ML20207P900
| ML20207P900 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/08/1987 |
| From: | Howard, Rachel Johnson, Russell J TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20207P893 | List: |
| References | |
| CO17301-SQN, CO17301-SQN-R04, CO17301-SQN-R4, NUDOCS 8701200386 | |
| Download: ML20207P900 (10) | |
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- +" , TVA EMPLOYEE CONCERNS REPORT NUMBER: 'C017301 SPECIAL PROGRAM. SQN REPORT TYPE: Sequoyah Nuclear Plant Element REVISION NUMBER: 4 (FINAL REPORT)
TITLE: Slope PAGE 1 0F 8 REASON FOR REVISION:
Incorporate changes based on TAS and SRP comments and discussions. Revision 1 Add (2) additional concerns to this element and make editorial and Revision 2 typographical changes Revised to incorporate line management response and finalize report. Revision 3 Revised to incorporate grammatical corrections and finalize report. Revision 4 PREPARATION PREPAY BY: [ N l k h-
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SIGNATURE a DATE CONCURRENCES CEG- r ll% l~?Af ka h, hendk / 87 SIGNATURE DATE SIGNATURE
- DATE APPROVED BY:
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/M7 DATE NA MANAGER OF NUCLEAR POWER DATE CONCURRENCE (FINAL REPORT ONLY)
- SRP Secretary's signature denotes SRP concurrences are in files.
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TVA EMPLOYEE CONCERNS REPORT NUMBER: C017301 SPECIAL PROGRAM SQN REVISION NUMBER: 4 PAGE 2 0F 8 SUPPLEMENT FOR SEQUOYAH NUCLEAR PLANT I. INTRODUCTION Ten concerns involving instrument line slope have been evaluated in this report:
IN-85-68-N07 IN-86-222-001 IN-85-119-001 IN-85-197-001 IN-85-218-001 IN-85-982-002 IN-85-985-001 PH-85-001-002 c XX-85-046-001 SQP-86-001-001 II.
SUMMARY
OF PERCEIVED PROBLEMS Installed instrument sensing lines do not comply with the minimum slo'pe requirements of TVA drawing 47W-600-24 and are susceptible to air / gas entrapment which can affect instrumer.t accuracy and reliability. '
III. EVALUATION METHODOLOGY
,s Categorizing the above employee concerns as a generic issue, a review was performed to determine whether previous evaluations performed by NSRS, DNE, and the Sequoyah Generic Concern Task Force (GCTF) have' adoquately addressed and resolved employee concerns related to ,
instrument line slope.
A. Interviewed 3 individuals (Project Manager and (2) Lead Engineers) from the Watts Bar Instrument Project to determine if the results of their evaluation and the corrective action taken were potentially applicable to Sequoyah.
B. Interviewed the Supervisor of Electrical Engineering I&C (SQEP) to determine the history of the sensing line slope issue, including previous evaluation results and documentation.
C. Reviewed letter from Wohld to MEB files, dated November 17, 1978 (RIMS MEB 78 1120352), titled " Instrument Sensing Line Problems - .
Report of October 17, 1978 - Field Trip Findings," concerning ,
pre-op test deficiencies caused by air entrapment in instrument sensing lines.
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a TVA EMPLOYEE CONCERNS REPORT NUMBER: C017301 SPECIAL PROGRAM SQN REVISION NUMBER: 4 PAGE 3 0F 8 D. Reviewed letter from Pierce to Patterson, dated December 5, 1978 (RIMS SWP 781205011), titled " Instrument Sensing Line Problems,"
which was the Design Projects Manager's response to reference
^* III C.
E. Reviewed letter from Whitt to Parris, dated December 27, 1985 (NSRS Report No. I-85-590-SQN), titled "NSRS Investigation Report," which covered the results of the NSRS evaluation of instrument sensing line. slope at SQN for Employee Concern XX-85-046-001.
F. Eeilewed letter from Vineyard to Rankin, dated December 20, 1985 (RIMS B2585120003), titled " Sense Line Slope Enployee Concern,"
which summadizes the evaluation by OE of the sensing line slope issue requested by NSRS in reference III E.
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G. Reviewed letEer from Abercrombie to Wilson, dated April 18, 1986 (RIMS S53 860417983), titled " Sense Line Slope Employee Concern I-85-590-SQN," which responds to reference III F.
