ML20215D888

Rev 4 to Location of Cold Leg Accumulator & Refueling Water Storage Tank Level Transmitters

ML20215D888
Person / Time
Site:	Sequoyah
Issue date:	12/08/1986
From:	Gardner G, Murphy M, Stewart D TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20215D785	List: ML20215D780 ML20215D796 ML20215D813 ML20215D816 ML20215D844 ML20215D857 ML20215D866 ML20215D876 ML20215D884 ML20215D888 ML20215D892 ML20215D902 ML20215D911 ML20215D914 ML20215D922
References
303.02-SQN, 303.02-SQN-R04, 303.02-SQN-R4, NUDOCS 8612170109
Download: ML20215D888 (7)

Text

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.' TVA EMPLOYEE CONCERNS REPORT NUMBER: 303.02-SQN SPECIAL PROGRAM REPORT TYPE: Sequoyah Nuclear Plant - Element REVISION NUMBER: 4 .

TITLE: Location of Cold Leg Accumulator and RWST Level Transmitters REASON FOR REVISION:

Revised to incorporate SRP comment. Revision 1 Revised to incorporate SRP comments and partial SQN Corrective Action Response. Revision 2 Revised to incorporate SQN Corrective Action Response. Revision 3 Revised to incorporate SRP comments. Revision 4 PREPARATION PREPARED BY:

G. Danell Gardner // -2/- fi'd SIGNATURE DATE i REVIEWS PEER:

//)' /$ }l~5lSb DATE

' [ [ SIGNATURE y bfhk SIGNATURE ll-M 46 DATE CONCURRENCES l' #

e CEG-H SRP: W * -

" M N SIGNATURE DATE y SIGNATURE

• DATE APPROVED BY:

N"8'Oh N/A ECSP MANAGF# DATE MANAGER OF NUCLEAR POWER DATE

{

CONCURRENCE (FINAL REPORT ONLY)

• SRP Secretary's signature denotes SRP concurrences are in files. (

2288T 8612170109 861210 ,, f ADOCK 0500 /. l DR

TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT EMPLOYEE CONCERNS TASK GROUP OPERATIONS I

CEG Subcategory: Instrumentation and Radiation Monitoring Employee Concerns: Location of Cold-leg Accumulator and RWST Level Transmitters Report Number: 303.02 - SQN Revision 4 IN-85-281-003

, s IN-85-142-006 Evaluator: G. Darrel Gardner //-5/-fd G. Darr 11 G dner Date Reviewed by: [

OPS CH4 lydEber

//-l/"F[

Date Approved by: W // A' W. R. Lagergren Date 1522T

i

.- Revision 4 I. ' Location of Cold-Log Accumulator and RWST Level Transmitters This report' evaluates two employee concerns for Sequoyah Nuclear l Plant (SQN) regarding the calibration of level transmitters. IR1 These concerns were determined potentially safety-related by the Employee Concerns Task Group (ECTG) Technical Assistance Staff (TAS).

II. Specific Evaluation Methodology The employee ecncere identified to Quality Technology Company (QTC) for Watts Bar Nuclear Plant (WBN) are as follows:

IN-85-281-003 "The two level transmitter on each of the cold-leg accumulators will not read the same level due to difference in elevation. Transmitters have been calibrated as per scaling data sheet. When put in service transmitters will read a 5% difference in level. When the engineers were told about the problem they said don't worry about it adjust one until both level indicators read the same. (Unit 1)"

IN-85-142-006 "RWST in Unit 1 narrow range 1-LT-63-46 & 1-LT-63-49 reading were 6% off inst eng (name known) directed instrumentation mechanic to adjust to zero. This would make reading match the control room. Similar on SIS accumulators 1-4, elev 716. Two transmitters on each accumulator. This practice causes false readings in control room."

Since these concerns were identified specifically for WBN, this evaluation was limited to a review of the calibration methods and historical performance at SQN for the same instruments and i did not consider allegations of improper adjustment instrut lons IR1 from engineers. l SQN Technical Specifications (TS) were reviewed for requirements on the l cold leg accumulator (CLA) and the refueling water storage tant (RWST) J 1evels. Surveillance Instruction (SI) data and scaling sheets were l reviewed for historical data on the CLA level transmitters. sis, lR1 Maintenance Requests (MRs), and SI data was reviewed for historical l performance of the RWST level transmitters. The historical data was I supported by informal interviews with the cognizant instrument maintenance engineer and the assistant section supervisor.

