ML20101L886
| ML20101L886 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 12/12/1984 |
| From: | Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-84 SDR-#163, NUDOCS 8501020409 | |
| Download: ML20101L886 (12) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA, PA.19101 JOHN S. KEMPER V IC E-PR ESI D E NT DEC 121984 Dr. Thomas E. Murley, Director United States Nuclear Regulatory Commission Office of Inspection and Enforcement, Region I 631 Park Avenue King of Prussia, PA 19406
SUBJECT:
Limerick Generating Station, Units 1 and 2 Significant Deficiency Report No. 163 l
Potential Leakage Path on Rosemount Pressure Transmitters
REFERENCE:
Telecon of November 20, 1984 P. K. Pavlides (P.E.Co.) to Jim Beall (USNRC)
ATTACHMENT:
1)
Letter:
R. C. LaSell (Rosemount) to Wes Schilling (Bechtel) dated 9/10/84 2)
Letter:
R. C. LaSell (Rosemount) to Wes Schilling (Bechtel), dated 10/2/84 3)
Letter:
R. C. LaSell (Rosemount) to Wes Schilling (Bechtel), dated 10/15/84 FILE: QUAL 2-10-2 (SDR #163)
Dear Dr. Murley:
l The enclosure to this letter is provided as a final report concern-ing Rosemount Model 1153 Series B transmitters that may be affected by questionable integrity of the electronics housing neck seal.
This situation has been evaluated and determined to be reportable under 10CFR Part 21.
Previous information was forwarded to the USNRC via the reference.
Sincerely,
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Dr. Thanas E. Murley, Director- 0EC 12 $84 a
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~ Director of Inspection and Enforcement-Copy to:
United States Nuclear Regulatory Ca mission-Washington, DC 20555-l J. Uiggins, Resident NRC Inspector (Limerick)
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Limerick Generating Station Significant Deficiency Report #163 Potential Leakage Path on Rosemount Pressure Transmitters
- Final Report SDR - 163 1.0 Introduction This report is intended as a final report concerning a potential leakage path on Rosemount pressure transmitters at the Limerick Genera-ting Station (LGS).
The USNRC was notified of this reportable condition in a telecon, dated November 20, 1984.
2.0 Description of Problem On September 10, 1984 Rosemount issued a letter to Bechtel Power Corporation notifying them, as required by 10CFR Fart 21 regulations, of a potential deficiency in Rosemount Model 1153 Series B pressure transmitters.
P.E.Co. Quality Assurance was formally notified on October 17, 1984 and immediately initiated an evaluation to determine if this condition was reportable in accordance with established proce-dures.
This notification along with subsequent correspondence defined the deficiency to be associated with Model 1153 Series B pressure transmitters manufactured from January 1984 to August 1984.
The deficiency involves a potential leakage path in the seal of the threads between the sensor module and the electronics housing.
This leakage path could allow moisture from the surrounding environment to enter the electronics housing during abnormal operating conditions (i.e., HELB or LOCA environmental conditions).
This moisture may cause the trans-mitter to stop functioning (i.e., the output signal may saturate high or low or become unstable).
To correct the deficiency, Rosemount recommended that the trans-mitters in question be returned to the factory to rework the question-able seal.
The seal will be disassembled, cleaned, and reassembled, including the addition of an elevated temperature cure for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> at 200*F.
A review of Rosemount model 1153 Series B pressure transmitters purchased for use at LGS resulted in the finding of six pressure transmitters susceptible to this deficiency.
These transmitters were located in the spare parts inventory.
3.0 Safety Implications The six transmitters in question were purchased as safety-related replacement transmitters for use in safety-related instrument loops.
If these replacement transmitters were installed, safety-related actuation, trip, or isolation functions could be adversely affected.
Since these transmitters were located in the spare parts inventory, there was no immediate impact on the safety or reliability of the plant.
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4.'O' Corrective Action i '
The six transmitters in question will be returned to Rosemount by
-June 1, 1985 for' rework of the questionable seal per Rosemount's recomunendation. A non-conformance report has been written to track the return to, and rework by Rosemount of the six transmitters in question.
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Be'chtel Pow er Corp Agent for Philadelphia n ectric Company P. O. Box 3 96 5 San Francisco, CA 94119 Attention: Wes schilling O
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Notification Under 10CFR Part 21 Regulations R ef er en ce: Pur chase Order 8031-M-206-AC/Rosemount H,. o. 41 8885 Gentl e en t Rosemount has determined that a notification to you, our custom er, is required under the regulations called out in' 10CFR Part 21.
This notification applies only to any Model 1153 Series B Pressure Transmitter manuf actured af ter Janua ry 10, 1984 and does not af f ect any oth er model.