H. Reviewed letter from Whitt to Abercromble, dated February 25, 1986 (NSRS Report No. I-86-128-SQN), title'd'"NSRS Investigation Report,"
whi'ch covered the results of the NSRS evaluation of instrument sensing line slope at SQN for Employee Concern SQP-6-001-001.
I. Reviewed letteI'fdom Mason to Whitt, dated January 28, 1986 (RIMS S53 860113843F, titled "NSRS Investigation Report No.
I-85-590-SQN," which responds to reference III E.
J. Revieded letter from Whitt to Mason, dated April 16, 1986, titled n " Corrective Action Response Evaluation," which responded to and I'
accepted reference III I, t
j K. Reviewed Sequoyah Generic Concern lask Force evaluation report
< covering Employsh Concerns IN-86-222-001 and IN-85-197-001.
I4 g L. Interviewed 2 individuals (Maintenance Supervisor and assistant) from Sequoyah Nuclear Power Instrument Maintenance Section to discuss instrument maintenance and calibration techniques related to entrapped air in sensing lines. Discussed backfill procedure minimum flow rates-and restrictions on backfilling cold desineralized water back to a hot process nozzle.
wx M. Reviewed maintenance and work requests associated with units I and
-, II feedwater Llow transmitters, steam generator Aux level
\ transmitters and RCS flow transmitters to determine if, based on a sample, there were any indications of maintenance problems related to poinntial air entrapment.
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.c TVA EMPLOYEE CONCERNS REPORT NUMBER: C017301-SPECIAL PROGRAM SQN REVISION NUMBER: 4 PAGE 4 0F 8 N. Reviewed Norris Test Lab reports WR28-1-85-107, 109, 110, 113, 116, 120, and 121 related to air bubble migration in sensing lines and the effects of entrapped air on transmitter output signals.
O. Reviewed Reg Guide 1.97, Rev 3,' dated May, 1983, WBN " Draft," l calculation number WBPEVAR8603010 WBN and calculation number - l R4 WBPEVAR 8511002 to develop a sample ccope of post accident l monitoring (PAM) instruments required to function during and after a Design Basis Accident (DBA).
IV.
SUMMARY
OF FINDINGS The following. summary of findings, paragraphs IV, A through 0, correspond to the evaluation methodology which is detailed in paragraphs III A through 0.
A. The Watts Bar Project handled the sensing line slope employee concerns by creating the Instrument Project which performed a case by case evaluation of selected safety related and sensitive instrument sensing lines. A significant amount of rework has been identified as a result of these evaluations. This approach differs from Sequoyah's in that Sequoyah is utilizing several years of successful operating experience as their basis for acceptability of installed sensing line slopes.
B. Based on discussions with the Supervisor of Electrical Engineering I&C (SQEP), evaluations have been performec by NSRS, OE, and GCTF con'cerning instrument sensing line slope adaquacy. All reports l issued as a result of these evaluations (reference paragraph IV E, H, F, & K), basically agree that, based on several years of operating experience utilizing enhanced maintenance and calibration procedures, the installed configurations of sensing lines are technically and functionally acceptable. Maintenance / work requests do not reflect the existence of any operational problems which can be attributed to sensing line slopes.
C. The letter from Wohld to the MEB flies provides solutions to pre-op test deficiencies which were attributed to air atrapment.
D. The letter from Pierce to Patterson acknowledgee implementation of recommended corrective actions provided in parag aph IV C. This intter nise mentioned that SQN would discuss witt, the Electrical Engineering Branch the need for a construction specification to prevent recurrence of slope problems on later pisnts.
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L TVA EMPLOYEE CONCERNS REPORT NUMBER: C017301 SPECIAL PROGRAM SQN REVISION NUMBER: 4 PAGE 5 OF 8 E. NSRS Report No. I-85-590-SQN concludes that even though the employee concerns were substantiated, there is no history of functional problems which would require further action. The NSRS report makes five recommendations related to closing this issue:
- 1. Engineering Evaluation of Instrument Sensing Line Slopes
- 2. High Point Vent Valves
- 3. Returning RCS Flow Transmitters to Service
- 4. Sensing Line Installation Procedure
- 5. NCR 6172 Evaluation for Generic Applicability to other TVA Facilities.
