IR 05000324/1988003
| ML20148T606 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 01/27/1988 |
| From: | Merschoff E, Shymlock M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20148T568 | List: |
| References | |
| 50-324-88-03, 50-324-88-3, 50-325-88-03, 50-325-88-3, NUDOCS 8802030350 | |
| Download: ML20148T606 (68) | |
Text
{{#Wiki_filter:- - _ - _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _______ _ ____-_____- -_-_-_____- - ____-__, p,* ucg UNITED STATES q 'o NUCLEAR REGULATORY COMMISSION
p' REGloN il , g j 101 MARIETTA STRE ET. N.W.
"e ATLANTA. 3 EORGI A 3o323
- %,....*,/
U. S. NUCLEAR REGULATORY COMMISSION
REGION II
AUGMENTED INSPECTION TEAM Report Nos.: '50-325/88-03 and 50-324/88-03 Licensee: Carolina Power and Light Company P.O. Box 1551 Raleigh, NC 27602 Docket Nos.: 50-325 and 50-324 License Nos.: DPR-71 and DPR-62 Facility Name: Brunswick 1 and 2 Inspection Conducted: January 5 - 9, 1988
- A
/ W -88 Team Leader: , M. Shymiock, Chu f Date Signed Operational Programs Section Team Members: R. Gibbs, Reactor Inspector, Region II G. Hammer, Mechanical Engineer, MEB, NRR P. Kellogg, Reactor Engineer, Region II M. Shannon, Reactor Inspector, Region II 0. Stadler, Reactor Engineer, Region II E. Sylvester, Brunswick Project Manager, NRR S. Vias, Brunswick Project Engineer, Region II L. Wats ,R ctor En 46eer on II < . Approved by: . !-
E. W. Merschoff, 0 'r /-27-87 . trector Date Signed i Division of Reacto fety i Region II i i i
Table of Contents Page I.
INTRODUCTION - FORMATION AND INITIATION OF AIT...........
A.
Background..........................................
B.
Formation of Augmented Inspection Team (AIT)........
C.
AIT Charter - Initiation of Inspection..............
D.
Persons Contacted...................................
E.
Abbreviations, Acronyms and Description of Operations Shift Staffing at the Time of the Event.........................................
F.
Design Descriptions.................................
II.
DESCRIPTION OF EVENTS....................................
A.
Overview of Event for Brunswick Unit 2..............
1.
Initial Conditions.............................
2.
Manual Scram of Reactor........................
3.
Verification of Group 2 Isolations and Discovery of the Failure of Four Primary Containment Isolation Valves to Close........
4.
Subsequent Post-Scram Operator Actions.........
5.
Detailed Sequence of Events for Brunswick Unit 2.......................................
B.
Evaluation of Equipment Operability and Continued Operation of the Operating Unit (Unit 1)..........
III.
EQUIPMENT STATUS, FAILURES / MALFUNCTIONS, AND ANOMALIES..
A.
Equipme~t Deficiencies Noted Prior to Event........
B.
Containment Isolation Valves - Failure to Close....
C.
Licensee Investigation of Unit 2 Containment Valve Failures...................................
1.
Operability Tests.............................
2.
Disassembly and Inspection of 2-G16-F019 Solenoid Valve on January 2, 1988...........
3.
Disassembly and Inspection of 2-G16-F003 Solenoid Valve on January 7, 1988...........
4.
Vendor Inspection of Solenoid Valve 2-G16-F020.................................
5.
Inspection of the Instrument Air System....... 14 6.
Inspection of Primary Containment Isolation System Relays K-17 and K-18 on January 9, 1988.............................,
_ _ _ _ __ _ ____ __ _ _ ___ _ _ _ , ii Page , D.
AIT Investigation of Event.........................
1.
History of Modifications......................
< 2.
History of Maintenance.......................
3.
History of Unit 2 Surveillance Testing / Section XI Testing.........................
i 4.
Field Inspection of Valve Installation on
Units 1 and 2...............................
' 5.
Comparison of Vendor Instructions to Licensee 's Procedures.......................
i . 6.
Maintenance and Operator Training.............
, 7.
Trending Programs.............................
8.
Maintenance History of Other ASCO Solenoid ,
Valve s at Brunswi c k.........................
> 9.
Review of Quality Control (QC) Involvement....
10.
Vendor On-site Interview......................
E.
Equipment Vendor Involvement.......................
I t F.
Preventive Maintenance................... .........
' IV.
POTENTIAL RADIOLOGICAL CONSEQUENCES.....................
V.
COMMUNICATIONS AND THE ACCURACY, TIMELINESS AND , l~ EFFECTIVENESS OF REPORTS TO THE NRC...................
1 ' VI.
ROOT CAUSE DETERMINATION................................
l , t VII.
FINDINGS OF FACT........................................
l A.
Potential Radiological Consequences...............
l
B.
Failure Investigation..............................
l '
- ! C.
Mod i f i c a t i o n s...................................... 3 4 e s D.
Maintenance........................................
, ! i l' E.
Surveillance Testing Program.......................,
i l F.
Post Event Operability Checks and Surveillances....
, ! ! G.
Operations.........................................
[ j H.
Training...........................................
l t I.
Miscellaneous......................................
' vIII.
C0NCtuSIONS.............................................
! i IX.
EXIT INTERVIEW WITH LICENSEE MANAGEMENT.................
i ATTACHMENT 1 - AUTOMATIC SWITCH COMPANY (ASCO) BULLETIN 206-832 ATTACHMENT 2 - G16-F003, -F004, -F019 -F020 CONTROL AND LOGIC CIRCUIT ORAWING l t L I - - - - - - - - -., _, .- _ .. - - -. _ _ . ..
. - _ _ _ _ _ - _ _ _ _ _ _ _____________-____- __- ____ _-_ _ __ ___-_-___ _ _ _ - _ _ _ _ _____ __-____ _ _- _ ___ ____-___ i iii APPENDICES APPENDIX 1 - PERSONS CONTACTED ACRONYMS AND ABBREVIATIONS APPENDIX 2 - DESIGN DESCRIPTIONS APPENDIX 3 - . A.
Drywell Equipment and Floor Drains and Group 2 Primary Containment Isolation System (PCIS) 8.
Description and Operation of the Solenoid Valves 4.
C.
Automatic and Manual Valve Logics for G16-F003, -F004, -F019, and -F020 D.
Drywell Equipment Drain System Description E.
Drywell Floor Orain System Description F.
Instrument and Service Air Systems Descriptions REVIEW 0F INITIAL CONDITIONS AND OUT-OF-SERVICE EQUIPMENT APPENDIX 4 - A.
Overview of Initial Power Evolutions B.
Train A and B Offgas Flow Recorders ' C.
Hydrogen Recombiner Catal.yst Bed Temperature Recorder D.
Effect of Inoperable Offgas Instrumentation on Unit 2
Operation and Scram E.
Unit 2 Condenser Vacuum Leak (Air Inleakage History and Out of Calibration Low Vacuum Alarms) i DETAILED SEQUENCE OF EVENTS FOR BRUNSWICX UNIT 1 APPENDIX 5 - DETAILED SEQUENCE OF EVENTS OF LICENSEE INVESTIGATION . APPENDIX 6 - i EMERGENCY RESPONSE FACILITY INFORMATION SYSTEM (ERFIS) APPENDIX 7 - , ,
_ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -
. . REPORT DETAILS I.
INTRODUCTION - FORMATION AND INITIATION OF AIT ' -A.
Background Brunswick Units 1 and 2 are General Electric (GE) boiling water reactors (BWR) IV with Mark I containments. The units are located 20 miles south of Wilmington, N.C. at the mouth of the Cape Fear River in Brunswick County, N.C.
Unit 2 went critical in March 1975 and was commercially operational in November 1975.
Unit I went critical October 1976 and commercial operations began in March 1977.
On Saturday, January 2,1988, Carolina Power and Light Company reported to the NRC that, during a manual reactor trip from 51 percent power, Brunswick Unit 2 experienced a failure of four con- ' tainment isolation valves to close upon receipt of an automatic actuation signal. The four containment isolation valves involved , were two redundant isolation valves in the drywell equipment drain system and two redundant isolation valves in the drywell floor drain system.
The two drywell floor drain valves closed on manual actua-tion. The two drywell equipment drain isolation valves failed to close on receipt of a manual signal.
The two valves were later determined to have closed at six and eight minutes after the scram, respectively. The Region II Senior Resident Inspector conducted a preliminary assessment of the event.
B.
Formation of Augmented Inspection Team (AIT) . On the morning of Monday, January 4,1988, the Regional Administrator, after further briefing by the Regional and Resident staff and consultation with senior NRC management, directed the dispatch of an Augmented Inspection Team (AIT) headed by the Section Chief of the Region II Operational Programs Section.
The team included participation by NRR.
, C.
AIT Charter - Initiation of Inspection , The Charter for the AIT was prepared on January 4, 1988 and the AIT - ' members arrived at the Brunswick site on January 5, 1988.
Security ' badging was completed for the Team, and the special inspection commenced with an Entrance Meeting and briefing by licensee management at 1400 hours on January 5,1983.
The Charter for the AIT specified that the following tasks be completed: 1.
Develop and validate a detailed sequence of events associated with the January 2,1988 reactor trip of Brunswick Unit 2 and the subsequent failure of four containment isolation valves to close when required.
t
_- --,
_ _ -_ _____ _ __ -__ ___ _ _ - _ !
r k
3 , ,'
2.
Evaluate the significance of the event with regard to radiological consequences, safety system performance, and plant i proximity to safaty limits as defined in the Technical i Specifications.
l ' 3.
Evaluate the accuracy, timeliness and effectiveness with which information on this event was reported to the NRC.
4.
For each equipment malfunction, to the extent practical, [ determine: I a.
Root cause l b.
If the equipment was known to be deficient prior to the
event.
c.
If equipment history would indicate that the equipment had , , either been historically unreliable or if maintenance or , modifications had been recently performed.
! d.
Any equipment vendor involvement prior to or after the , l event, i e.
Pre-event status of surveillance, testing (e.g., Section
i XI), and/or preventive maintenance.
f.
The extent to which the equipment was covered by existing ! corrective action programs and the implication of the
' failures with respect to program effectiveness.
. 5.
Evaluate the licensee's action taken to verify equipment
operability on the operating unit.
, , ! } 6.
Identify any human factors / procedural deficiencies related to j ' the event.
! ' 7.
Through operator and technician interviews, determine if any of i the following played a significant role in the event: plant [ i . material condition; the quality of maintenance; or the responsiveness of engineering to identified problems.
' , $ i 0.
Persons Contacted ! ! t i See Appendix 1.
- ' E.
Abbreviations, Acronyms and Description of Operations Shift Staffing l l at the Time of the Event i ! Abbreviations and acronyms are provided in Appendix 2.
Abbreviations ! i ' ! for the Operations staff are used for convenience throughout the report.
The following brief explanation of each position is l ) provided:
a l SOS Shif t Operations Supervisor - Senior Reactor Operator (SRO) [ ! licensed individual responsible for both Unit I and Unit 2
i operations, t ! ! t -. .. - - _ . -. - - - - _. _ _ _ _ _ _ _ - _ - - _. _, .- -. _._ .- - - -. -.
- _ _ _ _ _ _ _ _ - _ _ _ _ - - _ , b 3-j SF Shift Foreman - SRO licensed individuals, one responsible , for each unit.
The SF directs operators through the , Emergency Operating Procedure (EOP) flowpaths following a scram or unit event. At the time of this event, the Shift ! Foreman for Unit 2 was on vacation and a fully qualified SRO was acting in the Shift Foreman's position. The j acting Shift Foreman is referred to as the ASF in this report.
'C0 Control Operator - Licensed reactor operator responsible for the operation of one of the two reactors.
BOP Balance-of-Plant Operator - Licensed reactor operator responsible for the operation of balance-of plant equipment such as the turbine generator and auxiliaries.
' F.
Design Descriptions ' Design descriptions for the equipment and systems discussed in the report are provided in Appendix 3.
I II.
DESCRIPTION OF EVENT A.
Overview of Event for Brunswick Unit 2 1.
Initial Conditions
s
On the evening of January 1, 1988, Unit 2 was at 69 percent > . power due to fuel depletion and preparations were being made for t ' a shutdown for a refueling outage. Unit 1 was at 100 percent ' . power. At approximately 2015 hours, the operators began a power ! reduction utilizing a combination of recirculation flow decrease and control rod insertion.
During this period, the offgas system flow rate was running approximately three times normal
(140 standard cubic feet per minute (sefm)) due to suspected air inleakage.
Between 2115 and 0018 hours, the operators altered reactor power f
to maintain condenser vacuum.
These evolutions were complicated - - ) by out-of-service equipment.
The inability to maintain i condenser vacuum eventually resulted in the decision to manually scram the reactor.
The sequence of events prior to the scram > l and review of out-of-service equipment is discussed in Appendix i 4, paragraph A.
! 2.
Manual Scram of Reactor At 0016 hours on January 2, 1988, the condenser vacuum had decreased to 22.5 inches, and at 0017 hours the "A" train exhaust hood low vacuum alarm was received at 22 inches Both the "A" and "B" train low vacuum alarms should have been -
- received at 25 inches of vacuum. At this point, the Shift I Operations Supervisor (505) made a decision to scram the reactor l l and directed a reduction in recirculation flow. At 0018 hours, } the SOS directed a manual scram of the reactor.
. ! . . -. - ._ . .. .. - - - --..-. . .
i
r
Following the scram, the acting Shift Foreman, referred to herein as ASF, began directing the operators through the Emergency Operating Procedure (EOP) flowpaths for a reactor scram. At 0018 hours the process computer (PC) documented that five control rods were not inserted and were at position 02, 3.
Verification of Group 2 Isolations and Discovery of the Failure of Four Primary Containment Isolation Valves to Close-At 0020 hours, the step was reached in the E0P flowpath that requires verification of Group 2, 6 and 8 isolations if reactor water level has decreased to less than low low level "1" (+ 162 inches).
The narrow range water level recorder indicated that reactor water level had dropped to 153 inches.
The process computer would later indicate that the actual minimum water level reached was 155.9 inches.
At this point, the ASF directed the operators to verify groups 2, 6, and 8 isolations. Group 6 isolation contains numerous valves and is verified utilizing an E0P alignment checklist.
Groups 2 and 8 however, contain a limited number of valves which are specially labeled on the control boards.
Therefore, the control operator (CO), af ter performing the scram immediate actions, verified Group 2 isolations first.
The C0 noted that four Group 2 primary containment isolation system (PCIS) valves were still in the OPEN position with the red indicating lights illuminated.
These four valves were 2-G16-F003 and -F004, the redundant containment isolation valves on the drywell floor drain line, and 2-G16-F019 and -F020, the redundant containment isolation valves on the drywell equipment drain line.
The CO immediately attempted to manually close these PCIS valves utilizing the control board manual switches by moving these switches to the CLOSE position.
Upon receiving a manual close signal, 2-G16-F003 and -F004 CLOSED as indicated by a light change from red to green.
Despite several attempts and holding the switches in the CLOSED position for 5 to 10 seconds, the 2-G16-F019 and -F020 valves could not be manually closed by the CO.
The SF from Unit 1, noticing that the operator was experiencing difficulty closing the valves, offered to continue the manual closure attempts allowing the C0 to continue with post-scram activities. The SF (Unit 1) held the 2-G16-F019 and -F020 switches in the CLOSE position for at least 10 seconds but was also unsuccessful in achieving closure.
The SF (Unit 1) left the valve switches and continued a walkdown of the Unit 2 control boards.
At approximately 0024 hours, the 2-G16-F020 valve was ob %rved to be in the CLOSED position with the green position indicating
t
. ' i i
! light illuminated.
The closure of 2-G16-F020 provided a single isolation of the breach in primary containment that had existed - since 0018 hours.
At this point, the 2-G16-F019 valve was still in the OPEN position with the red indicating light illuminated.
The SF (Unit 1) gave the 2-G16-F019 valve an additional 10 i
- -
second closure signal but was again unsuccessful in closing the valve.
At approximately 0026 hours, the 2-G16-F019 valve was observed to be in the CLOSED position with the green indicating iIght illuminated. With all four valves CLOSED, Group 2 primary { ! containment isolation was completed.
Following closure of the ' 2-G16-F019 valve, the reactor scram and Group 2, 6, and 8 isolations were reset.
- , l 4.
Subsequent Post-Scram Operator Actions
. At 0027 hours, the ASF directed operators to verify all control , rods were fully inserted per the E0P flowpath. At 0028 hours, ' the operators determined that five control rods were not fully i inserted and were at the 02 position.
The ASF directed the a i operators to place the reactor mode switch to the refueling , position and to fully insert the five control rods utilizing the l , "emergency in" switch. At 0029 hours all five control rods were ! fully inserted to position 00.
