ML20030A748
| ML20030A748 | |
| Person / Time | |
|---|---|
| Site: | 05000000 |
| Issue date: | 11/05/1981 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| IEC-81-14, NUDOCS 8107230037 | |
| Download: ML20030A748 (9) | |
Text
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SSINS No.:
Accession No.:
8107230037 IEC 81-14 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 November 5, 1981 IE CIRCULAR N0. 81-14: MAIN STEAM ISOLATION VALVE FAILURES TO CLOSE Description of Circumstances:
Based on data available in Licensee Event Report (LER) files, the failure rate of main steam isolation valves (MSIVs) closing has ranged from a ten-year low of three to fourteen in 1980.
Recent failures, similar to those occurring over the last ten years, are primarily related to the following two causes:
(1) poor quality control air to the pilot valves, and (2) binding of the MS!V valve stems with the valve stem packing.
(Refer to IE Infomation Notice 80-16 for additional details.) These two failure modes contributed to about 85% of the MSIV failure to close events. Both causes also represent comon-mode failure mechanisms of which two examples occurred in 1980:
(1) two valves fdled to close at Nine Mile Point Unit I because of rust in the pilot solenoid valves, and (2) three valves failed to close at Trojan Unit 1 because of stem binding.
These two failure modes are significant in that; (1) they idertify mechanisms by which more than one MSIV may fail to close at the same time thus leading to conditions which have no' been considered in the plant's safety analyses,* and (2) they are continuing to occur even though corrective actions reported in the LERs indicate that the technology is available to prevent such failures.
It was noted that more than half of the current operating reactor units have not reported any failure of an MSIV to close in ten years, whereas the 28 reporting units experienced at least 90 failures (from all causes).
This indicates that major differences may exist in MSIV reliebility and in the quality of support systems and operational controls that offect the MSIV reliability.
Data from the LER files is attached to show trends, recent history, and detailed data showing licensee expertence:
Table 1 - MSIV Failures To Close Per Year, shows the ten-year history of all reported failures by three categories: solenoid or pilot valve related, stem binding, and other. The first two categories account for 92% of the failures.
(The 85% for the two causes stated in the first paragraph of this circular was obtained by disregarding what appeared to be truly isolated solenoi_d or solenoid installation failures not related to control fluid quality.)
- Note:
The potential for poor quality air leading to multiple valve control failures in other safety-related systems is currently under evaluation su nor giona cord
IEC 81-14 November 5, 1981 Page 2 of 2 Table 2 - MSIV Failures To Close, by Plant, for 1979 and 1980, shows failure experiences by plant for the last two years.
Table 3
_LER Data, by Plant, on MSIV Failures To Close (1970-1980), is an extraction of all the LER data from 1970 to 1980 that show details of each plant's experience.
Tables 1 and 2 were developed from data in this table.
Recommended Actions for Holders of Operating Licenses:
1.
Review MSIV operating experience for problems that are causing failure to close events or are causing equipment degradation that requires other than routine maintenance to prevent a failure to close.
2.
Evaluate corrective action identified in maintenance records, LERs, etc.,
for adequacy in addressing the root cause of problems and develop plans for additional corrective action as necessary.
3.
Where control air quality is suspected of contributing to problems:
a.
Review the air system (s) to ensure that measures have or will be taken to prevent air quality degradation in the future.
b.
Consider monitoring and/or alarms (such as dew point alarms) to warn of air quality degradation.
4.
When stem binding is contributing to problems, maintenance procedures should be reviewed to ensure that they:
Include precautions against detrimental affects such as over tightening a.
packing glands or using inappropriate lubricants.
b.
Require tests to demonstrate that the valves will perform under operating conditions before being placed in service.
Recommraded Action for Holders of Construction Permits:
1.
Evaluate MSIV control air system designs in light of both successful and unsuccessful indutry experience.
2.
Consider design changes where appropriate to ensure high reliability and to minimize or eliminate the common-mode failure potential present in current designs.
No written response to this circular is required.
If you desire additional information regarding these matters, please contact the Director of the appropriate NRC Regional Office.
Attachment:
Tables I, II, III
T Attacnment 1 TABLE 1 Pilot Valve Stem Year Related Binding Other Total 1970 9
9 71 2
1 3
72 3
3 73 1
1 1
3 74 8 (7) 8 (7) 75 5 (1) 1 6 (1) 76 4 (1) 3 2
9 (1) 77 4 (1) 1 5 (1) 78 5
2 7
79 3 (4) 5 1
9 (4) 80 7
6 1
14 Ten-Year Total 65 (14) 18 ~
7 90 (14)
Sites reporting failures: 22 Reactor units involved:
28 Numbers in parentheses represent failures listed in the LERs as previous occurrences but not found reported in other LERs in the file.