F. The Vineyard to Rankin letter documents tha results of OE's evaluation of instrument sensing line slope, as requested by NSRS and SQN management. This letter summarizes corrective actions taken during pre-op testing and during normal plant operation for problems caused by inadequate sensing line slope. Included in this evaluation were the results of an OE & Maintenance walkdown of sensing lines, a review of maintenance histories and a review of maintenance procedures. This report concluded that no plant safety problem exists at SQN based on successful operating experience, current and planned instrument maintenance practices and administrative detection methods for entrapped air in sensing lines.
G. The Abercrombie to Wilson memorandum responds to the OE evaluation report (reference IV F), basically agreeing with recommendations to monitor maintenance / work request trends. This memorandum states that programs are already in place to do trending and that the Instrument Maintenance Section is responsible for performing this function.
H. NSRS Report No. I-86-128-SQN is very similar to the report issued in reference IV E. Three recommendations were made related to i closing this issue:
- 1. Engineering evaluation of instrument sensing line slopes
- 2. Returning transmitters to service
- 3. NCR 6172 evaluation for generic applicability to other TVA facilities.
I. The Mason to Whitt memorandum responded to NSRS Report No.
I-85-590-SQN recommendations mada in reference IV E.
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TVA EMPLOYEE CONCERNS REPORT NUMBER: C017301 SPECIAL PROGRAM SQN.
REVISION NUMBER: 4 1
PAGE 6 0F 8
.J. The Whitt to Mason memorandum accepted all responses made in reference IV I.
K. The SQN Generic Concern Task Force (GCTF) evaluation report reiterates the results of previous NSRS and OE evaluations. The GCTF endorses the recommendations made in the NSRS report (reference IV E) and makes no further conclusions or recommendations.
L. Individuals from the SQN Instrument Maintenance Section discussed existing maintenance and calibration techniques being applied to sensing lines and instruments with associated high points and low
- points in the line routings. Sensing lines susceptible to air entrapment have been identified and are adequately covered by procedures. Maintenance histories do not reflect any recurring problems in this area.
M. An independent review of maintenance / work requests (MRs and WRs) for a portion of safety-related instruments was performed, looking specifically for problems caused by possible air entrapment in sensing lines. Two hundred twenty two (222) records were reviewed, with approximately seven potentially related to air entrapment.
Further review found that these MRs and 40Rs were issued in a timeframe when system maintenance involving numerous pump starts
! and stcps were occurring.
N. A general review of various Norris Lab test reports was performed
' to determine the total effects of entrapped gas or air bubbles on an instrument's accuracy and performance. These reports. validate the potential problems caused by gas or air bubble entrapment. The reports also establish minimum flow rates for backfilling of sensing lines.
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- 0. Evaluation reports issued by NSRS, OE, and GCTF all bssically l
concluded that there was no safety problem at SQN involving sensing l line slope, based largely on several years of operating experience. Since this operating experience does not include esperience during and after a design-basis accident (DBA), the calculated effects of a DBA on sensing lines associated with post
- accident monitoring (PAM) instruments must be determined. Reg Guide 1.97 was reviewed for any special conditions or criterion applicable to PAM instrument sensing lines. TVA's commitment to -
Reg. Guide 1.97 implementation at Sequoyah is currently l September, 1987.
TVA EMPLOYEE CONCERNS REPORT NUMBER: C017301 SPECIAL PROGRAM SQN REVISION NUMBER: 4 PAGE 7 0F 8 CONCLUSIONS A. All specific and generic concerns related to instrument sensing line slopes not conforming to the installation requirements of drawing 47W-600-24 are valid.
B. For " Normal" operating conditions, the installed configurations of sensing lines do not create an operating or safety concern.
C. Evaluations performed by NSRS, OE, and GCTF do not address the acceptability of sensing line slopes during abnormal or accident conditions. Engineering design criteria is inadequate in this area.
D. Based on the results of Norris Lab testing, the SQN backfilling procedure for sensing lines should specify a minimum flow rate to assure that entrapped air or gas is purged from the line.
E. SQN Backfilling procedures should be evaluated to determine if restrictions are required on backfilling cold demineralized water into potential hot process nozzles.
V. ROOT CAUSE A single root cause for this condition has not been determined. This evaluation concludes the following:
- Installation requirements from design output drawings were inadequate and not restrictive enough.
- Engineering design criteria which covers all modes of plant operating conditions is inadequate.
- Installation practices were inadequate.
- Inspection techniques were inadequate.