5.
Detailed Sequence of Events for Brunswick Unit 2 The following detailed sequence of events for Brunswick Unit 2 I was determined from those sources indicated in the "Data Source"
! column. The sequence of events was developed from discussions with licensee management, written statements of the operators, independent interviews with plant operators, review of a tape
recording taken in the control room during the event, and review l of plant logs and event investigation packages.
'
I , I l I i ! l f
!
l , l i l F \\ l L . - - . . _
_ _ _ _ _ _ _ _ _ _
DETAILED SEQUENCE OF EVENTS BRUNSWICK UNIT 2 - SCRAM AND CONTAINMENT ISOLATION VALVE FAILUR' General Status of Subsequent to the shift turnover at Unit 2, prior to 2000 hours on 1/1/88, Unit 2 was being event on night shutdown per GP-05 to enter a refueling outage, shift 1/1/88 At shift turnover, Unit 2 was at 69 percent (Operator inter-power.
Offgas flows of approximately three view and control times normal flow were being experienced.
At room logs) 2015 hours, the SOS directed a power reduction toward unit refueling shutdown.
Specific Equip-The offgas outlet flow indicators for ment Status prior trains "A" and "B" (recorder # to the event 2-0G-FR-4283/4323) were reading low with an outstanding maintenance work order.
The hydrogen recombiner "B" catalyst bed temperature indicator (recorder # 2-0G-TR-4320) was out of service reading low with an outstanding maintenance work order.
JANUARY 1, 1988 Time (EST hours) Data Source Item 2015 SF Log Commenced power reduction from 69 percent C0 Log power utilizing reduction in recirculation flow and control rod insertion. Offgas flow was at 140 scfm.
2115 CO Log Reactor power at 55 percent power. Offgas flow at 140 scfm.
2125 CO Log A0G Bypass Valve opened automatically on SF Interview high offgas flow (setpoint: 150 scfm).
Chemistry notified.
2145 C0 Interview At 55 percent power the "A" reactor feed pump was taken off.
Steam seals were left on to hold vacuum.
2210 C0 Log Operator secured the "B" SJAE per GP-05 at C0 Interview approximately 50 percent power.
2215 CO Log Reactor power at 48 percent powe C0 Statement Operator inserted control rods per GP-10, up ta and including Group 73.
2220-ASF/SR0 Condenser vacuum decreasing slowly.
2245 Interview Operator attempted to restart the "B" SJAE, however permissives were not met due to the hydrogen recombiner temperature indicator being out-of-service.
(Permissive setpoint at 300F.)
2240 C0 Statement Stopped inserting rods to allow nuclear engineer to run computer program.
2245 CO Log Vacuum decreasing. Operator increased SJAE "A" to full load since SJAE "B" unavailable.
2246 C0 Log Reactor power increased to 53 percent to maintain vacuum by increasing recirculation pump flow. Vacuum increased to about 26.5 inches and was maintained.
2246 C0 Statement Operators were walking down plant looking for vacuum and steam leaks.
2250 C0 Statement Approximately 15 minutes after group 73 rods inserted, vacuum began decreasing more rapidly.
2330 CO Log Operator reported unusual noise near west AO Log moisture separator reheater drain tank ASF Interview indicating potential vacuum leak.
2356 C0 Interview Pulled control rods per sequence determined by nuclear engineer in attempt to increase power and stop the vacuum leak.
2359 PC Stopped rod pull at approximately 56 percent power.
Vacuum was at 24.4 inches.
ASF Interview SOS decided to trip the reactor if vacuum
SOS Interview continued to decrease based on the inability to recover vacuum and to avoid a turbine trip and GP-1 main steam isolation valve isolation.
r Indicates that event is entered at approximate time frame,
i
_ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ l l
EVENTS SURROUNDING MANUAL SCRAM JANUARY 2, 1988 !
Time
' (EST hours) Data Source Item , NOTE: Approximately three minutes before the manual scram, i.e.,
, approximately 0015, operators initiated a tape recording of control room scram activities.
0016 PC Vacuum at 22.5 inches.
i .0017 CO Log Received annunciator 2-VA-23 "Exhaust hood ! C0 Interview A Vac Low".
Noted that B train alarm was , , Tape Recorder not in.
. 0017 CO Interview Ran recirculation pump flow back to , Tape Recorder minimum.
- 0018 Tape Recorder SOS directed manual scram of reactor.
! 0018 PC Operator inserted manual reactor trip ! C0 Interview signal and initiated E0P scram flowpath.
! Tape Recorder i . 0018 PC Process Computer reactor water level Log indication at lowest level (155.9 inches).
Strip chart recorder indicates reactor water ! , , level at lowest level (153 inches).
0018 PC Five (5) control rods inserted only to l Position 02.
- 0021 Co Interview Started verifying Group 2, 6 and 8
' isolations.
Group 2 verified by CO and
Group 6 by BOP operator utilizing E0P t
alignment checklist.
j , ! i ! 0021 CO Log C0 noted 2-G16-F003 and -F004 (drywell
Tape Recorder floor drain PCIS valves) and, 2-G16-F019
and -F020 (drywell equipment drain PCIS valves), did not automatically close on
Group 2 isolation.
C0 attempted to manually ., close the four PCIS valves.
2-G16-F003 and ., -F004 closed immediately when handswitch was ! , - placed to CLOSE position.
2-G16-F019 and ! ' -F020 did not close nn manual switch I actuation.
C0 cycled 2-G16-F019 and -F020 ! ) switch to CLOSE three to five times each, holding for 5 to 10 seconds in the CLOSE i
i position each time.
2-G16-F019 and F020 i remained OPEN.
t . _.,. ,,... - - ,,
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -
0022 SF (Unit 1) SF (Unit 1) also held switches for Statement 2-G16-F019 and -F020 to CLOSE position for greater than 10 seconds.
2-G16-F019 and-F020 remained OPEN.
0024 SF (Unit 1) SF (Unit 1) noted that 2-G16-F020 valve had Statement CLOSED and that 2-G16-F019 was still OPEN.
Tape Recorder SF held manual switch for 2-G16-F019 to CLOSE position for additional 10 seconds.
2-G16-F019 remained OPEN.
0026 SF (Unit 1) SF (Unit 1) noticed that 2-G16-F019 had Statement CLOSED Tape Recorder 0027 Tape Recorder SF (Unit 1) directed operators to verify all controls rods fully inserted.
0028 Tape Recorder Five rods were determined to be at position 02.
0028 Tape Recorder All five rods were fully inserted to position 00.
0407 SF Log NRC Red Phone report on scram and PCIS valve failures.
B.
Evaluation of Equipment Operability and Continued Operation of the Operating Unit (Unit 1) As a result of the valve failures on Unit 2, the licensee manually cycled the similar four valves in Unit 1 from the control room on January 2 to verify operability.
All four valves functioned normally when cycled with the control room hand switches.
Additionally, on January 4, the licensee conducted a modified 18-month surveillance logic test, Special Procedure (SP) 88-003, Rev. O, on Unit 1 to verify the wiring logic for the Group 2 primary containment isolation system (PCIS).
This test verified the logic from the K5A, B, C, and D relays, reactor water low level "1," through relay K-17 and K-18 which cycled 1-G16-F003, -F004 -F019, -F020 valve independently.
The SP was satisfactorily completed when all valves closed as required.
Based on a special test on Unit 2 which indicated that the logic circuits were properly wired, the licensee closed the corresponding Unit i valves.
The AIT concurred with the closing of the four valves. The licensee stated that these valves will remain closed, except for pumping of the floor and equipment drains, until the root cause of the failure in Unit 2 is determined and corrected or until
-.
Voit 1 is shutdcun for a stheduled maintenance outage on about Jaeuary 18, 1988.
A detailed seavance of events for Brunswick Unit 1 was determined from those tources inyicateo its the '9ata Source" column.
This secuence of tvants is provided in Appendix 5.
The sequence of events was oeveloped from discussio0s with licensee management and i Adeput: dent intervfews with plant operators and review of plant logs and 6Ytht InveStigatioQ packBge$. ill. EQUIPMENT STATUS. FAILURES /MALPJNCT164'S,. AND ANOMALIES A.
Ecuipment Deficiencies Noted Prior te Evemt Unit 2 eauipment that was out-of-service prior to the event is discussed in Appendix 4.
Other equipm13L cut-of-service p. tier to the event did not appear to affect the plant resp 6nse subsequent to the scram or the failure of the containmer,t isolation valves.
B.
Containment luoi+ tion Vsives - Failue6 to Close '/alves 2-G16-F003 and -F004 in the drywell floor drain system piping and valves 2-G16-F019 and sF020 ir the drywell equipment drain system piping are componos*,s of the primary containment isolation system (PCIS).
These valves ars three inch 150 lb. gate valves.
The valves ,<ern manufactured by Anchor Valve Company of cast carbon steel.
The valves are opened by an air actuation cylinder, controlled by Automatic Switch Company (ASCO) solenoid valves, and are spring i assisted closed upon loss of air pressure, The PCIS is a safety-related system that is designed to prevent or limit the release of radioactive materials that may result from postulated accidents through rapid, automatic isolation of process lines which penetrate the primary containment.
As a result of the manual scram. Unit 2 reactor vessel water level decreased to below the low level "1" setpoint, and the Group 2 containment isolation signal was generated.
Neither the drywell floor drain system nor the drywell equipment drain system are essential for accident mitigation, and, therefore, the PCIS valves in both systems (2-G16-F003, -F004, -F019 and -F020) received an automatic isolation signal but failed to close.
Since these drain systems are cpen to the containment atmosphere, redundant, automatic ' isolation valves are provided outside and adjacent to the containment penetration in accordance with the criteria for the PCIS design basis.
Redundant PCIS valve failure, therefore, represents a condi-tion that is outside the design basis for containment isolation.
The design basis assumes that only a single random failure of a safety system component will occur.
This failure was a multiple, i common-mode failure of redundant safety system (PCIS) component __ . _ _ _ _ _ _ _ _ _ _ _ ! "
i ! C.
Licensee Investigation of Unit 2 Containment Valve Failures The licensee initiated a Scram Incident Investigation Team (SIIT) at
0230 hours on January 2, 1988 to investigate the event.
During
I meetings with the AIT, the licensee indicated that the SIIT investigation was continuing but initial indications were that the Automatic Switch Company (ASCO) solenoid valves (Model 206-832) which ! actuated the containment isolation gate valves had failed.
The , licensee conducted special tests and disassembled and examined two of the solenoid valves prior to the end of the inspection. The licensee i also determined on January 9, 1988 that a set of contacts in a GE ! , CR120A relay (K-18) had indication of not properly opening.
The ! licensee has continued the investigation by providing ASCO with ' several valves for analysis. A detailed sequence of the testing and
licensee investigation through January 9, 1988 is provided in i Appendix 6.
Highlights of the licensee's efforts observed and/or
reviewed by the AIT are provided below.
' 1.
Operability Tests , The Operations Engineer indicated that at 0500 hours and again at 0930 hours on January 2,1988, the licensee manually cycled all four valves on Unit 2 fully open and closed to pump down the - drywell sumps. The valves operated properly and were left in , the closed position. At 1200 hours on January 2, 1988, the four Unit i valves were manually cycled fully closed and open.
The i valves operated under the manual signal and were left in the ' l open position.
l The licensee conducted initial testing on Unit 2 valves G16-F003, -F004, -F019 and -F020 using a special test procedure ( ) SP-88-003, Group 2 Isolation Logic System Functional Test, based ! on the 18-month surveillance test. This test was completed at 1930 hours on January 2, 1988. No problems were identified.
The licensee also conducted a modified monthly channel l functional test which verified proper operation of two valves.
I i The licensee conducted a modified 18-month surveillance test , I utilizing special procedure (SP) SP 88-004, PCIS Valves j G16-F003, F004, F019 and F020 Functional Test, on January 6, '
1988.
This test was observed by the AIT. The purpose of this special test was to verify operation of the logic circuits from ' the Master Trip Units to the actuator on the valves. A ' simulated low water level was inserted into each of the four ' Master Trip Units to simultaneously simulate a vessel level of
! 153 inches as indicated on the strip chart recorder during the
! event of January 2, 1988.
This simulated low water level "1" l I ' caused a Group 2, 6, and 8 isolation and valves 2-G16-F003, !' -F004, -F019 and -F020 closed as required.
This test simulated
i as closely as possible, i.e., without actually lowering reactor t vessel level, the conditions in the logic circuitry that existed
. ! . -
_ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _
when the actual isolation signal was generated on January 2, 1988.
The valves CLOSED as required upon receipt of this isolation signal generatad by the special test indicating that the logic circuits were correctly wired.
During the special test the 2-G16-F004 valve red OPEN light remained illuminated for approximately ten seconds af ter the automatic closure signal and the illumination of the green CLOSED light.
The red OPEN light is normally extinguished before the green CLOSED light illuminates.
' 2.
Disassembly and Inspection of 2-G16-F019 Solenoid Valve on January 2, 1988 Following the failure to close, the licensee issued a work , , request, WR/JO 88-AABE1 on January 2,1988 to remove solenoid valve 2-G16-F019 for testing and inspection.
Prior to disassembly, the solenoid valve was bench tested.
Input air pressure was varied between 5 psig and 40 psig during the bench test and valve operation was satisfactory throughout the entire range.
Disassembly of the solenoid valve resulted in the following findings: a.
Coil and wiring appeared to be in good physical condition.
b.
No debris or foreign material was noted inside the solenoid body.
c.
"0" rings were resilient and showed no signs of damage, d.
No signs of excessive west were noted on metal parts and no assembly anomalies were noted, e.
The lower disk stroke was identified as being 7 mils out-of-tolerance.
Critical measurem<'nts (data in inches) were taken with these results: Desired Stroke As Found As Left Upper Disc .060 +.005 .060 .060 Lower Disc .040 +.005 .052 .052 f.
A light oily film was apparent inside the assembly, g.
Minor signs of discoloration on the lower disc seating area were noted but no signs of seat degradation were apparent.
The lower disk stroke was not corrected and no other changes were made to the valve as it was desired to return it to service , in an "as found" condition for further in plant testing.
! Following inspection of the valve internals, the valve was l reasserbled, bench tested and reinstalled.
[ l L t
- } ' ~ I ^ \\ , l y
' i 1 y , s., '3.
DisaIsemb1) Inspection of 2-G16-F003 Solenoid Valve on January 7, 1948
The inspectors observed the testing, disassembly, inspectton and .; ./ reassembly of valve 2-G16-F003 in accordance with .. ", M , ', ' WR/JO 88-AABC1.
Prior to disassembly, the solenoid valve was ' N bench tested.
Input air pressures were varied between 5 psig' and 100 psig during the bench test and valve operation was satisfactory throughout the entire range. Also, during this , y M, testindthevalvewasorisntedatseveraldifferentangics N J (including upside down) and was actuated and de-actuated to {,',' h\\* determine the effects on the valve of deviations from the "vertical and upright" position required by ASCO instructions.
The orientation angle did not appear to effect valve operation, as the valve properly relieved the air pressure in all positions.
All actions concerning the disassem'aly, inspection and reassembly were accomplished in accordance wi'..lmprocedural . , .fquiremints. Observation included torquing of <;omponents and pMper calibration of torque wrenc5es, inspection for clean ihess, observation of a hold point, and pocedural i compliance by the licensee's maiatenance techr Mian.
No deficiencies were noted in this area.
~
' , a Disassembly of solenoid valve 2-G16-F003 resulted in the ' fcWowing findings: , _ // ' ' M ,d - , ,, a. ? Visual inspectic.n of the talve internals did not indicate .\\,. .s ' any scoring / scratching otjdamage to camponent parts.
\\. ' -s o ' , b.
There was a small amount tf foreign material (lint and ' jnallcoppershavings)inibevalve,butnotofsufficiert , i q nntity to causc the valve tg' improperly operate.
l( I q, c.
0" rings were resilient and> si owed no si rjs;of damage.
" g VendorInspectionofSoknoidVaive2-G1hF020 4.
On January 9, 1988, vendor representatives from ASCO were broughtonsitebythelicenseetoassistindeterminingty i , I root cause of the solenoid valve failures.
The vendor representatives observed the testing, disassembly, inspection,n - s and reassembly of valve 2-G16-F020.
The vendor and licensee ~ inspection of this valve did not determine a cause for valve failure. ' 'The vendor's investigation is continuing at the ' f manufacturing facility utilizing valves which were provided to " ' the vendor by the licensee.
/ .
.; .k ' < , A.
s .
i v ' \\
5.
Inspection of the Instrument Air Systems At the request of the inspectors, the licensee checked the air pressure in the Unit 2 instrument air system at valve 2-G16-F003 and, also,-flushed air for three minutes through a lint free cloth to determine if the air system was dirty.
The air pressure was determined to be 74 psi which is within the specification for the solenoid valve.
