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Prior to July 11, 1989 and Installed in Safety.Related or Anticipated Transient Without Scram Systems-t I
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TABLE 1 Limerick Generating Station, Units 1 and 2 Peach Bottom Atomic Power Station, Units 2 and 3 Response.to NRC Bulletin No. 90-01, Supplement 1 n quested Actions for Rosemount Transmitters Manufactured e
Prior to July 11, 1989 and Installed in Safety Related or Anticipated Transient Without Scram Systems No. of Transmitters (2)(2)
Requested Actior Enhanced Surveillance Program PBAPS
) JS Monitoring Method (3)('ItI Classification Criteria Units 2 & 3 Units 1 & 2
- 1) 5500 pai (Action 1.f) 8 84 ExcludedI6)
- 2) >500 psi 51500 psi f
< threshold 72 93 RC, ZD, ORI7) criteria RPS, ESF & ATWS (Action 1.c)
- 3) >500 psi 51500 poi
< threshold 0
16 oR criteria non-(RPS, ESF or ATWS)
(Action 1.d)
- 4) >500 psi 51500 psi
> threshold 0
21 Excluded (6) criteria (Action 1.e)
0 Not applicable (Action 1.a) i
Not applicable (Action 1.b) 9
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Page 1 of 2 TABLE NOTES 1)
Rosemount Model
- 1153, Series B
and D,
transmitters manufactured before July 11, 1989, that are used in safety related systems or systems installed in accords.nce with 10CFR50.62 (i.e., the ATWS rule).
There are no Model 1154 transmitters within the scope of NRCB No. 90-01, Supplement 1 installed at Limerick Generahing Station (LGS), Units 1 and 2, or Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3.
Transmitters replaced or refarbished with models or sensor modules manufactured after July 11, 1989 are excluded.
2)
The number of transmitters at each site which meet the classification criteria as defined by the " Requested Actions" in NRC Bulletin No. 90-G1, Supplement 1.
These numbers may 4
change based on transmitter replacement, refurbishment, or time-in-service et normal operating pressure.
3)
Each transmitter within the scope of NRCB No.
90-01, Supplement 1,
is monitored through the enhanced monitoring program (see attached Exhibit 1) unless a transmitter is excluded from the program based on the guidance provided in the Supplement.
If a transmitter is identi fied as exhibiting symptoms indicative of loss of fill-oil ana fails to meet the operability acceptance test / criteria, the appropriate corrective actions are taken (i.e.,
Item D in the attached Exhibit 1 ).
4)
Monitoring Methods are as follows.
a)
RC - drift trending of process operating data for redundant channels (i.e.,
Data Analysis Methods 1 and 2 in attached Exhibit 1).
b)
ZD - zero drift trending of process operating data (i.e.,
Data Analysis Method 3 in attached Exhibit 1).
c)
OR - zero drif t trending of calibration data (i.e., Data Analysis Method 4
in attached Exhibit 1) and extended span response check (i.e.,
Item E in attached Exhibit 1).
An extended span response check is not performed for reverse-calibrated transmitters (i.e., reactor vessel water level), or for transmitters, in particular, those that provide indication only, where a transmitter output greater than 100% can not be indicated.
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5)
The trending analysis results from process or calibration data may allow the " Monitoring Method" of a transmitter, or group of transmitters, to be changed.
6)
These transmitters are excluded from the enhanced monitoring program based on the guidance provided in NRCB No. 90-01, Supplement 1.
A high degree of confidence is maintained for detecting failure of these transmitters caused by a loss of fill-oil, and a high degree of reliability is maintained for the function of these transmitters consistent with their safety significance.
7)
The frequency of data collection for trending process data may be modified based on the results of the drift analys3e.
On a case-by-case basis, if sufficient justification exists based on a transmitter's performance in service and specific safety function, the trending of process data may be suspended, and the trending of calibration data only continued on the required routine testing frequency basis.
The justification for such cases will be provided to the NRC at that time.
