Information Notice 1988-30, Target Rock Two-State SRV Setpoint Drift Update
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, DC 20555
May 25, 1988 NRC INFORMATION NOTICE NO. 88-30: TARGET ROCK TWO-STAGE SRV SETPOINT
DRIFT UPDATE
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose
This information notice is being provided to alert recipients to continuing
problems associated with setpoint drift occurring in Target Rock two-stage
safety/relief valves (SRVs) originally described in Information Notices (INs)
82-41, 83-39, 83-82, and 86-12 (References 1 - 4).
It is expected that re- cipients will review the information for applicability to their facilities
and consider actions, if appropriate, to avoid similar problems. However, suggestions contained in this information notice do not constitute NRC require- ments; therefore, no specific action or written response is required.
Background
On July 2, 1982, at Hatch Unit 1, all 11 Target Rock two-stage SRVs failed to
open at their setpoints of 1080 psig, 1090 psig, and 1100 psig. Pressure in
the reactor coolant system (RCS) rose to 1180 psig before three SRVs on one
steamline opened and relieved RCS pressure rapidly. This incident focused
concern on a problem that was beginning to be seen in those SRVs, called
"setpoint drift".
The Georgia Power Company, the General Electric Company (GE), and the Target
Rock Company initiated a study of the cause of the event at Hatch Unit 1.
Other utilities that had installed two-stage Target Rock SRVs Joined Georgia
Power in an owners' group to look into the nature of the problem and its
solutions.
Similar problems had been observed throughout the industry and reports in
dicated that the number of valves affected and the extent of the observed
setpoint drift had been increasing. The problem was ultimately identified
as one or both of two situations:
(1) binding in the labyrinth seal area
caused by tolerance buildup during manufacturing or (2) disc-to-seat bonding
caused by oxides of the disc and seat material forming a continuous film and
inhibiting disc movement.
88
030
It
May 25, 1988 To address these problems, additional maintenance was performed to refurbish
valves and replace parts found to be out of tolerance in the labyrinth seal
area.
This proved to be effective in some cases; however, problems caused by
disc-to-seat bonding continued. A material, PH13-8Mo, whose oxide would not
form a continuous film with the oxide of the seat material, was chosen for new
discs. A trial test of valve performance after about 50% of the valves on a
plant had new discs installed is currently being conducted.
Test Results:
Initial results of the test of the new discs were obtained in May of 1987 when
the Hatch Unit 1 valves were tested.
Of the five valves that had new discs
installed, four had pilot valves that leaked before the test. Only one of
these four pilot valves did not leak after the test.
The valve that did not
leak before the steam test had first been tested with nitrogen gas (N2) to
determine if the disc was stuck. It lifted at 5 psig N2.
The remaining four
valves lifted within 2% of setpoint. The technical specification (TS) limit is
+/- 1% of the setpoint.
One of these leaked so much that the bonnet pressure
could not be stabilized and the delay time (time between lift of the pilot disc
and the lift of the main disc) was excessive. Subsequently, the remaining
valves were tested.
Test values for all 11 valves are given in Table 1.
Disc numbers 313 and 1186, which are new discs, showed a lighter-color oxide
which was less-adherent and softer in the steam area than was seen on the old
discs in previous tests. Also, the seating area was bright and was not banded
with the apparent cleft of the corrosion seen on the old discs in previous
tests.
Discs 1189 and 1002 showed similar corrosion properties, but were
obviously steam drawn around the entire circumference.
Disc 1189 showed signs
that foreign material had been lodged between the disc and the seat. A stabi- lizer disc (Stellite) from one valve exhibited the same darker, harder, more-adherent corrosion as had been seen previously on the old (Stellite)
discs. The decision was made to turn the new disc over to GE for testing and
to replace the new discs with other new discs, but not to replace the old discs
at that time.
Brunswick Unit 2 completed Its testing for this cycle in early 1988.
Initial
reports indicate that valves with the PH13-8Mo discs lifted at +1.9%, -O.1%*,
-1.2%, +0.6%, and +4.0% of their setpoint.
One valve was not tested.
The
old-style valves, with the Stellite 6 discs, lifted at +9.3%, -1.4%, -0.2%,
+0.6%, and +2.6%*. Details are shown in Table 2.
-Hatch Unit 2 test results were also recently received. They show the valves
with PH13-8Mo discs lifted at +2.9%, +1.8%, +0.7%, and -1.1%.
The valves with
the Stellite discs lifted at +1.5%, +0.3%, +4.1%, +0.2%, +2.8%, and +1.6%.