Visual inspection of the cloth noted only a very minor amount of debris on the cloth (lint and one small steel metal particle).
The inlet air filter for 2-G16-F003 was removed and inspected.
The filter had been in service for three years.
The filter bowl contained no moisture. A light coating of fine metallic appearing particles coated the supply side of the filter internals.
No evidence of filter blockage or bypass flow was indicated.
Additional investigation into air quality revealed that the licensee had sampled the air system on December 15, 1987.
During this procedure nine samples were obtained from various locations in the plant.
The results of these samples indicated an average total hydrocarbon content of 1.8 ppm.
The lowest sample value was 1.7 ppm and the highest was 2.0 ppm.
These results are less than the maximum concentration of 5 ppm allowed by Compressed Gas Association Specification G-7.1 (ANSI F86.1-1973).
This is the quality standard for breathable air used by the licensee as the air systems also provide breathing air throughout the plant.
The results exceed, however, the maximum hydrocarbon content specification of 1 ppm contained in the Instrument Society of America Standard 57.3 (ANSE MC11.1-1976).
This is a quality standard for instrument air. However, the licensee is not committed to this stand &rd.
As indicated in paragraph VI, the licensee had previously experienced failure of the main steam isolation valve ASCO solenoid valves due to hydrocarbon and temperature effects.
, ! These failures may have been partially attributable to oil contamination in the air systems.
The air system has not been ! modified since these failures.
6.
Inspection of Primary Containment Isolation System Relays K-17 and K-18 on January 9, 1988 PCIS relays K-17 and K-18 were inspected by the licensee and an AIT member on January 9 with the following results.
K-18 had an ( apparent arc strike on the neutral terminal of the operating - l coil. Additionally, the contact associated with terminal 12, immediately next to the neutral terminal, exhibited a small ' amount of metal transfer on the movable contact indicating the possibility of the contact having been welded in the closed position.
Evidence of arc.ing was visible around the area of ! ! -_ _- - . . - - - -... . .
. _ _ _ _ _ _ .-
this contact which is associated with the G16-F004 valve.
The other contacts had no indication of metal transfer.
Inspection of K-17 did not reveal any adverse conditions.
The K-17 and K-18 relays are GE CR120A industrial relays.
The specific relays installed are CR 120A06002AA which do not have covers, have six normally open poles, and no normally closed poles, have 115 volt - 60 cycle coils and are provided with clamp type convertible contacts.
D.
AIT Investigation of Event i The AIT conducted an inspection of the failure of the containment isolation valves including historical maintenance and surveillance data and various aspects of the licensee's maintenance program.
The inspection concentrated on the two major potential causes of the failures, i.e., failure of the solenoid valves to properly operate and/or failures in the electrical circuitry.
1.
History of Modifications The solenoid valves, which control the opening and closing of the instrument air supply to Unit 1 and Unit 2 containment isolation valves G16-F003, -F004, -F019, and -F020, were modified to meet the environmental qualification (EQ) requirements of 10 CFR 50.49.
The solenoid valve modification was performed with Plant Modification (PM) 82-65 for Unit 1 and PM 82-66 for Unit 2.
The PMs installed EQ solenoid valves and new termination boxes for isolation valve indication and solenoid valve control power.
PM 82-65 was completed on Unit 1 during April of 1985 and PM 82-66 was completed on Unit 2 during April of 1986.
During the inspector's review of PM 82-65 and 82-66, it was found that the wrong replacement valves were purchased for the modifications. During discussions with the licensee, the inspector was informed that the valve drawing identified the four containment isolation va hes (CIVs) as fail open valves.
The ASCO replacement valves were purchased based on this information.
The component drawing FP-6894 1968-3, Rev. 3, clearly identifies the CIVs as fail close valves.
The component drawing also lists the ASCO valve as a 8302-C26-RU, which is a universal valve that can be used for fail open and fail close applications. An ASCO valve, model 206-832, Type "G", which normally is used for control of a fail open valve, was purchased.
During system testing of the PM, it was found that the solenoid valves for the CIVs did not operate properly. At this point the vendor was contacted for guidance on making a modification to the solenoid valve.
The vendor suggested replacing the valve springs with the springs from a model 206-832, Type "F", rebuild -. _ _ _ _ _ ._...- . -. -- -- - -
kit, to obtain proper operation. The springs were replaced and the valves functioned properly.
A further discussion of Type "G" and Type "F" valves, rebuild kit installation, and noted vendor clarification can be found in Appendix 3, paragraph B, and paragraph III.D.10.
2.
History of Maintenance The inspector requested a maintenance history for all eight solenoid valves (G16-F003, -F004, -F019, and -F020 for Unit 1 and Unit 2) from 1983 to the time of the event on January 2, 1988.
A review of the valve history from 1983 until the Unit 1 modifications (PM) in 1985 (PM 82-065) and the Unit 2 modifications in 1986 (PM 82-066) revealed that there was no history of solenoid valve failures resulting in a failure of the associated CIV to close.
Review of the valve history after the PMs noted that no failures had occurred on Unit 1 involving the solenoid valves, , Several failures had, however, occurred on the Unit 2 valves.
The failures and associated corrective actions taken by the licensee were as follows: Valve 2-G16-F020 WR/JO 86-ASDZ1 - April 26, 1986: This work request reported that the valve failed to close and therefore would not pass the surveillance test.
Corrective action included a rewire of the valve to the spare limit switch.
Surveillance test PT-11.3, Drywell Drains System Operability Test, was satisfactorily performed and the valve was returned to service.
Valve 2-G16-F003 WR/JO 86-BDGD1 - July 11, 1986: This work request reported that the valve did not close upon receipt of an automatic signal and would not close with the manual control switch from the control room.
Corrective action included cycling the valve with the control switch and lifting of leads to simulate an automatic signal.
The valve functioned properly.
WR/JO 86-BDLK1 - July 12,1986: This work request stated that the solenoid valve needed to be replaced.
Corrective action was to replace the solenoid valve with one from stock.
This action was accomplished but the new valve had . a leak through the exhaust port.
The wrong valve was drawn ! from stock and installed, a Type "G" versus a Type "F".
l L
l Installation of the wrong valve caused the leaking exhaust port.
The old-valve was reinstalled and operationally checked.
Surveillance test PT-11.3 was satisfactorily performed and the old valve was returned to service.
No further corrective action was taken at this time.
WR/JO 86-BFQA1 - July 30,1986: This work request reported that the valve failed to close during the surveillance test.
During the troubleshooting process, the valve was tapped to unstick it.
The valve was then cycled several times.
Surveillance test PT-11.3 was satisfactorily completed and the valve was declared operable. WR/JO 86-BFQB1 was written to rebuild / replace the solenoid valve.
WR/JO 86-BFQB1 - July 31, 1986: This work request reported that the solenoid valve sticks intermittently and indicated that the sticking may have been caused by debris in the valve.
Corrective action included rebuilding of the valve with a rebuild kit, verification of proper wiring of the valve, and an operational check of the valve to prove operability.
Surveillance test PT-11.3 was satisfactorily completed and the valve was returned to service.
WR/JO 87-ANDG1 - April 27, 1987: This work request reported that the valve failed to close during the surveillance test. Maintenance informed Operations that the valve control switch must be held in the closed position until the valve was fully closed.
This information was incorrect for valve operation.
(See discussion of Maintenance / Operations communications on this , discrepancy in paragraph III.D 6.c.)
The valve was cycled, surveillance test PT-11.3 was performed satisfactorily and the valve was returned to operable status.
No corrective action was taken.
WR/JO 87-AYMF1 - July 17,1987: This work request reported that the valve would not close using the manual control switch.
During the troubleshooting process, licensee personnel tapped the solenoid lightly and the valve began working properly. The licensee attempted to replace the valve two times with two incorrect valves (Type "G" in lieu of "F"). The licensee eventually installed a rebuild kit in a new valve per corrective maintenance instruction OCM-SV004A, Corrective Maintenance Instruction for ASCO 206-832 Series Solenoid Valves, Rev. O.
Surveillance PT-11.3 was satisfactorily performed on July 19, 1987 and the new rebuilt valve was returned to service.
During the AIT review, it was noted by the inspectors that Section 7.2.2 of OCM-SV004A had been changed to allow for pipe compound usage for the installation of the new valve
. -.
seats. This was not in accordance with the manufacturer's instructions which require the use of Neolube lubricant.
Valve 2-G16-F004 WR/JO 87-BHTX1 - October 28, 1987: This work request reported that the valve had failed the surveillance test.
Investigation by the licensee determined that the solenoid had stuck.
During the troubleshooting process, the valve was tapped and cycled.
The valve then appeared to function properly.
Even though this was the case, the licensee rebuilt a new valve from supply using a vendor supplied spare parts kit and installed the new rebuilt valve in the plant.
Surveillance test PT-11.3 was satisfactorily performed and the new valve was returned to service.
3.
History of Unit 2 Surveillance Testing /Section XI Testing Unit 2 containment isolation valves (CIVs), 2-G16-F003, -F004, -F019, and -F020 are tested for operability by performance of PT-11.3, Drywell Drains System Valve Operability Test, which verifies CIV stroke time.
The inspector reviewed surveillances performed under PT-11.3 from 1984 thru 1987 for Unit 2.
, It was found that nine quarterly tests were performed during 1984 and 1985 and no failures were reported.
During 1986 and 1987, after PM 82-66 was installed, 21 tests were performed and failures to close were reported.
The following is a listing of those failures: Date Failure to Close CIV 4-26-86 During surveillance testing F020 7-11-86 During automatic initiation F003 7-30-86 During surveillance testing F003 4-27-87 During surveillance testing F003 7-17-87 During manual closure F003 10-28-87 During surveillance testing F004 CIV 2-G16-F003 had the majority of failures with two failed - surveillances, a failure to close on an automatic signal and a failure to close on manual actuation from the control room.
The inspector also found that 2-G16-F003 had an abnormally high stroke time of five seconds documented for the October 28, 1987 surveillance.
The average stroke time for F003 was 2.83 seconds, during the previous 18 surveillances.
- The licensee performs surveillance testing in accordance with Section XI of the 1980 ASME Code.
Section IW 3417 of the ASME Code requires that when the stroke time increases by 50 percent from the previous test, then the test frequency shall be _., _, . _ _ . -. - - _
' \\ . \\ \\
increased to once each month.
It also requires that any abnormality or erratic action shall be reported.
By implication, the reporting process includes an evaluation of the erratic action to assess the need for further investigation or corrective action.
The licensee's engineering procedure iNP-16.1, Pump and Valve Graphing, Section 5.2.12, requires valves, with a stroke time between 0 and 5 seconds, to be tested monthly until the next regularly scheduled surveillance if the stroke time increases by more than two seconds.
The following table identifies the abnormal stroke times: Stroke Time (in Seconds) Date of Valve Valve Valve Surveillance 2-G16-F020 2-G16-F019 2-G16-F004 7-25-86 2.99s.
3.41s.
3.04s.
7-30-86 1.12s.
1.30s.
1.27s.
8-07-86 2.74s.
3.45s.
3.13s.
10-25-86 3.97s.
3.43s.
2.95s.
1-25-87 0.84s.
0.98s.
0.72s.
4-27-87 2.99s.
3.14s.
2.60s.
A detailed review identified various discrepancies in the ASME Section XI testing program.
They are listed below to clarify the various concerns: There is a difference between the ASME Section XI - requirements and the licensee's pump and valve graphing procedure, ENP-16.1. ASME Section XI requires increased testing when stroke time increases by 50 percent and ENP-16.1 requires increased testing when stroke time increases by two seconds.
The three valves listed on the chart exhibited a stroke - increase of greater than 50 percent from the July 30, 1986 surveillance to the August 7, 1986 surveillance.
The ASME Section XI required CIVs 2-G16-F004, -F019, and -F020 to be placed on a monthly surveillance following the August 7, 1986, surveillance and this was not done.
Valve 2-G16-F019 had a stroke time increase of 2.15 seconds - on August 7, 1986, and the valve was not placed on a monthly surveillance interval, per ENP-16.1.
. The abnormally short stroke times recorded on July 30, - l 1986, and again on January 25, 1987, are indications of l valve failures such as a broken valve stem.
In order to - . ... .
_ _ - _ _
meet the intent of the ASME Code, the condition should have been evaluated and an additional surveillance performed to ensure operability.
Discrepancies were noted in the documentation of -- surveillances. On July 24, 1986, the stroke time for 2-G16-F003 was logged in as 6.8 seconds, lined out, initialed, and relogged in as 2.6 seconds. On April 27, 1987, 2-G16-F003 failed to close during its surveillance test and the failed surveillance test was not documented.
4.
Field Inspection of Valve Installation on Units 1 and 2 The inspectors performed an inspection on.the Unit 2 installation on January 6, 1988.
Various discrepancies were noted during the course of the inspection as follows: 2-G16-F003 was found to be missing a nameplate which identifies the manufacturer's serial number, manufacturer's part number and t a modification number.
The terial number would identify the valve for traceability, the part number would identify the valve
for type and function, and the modificution number would identify any installed modification to the valve.
2-G16-F003 was found to have plier marks on the part identified as the "end cap" on Figure 3 of ASCO Bulletin 206-832.
The ASCO valve reassembly instructions, Step 4, requires that the'end cap be torqued to 50 +/- 5 foot pounds.
The plier marks indicate that the end cap may have been tightened at one time without using a torque wrench.
The ASCO valves are required to be mounted in a vertical and upright position. The inspector found that the solenoid valve for 2-G16-F020 was installed at an angle of about 10 degrees from vertical.
The valves were inspected to verify the air supply to the solenoid valves was in accordance with the manufacturer's ' instructions. The valves were properly oriented and connected to the air supply and actuation cylinder.
The air supply was also filtered and regulated as required by the manufacturer.
The air regulator for solenoid valve 2-G16-F003 was inverted as compared to the other three valves, but should not have had an effect on valve operation.
The instrument air filters were visually inspected for signs of water or oil and they appeared to be clean.
A reject tag was found on the instrument air supply header isolation valve supplying solenoid valves 2-G16-F003 and -F004.
Due to the location, tag numbers could not-be obtained.
_ _. _ . _ _ _. _, _.
_.
. _. _ . _.. _.
_.. _ _
.
An inspection of the Unit 1 installation was conducted on January 8, 1988. The inspection determined that the valves in Unit I were installed with orientations similar to the valves in Unit 2 with the exception that two of the valves had a different type of filter in the air line to the solenoid valves.
5.
Comparison of Vendor Instructions to Licensee's Procedures The inspectors conducted a review of the licensee's maintenance , procedure, OCM-SV004, Corrective Maintenance Procedure for ASCO 206-832 Series Solenoid Valves With Resilient Seating, Rev.1, against the vendor instructions for this series of valve, Bulletins 206-380/206-832, attachment 2, ASCO Installation and Maintenance Instructions issued in 1981. ASCO supplies these instructions / bulletins with purchased parts and equipment.
This review revealed several areas where the licensee's procedures were different: - The ASCO Bulletin, in the improper operation section, requires the coil voltage to be at least 85 percent of the rating on the name plate. No instructions are provided in OCM-SV004 to check the coil voltage.
The ASCO Bulletin, for installation of a new spare parts - ki t, specifically indicates that installation of the entire kit without any interchanging of old and new parts is "important". OCM-SV004 does not include this requirement.
(Reference is made here to the vendor discussion on this subject included in paragraph III.D.10 of the report.)
The ASCO Bulletin requires that the valve be mounted in the - vertical and upright position.
This requirement is not included in OCM-SV004.
Inspection of the Unit 2 valves determined that three of the valves were installed vertical and upright.
Valve 2-G16-F020 was installed at ' approximately a 10 degree angle. Note: All four valves , had a sticker attached which specified the requirement to install the valve in a vs.rtical position.
l l The ASCO Bulletin, for kit installation, recommends - ' installation of a new coil if the coil is included in the kit.
OCM-SV004 does not include this requirement.
(Note: , The kit observed by the inspectors did not include a coil.)
I The ASCO Bulletin included drawings which show proper - connection in the piping system (orientation). OCM-SV004 ' does not provide any instructions or drawings on valve orientation.
Note: Inspection of the valves in Unit 2 i confirmed proper valve orientation.
l l l l __
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - 22' 6.
Maintenance and Operator Training The inspectors reviewed the adequacy of Maintenance and Operations training related to this event and noted several potential areas of concern: a.
The Maintenance Superintendent and other maintenance personnel were interviewed in reference to training for maintenance activities on ASCO valves.
Three generic courses on solenoid valves are provided to Instrument and Control (I&C) technicians.
No formal training in the specific requirements of kit replacement for ASCO Model 206-832 valves had been provided to the I&C technicians.
b.