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4 EKHIBIT 1 Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 50-353 Peach Bottom Atomic Power Station, Units 2 and 3 Docket Nos. 50-277 50-278 Response to NRC Bulletin No. 90-01, Supplement 1,
" Loss of Fill-Oil in Transmitters Manufactured by.Rosemount" Revised Enhanced Monitoring Program For Rosemount Transmitters Manufactured Prior to July 11, 1989 7
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L Page 1 of 7 EXHIBIT 1 Limerick Generating Station, Units 1 and 2 Peach Bottom Atomic Power Station, Units 2 and 3 Response to NRC Bulletin No. 90-01,-Supplement 1 Revised Enhanced Monitoring Program for Rosemount Transmitters Manufactured Prior to' July.11, 1989 Overview This revised enhanced monitoring program, implemented at.
Limerick Ger.erating Station (LGS), Units 1 and 2, and Peach Bottom Atomic Power Station (PBAPS),-Units 2 and 3, provides guidance to analyze Rosemount ' transmitter calibration data obtained during routine surveillance
- checks, and transmitter operating data obtained between routine' surveillance checks, to identify drift trends indicative of loss of fill-oil in Rosemount Model 1153, Series B and D transmitters.
There are no Rosemount Model 1154 transmitters within the scope of NRC: Bulletin (NRCB) No. 90-01, Supplement 1, installed at LGS or PBAPS.
The analyzed data is evaluated against drift limits and if these drift limits are exceeded, an engineering ' evaluation is performed. Based on the'results of the engineering evaluation, an operability acceptance test is performed, if necessary, to confirm transmitter operability.
The drift limits-are determined in accordance with the information provided in Rosemount Technical Bulletin No. 4.
This enhanced monitoring program also provides. for performing extended span response checks during routine.
surveillance checks.
This exhibit will discuss the following topics in the order presented below.
A)
Data Analysis Methodo B)
Determination of Drift Limits C)
Data Collection Methods D)
Operability Acceptance Test / Criteria E)
Extended Span Response Checks
Exhibit 1 Page 2 of 7 A)
Data Analysis Methods The transmitter calibration data and transmitter operating data collected as part of the enhanced monitoring program is analyzed using one or more of the following methods.
1)
Drift Trending of Process Operating Data For Three or More Redundant Instrument Channels.
2)
Drift Trending-of Process Operating Data For Two Redundant Instrument Channels.
3)
Zero Drift Trending of Process Operating Data.
4)
Zero Drift Trending of Calibration Data.
t The data analysis methods are chosen based on the availability of redundant instrument channels, the_ transmitter application, the ability to obtain meaningful data during normal plant operations, and the transmitter's applied static pressure.
The data analysis methods initially chosen may be revised to provide a more appropriate approach based on operating experience and analysis-results.
The _ following provides a more detailed discussion of each data analysis method and when they are utilized.
1)
Drift Trending of Process Operating Data For Three or More-Redundant Instrument Channels This data analysis method may be used when there are three or more redundant instrument channels monitoring the same process parameter.
Transmitter operating data is collected between calibration intervals.
A process average'is calculated using the opc sting data from all the redundant instrument channels Leing monitored.
A moving weighted average value, as a percent of the calibrated span, of the deviation of each transmitter's data point from the process average is calculated.
The moving weighted average value of deviation represents the drift of each transmitter's output from the average of the output of all of the redundant transmitters.
A moving weighted average value of the deviation is used to smooth the data scatter and provide a more stable graphical analysis and provide for easier detection of a shift or change in the-trend of this deviation.
The moving weighted average value of deviation is compared to a predetermined drift limit.
If the drift limit is exceeded, the plot is reviewed to assure there are no anomalies in the data used to obtain the plot ~, and an evaluation of the plot is performed to verify that the trend of the data has exceeded the drift limit.
If no anomalies are found, and the transmitter trend exceeds
i Exhibit 1 Page 3 of 7 the drift
- limit, the transmitter is identified as exhibiting symptoms of loss of fill-oil and the appropriate operability acceptance test / criteria are applied.
2)
Drift Trending of Process Operating Data For Two Redundant Instrument Channals This date analysis method may be used when there are only two redundant instrument channels monitoring the same process parameter.
Transmitter operating data is collected between calibration intervals.
A moving weighted average, as a percent of the transmitter's calibrated span, of each transmitter's data is calculated and plotted.
A moving weighted average value is used to smooth data scatter and provida a more stable graphical analysis.
The moving weighted average values of each transmitter are monitored to detect a shift or change in their positions relative to each other.
If the difference in the moving weighted average values of the transmitters converge or diverge by more than a
predetermined drif t limit, the plot is reviewed to assure there are no anomalies in the data used to obtain the plot, and an evaluation of the plot is performed to verify that the trend of the data has exceeded the drift limit.