Details are shown in Table 3.
Based on available test results, the valves with new discs appear to perform
better than valves with old discs, and valves with old discs appear to perform
better than they did in the past.
(*Second lift - the recorder was not running when the disc was first lifted).
May 25, 1988 If, when the analysis of the data is completed, the cause of the +4.0% drift
the Brunswick Unit 2 valve and the +2.9% drift on the Hatch Unit 2 valve can
determined, then PH13-8Mo may be proven to be an acceptable substitute for
Stellite 6. The NRC will continue to follow the testing program.
on
be
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
CCharles E. Rossi, Directot-
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Mary S. Wegner, AEOD
(301) 492-7818
Technical Contact:
Attachments:
1. Table 1, 1987 Test Results for Hatch Unit 1 Target Rock SRVs
2. Table 2, 1988 Test Results for Brunswick Unit 2 Target Rock SRVs
3. Table 3, Test Results for Hatch Unit 2 Target Rock SRVs
4. List of Recently Issued NRC Information Notices
References:
1. Information Notice No. 82-41, "Failure of Safety/Relief Valves to Open at
a BWR."
2. Information Notice No. 83-39, "Failure of Safety/Relief Valves to Open at
BWR - Interim Report."
3. Information Notice No.
BWR - Final Report."
83-82, "Failure of Safety/Relief Valves to Open at
4. Information Notice No. 86-12, "Target Rock Two-Stage SRV Setpoint Drift."
Attachment 1
May 25, 1988
Page 1 of I
TABLE 1
1987 TEST RESULTS FOR HATCH UNIT 1 TARGET ROCK SRVs
Valve Identifier
Disc
SNT
Setpoint
-t Fn #
Leak 11 U%04- TS
._ ~ ~ ~ ~
~
. Ws.vl
- .
ror
rs
-"a- I
lug
V
v, New
New
New
New
New
Old
Old
Old
Old
Old
Old
1189
313
1002
1186
1190[2]
1006
1187
1011
1009
1004
1003
1090
1080
1080
1100
1100
1090
1090
1080
1080
1090
1100
1072
1096
1101
5 (N2)
1083
1093
1076
1146[31
1053
1101
1116
-1.65%
+1.48%
+1.94%
LT 1%
+1.55%
LT 1%
-1.28%
+6.11%
-2.50%
+1.01%
+1.45%
Yes
Yes
Yes
No
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
Yes
No
Yes
Yes
Yes
SN = Serial Number
TS = Technical Specifications
Notes:
[12 Pilot disc leakage.
[2] Originally mounted on a Hatch body, but was removed due to leakage past
the main disc. Remounted on a slave (Wyle) body.
Pilot leakage was so
great that the 30-minute stabilization of the bonnet temperature was
waived.
[3] Failed to lift when tested on 5 psig nitrogen.
Attachment 2
May 25, 1988 TABLE 2
1988 TEST RESULTS FOR BRUNSWICK UNIT 2 TARGET ROCK SRVs
Valve Identifier
Part Number
Disc
SN
Setpoint
TS
As-h
ound I Ya-r
Leakrll
N2 Test
New
Old
Old
New
Old
Old
New
New
New
Old
New
1109
1103
1099
1102
1105
1091
1106
1107
1108
1101
1104 A
A
B
B
B
C
C
D
D
C
B[3]
1105
1125
1105
1115
1115
1105
1105
1115
1125
1115
1126
1230
1090
1114[21
1113
1112
1092
1122
1170
1144[21
+1.9%
+9.3%
-1.4%
-0.1%
-0.2%
+0.6%
-1.2%
+0.6%
+4.0%
+2.6%
Yes
Yes
No
Yes
No
Yes
Yes
Yes
No
No
Failed
No
Failed
No
No
No
SN = Serial Number
SL = Steamline
TS = Technical Specifications
Notes:
[12 Pilot disc leakage.
Second lift, valve was inadvertently lifted without recorder running.
Retainer bolts removed, spring preload lost, no as-found test done.
Attachment 3
May 25, 1988 TABLE 3
TEST RESULTS FOR HATCH UNIT 2 TARGET ROCK SRVs
Valve Identifier
Disc
SN
Setpoint.