The licensee's emergency operating procedure (EOP) flowpaths directed operators to verify Group 2, 6, and 8 primary containment isolations if reactor water levels had decreased to less than the low level "1" setpoint of 162.5 inches, which it had.
The E0Ps did not provide specific directions to operators to manually effect an isolation if the automatic isolation did not occur.
The E0P philosophy and related training emphasize that if required automatic actions such as primary containment do not occur, manual action should be initiated. When automatic isolation of the four PCIS valves did not occur at low level "1", the operators did, in fact, attempt to close the four volves manually. As addressed in other sections of this report, the floor drain valves 2-G16-F003 and -F004 closed upon the initial manual signal, but the equipment drain valves 2-G16-F019, and F020 did not.
These valves ren.af ned open for several minutes allowing a breach in primary containment and a potential release path had accident conditions existed.
During the period the valves remained in the OPEN position, ! the operators attempted repeated manual closures from the control room.
Both the licensee's E0Ps and the E0P ' guidelines had apparently not addressed the actions to be , l-taken in the event that both automatic and manual primary I containment isolation attempts were to fail.
The failure ! of two safety-related PCIS valves in series to CLOSE on l both automatic and manual signals was probably not l considered a viable scenario, and appears to exceed both ! the plant design basis and existing E0P coverage.
During the period that the 2-G16-F019 and -F020 valves were l stuck open, operators did not attempt local efforts at closure via tapping on the solenoid, removing the air supply, pulling fuses, etc.
Several Operations personnel interviewed indicated that if accident conditions had existed, they would have attempted measures to close the valves locally. As indicated in paragraph IV, however, the licensee's analyses indicate that during a design basis <
LOCA, the radiation level in the area surrounding these valves would be approximately 1000 R/hr and, therefore, the area would be inaccessible.
c.
Interviews with Operations personnel indicated some amount of confusion over the proper method of manipulating the drywell drain PCIS valve switches to CLOSE the valves manually.
This confusion may have resulted from the poor operating history of valve 2-G16-F003 and corrective actions stated on maintenance work request WR/JO 87-ANDG1.
This work request inaccurately indicated that the valve switch must be held in the CLOSED position until the valve is fully CLOSED. As indicated in Appendix 3, paragraph C, on a closure signal it is only necessary to hold the switch until the red OPEN light is extinguished.
From that point, a seal-in relay (K-34) ensures that the valve continues to travel to the full CLOSED position even though the switch is released. The inspectors agree with the licensee that most of the confusion procably occurrad after this event due to the manual closure failures and extended closure signals which were applied. Although most, if not all, licensed operators understs d the logic behind these valves and the manual closure ope *ation, there is concern that they have heard several different scenarios including the as-designed logic, the ten second closure signals and the traintenance instructions to held the switch until fully closed. When added to a pronounced operator loss of confidence in the reliability of these particular valves, this potential confusion is reason for concern. The licensee cocnitted to provide additional training to all licensed operators on the manual operation logic for PCIS . valves G16-F003, -F004, -F019, and -F020 which should adequately resolve the concern, d.
There were no human factor deficiencies noted that would have contributed to this event.
7.
Trending Programs The inspectors interviewed the Maintenance Manager on the use of trending at Brunswick.
The licensee provided the inspector with a copy of maintenance procedure (MP) MP-14A, Corrective Maintenance (Automated Maintenance Management System), which . describes measures the licensee takes to identify repetitive failures.
The procedure requires planners to review historical maintenance work order (WR/J0) data for Q-list WR/J0s being planned.
If a failure is identified as repetitive, the planner annotates the WR/JO to indicate that previous failures have occurred.
If the failure can not be corrected by the mechanic / technician, long __. . . , - _ _ __ _ _ .-
_ - _ _ _ _ __ _ _ _ _. __.
_ _ _ _ _ ._ _ - _ _
term actions should be listed on the WR/J0.
The completed WR/JO is routed through the Maintenance Supervisor to the Programs Maintenance Engineer for reporting, trending and followup necessary to resolve the repetitive failures.
The Maintenance Manager stated that the licensee primarily relies on the cognizant engineers and supervisors to recall repetitive problems or use personal tracking mechanisms.
The licensee provided the inspector with a printout, dated January 11, 1988 of those WR/J0s annotated with the word "repetitive." This list included 44 WR/Jos. The inspector was not able to evaluate the type of equipment on the list during the inspection period.
The licensee had recently conducted a special study of equipment reliability. The inspector reviewed the report titled, (Repetitive) Equipment Failure Analysis Project.
The study had been commissioned on July 31, 1987 and completed on September 4, 1987.
The study included all 160 plant systems, both safety-related and non-safety-related.
Repetitive failures were defined as any significant part/ piece of equipment which was replaced four or more times within one year.
The data base was established by retrieving a list of parts used during the last year and associated work requests.
Components used less than four times were eliminated.
Repetitive failures were then reviewed by the Maintenance Engineer / Technician for further elimination of less significant parts. The period of time included !n the study was from approximately July 1986 to ' September 1987.
The study identified 77 pieces of equipment which had been replaced more than four times.
Eighteen of these parts were utilized in safety-related equipment.
The licensee provided a corrective action summary for the Equipment Failure Analysis Project.
This summary indicated that action had been taken on 17 of the 77 items.
Six of these items were safety-related items (Q-list item) and one was a fire protection quality item.
Of the six safety-related items: three items were attributed to normal wear and no action had been ! taken; no action was taken on one of the items due to "no l repetitive failure history present"; one item was to be corrected by an EWR; and, the last item was under analysis.
An EWR had been issued to correct the fire protection quality item.
The licensee also stated that the Nuclear Plant Reliability Data System (NPRDS) was used to some extent.
l The licensee's trending program was not adequate to identify the
repetitive failures associated with the Unit 2 PCIS ASCO l solenoid valves, which resulted in the failures not being escalated to appropriate levels of management.
The inspectors l l .- _. . . . .. F .25 noted that the licensee is taking action to improve the trending program.
8.
Maintenance History of Other ASCO Solenoid Valves at Brunswick The licensee was asked if conversion kits were installed in any other ASCO valves, and the licensee was requested to supply a maintenance history for each converted valve.
The licensee stated that the data retrieval would be difficult and would take at least two weeks.
It is known that conversion kits were used on the ASCO solenoid control valves for 2-CAC-V8 and 2-CAC-V9.
No other information was available from the licensee.
A thorough review of this item will be compieted af ter the licensee supplies the appropriate data.
9.
Review of Quality Control (QC) Involvement During the original modifications to the solenoid valves accomplished by plant modifications (PM) PM 82-065 and PM 82-066, the valves were modified by installation of new springs (only) into the valves. QC involvement in the plant modifications was to veriff the torque values on the valve caps and inspect the valve openings for cleanliness.
The original revision of OCM-SV004, Corrective Maintenance procedure for ASCO 206-832 Series Solenoid Valves With Resilient Seating, maintained these QC hold points.
In OCM-SV004, Rev. 1, the responsibility to verify hold points was changed from QC to a lead technician.
The current hold points include torque values for valve seats and valve caps, internal disc stroke measurements, correct assembly, and component cleanlinass.
10.
Vendor On-site Interview . , During the inspection, the licensee requested on-site assistance from ASCO in determining the root cause of the solenoid valve failures. On January 9, the inspectors and licensee personnel
met with the ASCO representatives to discuss various concerns.
' During the inspection, a key issue arose concerning how to properly convert a valve from a Type "G" to a Type "F".
This stemmed from the fact that the vendor instructions are not clear in this area and the licensee had accomplished the original plant modifications by installation of springs (only) into the
valves. The vendor instructions in ASCO Bulletin 206-832 ' provide the following information: The "Changing Operations Form" section of the Bulletin refers to l the "New Spring Installation" section of the Bulletin which l discusses valve conversion by spring replacement only.
However, i the "Installation of New Spare Parts Kit" section (Subsection 12) specifically addresses as "important" that old and new parts ,. _. _ _ _ _ _ _ _ _ _. - _ _ _, _ . -.
- - _ - _ - - - _ _ - - - - - - - - - - _ _. - - - - - - - - - - - - _
, of a kit should not be interchanged and a complete-new parts kit should be installed.
This issue was raised with the vendor and he provided the following additional clarification: o When a conversion from the "G" flow type valve to the "F" flow type valve is made, the entire conversion kit should be installed. This assures that any set (or permanent deformation) the elastomer seats have taken will not affect the required disk travel in fully seating and unseating.
Changing out the springs to install stiffer springs only is not generally recommended. However, in the case at Brunswick where new valves with new internals were being installed as replacements (to support plant modification PM 82-065) the information received from ASCO in the spring of 1985,.was that it would be acceptable to install only the stiffer springs.
Several other issues were raised with the ASCO representatives during this interview and the information provided on these subjects is as follows: o The rebuilding and conversion hits are composed of materials which maintain the environmental qualification of the solenoid valves. (Note: The inspector had already received copies of the plant documentation for.the environmental qualification of the valves.
The documentation included a description of the etnylene propylene elastomers used in the kits.)
, o The recommended service time for rebuilding the valves is dependent entirely on the plant-specific service conditions.
Thermal aging and number of cycles should be considered but there was no specific recommended time.
o Other than the problems with hydrocarbon contamination and high temperature which have been reported in IE Information > Notices and GE Service Information Letters (SILs), the ASCO representatives knew of no other data involving problems with this type of solenoid valve.
There have been problems with air system oil contamination which destroys ethylene i propylene seals.
There have also been problems with steam l impingement causing high valve body temperatures and problems from solenoid overheating similarly causing high temperatures both of which can cause lubricants to become sticky which causes the solenoids or valve disks to stick.
, o ASCO has no formal program for routinely notifying customers of valve problems, valve maintenance problems or installation problems encountered in the field.
There have l ! t
_~
been a few field service bulletins; however, most assistance is given only upon request. ASCO has no training course for instruction of maintenance personnel for rebuilding or installation of the valves.
o The ASCO solenoid valves are recommended to be installed in the vertical and upright position, but they have been designed to operate in any orientation. Generally, the valves should not be installed greater than 45 degrees from the vertical position.
o The ASCO rebuilding kits do not contain replacement solenoid core and coil assemblies because the sliding parts are not expected to wear significantly.
The ASCO representatives also stated the solenoics contain no material which will. retain any residual magnetism even when the solenoid is continuously energized.
o The measurement of the disk travel for the required tolerance range is absolutely required when rebuilding the valves.
Since the seats are threaded into the valve body the position of the seats with respect to the disk travel may vary; therefore, the disks must be set to travel in the proper range.
E.
Equipment Vendor Involvement In 1985, to support plant modification (PM) PM 82-065, the licensee's engineering department (BESU) contacted the vendor to determine how to accomplish valve modification from a Type "G" to a Type "F".
Later, during the development of naintenance instructions for ASCO Model 206-832 valves (OCM-SV004), the vendor was contacted by Maintenance Engineering to obtain information concerning conversion ki ts. Neither Corporate Engineering nor ASCO Engineering were contacted by maintenance to assist in resolving solenoid valve failures prior to the event.
Subsequent to the January 2, 1988 event, the vendor was brought on site for technical assistance in resolving the failures.
The results of this investigation did not determine a reason for valve failure.
The vendor investigation is continuing at the manufacturing facility on valves 2-G16-F003, -F004, -F019, and -F020 and the old 2-G16-F004 which was replaced during October, 1987.
The vendor has indicated that an oily film was found in three of the five valves.
The lubricant is apparently being blown through the solenoid from the air actuator on the gate valves.
During the period when the team was on site the licensee deferred examination of the actuators until the solenoid evaluation was completed.
, _... _ _,.. -.,. _. ,,.. _,,. .. - . -.
F.
Preventive Maintenance The inspectors questioned the Maintenance Instrumentation and Control Supervisor regarding the preventive maintenance program for ASCO solenoid valves and lor the logic and control circuitry involved in the event.
The licensee indicated that no preventive maintenance program was in place for Model 206-832 ASCO solenoid valves.
The vendor instructions, ASCO Bulletin 206-832, Installation and Maintenance Instructions, address the following preventive maintenance areas: - Maintenance of instrument quality air that is oil free.
- Periodic operation of the valve while in service to ensure proper opening and closing.
- Periodic inspection and cleaning of internal valve parts and replacement of worn or damaged parts.
- Periodic part replacement based on ambient and service conditions.
The licensee also indicated that a preventive maintenance and inspection program was not in place for GE CR120A relays and contacts in the control and logic circuitry for the containment isolation valves. The inspectors notified the licensee of a November 22, 1987 failure of the same type of GE CR120A relay at Browns Ferry described in Licensee Event Report BFRO-50-296/87006.
This failure was attributed to "end-of-life".
IV.
POTENTIAL RADIOLOGICAL CONSEQUENCES The failure of the four PCIS valves on January 2, 1988 resulted in a short-duration breach of the Unit 2 primary containment via two 3-inch pipelines that communicate directly with the containment atmosphere.
Because there was no release of radioactive material from the reactor coolant system to the drywell atmosphere, there were no radiological consequences directly associated with the January 2, 1988 event.
However, an evaluation was performed to determine the potential radiological consequences of the PCIS valve failure relative to the design bases for the primary containment and PCIS.
l l The safety objective of the primary containment system, in conjunction ' with the engineered safety features (ESF), is to contain the energy released during the design basis loss-of-coolant accident (LOCA), and to limit the release, to the Reactor Building, of the fission products , associated with this accident. Any leakage of fission products to the ! l Reactor Building is processed and filtered by the standby gas treatment system to further limit the release of fission products to the ' l environment. The PCIS is provided to assure containment of fission l products through rapid, automatic isolation of process lines which penetrate the primary containment.
The failure of the two sets of redundant PCIS valves to shut automatically was evaluated relative to a i postulated concurrent design basis LOCA, and for the small-break LOCA l which is a less severe accident in terms of primary containment system design capability.
l l t
l i
During normal operation, valves G16-F003, -F004, -F019 and -F020 are kept open to facilitate the periodic transfer of the contents of the drywell floor drain sump and the drywell equipment drain tank to the floor drain collector tank and the waste collector tank, respectively.
Both tanks are located in the same room in the Radwaste Building.
In both drain systems, the piping from the sump pump to the inside interface with the penetration piping is non-safety-related piping.
The licensee has indicated that this piping is designated as seismic Category II/I, which indicates that it is non-seismic Category I piping that is supported by seismic Category I supports.
In both drain systems, the piping from inside the drywell penetration to immediately downstream of the second isolation valve (i.e., G16-F004 and -F020) is designed to Seismic Category I criteria. The rest of the piping, from the second isolation valve to the collector tanks has the licensee designation of seismic Category II/I. The nonessential piping is routed from the isolation valves in the Reactor Building to the "rattle space" between the Reactor Building and Radwaste Building, and then into the Radwaste Building to the collector tanks. The waste collector tank which receives eqt!pment drain discharge is seismic Category I; the floor drain collector tsnk is not designed to seismic Category I criteria. With the exception of valves G16-F003, -F004, -F019 and -F020, there are no safety-related isolat4n valves in either drain system, from the sump pumps to the cellector tanks.
Valves G16-F003, -F004, -F019, and -F020 would be inacces,sible for attempts at manual operation during a design basis LOCA due to a 1000 R/hr radiation field being present in the general area of the valves, Both the floor drain collector tank and the waste collector tank are located in the same compartment on the -3 ft. Elevation of the Radwaste Building.
Each tank is provided with a vent pipe from the top of the tank to a connection with the Radwaste Building ventilation exhaust ducting.
The exhaust ducting discharges into an exhaust plenum on the 35 ft.
Elevation of the Radwaste Building.
From the plenum, the exhaust flow is routed through combination roll-type filters and a HEPA filter bank, and into the suction of the Radwaste Building exhaust fans.
The two exhaust-fans are provided with variable inlet dampers operable from the control room.
The fan discharge is directed into a 34-inch diameter exhaust pipe which exits the Radwaste Building at the -3 ft. Elevation level.
The exhaust pipe is routed through the yard and discharges into the plant vent stack. The plant vent stack is provided with a radiation monitor which alarms on high and high-high level in the control room.
The vent path from the top of the collector tanks to the vent stack discharge is non-isolable except for the non-safety-related Radwaste Building exhaust , fan variable inlet dampers which can be shut from the control room.
For both of the drywell drain systems, the containment design basis is satisfied by the seismic Category I penetration piping and the redundant PCIS valves: F003 and F004 in the floor drain system, and F019 and F020 in the equipment drain system.
The Category I piping runs from just inside containment through the containment penetration to the first weld beyond the second isolation valve outside containment.
The remainder of the piping in these drain systems is not required to be leak-tight in a L , -- , -, -.r- ,_ ., - - - > -,
design basis event and the nonessential valves need not be operable.
Consequently, in the event of a LOCA, no credit can be taken for the integrity of any of the non-seismic Category I piping, or for the operability of any nonessential valves.