If no anomalies are found, and the transmitter's trend exceeds the drift
- limit, the transmitter is identified as exhibiting symptoms of loss of fill-oil and the appropriate operability acceptance test / criteria are applied.
3)
Zero Drift Trending of Process Operating Data This data analysis method may be used when the process being monitored is flow or dif ferential pressure and the process value is usually zero.
Transmitter operating data, representing zero process conditions, is collected between calibration intervals.
The operating data is plotted and the cumulative drift from zero is trended. If the accumulated drif t exceeds a predetermined drift limit, the plot is reviewed to assure there are no anomalies in the data used to obtain the plot, and an evaluation of the plot is performed to verify that the trend of the data has exceeded the drift limit.
If no anomalies are found, and the transmitter's trend exceeds the drift
- limit, the transmitter is identified as exhibiting symptoms of loss of fill-oil and the appropriate operability acceptance test / criteria are applied.
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Exhibit 1 Page 4 of 7 4)
Zero Drift Trending of Calibration Data This data analysis method is used for all transmitters included in the enhanced monitoring program.
Transmitter calioration data is collected from the i
station's routine transmitter calibration checks.
The calibration data la analyzed and the cumulative drift from zero is trended.
If the accumulated drift exceeds a predetermined drift limit, the plot 'is reviewed to assure there are no anomalies in the data used to obtain l
the plot, and an evaluation of the plot is performed to verify that the trend of the data has exce^deo the drift limit.
If no anomalies are found, and the transmitter's trend exceeds the drift
- limit, the transmitter is identified as exhibiting symptoms of loss of fill-oil and i
the appropriate operability acceptance test / criteria are applied.
[
I This analysis method also evaluates the drift rate of each transmitter included in the program to extrapolate out to the next routine surveillance check an estimate of cumulative drift for each transmitter at the v
next routine surveillance check.
If the estimated
't cumulative drift exceeds the predetermined drift limit, the plot is reviewed to assure there are no anomalies in i
the data used to obtain the plot, and an evaluation of i
the plot is performed to verify that the trend of the i
data could exceed the drift limit.
If no anomalies are 1
found, and the transmitter's trend could exceed the drift' limit, the transmitter is flagged as having the potential i
to exhibit symptoms indicative of loss of fill-oil prior to the next transmitter calibration.
Appropriate precautionary actions are taken on a case-by-case basis.
B)
Determination of Drift Limits Data collected during the monitoring program is analyzed and compared to a predetermined drift limit.
Maximum allowable cumulative drift limits are established in Rosemount Technical Bulletin No.
4.
In most cases, the manufacturer, Rosemount, provides a high side limit and a low side limit i
which differ from each other and are specific to each transmitter range code.
l For transmitters with range codes 1 through 7, the drift limit used for our analyses is the lower of the cbsolute value of the two limits published by Rosemount, corrected for span shift and the turndown ratio for the calibrated span.
If the lower of the two corrected values is greater than 3% of the calibrated span, the drift limit is capped at 3%.
If the trend of data exceeds the predetermined drift limit, and there are no anomalies in the plots, the transmitter is identified as exhibiting symptoms indicative of loss of fill-oil, and the
Exhibit 1 Page 5 of 7 appropriate operability acceptance test / criteria are applied to confirm transmitter operability or the appropriate corrective action is taken.
For transmitters with range codes 8 or 9, two (2) drift limits have been established for evaluating trends of operating data.
If the trend of operating data exceeds an initial drift limit that is derived from the published Rosemount limit and corrected for span shift and turndown ratio (i.e., typically 0.3%), the frequency of collection for the transmitter is increased.
If, based on continued monitoring, the trend of the operating data exceeds a final drif t limit of 1%, and there are no anomalies in the plot, the transmitter is identified as exhibiting symptoms indicative of loss of fill-oil and the appropriate operability acceptance test / criteria are applied to confirm transmitter operability or the appropriate corrective action is taken.
For transmitters with range codes 8 or 9, a single drift limit has been established for evaluating trends of calibration data.
If the trend of calibration data exceeds the drift limit that is derived from the published Rosemount limit and corrected for turndown ratio (i.e., typically 0.3%),
the transmitter is identified as exhibiting symptoms indicative of loss of fill-oil and the appropriate operability acceptance test / criteria are applied to confirm transmitter operability or the appropriate corrective action is taken.