The situation, is as f ollows:
s Rosemount has identified a potential leakage path in.the seal of th e th r ea ds be tw een th e s ensor modul e and th e el ect r oni cs housing.
Th er e i s a po s si bil i ty th a t th i s l ea k pa th co ul d allow moisture f rom the a:sbient surrounding environment to enter the electronics housing during abnormal operating conditions.
This moisture may cause the transmitter to stop f un ctionin'g (i. e.
th e output signal vill caturate high, approximately 27 mA,his 1eak in no way af f ects the pressure saturate low, approximately 3 mA, or become unstabl e. )
T integrity of th e transmitter prussur e boundary, As part of the Rosemount periodic quality audit a sample of transmitters is tested for electronic housing pressure int egr ity.. The test is perf ormed using a 5 PSI (air) pr ecsur e cource to pr essurit e th e internal el ect.ronics housing.
'5noop" is than used to detect 1esks on all sealing interf aces, i
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During the most recent audit, a leak was observed on two out
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of twe.1ve pr essur e tr ansmitters tested.
These units ver e randomly sel ect ed f rom product har dw ar e by 0. A.
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Product Audi t.
Based on these f ailur es, an additionkl 87
,QY production units were leak tested per the Product Audit T
Procedure.
Eight of th e 87 units f ail ed th e test.
b The validity of the Product Audit leak test is being verified by subj ecting several of these units to a LOCA simulation.
h This LOCA simulation is also being used to help determine the cause of th e l eak path and what ambient temperatur e/pr essure 2
lev els these pressur e transmitters will withstand.
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The Model 1153 Series B Pressure Transmitter has been placed
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on hold f or both production, and shi;xnent.
Testing is underway tc. dete:mine a specific cauce f or the lark path.
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specific cause has been identified (we anticipate in about two y
w eeks), a cor r ectiv e aetion will be establish ed.
An update
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letter vill be sent to you when further data is available regarding the units that you have and any corrective action that inay be necessary.
Saould you have any questions prior to Ieceipt of that ' update 1etter, please contaet us.
Very truly yours, P.i ch a r d C.
Lasell Manager
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. October 2. 1984 Y Th.f.[ve
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Mr. Wes schilling
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Bechtel Power Corporation 8
Agent for Philadelphia -Electric Co.
P.O. Box 3965 f
5 San Francisco, CA: 9,4119 S'ub.fect:
10 CFR Part 21 Notification Letter dated Septeinber 10. 1984
Reference:
- 1) Your Purchase order Number 8031-M-206-AC
- 2) Rosemount Order Number 418885 Centlemen:
Thisisafollow-uptotheabovenoliificationwhichwillprovide you with the serial numbers / tag numbers of those transmitters that may be affected by this potential problem. The enclosed listing identifies the 1153 Series 8 transmitters which were manufactured and shipped after January 10, 1984.
Again, the notification applies to only those 1153 Series B )yg J
transe.itters mnufactured after January 10. 1984, and those units installed in an environment subject to a LOCA or liELB, currently we are'in 'an extensive oysluation and test program to detemine the cause of the leak path. Again. once the cause is identified, a corrective action will be established.
We expect the results of our testing to be available in approximately two weeks. Another status letter will be sent to
.you at that tim.
Very truly yours, h-l Y'
R.C. LaSell
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osemount October 15, 1984 Mr. Wes' Schilling Bechtel Power Corporation Agt. for Philadelphia Electric Co.
P.O. Box 3965 San Francisco, CA 94119
Subject:
Our September 10, 1984 Notification Under 10CFR 21
Reference:
Purchase Order 8031-M-206-AC/ftMT Order 418885 Gentlemen:
This letter updates our findirgs and defines corrective action on the potential neck seal problem previously reported.
The past few weeks have been dedicated to investigating the problem, including the review of all associated production processes, piece part modifications and any other variation which could be possible contributors. A summary of our findings and corrective action is detailed in the attached memo of October 11, 1984. Some of the 1153 Series B transmitters manufactured from January 1984 to August 1984 may be affected by questionable integrity of the neck seal and will require rescaling. The transmitters serial numbers listed on the enclosure were manufactured in this timeframe.
We are unable to determine which of these units will leak, and therefore recommend rework of all units produced during this period.
Current production units have been successfully tested to LOCA conditions. We are prepared to receive, rework, and return to you, certified, all transmitters identified in the enclosure. The complete rework and retest facilities of the factory are available to accomplish and certify the rescaling.
We encourage the return of these transmitters to our Eden Prairie, MN. facility.
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The rework efforts.are being coordinated by Robert VandenBoom of our Nuclear Marketing Department at our Eden Prairie facility.