It must be assumed therefore, that for redundant PCIS valve failure coincident with a LOCA, the drywell atmosphere would have direct access to the downstream drain piping in the Reactor Building, the "rattle space" and the Radwaste Building.
In terms of offsite dose consequences, the worst-case assumption involves a postulated drain system pipe break or leakage in the "rattle space." The "rattle space" is a separation corridor between the Reactor Building and Radwaste Building which provides seismic interaction separation between the two buildings.
The space is approximately 4 feet wide and is essentially open to the outside atmosphere. The corridor has a weather covering of corrugated galvanized steel.
The roof and outside doors to the corridor are not leak-tight and are provided with vents to the outside. A postulated failure of the drain system PCIS valves coincident , with a LOCA could, in the worst case, result in an unisolable, unmonitured ground-level release of radioactivity from drain pipe leakage in the "rattle space."
For the design basis LOCA, the driving force for flow to the environs through drain system piping is the calculated peak drywell 6ccident pressure of 49 psig.
The design buis LOCA would result in the maximum flow rate from the drywell to the environs. However, this condition may not be the worst case for release of radioactivity offsite. A small-break LOCA could result in higher levels of radioactivity released because of . the lower resultant drywell pressure. A small enough break in the reactor coolant system could result in a drywell pressure that is too low to initiate flow from the drywell into the suppression pool.
That is, the absorption of fission products in the suppression pool, assumed to take place in a design basis LOCA, could be by passed during a small-break LOCA with low drywell pressures.
Flow from the drywell through the unisolated drain line PCIS valves would therefore occur at a lower flow rate but conceivably with a higher concentration of fission products.
However, more time would be available for manual efforts to close the PCIS valves before fission product release occurs.
As discussed above, no credit can 'oe taken for the leak-tight integrity of
l the drain system piping designated seismic Category II/I.
Pipe leaks ! inside the drywell and downstream of the PCIS valves result in the worst-case release of radioactivity offsite. The magnitude of the release ' would be mitigated to some extent but not entirely eliminated if the nonessential drain piping were to remain leak-tight.
Effluent from the containment would experience a higher frictional pressure drop through the , l intact piping and would be directed to the collector tanks.
Fission product release would occur at a lower rate via the tank vents into the
Radwaste Building ventilation exhaust system. Although the ventilation ! exhaust could be isolated by the exhaust fan variable inlet dampers, this course of action would result in pressurization of the Radwaste Building with a subsequent unmonitored ground-level release through Radwaste Building penetrations. With the dampers open and the exhaust fans , - - -. -- -. - -.- ... -. -. - - -. - - - -
.
running, radioactive effluent would-be monitored during release from the 100-meter high plant vent stack.
V.
COMMUNICATIONS AND THE ACCURACY, TIMELINESS AND EFFECTIVENESS OF REPORTS TO THE NRC The operating shift initially contacted the Scram Incident Investigation Team (SIIT) team leader at approximately 0130 hours regarding the reactor scram and the failure of Group 2 isolation valves to close.
For some reason this communication was-not effective in pointing out that all four PCIS valves in the drywell floor and equipment drain line had failed to close automatically and that two of the valves also failed to close on a manual signal. As a result, the SIIT team leader did not consider that the event warranted activation of the SIIT team at that time.
In communi-cation with other members of plant management, it appears that over the next hour or less, it was considered possible that some Group 2 valves may have not closed due to a "brush" with low level "1" setpoints. A similar "brush" with low' level "2" in 1987 had resulted in actuation of only part of the low level "2" ESF equipment. Additional management communication with Operations and the realization that all four PCIS valves had failed to close resulted in call out of the SIIT team at approximately 0230 hours.
The SIIT team arrived on site at approximately 0310 hours and began an investigation of the events surrounding the scram and PCIS valve failures. The delay u SIIT team activation resulted in the loss of ERFIS data on automatic signals to the four PCIS valves.
(See Appendix 7 for a discussion of the loss of the ERFIS data.)
The failure of the four containment isolation valves to close occurred at 0017 hours on the morning of Jar.uary 2, 1988.
The licensee notified the NRC by telephone at 0410 hours of the same day.
The timeliness of the notification was in accordance with the 4-hour reporting requirements of 10 CFR 50.72 for non-emergency events.
The failure of the valves to close, resulting in a breach in primary containment, occurred after plant shutdown, and therefore, a 1-hour notification was not required.
The initial notification did not accurately characterize the initial sequence of events.
The licensee's notification at 0410 hours accurately stated the plant initial conditions before the event and the failure to close of the four valves on the automatic isolation signal.
The notification did not, however emphasize that both redundant PCIS valves in each of the drywell drain lines had failed to close automatically or that two valves in one line had initially failed to close manually.
The initial report also did not specify that primary containment had been breached for a period of time following the Group 2 isolation signal and scram.
The initial information provided to the Resident Inspector was also not timely nor was the information complete.
At approximately 0800 hours the SIIT team noted that the initial notification to the NRC may have been less than adequate and requested that Operations personnel make a followup notification.
However, it was not until 1251 hours that the licensee provided an updated notification to
___ _ _ _ _ - _. ___ _ _ _ _ _ _ _ _, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ .
report that all four of the open isolation valves had been subsequently shut manually, and that full containment isolation had been achieved.
The failure to automatically close occurred at 0018 hours and the manual - -closure of all four valves was achieved by 0026 hours resulting in a breach of primary containment through the drywell equipment drain valves 2-G16-F019 and -F020 for approximately 6 minutes (2-G16-F020 closed) and 8 minutes (both valves closed).
The failure of two redundant PCIS valves in one line to also close on a manual signal and the breach of primary containment should have been part of the initial notification at 0410 hours.
VI.
ROOT CAUSE DETERMINATION During the inspection, the team was not able to discern with any certainty, nor was the licensee, the root causes of the Brunswick Unit 2 ASCO. solenoid valve failures on January 2, 1988. While there appears to have been problems in the electrical control circuitry leading to the valves, it also appears that there may have been solenoid valve mechanical problems.
There could also be mechanical problems with the main valve operators.
These areas are being investigated by the licensee to determine more definite root causes.
There are basically two major areas of mechanical sticking which can be postulated within the valve: between the disks and seats and in the annular space around the solenoid core. Because the spring and electromagnetic forces operating the valves are relatively small (on the order of 10 to 20 pounds), the valves are sensitive to frictional or viscous forces which may increase over some period of time between operation cycles.
There have been several reported occurrences in recent nuclear operating history, involving failures of several types of ASCO solenoid operated air valves, which may be similar in some ways to the Brunswick event. The recent event at the Perry nuclear facility involved a problem with high temperature steam leaking onto the solenoid valves which control the Main Steam Isolation Valves (MSIVs). The result was a much higher than normal valve body temperature which caused the resilient seats to harden and bind the disks.
There have also been several problems involving the break-down of hydrocarbon lubricant material on the moving parts inside the valves.
There have also been other problems with oil and other contamination in the air supply line.
In some cases particles have caused the disks to stick and in other cases oil has attacked ethylene propylene seats which has also caused sticking.
The licensee has experienced a continuing problem with service air quality and deterioration of pneumatic equipment supplied. An action plan is being considered to upgrade the filters to pneumatic equipment and to incorporate the filters into the preventive maintenance program.
In an earlier Brunswick Unit 2 event (LER 85-008), MSIV solenoid valves, ' of ASCO dual solenoid design, failed to operate due to a combination of 'l eg.
_.,_--, _.., - _ _ +, ..7 , , _ _ - ,.,-.-,.,_.7 .. _. , _, .. 9 ,. __ < . _ _
. . . l '
hydrocarbon attack of ethylene propylene seats and high temperature-effects. The seals were found brittle and broken and a decision was.aade to change to Viton material to protect against hydrocarbon attack.
These failures may have been partially attributable to oil contamination in the air system.
Since Viton is less resistant to radiation breakdown, the seals were placed on a more frequent replacement schedule. As far as the team could determine, the recent Brunswick Unit 2 valve problems were not clearly caused by the same root causes as in these past events since the valves appeared to be in workable condition and did function successfully several times following the event.
Weakness in the licensee's maintenance trending program resulted in failure of the licensee to identify the adverse trend concerning the previous ASCO solenoid valve failures.
This weakness also appears to have contributed to a lack of management involvement in the problem and failure to involve the vendor in establishing the root cause.
VII. FINDINGS OF FACT The AIT reached the following findings of fact: A.
Potential Radiological Consequences o The failure to isolate primary containment did not result in any ' radiological discharge to the environmen'. o Under accident conditions, a direct, unisolable path would have existed for approximately six minutes from the drywell to the environment through the plant vent stack or postulated break in non-seismic piping.
A design basis loss of coolant accident (LOCA) or small-break LOCA coincident with this condition has not been analyzed quantitatively in the updated Final Safety Analysis Report (FSAR) because such a sequence of events is beyond the design basis for the plant.
o Drywell drain piping inside primary containment and beyond the four PCIS valves is not seismic Category I.
This includes a four foot section outside the buildings.
o There are no safety-related manual or automatic isolation valves between the four PCIS valves and the plant stack, o Under design basis LOCA conditions, an analyzed 1000 R radiation field in the area of the four PCIS valves would have prevented local closure attempts.
' B.
Failure Investigation o Inspection of valves 2-G16-F003, -F004, -F019, and -F020 and the old 2-G16-F004 (which was replaced in October 1987) by ASCO, indicated the presence of an oily film in three of the five solenoid valves. The film appeared to result from lubricant - - _ ._ - -.__ _ - - -_-. _ _ . , - _ - -- - _
being blown through the solenoid from the actuator of the main valve.
The vendor is evaluating this area.
o ' Disassembly of valve 2-G16-F019' determined valve stroke ' tolerances to be outside of,the vendor's specification.
o Disassembly of valve 2-G16-F003 did not determine a reason for failure, o The PCIS actuation relay K-18 displayed an arc strike on the operating coil neutral terminal.
Evidence of arcing and metal transfer appeared on and around contact #12 which is the contact which must open to close valve 2-G16-F004 upon receipt of a PCIS signal. Another Region II facility has recently experienced failure of a CR120A relay which was attributed to "end-of-life" failure.
o Surveillance testing of the solenoid valves after the event ' indicated no obvious failure mechanism. All valves operated properly during the testing on both Unit 1 and Unit 2.
l o Preliminary checks of air system quality and pressure resulted in satisfactory results.
The licensee however has experienced a continuing problem with service air quality and deterioration of pneumatic control equipment and is planning improvements to the system.
C.
Modifications o In April 1985, new solenoid valves and conversion kits were - _ installed on Unit 1 PCIS valves G16-F003, -F004, -F019, and-F020 under environmental qualification plant modification 82-65, o In April 1986, new solenoid valves and conversion kits were installed on Unit 2 PCIS valves 016-F003, -F004, -F019, and-F020 under environmental qualification plant modification . 82-66.
+ . o On Unit 2, there was one failure on the solenoid valve for - 2-G16-F004 and several failures or, the solenoid valve for 2-G16-F003 after plant modification 82-066.
o There were no solenoid valve problems which caused failure of i the solenoid valves prior to implementation of plant modifica-tions 82-65 and 82-66 in 1985 and 1986, respectively.
o There were no solenoid valve failures on Unit 1 after plant modification 82-65.
l t . - - -- - - - . -- -- - - - - -
.. - - i
o Prior to implementation of plant modifications 82-65 and 82-66 there were no failed surveillances on Unit 1 or Unit 2.
o On Unit 2, there have been four failed surveillances and one failure to close on an automatic and manual initiation since plant modification 82-66 was implemented.
D.
Maintenance o The licensee indicated that a preventive maintenance and inspection program had not been established for relays in the valve control circuitry for CR120A contacts.
o The licensee indicated that a preventive maintenance program was not established for ASCO Model 206-832 solenoid valves.
The vendor manual, provided by the licensee, recommended "periodic" operation, inspection and replacement of certain parts.
The vendor did not, however, define or provide guidance on
' "periodic."
o Licensee procedures for maintenance did r.ct incorporate all of the vendor requirements and recommendations.
o The previous repetitive failures of the solenoid valves had not been brought to the appropriate level of management attention.
o Vendor assistance to resolve repetitive solenoid valve failures was not evident prior to the event.
o Vendor instructions for solenoid valve conversions are unclear.
E.
Surveillance Testing Program , o One failed surveillance was not properly documented.
o The licensee's engineering procedure ENP-16.1 did not adequately
implement the ASME Code Section XI requirements for an increase l in stroke time.
Surveillance frequency was not always increased to monthly for increases in stroke time per ASME Section XI.
o Abnormally short stroke times were not reported and evaluated as required by ASME Section XI.
F.
Post Event Operability Checks and Surveillance 4 o Unit 1 PCIS valves 1-G16-F003, -F004, -F019 and -F020 were , closed on January 6, 1988 at 2049 hours by the licensee as a precautionary measure.
These valves were to remain closed, except during periodic pump out of the drywell sumps, until the impending Unit 1 outage and/or identification and resolution of the failure mode of the Unit 2 valves.
.
'-P'a-
"
r m +4
w., , -- _y _.
- -, -,. c.
...-.9
- _..,-
o During the special 18-month surveillance test of the 2-G16-F003, -F004, -F019 and -F020 PCIS valves on January 6, 1988, the 2-G16-F004 valve red open light remained illuminated for approximately 10 seconds after the automatic closure signal.
o The special test on January 6, 1 E of the Unit 2 PCIS valves 2-G16-F003, -F004, -F019 and -F020 utilized a simultaneous automatic signal (simulated) injected at the Rosemont level transmitters for all four valves.
This test resulted in the automatic closure of all four valves indicating the low level "1" Group 2 isolation logic to be correct.
G.
Operations o 2-G16-F003 and -F004, the drywell floor drain PCIS valves failed to close automatically on the low level "1" Group 2 isolation signal but closed on manual actuation.
o 2-G16-F020, the outboard drywell equipment drain PCIS valve failed to close on the automatic low level "1" Group 2 isolation signal, or on the manual closure attempts.
The 2-G16-F020 valve was first noted to be closed, providing single isolation of the primary containment penetration approximately 6 minutes af ter the scram and Group 2 isolation signal.
o 2-G16-F019, the inboard drywell equipment drain PCIS valve failed to close on the automatic low level "1" Group 2 isolation signal or the manual closure attempts.
The 2-G16-F019 valve was first noticed to be closed at approximately 8 minutes following the scram and Group 2 isolation.
o The fact that all four PCIS valves in the drywell equipment and floor drain penetrations had failed to automatically close on Group 2 isolation and was apparently not effectively communicated to the SIIT team leader during a telephone call of 0130 on January 2, 1988.
As a result the SIIT team was not activated until 0230.
o Individual train offgas outlet flow recorders were inoperable resulting in the unavailability of total offgas flow information.
o The hydrogen catalyst bed temperature recorder was reading abnormally low, approximately 250F and less than the minimum 300F permissive for starting a SJAE which prevented a restart of SJAE "B" and an attempt to regain condenser vacuu..
o The "A" low exhaust hood vacuum alarm was not received until vacuum had reached 22 inches.versus the normal 25. inch setpoint.
The "B" vacuum alarm was never received prior to the manual unit screm.
o Five control rods did not fully insert and remained at position 02 following the scram.
Per the E0P flowpath, these rods _were ' found to be not fully inserted at 0328 hours, 10 minutes after the scram and were manually inserted, o A review of the control room scram tape recording, interviews of operators, and a review of charts and computer print-outs ' indicated that the scram was accomplished in accordance with E0P flowcharts.
H.
Training o No formal training in the specifics of ASCO solenoid valve kit replacement was provided to I&C technicians, o The licensee's omergency operating procedures did not address the operator actions to be taken in the event that both automatic and manual control room primary containment isolation attempts were to fail.
o The licensee committed to provide additional training on the manual operator logic for valves G16-F003, -F004, -F019 and-F020.
I.
Miscellaneous o A surveillance test by the licensee following the event determined that the low vacuum alarms were out of calibration low.
The alarm setpoints which are supposed to be set at 25 inches 1 inch, were found to be at 22.3 inches and 21.5 inches for "A" and "B" train respectively.
o The MSIV ASCO solenoids, which are a different type, had failed in September 27, 1985 and were the subject of I&E Notice 86-57.
! The failure may have been attributable to hydrocarbons and oil in the air system. The Unit 2 air system had not been modified since these previous failures.
o ERFIS post scram data on closure signals to the 2-G16-F003, -F004, -F019 and -F020 valves was lost due to untimely retrieval and system print-over.
i
,
. . -
VIII. CONCLUSIONS The AIT reached the following conclusions: o The event did not result in a radiological release or in exceeding a Technical Specification Safety Limit.
' o The common-mode failure of the four primary containment isolation valves was outside of the design basis of the plant and previously analyzed conditions.