The limits specified above for transmitters with range codes 8 or 9 are adequate for prompt detection of fill-oil loss symptoms since failure of transmitters in these range codes are readily identified by large rapid changes jn drift and a decreased response to process noise.
C)
Data Collection Methods 1)
Calibration Data Collection Calibration data is collected during each scheduled i
routine surveillance for transmitters included in the program.
Each scheduled surveillance includes an J
i extended range response check po5t at approximately 130%
j of calibrat<td span as discussed in Item E below.
2)
Data Collection for Trending of Process Operating Data Drift and Process Operating Data Zero Drift Using Panel Meters Instrument panel meters are used for data collection whenever the transmitter drif t limit, based on Rosemount Technical Bulletin No. 4 as discussed above, is equal to or cieater than 1% of the calibrated span.
- However,
Exhibit 1 Page 6 of 7 panel meters having a scale which starts at zero are not used for processes for which the measured parameter is normally zero (i.e.,
a zero based reading may be taken from a meter scaled from -300 to +300 but not a scale from 0 to +300).
Data is collected monthly using panel meters and is used for analyzing and trending transmitter operating data obtained during power operation (i.e., there is no data collection dur%c startup or shutdown periods due to the transient conditions during these periods).
3)
Data Collection for Process Operating Data Drift and Process Operating Data Zero Drift Trending Using Voltmeters Digital vo.'tmeters (DVMs) are used for data collection whenever the tr ansmitter drif t limit, based on the Rosemount Technical Bulletin No.
4 as discussed above, is below 1% of the calibrated span.
DVMs are also used when no panel meter exists or when the measured process parameter is normally zero and the panel meter scale starts at zero.
However, an exception to this met hod exists for the Redundant Reactivity Control System (RRCS) transmitters installed at LGS.
The resolution of the RRCS digital panel meters permits direct readings.
Data is collected monthly using DVM readings and is used for analyzing and trending transmitter operating data obtained during power operation only (i.e., there is no data collection during startup or shutdown periods due to the transient conditions during these periods).
The frequency of data collection for transmitter operating data trending during powar operations (Methods 2 and 3 above) may be modified depending on the analysis results.
The trending results may allow either increasing or decreasing the data collection frequency.
D)
Operability Acceptance Test / Criteria Operability acceptance test / criteria have been established to screen transmitters identified as exhibiting symptoms indicative of loss of fill-oil.
The drift' limits l
specified by Rosemount have been established such that, for any cumulative drift less than the limit, there remains sufficient fill-oil to allow the transmitter to function properly.
Any transmitter which is identified as exhibiting symptoms indicative of loss of fill-oil, such as exceeding the predetermined drif t limit, will undergo operability acceptance testing at the earliest possible opportunity.
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This operability acceptance-test consists of u
recalibrating the transmitter to the full upper range limit (URL) of the sensing module and observing the transmitter's response. For differential pressure transmitters, this URL calibration is performed for each side of the transmitter cell.
If a transmitter responds normally (i.e.,
observed response is essentially instantaneous and the expected output is reached), it is recalibrated to the normal calibration range and returned to service.
If a transmitter f ails to meet the operability acceptance test / criteria described above, it is considered inoperable and the appropriate action is taken in accordance with the applicable Technical Specifications (TS).
In addition, if a transmitter fails to meet the operability acceptance test / criteria and is not addressed by the TS, it is replaced at the earliest possible opportunity and, if necessary, a basis for continued operation is prepared and maintained in accordance with existing mechanisms.
E)
Extended Span Response Checks An extended span response check is conducted on the transmitter sensing module as part of the scheduled i
surveillance check for transmitters in the program.
The transmitter output is observed during application of an input pressure of approximately 130% of the normal calibrated range.
This extended span response check is not performed for transmitters which are reverse-calibrated (e.g.,
reactor vessel water level), or for transmitters, in particular, those that provide indication only, where a transmitter output greater than 100% can not be indicated (e.g., panel meters).
If a transmitter responds sluggishly during the extended span check (i.e.,
observed response is not essentially instantaneous) or fails to reach the expected output, it is identified as having symptoms indicative of loss of fill-oil, and the appropriate operability acceptance test / criteria are applied.
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