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. Revision 4

'III. Findings

~ IN-85-281-003 The SQN TSs-(reference 4) require a borated volume between 7,857 and 8,071 gallons in each CLA in modes 1, 2, and 3 which must be verified at least once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by the absence of alarms or measurements of levels and pressures. SQN SI-2 (reference 1) verifies these, requirements by checking for absence of. alarms and verifying levels. The SI requires that the two independent level channels agree with less than'4.5-percent i deviation between channels. lR1 The cognizant engineer in Instrument Maintenance Section stated that problems with CLA level transmitters existed at SQN. These problems consisted of deviations between level channels on the same CLA and were attributed to elevation differences on the sense line taps. The engineer stated these problems were corrected by adjusting the scaling for the transmitters to the narrowest span using SI-161 (reference 2);

however, instrument drift remains a maintenance problem. Design Change i

Request (DCR) 1848 (reference 6) was written to replace the obsolete Berton transmitters _and will be implemented by Engineering Change Notice (ECN) L6358 during the next outage. According to the engineer, this change should reduce the maintenance caused by instrument drift on this I system. The assistant section supervisor confirmed that the CLA level .lR1 transmitters were being replaced. 1 A random review of'5I-2 data packages for units 1 and 2 between April 1984 and April 1985 indicated that the CLA levels were indicating  ;

within the allowable maximum channel deviation.

• i- IN-85-142-006 (

The SQN TSs (reference 9) require that the boreted water volume in the RWST be verified at least once every seven days in modes 1 through 6.  ;

(Note: A lesser water volume is allowed in modes 5 and 6 than in modes 1.through 4). SI-3 verifies water volumes meet the TS requirements by ,

, verifying the two inoependent RWST level channels indicate the required .

j: level within a maximum 525-gallon deviation in modes 1 through 4 and a

! 5-percent deviation in modes 5 and 6.

j SI-3 records only one narrow range level channel for verifying compliance i I with TS RWST volume requirements and the specific channel used is not l designated during performance of the SI. In addition, the acceptance l ,

, critoria is specified as notes provided on the data sheet, and state that l operability is verified by having less than 525 gallons lR2 l (modes 1 through 4) or 5-percent (modes 5 and 6) deviation between l channels. As a result, channel calibration out-of-tolerance reports l  ;

cannot be evaluated for impact on SI results nor can an audit be l ,

performed to verify past compliance. l l I i l

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s Revision 4 III. _ Findings (cont'd)-

A review of MRs on RWST l'evel transmitters and indicators for units 1 and 2 revealed approximately 50 MRs related to calibration problems.

These MRs were generated from 1980 to 1985 and indicate a. recurring problem with instrument delft. The cognizant instrument engineer I. stated'that the' scaling had been corrected for elevation differences l on these transmitters in a similar manner to the CLA transmitters. IR1 ,

The assistant section supervisor stated that a lot of the problems may have been because of freezing of instrument lines which had been improved'in.the last few years. It was noted during the search for calibration related MRs, several MRs had been written for heat tracing lR1 on these instruments and that the frequency of MRs had reduced in 1984 and 1985 compared to earlier years.

The supervisor stated that a new maintenance trending program was in l place at SQN which will identify both old and new maintenance problems in the future. -He noted that, while no plans are currently underway to address problems with RWST level transmitters, increased maintenance l will continue to ensure their operability in accordance with TS l32 requirements. l T

Conclusions i The issues presented by employee concerns IN-85-281-003 and l IN-85-142-006 were validated for SQN in that problems were encountered l in the past with RWST and CLA level channel deviation because of sense IR2 l

line tap elevation differences. These problems were compensated by l rescaling the transmitters to the mosc conservative span based on l field. measurements. l Recurring maintenance problems exist with these level transmitters in IR1 the form of instrument drift. The CLA level transmitters are scheduled to be replaced during the next outage by ECN L6358 and should correct this problem. No plans have been made to address drift problems with l RWST level transmitters, however, maintenance will continue to be lR1 performed to ensure their operability in accordance with TS l requirements. The RWST level transmitter surveillance lR2 data and acceptance criteria in SI-3 were determined insufficient based l on recording only one channel and having its acceptability included as l a note within the SI. l IV. Perceived Root Cause Excessivt maintenance is required to meet TS requirements. The root lR2 cause is perceived as the lack of an adequate trending program in the ,

past to identify and resolve problems for high maintenance equipment. IR1 No root cause could be readily identified for the lack of documentation required by SI-3.

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. Revision 4 V. Generic Applicability These issues were evaluated generically for SQN and specifically for WBN with similar findings. These specific issues are not considered generically applicable to BFN or BLN; however, it is believed that BFN and BLN should address the maintenance trending issue ~.