The simultaneous failure of these redundant isolation valves, could have, under accident conditions, resulted in a direct, unmonitored, and unisolable radiological release to the environment.
o Under DBA LOCA conditions, this failure to isolate primary contain-ment either manually or automatically would have exceeded the guidance provided to operators '.a the existing emergency operating procedures (EOPs) and may have aceeded the guidance provided in the i licensee's Radiological Emergency Plan.
o This event has significant implications ano la potentially generic to all facilities utilizing similar isolation valves, circuitry, and emergency operating procedures.
o The simultaneous failure of the for primary containment isolation valves was probably due to multiple and diverse root causes such as solenoid sticking and relay cortact failures.
The licensee's investigation is continuing.
o The licensee's implementing prog m ms failed to trend the precursor failures of these PCIS valve anri to elevate them to appropriate levels of management.
o The scram and scram recovery we*e accm plished according to approved , emergency operating procedures and there were no other equipment - failures which affected the safe shutdown of the unit.
< ., r [ _.
_ _ _ _ _ ._ ... ._.. _ _ _ - - f
___ _____ __ _________ _____ - _ _ _ .
IX. EXIT INTERVIEW WITH LICENSEE MANAGEMENT-The findings and conclusions of the AIT's special inspection were discussed on January 9,1988, with those persons indicated in Appendix 1.
The licensee indicated that the investigation of the solenoid valve and electrical circuitry failures would continue and that the NRC would be promptly advised of any new information. The licensee made the following commitments during the exit interview: 1.
The licensee will revise and clarify NRC reporting procedures to assure that all pertinent information is promptly provided to the NRC Headquarters Duty Officer and the Resident Inspector.
In addition, the licensee will provide training on evaluating and understanding , the significance of events and the reporting requirements.
2.
The licensee will provide training to clarify the proper operation of the hand switches for valves G16-F003, -F004, -F019, and -F020.
3.
The licensee will continue action to review and revise as necessary the maintenance trending program to assure that repetitive failures are identified and will revise the program to assure escalation of repetitive failures to management attention if warranted.
' I
e i I' - i - ! , i
> l.
.- - , _ _ - -. - -.. _.., - - - -_-,, - - .- . -
- _ _ _ _ _ _ _ _ _ _ _ __ ATTACHMENT 1 AUTOMATIC SWITCH COMPANY (ASCO) BULLETIN 206-832 ,
h \\. -- -- . , m m...
4.
j J w N % Inspection Report Nos, 50-325/88-03,.50-324/88-03 QTT F W nlT 1 (nwa 1 nf 4) INSTA' LLATION AND
== l MAINTENANCE INSTRUCTIONS E$$ . 'i T 3 WAY DIRECT ACTING NUCLEAR POWER PLANT PILOT VALVES n }j
NORMALLY CLOSED,NORMALLY OPEN AND UNIVERSAL OPERATION 1/S,1/4,3/8 AND 1/2 NPT.. RESILIENT SEATING - AMERVICE , h INSTRUMENT AIR GiiRVICE Foein Nik, c w t _ OESCRIPTION ' CpslT10NING ' Bulieu n 106 380 vr hos are 3.way direct 4eting solenoid vejses dee.saed a., V.uve must be mounted with the solenoid nrtJeal and upr4bt.
! NucJear rower Plant Puol VaJves. Vejns are of ksus construenos eins onJr four moviaJ 3assa - a core a lever and two troppet type aabe dises, grybP*NNO ( Vahes are suppued with braas dlses and reallent seat unemblate of braaaf Yor be Jy t>oss mosating dAmeadoas, refer to Ptgure 3.
a ethy6ene propriene or braasNITON * construction. VeJns suppued for pgpg ' '
oaj free instruraeist aar sameo are elastomers. Va.ves with mf fia "V"provided with aj) etaylene propylene j ' La the estalog numter for lastrumeng {canael piptas to vajve accordias to taartings on valve body The form of +r390s) is Ladiested by the Suffla LAttar ("F "od lowingnow t yN isJse estalog number on the nameplate Ref"r to flow diagra au serwee (an cl free) are provided with au VHon etute.ners. Auteue or "U ") f ol.
206 34f' eajvm. are provided with a Waterusht NEM A 'hpe 6 Solanced , e E.neloeuse promo n. C A UTION : S alves Nepued for od.rne instrument att semee are suaeun s 32,42,ee are as ye o are designed to meet N[M A T rpe 4_/*.nuneun io..m esce i the vo,ee gg;d,,;'a',$,.@te y'*g;4tg=";,0?, g tyng,g are equipped with an E lomon-rroof ateru Solenoid Ene use stuch does not apply to vajves wt Vlton ela.stomers (Suf fla "V" La catalos auJa.
Wa te ht tC or D8 bers). hptas to allvtJve ports thiuld be Ortsated such that any secumulwd Hazardous Locations - C;aas I,,G*oope C or D. N EM A Type and NEM A Type 9 (E moisture bparucularty LOCA chamaca] spraybartu act etter the lawsJ F or G) Hazardous Locauons -l.aas II. Groups E. F or G. Insta11auen and anu of t e valve For appbeacons where es ust piptas is not reg.it.ed M ainte naaet instrueu ona for the !!aplosion Proof Matert.sht Solenoid Enclosure are showr. on Form h,o. Yb343.
instaJ1 a downwardwitteeted street elbow to the veJve exhaustdort..q)y pipe eompound op y to male pipe. threads only: if appopersuonai difficuJt d to v ove OPE R ATION on"vaJve t>od y' 'sh"ou'ld b'e'*a"oided by proper support and allanmeus cf
- ** 8 5 * *
$*
- ^d cau.
v Norreauy Closed (Suffts Lettet "F") pipi.nfe. When tighteruns comaecuona' body or ptptas are to bor solenota do not use vahe bod Solenoad De*nersaned: Mow La frora Cylinder Connecuon (1) to Enhaust as a ver. Wrenches applied to valve located at.. Connection (3).Presure Connection (2)is cJosed, close as posable to consecuon potat.
Di4 PORTA'NTr for the protection of the soleno64 enJve)e as close to the e Solenoid Ctwrgized. Mow is from Pnerure Conneeuon (2) to Cylinder install a strsaats: { Connectf+a tit. Enhaust Connecuos (3)is eJosed, or futer sustatJe for the somee tavolved tin the talet s6v Normat p Open (Sufft Letter "G") ut\\'o'as SU 'un' N N h 1 $ op d a on se m n eos.
a t ets Solen:r.d Deanergized: Flow is from Preneur, Connecton (3) to CyLLader As sa addit 6onal brocaution asajass maltumetson os startes reaaltiv Iuse pasueJee of pipe scala, wa64 splatter. or eser debels ta pap.fromuse.
Conaaeuos (1). E shsust conneeuos (2) La cJosed.
Solenosd EnegJed: Mow is from Cyttader Connocuon (1) to Enhaust these eaJees have a lars % mesh eenen (not a futarp at telet. This ec.rees to Conaeeuos (2). Freerute Connection (J) is eJosed, not a subeutute for the stranaers os fgtars retommended above, whose UaJversaJ (Suffta Lettet "U") fuattlos is to peovide oostsamous straanlag or filtrasary, wt the the fluid.
Uajntsaj valves can be used as sortaally open or normauy eJceed: eee oP* WIRilig koi"8 ""$['p"Td wb'b' N'r 8NN r obe a' OTE Ope su a to a sie Jdeaufled by catajos suita leuerc as foUows: Connees wiring throuth a conduit of suitable evalaty 16.s the espected en.l n d Suffia Letter "P"- NormaDr Closed Opersuon Suf fia Letter **G"- NorreaDr Open Operacon vironment to a ventM anectrical Juncuon bon located La m seme arte as $uf fia L4Lter "U"- L'ruiersal Operauon the sahe. The condus hunenom tres erstera shouJe tm Mented such t.r.at CH ANCING OPER ATION FORMS any accumulated moisture er LOCA spray stil not run nato the solenoid enclorure. The water.taght oojenoid enclosure may be rotated to facuatate Usuversaj vahes (Un may be used for either operation form without laterrd wirtris Refer to Por.a No. V6381 for a descrapues of the method to l>* , chanses. Howent normaDr closed (F) and normalJr opea (G) vajves can.
used ti tt is necessary to rotate the taploesc a Proof /Waterusht Solenoid not be used for a dafferent opersuon torre uajess taternaJ parts (upper and feeJoeure, lower sprins.sl are abanged. Consult ASCO for new internaJ garu ana marae.
Plate for proper vabe aderiuficauon. Refer to "NEW SPRLNG IN5T ALL A.
SOLENOlD TEMPE R ATURE TION" Secuon when chans. rig opersuon forma.
Standard catalog vsjves are supplied wttb eous deugned for continuous.
r%d PORTANT: No minunum operattag pressure La required, dwty semce. Men the solenoid sa energ3:ed for a long penod, de solenoid enclosure becomes bot and can be touched with tN hand only for an 171 FLOW DI AGR A.bf $ staa t. T his is a sa f e o pe rs uaq te m pe ra ture. Aa r e m etss i e b e s un g wsli e - intaca ed by the senoke a.nd odor of burna.ag 400 uis.suon.
*F I
aw *= omew= G
- * -. - ~ - U NAINTENANCE
- * * "
" " " ' * ' ' * * *
- * " ' ' * "
d ARMNG Turn off eleetrical power and depremasurias eeles before unabsg repuan.,4 sa pref erab's to remove sahe from pdpe unos for repairs. Howeve.
~ ~ ~~ f tf tais se stry unpraette.1, refes to parspaph under "Yahe Otsaanembly Fog ' ' t i i F, Generna Cleaaras and Laspectioa", for rurther tastruettona.
l l ~
r CLE ANING
md A pendae clean.irig of aD solenoed vajne is testable. The time between ' L, f ejearungs ed; *sry derendaag on medaum ace s=rvice rondatierta. In general, p tj Las voltage to the sca) he correct, ajwgpah taJve CD iauon,e acessave noise or leaka,ge wtlJ &n.d eate that c.Jve.leanand u reek. red. Clesa valve straaner or ~, - euter ei u. aevu e soieno d v , D , r1 TU
l PEVENTIVE PalNTENANC4 e 1.
Keep the mebm fleers t through the enJve as free from dirt asid -. = = = I su m .- l foreign malenal as pt rab.a. L'se.futrument quauty air od tree for h 2.
e twee, peerste oth e periodicaDy to Laeure proper openang i e
Q "*
- '
N and eloent ~~ % %* l f" gs 3.
Penodie triepeetion (det.r to.e upon seedsum arid eernce condauonal
of interna) *ahe parts tw damese or eseessee wear ta recomroended.
T h orow ghly clean au parts teplace aar parts tr.et ase worn e,r dam.
- g 4.
We thes may require enodae replacernent of t.he rod manual oper.
' ' ator auembly jopuon f e at w re ), and all the resdieel perte during
9 the r instaued ufe to ma4mir, evalaficeuen. The e a set replacement "
ha pened s til depend on amh tne end semce conditaons Spue raf ts K ats, e e..e. + eU Cods and Manual Opersior Anaembhes are ordered separately. See i i
- =. D
i Ordenns Information Conrwlt ASCO for spectfac recommenetions in an3T1. PCat uanalhCS 1.1 th0 3 CometSPOh0 0f atCTtY 'O a 8 'NC C p pph, [p"gp*'
- " "
M ANU AL OPER ATOR IOpt onal) 1.
Fauny Control Cueuat: Deck the eintneal esstem by energring u.e [,'"e[[c g in[c'e,No' r"e
out f uses, ope n <us uited or growstde f p'l"y VaJ es eah Swf t a "MO" after catajog number are provided eith a manual u f h eh r o se or b6cm s operator = hich a1 Joes manwaJ opersuon when destred or duties an inter * cod, brok en lead u tres or spiace ruption of electrical power. To netwate tabe rnanwaar. pwan anot wpeard c o nne c tic.na and rotate one-heJf (12) twrn. Vahe will now be in same position as when 2.
,B urned 4)ut Cod C* sect for open<treuated cod. Replace cod if net.
solenoid is energ aed. To d.sengage t anwal operator. route kncb epproni.
uaiv matets one4aJf (I d2) turn untal guide pta in manw&J operator stem engagee 3 Lcw Volt ag e : Ch.ek geltage acroaa de cod leads. Voltage must be at sJots in stwffing bon bonnet and deers doori C A U TION F or inhe to op.
ienst 85% of name,Nate reung , erste electricany, manual operator stem mwafbe fulls retracted.
4.
Inc orre ct Pre uure : Check preuwre at the solenoid wahe. Preuvre to s i n e o,a,b, ete m u s t n o,t e i c e e d,,th a t stam pe,,d on na m e p la t e.io,ane es thes INSTALLATION p,, uw, Co uon: nef Check namepla;e for correct cataJos number,preuwse. toltage aid somet, on nameplete and flee cLat'ams.
s owrones,e..ste,ed i,adema,6.
A S C O Valves - . Autoamitt Switch Co, haJ,abe 0= ?1. Foem No. M999R1 PRINTED IN U S A.
1981 '
NRC Inspection Report Nos. 50-325/88-03, 50-32a/88-03 ,f e.
see n tasia.. Oteasse=We veln an.d MalN13d }aa se@M de A M 2 s tah-eeunda t:0.2 21.
~~ c ara. L.eaage beime s me oesta and di ce o usuiuy eaused by iodge.
- NOT. The weaner of the ivo spnngs abouid ajwave be rocated ai the bei.
most of foreign material on the vajve seating purfaces The foreign matertal though not present upon asuaination, may have darassed tom. If the opnaga are tasuMod La Lat wrong posuoa, the valve wtij oot funcuen property.
Lao oestaag rurfaces enough to causeleakage. Letlage thAou b resibent "e'J'em. *e*A' tis *u'u'el"Me .'u' owe"fJ"i b":'e"r'e'an'a'sL'!'" To determlae which spring ts the weaker. place the two aprings on the d mafi ef e -aeariv.er *direenmon (Figure 1)t"ret ta the weak"es of ar=uastoolsad a a = * e =. r$ anas ehan w h e re ne ce anary LNST ALL ATLON"Refer to pareknptta on "NEW SE AT AND D15 compresses to the L under '1N T A LL ATION OF NEW SPARE springs and abould be placed on the bottom.
P ARTS K1T" secuom.
COtt REPLACEMENT (Refer to F gurs 31 MANt)AL OPER A TOR Of SAS$'M8LY AND RE AS$tM8LY (Refsf to F9are 3.)
Refer to Form No..V6381 for Esploson# roof /Waterught Solenoid Ea.
%- 1.
Unsenw stuf flag boa bonnet unemWr froca n cloesn.
g,ge,a,j,o,eer w,piy od 4t.conaaet eoa isa eins. r,oeee4
- , tag.,,,,,,,,,,,,,,,,,, y ro use ted. R em ove !n b manual operator etern La fuu the manual operator
,. ,,,,,,,,,,,,,,,,,, PATTn,NWo mioWW,fr, a i. uma cent senu. cs) and remon ove, wtta screw.. cove, gaaisi 8.
~*****= and uamep! ate.
). Vascrew and remon retalturLA ett) frota Solecold base sub4aserably 4.
E11mtaste any burre on etem te m removtag k.nobletam pta. to Sup yoke containlas eau alee ste and taeulaung washore off the sole Prennt damage to Capute gaatet seaJ LO.rtas) La stuf ftas bon bonnet a, acid base eutmasembly Mund washers (1) are omitwd when a abe6tWF' spring and aude stera from stuffind bon bounet asse maided toO to used.
6.
Runen 4.
$tp eoIl tasuistind waahere and aJerves frera yoke 4.
Au parts are now accenable for ejeantag.
6.
Reameemble na reverse order of disassemblF to emploded vteu provtded for LdenuSeauon. PaFt care ful attendon-7.
R eassetoble la nnroe ordet o( d.:ausemblF. DeFing earefu] attention and acernest of parts.
to emploded v1ew provtded for identt004uon aad placement of paMa.
4. M en reptactas retainias tJjp. tighten unuJ retainas eby ts aos free l.
}or$we stufftng bos bonnet assemWF to 190120 tact. pounds [ 21.6 to rotate, approntmatelt 9132 of as tach between screw besd and aut.
2. newtoa meterol'
Torque eent ac.nue evenly to 101me.a-pounda (1.1 neunos meterest to insure proper gasket compresstoa.
CAUTION: Soleno&d must be PuDF reuseabled.u the houstas and taternaJ parta are part of and tomolete the magneue strewt. Place na un.adattn4 L saner at osen and of cog.d required.
VALVE DISA51tMBLY FOR CENER AL CLEANING ANQ INSPECTION (Refer to Fys J.)
SPARE PARTS KITS Dennamurtse ettve and turn off electrical power suppir. It ta stronq 3p,,, p n, gjta. Cou.a and Manual Operstor Assembues e ameaded that the enJue be removed frora the pipe nias for ease or;Iy ne.