As-
-Fondij=
To
-V a rW
I aDvri
I
Old
New
Old
New
New
New
Old
Old
Old
New
Old
301
302
303
306
307
308
310
312
314
315
1001
'1100
'
1100
1110
1110
1110
1090
1090
- 1090
1090
1100
1100
1116
1132
1114
1130
1118
1078
1135
1092
1121
1109
1118
+1.5%
+2.9%
+0.4%
+1.8%
+0.7%
-1.1%
- +4.1%
+0.2%
+2.8%
+0.8%
+1.6%
Yes
Yes
Yes
Yes, badly
Yes, badly
Yes
No
Yes
Yes
Yes
Yes
SN = Serial Number
TS - Technical Specifications
Notes:
[1]
Pilot disc leakage.
Attachment 4
May 25, 1988 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
88-29
88-28
Deficiencies in Primary
Containment Low-Voltage
Electrical Penetration
Assemblies
Potential for Loss of
Post-LOCA Recirculation
Capability Due to
Insulation Debris Blockage
Deficient Electrical
Terminations Identified
in Safety-Related
Components
5/24/88
5/19/88
5/18/88
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
88-27
85-35,
Supplement 1
Failure of Air Check
Valves to Seat
5/17/88
All holders of OLs
or CPs for nuclear
power reactors.
88-26
88-25 Falsified Pre-Employment
Screening Records
Minimum Edge Distance for
Expansion Anchor Bolts
Failures of Air-Operated
Valves Affecting Safety-
Related Systems
Minimum Edge Distance for
Expansion Anchor Bolts
5/16/88
5/16/88
5/13/88
5/16/88
All holders of OLs
or CPs for nuclear
power reactors and
all maJor fuel
facility licensees.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
88-24
88-23 OL = Operating License
CP = Construction Permit
May 25, 1988 If, when the analysis of the data Is completed, the cause of the +4.0% drift
the Brunswick Unit 2 valve and the +2.9% drift on the Hatch Unit 2 valve can
determined, then PH13-8Mo may be proven to be an acceptable substitute for
Stellite 6. The NRC will continue to follow the testing program.
on
be
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Mary S. Wegner, AEOD
(301) 492-7818 Attachments:
1. Table 1, 1987 Test Results for Hatch Unit 1 Target Rock SRVs
2. Table 2, 1988 Test Results for Brunswick Unit 2 Target Rock SRVs
3. Table 3, Test Results for Hatch Unit 2 Target Rock SRVs
4. List of Recently Issued NRC Information Notices
References:
1. Information Notice No. 82-41, "Faillure of Safety/Relief Valves to Open at
a BWR."
2.
Information Notice No.
BWR -
Interim Report."
3.
Information Notice No.
BWR -
Final Report."
83-39, "Failure of Safety/Relief Valves to Open at
83-82, "Failure of Safety/Relief Valves to Open at
4.
Information Notice No. 86-12, "Target Rock Two-Stage SRV Setpolnt Drift."
PREVIOUS CONCURRENCES
- See previous concurrences
- Transmitted by memorandum to C. H. Berlinger from J. E. Rosenthal dated
March 16, 1988
- Comments received in memorandum to C. H. Berlinger from L. B. Marsh dated
April 18, 1988
- D/D 4
-W
- C/OGCB:DOEA:NRR*PPMB:ARM
- C/EMEB:DEST:NRR***EMEB:DEST:NRR
CERossl
CHBerllnger
TechEd
LBMarsh
PTKuo
05/20/88
05/09/88
04/15/88
04/ /88
04/ /88
- OGCB:DOEA:NRR **ROAB:DSP:AEOD**ROAB:DSP:AEOD**C/ROAB:DSP:AEOD ***EMEB:DEST:NRR
RJKiessel
MSWegner
MChirmal
JERosenthal
CGHammer
04/12/88
03/ /88
03/ /88
03/ /88
04/ /88
IN 88-XX
May xx, 1988 If, when the analysis of the data is completed, the cause of the +4.0% drift
the Brunswick Unit 2 valve and the +2.9% drift on the Hatch Unit 2 valve can
determined, then PH13-8Mo may be proven to be an acceptable substitute for
Stellite 6. The NRC will continue to follow the testing program.
on
be
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Mary S. wegner, AEOD
(301) 492-7818 Attachments:
1. Table 1, 1987 Test Results for Hatch Unit 1 Target Rock SRVs
2. Table 2, 1988 Test Results for Brunswick Unit 2 Target Rock SRVs
3. Table 3, Test Results for Hatch Unit 2 Target Rock SRVs
4. List of Recently Issued NRC Information Notices
References:
1. Information Notice No. 82-41, "Failure of Safety/Relief Valves to Open at
a BWR."
2.
Information Notice No.
BWR - Interim Report."