VI. References

1. SQN Surveillance Instruction (SI)-2, " Shift Log," Revision 40, July 3, 1986, and Data Packages Apell 1984-1985

2. SQN SI-161, " Channel Calibration of SIS Accumulator Tank Water Level and Pressure Instrumentation," Units 1 and 2, Revision ll, February 20, 1986, and Revision 9, September 11, 1983

3. SQN SI-165, " Channel Functional Test of SIS Accumulator Tank Water Level and Pressure Instrumentation," Units 1 and 2 Revision 6, August 16, 1984

4. SQN Technical Specifications, LCO 3.5.1.1, SR 4.5.1.1.1, Bases 3/4.5.1, Unit 2

5. Technical Instruction (TI)-41-63, " Scaling and Setpoint Document,"

Revision 4. July 10, 1985

6. Design Change Request (DCR) SQ-DCR-1848, January 13, 1983

7. Memorandum from H. B. Rankin to J. P. Vineyard on SQ-DCR-1848, dated January 3, 1985 (S58 841217 906)

8. Maintenance Requests (MRs) for LT/LI-63-46 and -49 on Unit 1 and Unit 2, search conducted August 4, 1986

9. SQN Technical Specifications, LCO 3.1.2.5, 3.1.2.6, 3.5.5, SR 4.1.2.5, 4.1.2,6. 4.5.5, Bases 3/4,5,5, Unit 2 10.'SQN SI-3, " Daily Weekly, and Monthly Logs," Revision 49, June 27, 1986

11. Memorandum from H. L. Abercrombie to W. R. Brown, Element Report l 303.02 SQN Corrective Action Plan, dated September 22, 1986 (S03 l 860918 808) l l

12. Memorandum from W. R. Brown to H. L. Abercrombie, Transmittal of ECSP lR2 Report and Corrective Action Tracking Documents, dated l

. September 29, 1986 (T25 860929 851) l l :

13. Memorandum from W. R. Brown to H. L. Abercrombie, concurrence with I (

Corrective Action Plan, dated October 9, 1986 (T25 861009 929) l Page 4 of 6

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.' Revision 4

, sVII. Immediate or Long-Term Corrective Actions SQN has provided the_following acceptable Corrective Action Plan for l

. Employee Concern Task Group Number 303.02 (IN-85-142-006) " Refueling Water-l Storage Tank (RWST) Upper Level Transmitters" (references 11 and 13). l

. . 1 Investigation of this employee concern at SQN has revealed a significant l number of MRs related to problems on the RWST upper level transmitters. l However, a large majority of these MRs were related to frozen sense lines 1 or heat tracing problems on the sense lines. Surveillance Instructions l SI-706.1, and 706.2 were initiated in February 1985 to verify operability -l of sense line heat trace circuits. The performance of these surveillance l instructions on a monthly basis should reduce the number of maintenance  !

-problems' relating to heat tracing. I l'

.SQN has recently implemented a new maintenance trending program to l

. identify potential maintenance problems. However,, sufficient data hac l not been collected since correcting sense line problems, to make any l conclus8ve determination. SQN Instrument Maintenance Group has plans to 1 initiate a new preventive maintenance procedure to monitor the transmitter I output signal for 1,2-LT-63-46 & 49 on a more frequent schedule (most I likely monthly). The performance of this PM will not only provide l additional trending information but will also ensure operability is l maintained. The PM will be implemented before unit 2 start up. l

?2 SQN Instrument Maintenance Section personnel have also taken field l measurements of the transmitters and sense line taps to compensate for i different head pressures at the transmitters. This was done to ensure l cn accurate redundant level indication between channels. This was l completed at the time the heat trace and freeze protection was I upgraded.

Therefore, since corrective actions have already been taken to remedy 1 maintenance problems associated with frozen sense lines and to correct I head pressure values causing inaccurate level indications, and l insufficient trending data has been collected to make conclusive l determinations, SQN has no plans to replace the RWST upper level l transmitters at present. As mentioned previously. SQN will continue to l monitor the transmitters operation with the new trending program and the i new preventive maintenance instruction which will be implemented before i start up. l l

An investigation of the RWST wide range level transmitters lR2 (1,2-LT-63-50, 51, 52, 53) has shown that no significant maintenance or l operability problem exists on these transmitters. l i

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< -. Revision 4 VII. Immediate or Long-Term Corrective Actic s (cont'd)