Parta rnark e d wtth an astertah (*) La FLgun 3 are suppbed La Span Parts Kita.
an anumble for ASCO valves.
ra ala.
tenance. If it La act proctical to remove the eaJve trosa the ptre une and re.
estung of strokes is reoutred or Li e new Spare Parta KJs La to be nestalled eeasult ASCO for speelaJ boanot tools wh6eJn are arenable. M hen consult _ ASCO re to toelude the valve estajos atuaber sad eartal auzaber ORDE AlNG INFORMTlM 1.
Otsa.asemWe n2ve la an order!, fashlon, partag careful attenuon to FOR SPARE PARTS KITS .- S. k.o oNo!nwe r's cNr w th'se a or totemotd. cover kasket and When Oroenne Soere Parts Kits or Coas, nam e pla te.
F or E splomon Proof /Watettttht e eJ osun, nfor to Lastauauon and Maintenance lastraeuona. base rabeuemWF.
Spooty VeM Catalog Numter, Form No. V6341.
3.
Unserte and remove retalatag the froto soJenced Ser6al Nurnbor and Voltage 4.
Shp yote eentaining coal aleene and tasulattas washore off the eole.
acad base autMmembly. httag wasbers (3) an ottutted when a eolded cod la used.
4. Unacre w solen oid base hb assenWF ustas stwetaj wTeneh adapter provided La Spare Pana KJL (% renca Adaptar Order rk. 1024491).
6.
R e m ove soleno64 base h b-asse m bly, upper soleacad base gas s e t, houstag. re Alser aasae and tosalaer.
7 Vascrew disc swde cape tboth enda) and reraave dise r.ude tap see.
kona, upper and lower aprings dlacs and disc stems. CA L. TION. Tas rprtags discs and dise stema as they an act laterchangesble and must SCR EWDRIVE R be returned to ao ortssaaJ iocanon. Tas "upper" and Sower" for (OR SIMILAR TOOL) -. L% ease of 6denuSeauom.
- S.
De act remove pta beartag sene pta beartag gathet er vejn lever.
0.
Remove end esp and end esp sasket $bp core sortag rob nasembly (- % off the end of the vejve lever and Lft at out trtrousa soieno64 taae \\' - ^ g gj - pubsasemsly opentrig. Rermose bodF 'bonaet gasatt from tahe body, 10.
bolt un;eis usatamas a complete span Paita Katas ni upper and lower sahe sesta but do not remose trosi =aJn C".ean al) parts and pain.agem a rs thoroughj r. Replace worn or da.ra.
STRONGER SPRING 11.
aged parts witb a coraclete Spare Fans KJt. nimen tastauats a com.
WE AKER SPRING p ete Span Fans KJs. It ta recoausented th.at the conj and reanual operstor assembly of oneent> also be teol ta ben.n g {A R T S.atal:ed, refer to secuea on "th.aeed. if a spare Parta K55 ORIFICE SIZE ST ALLATION OF NEW SPARE K17 " for tastrueuons IM PO R T AN T : lastajJ al.1 ne w pana. Do not retafa any old parts when rebuald at enjn. If (SEE NAMEPLATE) "L" DIME NSION coJ7 part.a1 tastauauon ta made, val.e asJNaetion ma7 occut.
I VALVf Rf A$$Esagt,y 3/16 & 1/4 14" 1.
R e ame m nie to reverse order of daassemWy pa r tag c ars hi a tt e n.
non emploded vie w provided for adeauticauon and piacement gj9 g 9,yggo 3.
neste aD aaskets fescept cover gasket) with a light toat of DOW CORNING 4 560 Flute lubricant 3.
Replace core opring rub assembJy through solenoid base sub<asemWy 4, 1[skau en f ask t a d e ca d es 4 newtoa metereb. Torque saa cap to SO 15 foot.
Fw 1.
hW to Ntede haw Sm pounds (47.8 4.
lastaD bod? / bonnet gaahet La valve bodf.
4.
lastaD upper solemond base gasket on solenoid base swbtasombly, 1 Poeuen solenoid base s a b-a ss e m blF to houa188 and thetall retainer t ! fnetaD soienoid base eu'-assembly unng speesaj wrench adapter Pto.
l f'g [ asset and reta2ner at base of solemoed base tab,naaeratiJr.
l S.
L,, o vsded ta Spare Farta Kit i Torque solenoid base sub-asserably to 1. 6 2 2 6 irach founds [19.8 2 [mm] - R 2 PL ACES tu each Aosf ter Order No. 102449 ll l r 2 8 newtoa meters).
p pgg g E at j 9.
$Lp yoke contain$as coll. aleeves and insujaung washore over the sole.
FCAesN WilNG s** noid base sub sasembly, 10. Reptoce retairung elap and ugriten unal retaJrung cJap is not free to r I rotate, approssmately 9/32 af an tach between eerse head and nut.
. 11. Replace cover gasket and cover with rtameptate and screes Torque [p co=er screes etenJF to 10 anch-pounds (1.1 newton raeteral to in.
,. ; pure pro $er gasket comg resson.P or stro e setung requ6tementa (ed straent of vajie dase stems) re.
l i 13,
I ut to "N EW SE AT AND DISC IN$ alt. ATION" Paragraphs under
- LNSTALL A TION OF NE W S PAlt E A R T5 KlT" Seehon j
) 13.
n i a,,u p r and toeer spnna. Refer to "NEW SPRING IN ST ALL A.
y,. dl f..h , [' _, ,,, i \\
, ; - 14. Replace dine gvide esp gaahets on djee runde tape (both enda) Tor =ue 2-O ( ou saide esos to 1 0 216 inch +ounds (20.J t 1.7 me. ton vrieteral.
I 16. After via4ntenance, operate the vaJoe a few t.mes to be ture of proper f5 W ','
' Wg j operuns and enoang A metaule ebek wuf.ee that the solenoid is I (% I I o p e rs u n g.
) [ T l NEW $# RING IN$TA LL A710N (Refer to Fpre 1.)
%Mn it ie dentred to change to a dafferent form of flow or opereurig cond1
- G
) taan l mms l me e upper and low er sonnga cortempendaris to the ne e r*Qmtements, be ingaJed. De pre newnr e wahe and turn o ff electricaJ twp pIr. R e rD on e j tha too dase gode esps and old sonngs Install ne m sprega t.4 tried proper locauon as tnd cated on the factory 4abeled tage. Replace dine saide cape Piture 2.
h4ountlas Dirnenmone M A S C O Valves _.
.. , - .
' " - ' ^ ~ " * "UECHAt? flRC Inspection Report Nos. 50-325/88-03, 50-324/88-03 ',~ gg,=j,v3l J,*,1,gll*,, n x.e.. ATTACHME!iT 1 (page 3 of 4) ra,5y.
ut6 e.3 r u 11:* :: nn s n 1,. 1 u P ARTS INCLUDE D IN Valve sesta ] $ PARE PAR T3 KITS * ( UP ' ' * * *'l ' ' * ' *"'I (hp,0 d{ C 180 116 30,421.7 l y s COVER WITH SCREWT (3) AND k Cover
1.1 s i N AWEPLATE ATTACHED M , s ut 4 on , WtM W2U . p r.. C., ,,,5,o,u,,,, .T. 2 u l COVE R G A3KET* ~ ' ' IMPORTANT TAG PARTS A$
g THEY AEE REMOVED RETAINING CLIP Q \\ SLEEVE % N' N ' g INSULATING w ASHE R ca.e c-g ease (0MITTED wHEN MOLDED w..= m e. - - Coll l$ USE D) t.
SOLENCIDBASE$ , SUB ASSEMBLY - .- 00it E eae w ( [g#E R MLE C $ w ASHE R $tCASKET woe ** . (CulTTED w HEN WOLDED s,. Coll t$ USE DI ' \\ ig"' **g.,, % SLEEVE g HOUSING .N .. 1/2 NPS OR 14 NPT CON 0ulf CONNECTION "*7 - L ATTAINER GA$KET ( . ~"$$ e. w.s."Ne."Tu?.' RE7AreEA*
"" e.
Ol1C GUICE CAP G ASKET$ COR E SPRING < $US ASSEMBLY )(- yppg, gp g,qq g 13TRONG) M 800Y/80NN E T C A$K E T - O T' " *""" UPPE R Dr$C $TEU $ $PECI AL ARENCH AD APTE R$
VPPER VALVE $E AT$ t FOR $0LE NO10 8 ASE ' , $UB ASSEVBLY M VALVE BODY (ORCE R No. 102 649 1) 3 h PIN 0E AmiNG GA3EET$ PIN SE ARiNG SCPEW
,
- Low!R VALVE $t AT $ , - INSE RT CO R E/ SPRING - $US AS$tv8LY THRu Lowt R O'5C STtu $ UPPE R BODY UPENING.
(8vilT iN STON ENGAGE IN END OF ' END CAP
-Low!R V ALVE D'SC$ VALVE LEvt R.
C ASK E T$ f LOWE R $F RING $ twt AK) END CAP VALVELEVER . DISC GuiCE CAP GA$KET$ THi$ VIEW SHow$ VALVES wlTH l't6 AND 1/4 CRIFICE$. ' FOR V ALVES wiTH L'16 ORIFICES THE E xTE R*.AL 800y Ot$C GulCE CAP AND INTE RNf L P ARTS CONFIGUR ATION ARE SLIGHTLY DifFERENT.
j B uU e tia 206380 RenWest Seatma - A4 Service Watertisht Solenoid f actosce show.. Figure 3.
Foe t P omon Proot/watertisht Solenoid Encloswee t'oed on suuetin 2064 22. 5ee Form No. V53tl l . - __ _
i NRC Inspection Report Nos. 50-325/88-03, 50-324/88-03 l ATTACHMENT 1 (page 4 of 4) ' l INSTALL ATION OF NEW SPARE PART11(IT The diffmnee between the two distances ("C" auaus "D") La the bepreasunse valve and turn off electrical power supply Disanaemble etJve town nem suoke. If t1*e stroke le more than that caJeujated in Step etnful attomuon to esploded news fd be re.
must be gicund off umul the proper stroke la obtal. net. Af ter gnadana.
. rovid ed No. St. the end of the lower dise stem which contacts the veJw lever ha as orderly f ash 6oa pa foe tdentifteauon of sarta os ease of smaintenaate, vaJve abou moond han the pipe Gae., the end of the dise stora asust be crowned absbuy ant pollahed smootE l 8' ' " ' * * * * * * ' " " ' 1.
Loossa cover screws (3) and remon towt with acnus, cover guket tad nuneplata. For espicaon-proof twatertiths solenoid encJoeun.
refer to lastajistion and Ma.totenance lastrucuons Forre No. V6381 38. With wajve energsed, measun Dunsaalos "E."
3.
Unaciew and remove retainAng chp from solenotd hue sub a.aeembly, 3.
Sim yoke containias eou sleens and insuistuis washers of f the sole.
g aold base rub <ssembly. inn 1 sting waabets (2) are omitted wbem a 31. Wlth vajve de.energted. measure Ditmensson "F."
} stoided eou ta used.
d.
Unactew sole nosd base nb4asembly ustas specia.1 wrenc h adapter provsded in Spare Pasta Kit (wnseas Adapter Order No.102<gde.11.
38. Dtraeaston "E" "F"e lower dise stroke.
Reinovo upper solenoad base gaahet frorn solemond base sub4asembly.
6.
Remove bouang, ntainar and tota aee asahat.
fe'0'"p",e'TaRow's "Ma*#'da"s d'"a!'s*** '"' '" "' *
- -
d A m *ff=na 6"waa thowo mes*=ca gt adowed La the "3uoke "=== "r % * io w - stroke. If the strohe la eore than [ar**,,baccordias to catalog number) the end of the lower d 1.
Aemove upper and tower iaJve seaLa vang a 1/2 ineh thia wall noekst t h 8.
Nm v end cap and end ca g ask e t.
tanan eter end) eM contacts @e lown valw dise (en Figure 9.
Shp corets rtas sub4asemb$r off the end of the vajn lever and lift on must be ground off untu the proper otroke La obtained. After out the solenoid base sub-assetably opening. Remove body / gnadang. the end of the lower disc stem must be chaafend altshL'y.
bonnet et from valve bod Lubncate lower dine stem with Huros Ladustries, tae. NEOLt'BE 10. Remove paa beanas screw anI a bearing gasket.
Type jower or 2 provided La Spare Parta KJt) and anos pa.rt to aAr<iry.
th. Sude rajve lever out through the end cap opentrts of the vajve body,beau se stm and lower vajn disc.
. Au parta ase now accesable for repta tement Clean au internaJ passage.
H. pen the such,,ee have been set la accordance with Figure 4 and the ways. Instan a complete Spare Parta KJt. IMPORT ANT: InstaD ad now Stroke Chart. a gap wiu automaucaur be obtained betwere the parts. Do not retaan any old parts when rebuddlag vajve. lf onJF par.
tower dt:t stem and the lever when the polanoid u energaad. This gap ttaJ tastanauon ta made. vaJve maltwicuon may occur.
wtU assare proper operanon of the valve.
Replace town vajw sged.
13. Reusemble veJte in an orderly fashlos.
7 tag caJeruj attention to 18 rta g weak : nag). diae runde cap with dise P e o que twde cap to 180 216 inch.
da'(2b 2 bttac e cuo and esploded news provide for adenuticauon and place * 14., Lubricate alJ'gasketa (eacept cover gaaket) with DOW CORNING G 41. After maAntenance, operate the vaJve a few times to be sure of proper openlag and cloans. A metaDje cJack sgnJ6es that the solenoid La 16. p60 Fluad lubncant.
lasert vajve leur and replace pLa besitas guket and pla bearing screw o pne tans.
thsouph the vabe leter. Torque pounas (4,2 i'O.6 newton meters)pta beartag screw to 6615 inch.
, 16. Pomuon body bonnet gasket in tajve body. PomuoS core! spring sub.
f w,,ecu.0,n e.ona.pa m w asse ra bly throu gh solenoid base mb4anembly openAng and engage I with valve kver.
C
a 17. InstaU end esp Jaaket and end esp. Torque end cap to 6016 foot.
- "9 I M da ( 4 7.8 i s.8 ne w ton m ete rs l. A 19.
8.
.aM upper solenoad bue gasaet on solenold base sub4asombly, mQ, - uon solenoid base rut >4membly La houang and install retaJ.ner _* e-gasket and retainer at base of solenoid bue sub+ssembly.
20. Instad solenotd taae rutrassernbly usag rpectaJ wnnch adapterfro.
I l 3' vided in Spare Parta KJta (% rench A daou.? Order No.10344v.14 G w w Torque solenoid base sub4asembJF to 116 2 35 tach pounds (19.8 f 3 8 newtoa meters) o,,,, j ] St. Siip yoke contaAning eau, sJuws and 'nsulating waabers over the sole.
se %,,e e., w, mosd base eub4membly.
m,,,,,,,,. ,_, . 33. Reptace reintes cup and tighten undJ retaining elly is not free to rotate. approatrustely Sist of an inem between screw bead and aus.
h a A Reptace cover gastet and coser with nameplats and errews. Torque 5 - F, y cover screws evenJr to 10 nnchf ounda (1,1 ne wton meters) to insure even gasket cornpreemon.
% _ w 13. InstaD upper and lower vajve seats ustas a una.U armount of pipe - Op e=a w, y - compound on the seat th. reads to avoid poemble leakage. Torque up.
Lg::u 'N' d per ami. lower valve oeste to 80 2 3 tech 9ounds (9.010.9 newton '"g ~ j k = ete n l l e . , _e I I NEW SE AT AND DISC INSTAt.L ATION ,, 'N O, go, 34. New upper and lower seats and d.sce cannot be Last&Ued without mah.
m m,, %,,,,%,,,,,,% , nr.g sorne sataor adNatments It to traportant that the strote of Las $1Jee 44aca be 6et caretudy to Cbtra the proper onftte operking and rehable opersuon of the vahe. Cheek vaJve nameplate for the estaJol Ftture 4.
Wethod of Stroke Metaurement n um be r an d re fe r to "S u o t e Ch art" for stroke eetung requirements.
Refer to Firuse 4 for the method of measunes the stroke a.nd Figure 6 for stroke setting (gitadj.ng). $ paces are provided oo thAs sheet for
Four tajeulauoas.
$ 6.
Flace the valve tolenoid in a veruaal and upnght posuon. NOTE: = -w Solenoid. corv <sprtas sab assembnr and lever must be assembled sa the """"" vaJve when stroke are measured. A temporary elecuscaJ bookup must ajao be made. Instau upper d.se stem tiarse d.ameter hrst) and veJve d2ac. L'ae a depth gauge to measure the d2 stances. NOTE L'oper atac @ fl stern la a suaaght stem, but the lower disc, Lam has a twAJtta stop.
y ? Refer to Ftrure 6.