3.
Information Notice No.
BWR - Final Report."
83-39, "Failure of Safety/Relief Valves to Open at
83-82, "Failure of Safety/Relief Valves to Open at
4.
Information Notice No. 86-12, "Target Rock Two-Stage SRV Setpoint Drift."
PREVIOUS CONCURRENCES
- See previous concurrences
- Transmitted by memorandum to C. H. Berlinger from J. E. Rosenthal dated
March 16, 1988
- Comments received in memorandum to C. H. Berlinger from L. B. Marsh dated
April 18, 1988
D/
R
- O4B:DOEA:NRR
RJKiessel
04/12/88
- C/OGCB:DOEA:NRR*PPMB:ARM
- C/EMEB:DEST:NRR***EMEB:DEST:NRR
CHBerlinger
TechEd
LBMarsh
PTKuo
05/09/88
04/15/88
04/ /88
04/
/88
- ROAB:DSP:AEOD**ROAB:DSP:AEOD**C/ROAB:DSP:AEOD ***EMEB:DEST:NRR
MSWegner
MChirmal
JERosenthal
CGHammer
03/ /88
03/ /88
03/ /88
04/ /88
IN 88-XX
April xx, 1988 If, when the analysis of the data is completed, the cause of the +4.0% drift
the Brunswick Unit 2 valve and the +2.9% drift on the Hatch Unit 2 valve can
determined, then PH13-8Mo may be proven to be an acceptable substitute for
Stellite 6. The NRC will continue to follow the testing program.
onbe
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Mary S. Wegner, AEOD
(301) 492-7818 Attachments:
1. Table 1, 1987 Test Results for Hatch Unit 1 Target Rock SRVs
2. Table 2, 1988 Test Results for Brunswick Unit 2 Target Rock SRVs
3. Table 3, Test Results for Hatch Unit 2 Target Rock SRVs
4. List of Recently Issued NRC Information Notices
PREVIOUS CONCURRENCES
- Transmitted by memorandum to C. H. Berlinger from J. E. Rosenthal dated
March 16, 1988
- Comments received in memorandum to C. H. Berlinger from L. B. Marsh dated
April 18, 1988 A
D/DOEA:NRR
CERossi
04/ /88
- OGCB:DOEA:NRR
RJKiessel
04/12/88 C/OGCB: DOEA:NRR
CHBerlinger
q5/cq /88
- ROAB:DSP:AEOD
MSWegner
03/ /88
- PPMB:ARM
- C/EMEB:DEST:NRR
TechEd
LBMarsh
04/15/88
04/ /88
- ROAB:DSP:AEOD*C/ROAB:DSP:AEOD
MChirmal
JERosenthal
03/ /88
03/ /88
- EMEB:DEST:NRR
PTKuo
04/ /88
- EMEB:DEST:NRR
CGHammer
04/ /88
IN 88-XX
April xx, 1988 When the analysis of the data is completed, and the cause of the +4.0% drift
the Brunswick Unit 2 valve and the +2.9% drift on the Hatch Unit 2 valve can
determined, then PH13-8Mo may be proven to be an acceptable substitute for
Stellite 6. The NRC will continue to follow the testing program.
on
be
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
Mary S. Wegner, NRR
(301) 492-7818 Attachments:
1. Table 1, 1987 Test Results for Hatch Unit 1 Target Rock SRVs
2. Table 2, 1988 Test Results for Brunswick Unit ? Target Rock SRVs
3. Table 3, Test Results for Hatch Unit 2 Target Rock SRVs
4. List of Recently Issued NRC Information Notices
PREVIOUS CONCURRENCES
- Transmitted by memorandum to C. H. Berlinger from J. E. Rosenthal dated
March 16, 1988
- Comentb received in memorandum to C. H. Berlinger from L. B. Marsh dated
AprilW, 1988
D/DOEA:NRR
CERossi
04/ /88 OGCB:DOEA:NRR
RJKiessel
04/a/a
> <
C/OGCB:DOEA:NRR
CHBerlinger
04/ /88
- ROAB:DSP:AEOD
MSWegner
03/ /88 PPMB:ARM
- C/EMEB:DEST:NRR
TechEd 8Ž.b
LBMarsh
04/l&'/88
04/ /88
- ROAB:DSP:AEOD*C/ROAB:DSP:AEOD
MChirmal
JERosenthal
03/ /88
03/ /88
- EMEB:DEST:NRR
PTKuo
04/ /88
- EMEB:DEST:NRR
CGHammer
04/ /88