VI. CORRECTIVE ACTION The following is the Line Management Corrective Action response. The corrective actions are restart items.
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TVA EMPLOYBE CONCERNS REPORT NUMBER: ,C017301 SPECIAL PROGRAM SQN r
i REVISION NUMBER: 4 PAGE 8 0F 8 L
CATD 17301-SQN-01 The concern is associated with' outgassing in the sensing lines during I accident conditions. This problem has-been evaluated by EEB and NEB l
-SQN DNE utilizing an unofficial calculation provided by Stone & Webster l Engineering Corporation. This preliminary evaluation has concluded. I r ,that the installed configuration of PAN instruments-is acceptable IR4-and they will function during and after a Design Basis Accident. l The formal EEB analysis will be performed by Frank Tanner I (Activity Number 292180108). If this analysis'is in agreement with the l e Stone & Webster calculations, then the outgassing issue can be closed. I CATD.17301-SQN-02 ' l.
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A. -A copy of the Norris test report which addresses the required flow l rates for backfilling, is being sent to the Plant Operations. Review l
- Committee (PORC) by Jerry Shole (Division of Air and Water l Resources).The report will be evaluated by PORC and the results l will be coordinated with the Instrument Maintenance Section to l L -include in their backfilling procedure. In addition, Instrument I j Maintenance will implement any other corrective action that may 1 .*
, be required. I s.
B. A thermal shock analysis was performed by Westinghouse for- l i; Watts Bar's pressurizer. Work on this item is to continue, and will I i- have the scope expanded to include the steam generators. The l report will be evaluated by PORC and the results will be coordinated IR4 with the Instrument Maintenance.Section to include in their 1 -i backfilling procedure. In addition, Instrument Maintenance will I implement any other corrective action that may be required. l
.DNE will perform a detailed evaluation of the thermal shock problem l 1 (Activity Number 20060992). Data has been collected by PORC to l determine the number of times specific nozzles have been backfilled lR4 in the past. This data will be used with the DNE evaluation to I determine if any nozzles have already been overstressed (Activity I s Number 20060994). l i:
VII. GENERIC APPLICABILITY All employee concerns listed in Section I of this report have already been deemed generic for all TVA nuclear facilities.
VIII. ATTACHNENTS i Attachment A - Listing of concerns indicating Safety Relationship and l- Generic Applicability.
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1 SLOPE ATTACimENT A PAGE I 0F 2 G:NERIC APPL QTC/NSRS P Concern SUB PLT 88SW INVESTIGATION S CONCERN Ntaber CAT CAT LOC FLQ8 REPORT R DESCRIPTION ~
4 41-85-001-002 CO 173 WBN YY YN PH-85-001-002 SS SLOPE PROBLEM WITH INSTRUMENT LINES IN SYS. 68.
K-FORM PANELS 226, 227, 228. PREVIOUS NCR ONLY ADDRESSES 4 T50001 0F 28 SPECIFIC LINES FROM THESE PANELS. MORE 3 SPECIFICS MAY BE AVAILABLE LATER AS INDIVIDUAL CLAIMS TO HAVE A DIARY, HOWEVER, CONTACT IS NOT PRESENTLY POSSIBLE.
.N-85-068-N07 CO 173 WBN NNNN NS NRC IDENTIFIED THE FOLLOWING CONCERN FROM REVIEW OF QTC K-FORM FILE. " FAILURE TO CORRECT TWO ERRORS ON A LINE MAY RESULT IN REACTOR SHUTDOWN." REVIEW OF FILE INDICATED THAT NRC 15 REFERRING TO AN INSTRUMENT LINE.
YYYY IN-85-il9-001 SS DRAWING 47W600 REQUIRES 1/8" PER FT. SLOPE, CONTRARY
-N-85-il9-001 CO 173 WBN I
T50065 REPORT TO THE AB0VE, SYSTEM 68 (REACTOR TRIP) UNIT I, 702' ELEV. IN CONTAll#9ENT. INST. LINES LAYING IN RACEWAYS 1 00 NOT HAVE I/8" PER FT. " SLOPE". SPECIFIC AREAS NOT AVAILABLE, BUT C/l INDICATED THAT A TOUR OF THE ELEVATION WOULD PROVIDE SEVERAL EXAMPLES.