The SQN response t'o CATD-30302-SQN-01 establishes a different technical IR4 position than that of the evaluator. l Briefly, the SQN response establishes that those instruments used to l ensure compliance-to_ technical specification parameters (compliance lR4 instruments) are not subject to the same requirements as technical i specification required instruments. l The SQN corrective action response is as follows: lR4 The report appears tc be in error because of confusion between l Compliance Instrumentation and Technical Specification (TS) l Instrumentation. TS instruments are specifically identified in the l specifications and these instruments usually require a channel check for l instrument operability verification. An example of a TS instrument is l the RWST wide range level channels ir. TS 3.3.2 for ESF instruments. A l compliance instrument is an instrument which is not specifically l identified in the TS; however, these instruments are used to obtain data lR3 to verify operability of a Technical Specification system. A channel l check of compliance instruments is not required by TS. An example of I compliance instruments are the RWST narrow range level channels used to I verify operability of the water volume in the RWST for TS 3.1.2.6 and TS l 3.5.5. Therefore, because a channel check of the RWST narrow range l '

1evel indicators are not required by TS, the data recorded in SI-3 1 weekly is adequate to ensure operability of the RWSI TS 3.1.2.6 and TS I i

3.5.5. We do not plan to initiate a PRO for this concern. l We do agree that the note in SI-3 has the potential to be overlooked. l Therefore, as a long-term goal for the notes in SI-2, SI-3 daily, SI-3 I weekly, and SI-3 monthly, the operations procedure group will attempt to l incorporate the notes into the text of the data sheets as applicable. l 1

Also, a clarification that a failure of the RWST narrow range channel l check does not necessitate encry into the TS LCO is being considered for l a future revision to SI-3 weekly. However, we do not consider these l enhancements to be required for compliance with TS and the employee l concern report, therefore, no future commitments date is listed in the l corrective action plan. The operations procedures group anticipates the I revision to SI-2 and SI-3 within approximately 12 months. l 4

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TENNESSEE VALLEY AUTHORITY PA%E- -

REFERENCE - ECPS120J-ECPS121C -RUN-TIME *,,11:5

- REQUEST OFFICE OF NUCLEAR POWER FREQUENCY EMPLOYEE CONCERN PROGRAM SYSTEM (ECPS) RUN DATE - 10/.T

• ONP - ISSS - RHM LIST OF EMPLOYEE CONCERN INFORMATION .

CATEGORY: OP PLANT OPER. SUPPORT SUBCATEGORY: 30302 LOCATION OF COLD LEG ACCUMULATOR LEVEL XMITTERS KEYHORD A S GENERIC -

KEYHORD B' H APPL QTC/NSRS P

$ CONCERN KEYHORD C-

' CONCERN SUB R PLT 5BSH INVESTIGATION ~ KEYHORD D CAT CAT D LOC FL48 REPORT R DESCRIPTION HUMBER NNYN I-85-327-NBN NS RHST IN UNIT 1 NARROH RANGE 1-LT NONCONFORMANCE IN 142-006 OP 30302 N HBN CALIBRATION T50092 REPORT 46 a 1-LT-65-49 READING HERE 6% OFF-INST ENG (NAME KNOHN) DIRECTED INSTR INSTRUMENTATIO UMENTATION MECHANIC TO ADJUST TO ZER. DEVICES

0. THIS HOULD MAKE READING MATCH TH E CONTROL ROOM. SIMILIAR ON SIS ACC UMULATORS 1-4, ELEV 716. TH0 TRANSM ITTERS ON EACH ACCUMULATOR. THIS PR ACTICE CAUSES FALSE READINGS IN CONT ROL ROOM.

I-85-208-NBN SS THE TH0 LEVEL TRANSMITTER ON EACH OF CORRECTIVE ACTION IN 281-003 OP 30302 N HBN NNYN CALIBRATION T50059 K-FORM THE COLD-LEG' ACCUMULATORS HILL NOT READ THE SAME LEVEL DUE TO DIFFERENC OPERATIONS E IN ELEVATION. TRANSMITTERS HAVE B DEVICES EEN CALIBRATED AS PER SCALING DATA S HEET. WHEN P'JT IN SERVICE TRANSMITT ERS HILL READ A 5% DIFFERENCE IN LEV EL. HHEN THE ENGINEERS HERE TOLD AB OUT THE PROBLEM THEY SAID DON'T H0RR Y ABOUT IT ADJUST ONE UNTIL BOTH LEV El INDICATORS READ THE SAME. (UNIT 1) g 2 CONCERNS FOR CATEGORY OP SUBCATEGORY 30302 .

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