Bob can be reached at A/C 612-828-3540.
It is our intention to perform this repair in the shortest time possible to minimize your inconvenience while considering each cutomers particular need.
We are confident of your cooperation and understanding during this period.
Very truly, k
R.C. LaSell Manager Enclosure o
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I NOSemOUR INTRACOMPANY MEMO 4r368953 CIRCULATE TO:
Jerry Anderson A8 John Berra A26 Andy Habiger C6 DATE:
October 11, 1984 TO:
Dick LaSell - Manager, Nuclear Products (A10)
FROM:
Bill Koch - Director, Quality Assurance (A3)
SUBJECT:
H000LE NECK SEAL - H0 DEL 1153B BACKGROUHD Process Control Audits on Nuclear Pressure Transmitters were started as an internal control procedure in March, 1981. Between 3/81 and 6/84, 146 units were checked for seal integrity by pressurizing the inside of the transmitter to 5 psi and checking t,he module / housing interface point for leaking with a special soap solution.
Of the 146' units, nine were found to be questionable and worthy of further investigation. Seven of the questionable units were detected in April and May of 1982. These units were found to have lower.than specified torque on the lock nut and lacked the usually visible excess sealant at the hous'ing/ module neck joint. Qualification testing (which included a LOCA Simulation Test) was being conducted on units built at about the same time as the questionable units and there was no other information to indicate a change in process may have occurred. An in-depth study brought forth no assignable cause. All units passed the LOCA Simulation Test and the process was determined to be "in control." To add assurance, operators were reinstructed regarding proper' torquing techniques and to use an increased amount of sealant. Subsequent process control checks were found to be acceptable throughout 1982.
In June of 1983, two more questionable units were detected. Casting flash on the housing lock nut interface was determined to be causing low torque values. Qualification testing on units produced shortly after the audit test units (same process) were found to pass the LOCA Simulation Test.
This indicated the process was "in control" as determined'by the only true indicator we have -- the LOCA Simulation Test (a destructive test).
Subsequently, the 5 psi process control seal integrity checks produced no questionable units until June, 1984. The June, 1984 check initiated the sequence of actions which resulted in the 9/10/84 notification to affec'ted customers.
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- I MODULE NECK SEAL - MODEL 1153B 4
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10/11/84 EVENTS LEADING TO NOTIFICATION During Product Audit Testing conducted in June,1984, two questionable seals were detected. The in-depth followup investigation was unable t identify an assignable cause. No qualification program that included LOCA Simulation Test was ongoing or planned at that time; therefore, a special LOCA Simulation Test (completed 8/29/84) was planned and perfo.
During this LOCA to determine if a true leakage problem existed.
Simulation Test, 5 of 8 units failed to complete the 72-hour test. Al five units were found to have moisture in the electronics housing. A notice had been previously issued on 8/22/84. Following the completto; l
the LOCA Simulation Test, the matter was referred to the Nuclear Revie Comittee. Additional investigation of the process and the units whi failed in the LOCA Simulation Test resulted in a Nuclear Review Comi@
meeting on 9/5/84. The Comittee recomended a customer notification issued. A notification letter was issued on 9/10/84 to all affected customers. To determine the block of units.which could be affected, G manufacturing date of 1/13/84 was used. All units prior to this date considered to be conforming, based on the previous acceptable product and LOCA Simulation Test results. Although tnis approach may include large number of conforming units, it appears to be a reasonable crites under the circumstances.
CORRECTIVE ACTION Detailed information regarding all materials an'd parts was accumulated Themostsignificantinformationobtainedindicatedthat12hoursof3 at elevated temperatures provides a more predictable seal. Six test samples were produced with this process change. These samples were successfully tested in a LOCA Simulation Test ending on 10/3/84. The notice was conditionally released on 10/9/84. All units manufactured this date will include this process change in order to assure only qualification level units are shipped.
REMEDIAL ACTION All units within the block of potentially questionable units in custo; control should be disassembled, cleaned, and reassembled per our new process (including elevated temperature cure for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> at 200*F).
can be accomplished in the factory at Eden Prairie, Minnesota.
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.s ATTACHMENT A Purchase Order No. 8031-M-206-AC Rosemount Order No. 418885 Tag No'.
Serial No.
8031-M-206-AC; Item 78.1;FTD0-101A 409394 a
8031-M-206-AC; Item 78.1;FTD0-57101B
- 409395 8031-M-206-AC; Item 79.1;FTDO-102A 409396 8031-M-206-AC; Item 79.1;FT00-1028 409397 8031-M-206-AC; Item 80.1;PTD0-102A 409398 8031-M-206-AC; Item 80.1;PTD0-1028 409399 f
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