4 N-85-197-001 CO 173 WBN YYYY SS SYSTEM 68 IN UNIT I REACTOR BLDG. RACEWAY AREA T50156 K-FORM INSTRUMENTATION SENSING LINES HAVE NEGATIVE SLOPE IN SOME AREAS WHICH COULD TRIP REACTOR. THIS SITUATION WAS LOOKED AT BY ENDES IN KNOXVILLE AND THEY STATED ON NCR 5750 TO USE-AS-IS. CONSTRUCTION DEPT. CONCERN.
Cl HAS NO FURTHER INFORMATION. NO FOLLOW UP REQUIRED.
IN-85-218-001 CO 173 WBN YYYY IN-85-218-001 SS INSTRUMENTATION LINE, SYSTEM 68, IS NOT PROPERLY SLOPED l [50008 REPORT ON UNIT l. DESIGN /ENG RECEIVED THAT AS-BUILT CONDIT10N BUT MAY NOT HAVE APPROVED CONDIT10N.
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SLOPE ATTACMENT A PAGE 2 0F 2 GENERIC APPL QTC/NSRS P Concern SUB PLT BBSW INVESTIGATION $ CONCERN Natper CAT CAT LOC FLQB REPORT R DESCRIPIl0N N-85-982-002 C0 173 WBN YYYY NS OVERALL MINIMUM SLOPE REQUIREMENTS COUtI) NOT BE MET; T50lli REPORT BUT DRAIN LINE HAD TO BE REWORKED TO ESTABLISH 1/2" SLOPE OVER PARI 0F LINE (PREVIOUS INSTAlLAT10N HAD 1/8" SLOPE IN SAME AREA-BOTH LINES ENDED IN UP-HILL VERTICAL RUN OF SEVERAL FEET TO ROOT VALVE) LOCATIONS GO FROM AUX. 737' DOWN 713' ELEV. BY SECURITY FENCE.
ROOT VALVE IS AT CORNER WHERE FENCE TURNS LEFT. LINE RUNS APPROXIMATELY I4' ALONG LEFT LEG OF FENCE INTO SECURITY FENCE AND INTO PANEL AGAINST FENCE. Cl HAS NO FURTHER INFORMATION.
' N-85-%5-001 CO 173 WBN NNNN NS INSTRUMENTAll0N EEINEERIE IS NOT HELD RESPONSIBLE 150!!? MP 712 REPORT FOR MISTAKES THEY CAUSE. EXAMPLE: (I)
QA 802 "INSTUMENTATION LINES WlIH INCORRECT LOPE. (APPROVED' BY ENG.). THESE ARE NOW BElE ADDRESSED BY NCR'S.
(2) THE ENGINEERING DELETION OF STAINLESS STEEL CLEANLINESS REQUIREMENTS UNIT I WHICH IS A QC REQUIREMENT. Cl HAS NO ADDITIONAL INFORMATION. NO FOLLOW UP REQUIRED.
N-86-222-001 CO 173 WBN YYYY SS INSTRUMENT LINES ON AUXILLARY FEEDWATER, STEM 150194 REPORT GENERATOR BLOWDOWN, AND STEAM GENERATOR LEVEL; POSSIBLY DO NOT MEET MINIMUM SLOPE REQUIREMENTS AS SHOWN ON 47W600 DRMINGS, SHEET 0. UNIT I & 2.
CONSTRUCTION INSTR. ALL SYSTEMS. CONSTRUCTION DEPT.
CONCERN. Cl HAS NO FURTHER INFORMATION.
- QP-86-001-001 CO 173 SQN YYYY l-86-128-SQN SS DRAWlES REQUIRE AN 1/8" PERF000T SLOPE AND CONTRARY 150240 REPORT TO THIS THE INSTRUMENTATION LINES DO NOT COMPLY WITH DRAWING REQUIREMENTS. CONSTRUCTION DEPT. CONCERN. Cl HAS NO FURTHER INFORMATION. NO FOLLOW UP REQUIRED.
0(-85-046-001 CO 173 SQN YYYY l-85-590-SQN SS INSTRUMENT SENSING LINES FOR SYSTEM 68 AT SEQUOYAH MAY T50143 REPORT HAVE SLOPE DEFICIENCIES. DETAILS KNOW TO QTC, WITHHELD DUE TO CONFIDENTIALITY. CONSTRUCil0N DEPT, a CONCERN. Cl HAS NO FURTHER INF0MATION.
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