TABLE 2 Pilot Valve Stem Year Related Binding Other Total 1979 Point Beach 2 3
3 Quad Cities 1 1
1 2
2 Trojan 1 i
Vermont Yankee 1
1 Zion 1 1
1 Zion 2 1
-1 Total 3
5 1
9 l
i i
1980 E. I. Hatch 2 1
1 e
Nine Mile Point 1 2
2 Quad Cities 1 3
3 Trojan 1 4
4 1
1 Big Rock Point Monticello 1
1 North Anna 1 1
1 Point Beach 2 1
1 Total 7
6 1
14 i
i 4
l i
l e
e i
l i
1
_,,.. _ _ _ ~.. _ _ -,,,,,,....,.,,, _.,...,,
TABLE 3 LER DATA, PLANT, ON MSIV FAILURES TO CLOSE (1970-1980)
Number of Nature of Plant Failures Failures (Note 1*)
Event Date' (Notes'2-4*)
(Note 5*)
Manufacturer Beaver Valley 1 09-19-76 1
c Unknown Schutte & Koerting Co.
Big Rock Point 09-06-78 1
b Packing / binding stem Wm. Powell Co.
03-03-73 1
b~
Packing / binding stem Wm. Powell Co.
11-01-80 1
b Packing / binding stem Wm. Powell Co.
Dresden 1 04-11-73 1
c Unknown Not listed Dresden 2 01-22-71 1
a Air pilot valve / residue Not listed 05-08-70 4
a Pilot valve / clearance Not listed
.12-04-70 4
a Pilot valve / thin film Not listed i
E. I. Hatch 1 04-17-75 1
a Pilot solenoid / stuck Atwood & Morrill Co.
06-15-75 1(+1)a Solenoid / debris buildup Automatic Valve Corp, 07-07-75 3
a Solenoid / operated improperly /
Model 443812 air filters cleaned E. I. Hatch 2 05-21-80 1
a Solenoid / faulty 0-ring ASCO H. B. Robinson 2 12-17-78 1
b Packing gland / misadjusted Schutte & Koerting Co.
Haddam Neck 1 01-22-76 1
a Solenoid Valve / frozen moisture Schutte & Koerting Co.
09-16-77 1
b Pack 1ng gland /too tight i
Ind!an Point 3 12-17-76 2
b Packing gland / shaft binding Atwood & Morrill Co.
La Crosse BWR 07-02-71 l
a Pilot valye/ residue buildup Not listed i
- See fciotnotes on last page of table.
2 of 4 TABLE 3 (continued)
Number of Nature of Plant Failures Failures (Note 1*)
Event Date (Notes'2-4*)
(Note 5*)
Manufacturer Millstone 1 11-19-70 1
a Slide valve / failed to vent air Not listed 11-04-74 1(+3)a Pilot valve / crud buildup Numatics 11-15-74 1
a Air slide valve / foreign Numatics material Monticello 1 02-16-74 2
a Solenoid Valves / metal shavings Automatic Valve Corp.
08-17-80 1
a in air manifold / Solenoid /part-iculate in solenoid plunger Atwood & Morrill Co..Inc.
Nine Mile Point 1 03-.03-80 2
a Pilot valves / rust buildup Numatics North Anna 1 01-13-80 1
c Auxiliary relay /open Westinghouse Electric Corp.
i Oyster Creek 1 04-23-77 1
a Solenoid valves / deformed gasket Not listed 01-16-74 1
a Pilot valve / residue Numatics 12-29-72 1
a Pilot valve / fine duct Not listed 11-16-71 1
c Dashpot piston / iron cushion spud failure Not listed Peach Bottom 2 11-18-76 1
b Backseat / gouging stem Atwood & Morrill Co.
Peach Bottom 3 01-02-76 1
a Solenoid valve / seat damaged Allied Control Co.
07-22-77 1
a Solenoid valve / winding failure Automatic Valve Corp.
Pilgrim 1 11-16-73 1
a Activator /small foreign particle Not listeo J1-29-72 1
a Pilot valve / stuck Not listed 07-25-74 1
a Spool piece / containment build-up (air system)
Not listed Point Beach 2 02-19-79 2
b Valve Shaft / binding Atwood & Morrill Co.
+
02-29-79 1
b Packin / binding shaft 09-12-80 1
b Packin / binding shaft
i 3 of 4 TABLE 3 (continued)
Number of Nature of Plant Failures Failures (Note 1*)
Event Date (Notes 2-4*)
(Note 5*)
Manufacturer Quad Cities 1 09-14-79 1
a Pilot valve / sticking Automatic Valve Co.
02-24-80 1
a Pilot valve / blockage t
06-21-80 2
a Pilot valve / exhaust restrictor l
11-15-72 1
a Pilot valve / dirt fm instrument Not listed air 1
i Quad Cities 2 03-19-76 1
a Pilot assembly / foreign material Automatic Valve Co.
09-22-77 1
a Pilot valve / damaged o-ring Automatic Valve Co.
Surry 2 02-04-76 1
c Disc / binding against body Schutte & Koerting Co.
I Trojan 1 02-21-78 1
a Solenoid valve / rust accumulation Not listed 04-14-79 2
b-Packing / binding Atwood & Morrill 04-11-80 3
b Packing / binding Atwood & Morrill 10-03-80 1
b Component failure (binding of i
stem?)
Atwood & Morrill Turkey Point 3 10-26-75 1
c Unknown Schutte & Koerting Vermont Yankee 1 02-04-78 1
a Pilot valve / foreign particle Rockwell Mfg.
12-09-77 1(+1)a Pneumatic spool / foreign particle Rockwell Mfg.
04-03-79 1
c Spring / binding on guide shaft Rockwell International 01-24-74 1
a Pilot yalve/ sticking Not listed 09-15-74 1(+4)a Pilot valve / failed to actuate Numatics Zion 1 05-06-78 1
a 4-way directional control valye/
Rexroth i
05-23-79 1(+4)a jammed hydraulic /DC solenoid /
stuck / hydraulic Teledyne
~
i.
1 4 of 4 4
TABLE 3 (continued) 3 4
Number of Nature of 4
Plant Failures Failures (Note 1*)
Event Date (Notes 2-4*)
(Note 5*)
Manufacturer j
Zion 2 06-03-76 1(+1)a DC solenoid / corrosion / hydraulic Teledyne 10-15-71 1
a Solenoid valves / Failed to operate
)
02-05-F3 1
a Solenoid valves failed to operate 02-09 79 1
a Solenoid valves / failure to operate /
hydraulic j
1 Notes:
- 1) All data are extracted from the LER file.
- 2) Numbers in parentheses represent "other related failures" mentioned by the LER but not the subject of another LER in the file,
- 3) Numbers greater than one represent several failures being reported by the same LER.which frequently, but not necessarily, represent simultaneous failures.
- 4) The letter "a" represents an input to Table I under " Pilot Valve Related" problems, "b" represents Stem Binding, and "c" represents "Other" on the table.
- 5) Some liberty was taken in interpreting the cause of failure where clear descriptions were not available.
j 3
I
IE Circular No. 81-14 November 4, 1981 RECENTIY ISSUED IE CIRCULARS Circular Subject Date Issued To Issued 81-04 The Role of Shift Tech-4/30/81 All power reactor facilities nical Advisors and Imper-with an Operating Licenses (0L) tance if Licensee Event or near-term Operating Licenses (0L)
Reports 81-07 Control of Radioactively 5/14/81 All power reactor Contaminated Material facilitiec with an Operating License (0L) or Construction Permit (CP) 81-08 Foundation Materials 5/29/81 Alt power reactor facilities with an Operating License (OL) or Construction Permit (CP) 81-10 Steam Voiding in the 7/2/81 All power reactor facilities Reactor Coolant System with an Operating License (OL) during Decay Heat Removal or Construction Permit (CP)
Cooldown 81-09 Containment Effluent 7/10/81 All power reactor facilities Water that Bypasses Radio-with an Operating License (0L) activity Monitor or Construction Permit (CP) 81-12 Inadequate Periodic 7/22/81 All power reactor facilities Test Procedure of with an Oparating License (OL)
PWR Protection System or Construution Permit (CP) 81-11 Inadequate Decay Heat 7/24/81 All BWR facilities witn an Removal During Reactor Operating License (OL) or Shutdown Construction Permit (CP) 81-13 Torque Switch Electrical 9/25/81 All power reactor facilities Bypass Circuit for Safe-with an Operating License (0P) guard Service Valve or Construction Permit (CP)
Motors Enclosure
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