26 h tth waJve de rnergized, metrare Dimension " A ". c0 i Dtmertaaon "A" La from the top of the vaave body g -ag to the top of the upper d2ac. as tuustratae La M*4 Farure 4.
37 W th veJve enevglsed. measure Duneason "B".l h
i Diamenson "B" is from the top of the talte body y - to the top of the upper dane, as tuustrated inI Figure 4.
... _,,, - . -.. _ , b _ _.., 38. Dtre e an on "A " "B " e u ppe r disc stao k e.
.. The dafference between the too dtstances (" A" minus "B")'Suote f.
ta the upper disc suoke If th e suc h e ta m ore tha.n aU o m ed ta th e Chart" (iameter end) w hach contacts the upper vajve dame oes Figure 6) according to catajos number), the end of the upper dine stern Fls us e S. S ettu g 5 trote (G rted tas) t ern ajj d
rnust be ground off untd the pro?er stroke is obta.ned. Af ter gnndans.
'*S T R O K E C H A R T " -- i the end of the vpper One stem must be chamfered nJ.thtJr. Lubncate ' ' ~ upper disc stem with Huron Industnes, lae. NEOLtl6E ty pe 1 or 2 Pipe Ose C a t alo s O ntnc e g g,,,h e (provided in $ pase Parta K6t) a.nd aljon to a2s dry. Instau wpper s2ac N f'T N u m be r $nas L'eper Dise Lom er Disc stem anJ wpper vajve dasc.
St. Replace upper vaJve sprtng (suons spnnt), dine guide esp with disc 206 330 lR &.1R V 3/16 runde car gasket attached, torqwe disc sde cap to 1801 IS inch.
I'0 206 332 lR & lRY 3sl6 pounds (20.323.7 new ton metey. 30.
T u rn vahe upside down to instau lower dise stem ithout lower 206-330 2R & 2RV 3/16 vaJve dm). The lower d.ac stem stroke must be.010 (=002
le ss th a n 206 3 3 2 2R &.2 R Y 3,16 the upper disc suoke I'4 206-330 3 R &.3 R V 1/4 St. 1.?pper 42se strok e mtn.as 010 etwaJs the 206 332 3R & 3RV 1,4 s orrect lon er stem stic,ae.
2.002 .060. oog .040.oog , poo , con 206 3304R & 4RV 3'16 206 332 aR & 4R V Si16 33. With s ejve energized. m e n.sure Dimen s on "C."
206 3g0 bR & 5R V
- 206 332 SR & &R V 1.4 33. With t ajve de e ne rgued. m easwre Dime nuon "D."
206 3304R & 4RV S 16 206 3324R & 4RV Sil6 , nog 050 + 005 h$$ f ;$ [N 34.
Dimens on"C" "D" * low e r stem suc he. l ] li2
A S C O Valves _.
-- u me,e u c,v w m
i
. i , ATTACHMENT 2 G16-F003, -F004, -F019, AND -F020 CONTROL AND CIRCUIT LOGIC f I P
4 - l __ - _ _ _ _ _ _.
_ NRC Inspection Report Nos. 50-325/88-03, 50-324/88-03 ATTACH"ENT 2 (page 1 of 1)
. RPS N017 A1 = = B1== C1== D1 "" RPS K6A K68 - - - - " " K6C
_ _
K6D
i . PCIS KSA KSB KSC KSD _ K 17 _. RESET K1s ' RESET -- I I TEST SW .. DRYWELL PRESSURE PCIS _ "" LL 1 K5A B C D K18 K17 GP.2 K17 g3g F003 F019 F004 F020
Typical Valve Control Circuit OPEN AUTO RESET OPEN CLOSE OPEN LS Xf 7 GP 2 LS SOL RESET R G OPEN ERFIS
.. -- e - - - - -- - ,, _
._ _._ _ _ _ _ _ _._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - , ,
'l APPENDIX 1 , PERSONS CONTACTED i Licensee Employees , ! (Listed in alphabetical order)
- E. Bishop, Manager, Operations S. Boyce. orofessional Engineer, Systems
, B. Bracy, stems Specialist -
- S. Callit site Licensing Engineer D. Cerasuvio, Senior Engineer, Systems
,
- R. Creech, Instrumentation, Control and Electrical Maintenance Supervisor
,
- C. Dietz, Plant General Manager, Brunswick
- E. Eckstein, Manager, Technical Support
- K. Ensor, Director, Regulatory Compliance
- J. Holder, Manager, Outages
- P. Howe, Vice President, Brunswick L. Jones, Director Quality Assurance / Quality Control
. J. May, Environmental Qualification Project Manager ~t , '
- M. McDuffie, Senior Vice President, Nuclear Production
O. Miller, Environmental Qualification Field Engineer f 0. Quidley, Senior Specialist, Maintenance l
- J. O'Sullivan, Manager, Maintenance
, '
- R. 'Poulk, Jr., Project Specialist, Regulatory Compliance
- S. Scharff, Operations Engineer i
'
- J. Titrington, Principal Engineer, Operations
. ,
- D. Warren, Engineering Supervisor, Technical Support Other licensee employees contacted included control operators, senicr
, , . reactor operators, engineers, technicians, mechanics, office personnel, ' I and the Shif t Technical Advisor, t
Other Personnel Contacted
J. Shank, Automatic Switch Company, Product Engineering Manager K. Thomas, Automatic Switch Company, Senior Service Engineer
NRC Representatives ,
- B. Ruland, Senior Resident Inspector, Brunswick j
- Attended exit interview on January 9,1988.
, j l I
Appendix 1 l I
' ._.
. ._ - - - -,_ . ,. _ _ _... _ _ _ _ - _ _ _... _ _, - _. _, .. .. .. ~ - - -. - - ,
_ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ - _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ . _ _ - - _ _ ._______ _______ _ _ ______ ____-_____ APPENDIX 2 ' ACRONYMS AND ABBREVIATIONS AIT Augmented Inspection Team A0 Auxiliary Operator A0G Augmented Offgas System ASCO Automatic Switch Company . BOP Balance of Plant C0 Control Operator CP&L Carolina Power and Light Company CR control room - OBA Design Basis Accident . E0P Emergency Operating Procedures . ERFIS Emergency Response Facility Information System ESF Engineered Safety Feature i GE General Electric GP group I&C Instrumentation and Control . LOCA Loss of Coolant Accident
Mgmt Mtg Management meeting l MSIV Main Steam Isolation Valve
MST Maintenance Surveillance Test i - MWR Maintenance Work Request NRC Nuclear Regulatory Commission ! NRR Office of Nuclear Reactor Regulation , , PC Process Computer '
PCIS Primary Containment Isolation System j PM plant modification < psig pounds per square inch gage i , a PT Performance Test QC Quality Control ! i RPS Reactor Protection System r scfm standard cubic feet per minute e ' SF Shift Foreman l SIIT Scram Incident Investigation Team SJAE steam jet air ejector ,. SOS Shift Operations Supervisor [ SP Special Procedure t SRO Senior Reactor Operator ^ i STA Shift Technical Advisor TIP Transversing Incore Probe i WR/JO work request / job order (maintenance work request) ? ! ' i ! [ r
I Appendix 2 L l - -.- - - - - - - -. .... -_ - .__
APPENDIX 3 DESIGN DESCRIPTIONS A.
Drywell Equipment and Floor Drains and Group 2 Primary Containment Isolation System (PCIS) The drywell equipment and floor drain sumps provide an accumulation point for leakage within the drywell.
The contents of these sumps are automatically pumped on a periodic basis to the radwaste collector and floor drain.
The discharge from these drywell sumps is via two separate pipes which penetrate the primary containment (drywell).
Since these lines communicate directly with the drywell atmosphere, but not the reactor vessel, they are considered Class "B" penetrations requiring two automatic isolation valves in series outside containment.
The drywell equipment drain primary containment isolation system (PCIS) valves are G16-F003 (inboard) and G16-F004 (outboard).
The floor drain PCIS valves are G16-F019 (inboard) and G16-F020 (outboard).
These four drywell drain PCIS valves receive an automatic closure signal on a Group 2 primary containment isolation signal. A Group 2 primary containment isolation signal will be generated when the following parameters exceed the indicated Technical Specification setpoint: 1.
High drywell pressures ( S 2 psig); or 2.
Reactor vessel low water level "1" ( y 162.5 inches).
A Group 2 isolation will also result in the closure of the following valves: 1.
Transversing Incore Probe (TIP) ball valve.
2.
Residual Heat Removal (RHR) discharge isolation valves to radwaste (valves E11-F040 and E11-F049).
3.
RHR Process Sampling Valves (E-11-F079A and B and E-11-F080A and B).
The two signals listed above for Group 2 primary containment isolation will also result in isolation of Groups 6 and 8 valves.
B, Description and Operation of the Solenoid Valves Automatic Switch Company (ASCO) Model 206-832 Type "F" solenoid valves are used for control of containment isolation valves G16-F003, -F004, -F019 and -F020.
The valves are 3-way direct-acting solenoid valves designed for nuclear power plant service and are environmentally qualified.
The valves are of brass construction with four moving parts: a core, a lever and two poppet type valve disks.
The disks are brass with resilient seat assemblies of brass /EPDM (ethylene propylene) construction. An assembly drawing of the valve is included in the attached copy of ASCO Bulletin 206-832 (Attachment 1).
Appendix 3
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -. _ _ In the de-energized state, the upper spring forces the upper valve disc against the upper valve seat, sealing the supply pressure from the process cylinder.
The upper valve disc pushes the upper disc stem against the valve lever, The valve lever, in turn, applies this force to the lower disc stem, unseating the lower valve disc and allowing the process cylinder to exhaust to the atmosphere through the lower valve seat.
Upon energizing the solenoid coil, the core is lifted, which, in turn, lifts the valve lever and overcomes the upper spring force to unseat the upper valve disc and allow air to flow to the process cylinder. When the valve lever is lifted by the core, the weaker lower spring pushes the lower valve disc against its seat and seals the exhaust path.
The Brunswick valves are configured to normally operate in the energized state which allows the instrument air to supply and hold the main air-operated gate valves in the open position with closure spring compressed.
On actuation to close, the solenoids are de energized which isolates the instrument air supply and allows the main valve cylinder to vent which allows the closure spring to force the valve closed. The ASCO Model 206-832-3RF (or Type "F") valves are used to meet the design conditions for operation of the valves.
The licensee originally purchased ASCO Model 206-832-3RG (or Type "G") valves. A Type "G" valve operates in a reverse fashion when compared to a Type "F" valve.
The Type "G" valve would allow air pressure to supply and hold the main air-operated gate valves in the open position when the solenoid was de-energized.
The Type "G" valve can be converted to a Type "F" valve through the use of a conversion kit supplied by ASCO.
The Type "F" incorporates stiffer upper and lower springs than those for the Type "G" in order to preclude leakage through the bottom seat.
The component parts of a conversion kit can be found in the manufacturer's Bulletin 206-380, 206-832 (Attachment 1).
It was noted that the replacement kit received by the licensee from the vendor does not include the core sub-assembly or solenoid base sub-assembly as listed on the manufacturer's bulletin.
C.
Automatic and Manual Valve Logics for G16-F003, -F004, -F019, and -F020 1.
Automatic Operation The G16-F003, -F004, -F019, and -F020 PCIS valves are designed to automatically close on a Group 2 isolation signal.
The ASCO solenoids for the four valves are normally maintained in the energized position by the reactor protection system (RPS) power source.
In the energized condition, the ASCO solenoid allows instrument air pressure to hold the associated gate valve open against spring pressure.
The "A" RPS channel provides power to the inboard isolation valves G16-F003 and -F019 (one valve in each line) and the "B" RPS supplies the outboard isolation valves G16-F004 and -F020.
On a Group 2
Appendix 3
, -_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ! ! . isolation signal, independent isolation signals interrupt the RPS power source to the inboard and outboard valves, respectively,
theoretically ensuring closure of at least one isolation valve in each line.
An "A" train Group 2 1 solation signal will de-energize the K-17 relay disrupting power to the ASCO solenoids for G16-F003 and -F019.
De-energizing the ASCO solenoid causes the air to vent from the valve, allowing spring tension to close the valve in less than 20 seconds. This control logic is illustrated in Attachment 2.
The logic circuit for the outboard valves is identical except that a "B".
, train signal de-energizes the K-18 relay resulting in the closure of valves G-16-F004 and -F020.
On an automatic closure signal the red OPEN indicating lights in the control room extinguish and upon the
valve reaching full CLOSED, the green CLOSED light illuminates.
, , 2.
Manual Operation The drywell equipment and floor drain PCIS valves are controlled from the main control room operating panels via four identical, three position, spring return to automatic, hand switches.
Each switch has a CLOSE, AUTOMATIC (normal), and OPEN position available to the ! operator. When a valve control switch is placed to the CLOSE > position, the red OPEN light will extinguish almost immediately when L a contact opens interrupting power to the ASCO solenoid. This action [ also de-energizes a K-34 relay which provides a "seal-in" feature and ensures full closure of the valve even though the switch is released.
The K-34 seal-in relay is located in the operating panels under the control switches and provides an informal audible confirmation to operators of a valve closure. When the PCIS valve switches are , placed to the OPEN position, there is no "seal-in" feature and the
,
switch must be held until the valve is in the full OPEN position with the red OPEN light illuminated.
Failure to hold the switch in the ! OPEN position until the valve is fully OPEN will result in the valve returning to the CLOSED position.
D.
Drywell Equipment Drain System Description j .
Orywell clean radioactive drains are collected by the drywell equipment i i drain tank.
This tank is composed of two tanks interconnected by an eight
j inch drain pipe. One tank is located inside the sacrificial shield wall, '
the other outside.
The tank outside the wall is equipped with two i ' centrifugal pumps to transfer the collected drainage to the radwaste
facility waste collector tank. The containment isolation valves in this ! line are G16-F019 and G16-F020.
The inside tank is not pumped, but ' ' , . ! ' i ' . i
I i
Appendix 3 l ' , ,- - -, - . - - -, -, _,., - - _. - - - -.,., - -. -. ,- --
-. . - . I h , t r gravity drains to the outer tank. The following systems contain valves , ' within the drywell with vent and leak-off drainage to the drywell t equipment drain tank-t 1) Nuclear Steam Supply System 2) Reactor Coolant Recirculation System 3) Residual Heat Removal System 4) Core Spray System 5) High Pressure Coolant Injection System , 6) Reactor Core Isolation System
7).
Reactor Water Clean-Up System
8) Fuel Pool Cooling and Filtering System '
E.
Drywell Floor Drain System Description ' , ' Drywell dirty radioactive drains are collected by the drywell floor drain sump.
This drainage originates from the Reactor Building closed cooling ' water utilized to cool various components contained within the drywell.
The floor drain sump and centrifugal pumps are identical to the drywell i ! equipmen+. drain tank and pumps.
The collected drainage is pumped to the radwaste facility floor drain collector tank. The containment isolation
valves in this line are G16-F003 and G16-F004.
F.
Instrument and Service Air Systems Descriptions F The Instrument and Service Air Systems have a common air supply provided i by one 1,267 scfm oil-free rotary screw compressor, with three 334 scfm oil-free reciprocating compressors as backup.
The discharge of the screw , compressor flows to a 93 cubic foot air receiver which in turn flows to a a common discharge header that connects downstream with the discharge from i the reciprocating compressors. The discharge header then flows into three ' ' 96 cubic foot air receivers via a dual tower desiccant-loaded air dryer (service air dryer). The rotary screw compressor is a two-stage package ' unit complete with air intake filter and silencer, a water-cooled intercooler and aftercoolec, and a moisture trap.
Each reciprocating compressor is single stage with cylinder water jacket, air intake filter '
i and silencer, and a water-cooled aftercooler and moisture separator.
The outlet of each of the three air receivers discharges to a common header , which supplies the total plant air requirements through the two systems.
1 < Service air is supplied through a backpressure control valve which closes , if the upstream header drops below 105 psig.
This ensures that instrument ' air requirements take priority over service air requirements.
Service air ' is piped from the service air header to selected auxiliary equipment and hose connection stations throughout the plant, i i i I > l
l
Appendix 3
-- , _ . _ _ _ _ _ _. _, _ _ _ _ _ _ _. - __ _ - _ _ __ . _
_- --. .. -_
I ! ! Instrument air is supplied by the receiver discharge header via a second i dual tower desiccant type air dryer (instrument air dryer).
This air is dried to a dew point of -40 degrees F and discharged through a , ' dual-simplex afterfilter.
The afterfilter prevents pipe scale and
desiccant from being carried into the Instrument Air System. After
leaving the afterfilter, instrument air divides into two main' air systems; non-interruptable instrument air and interruptible instrument air.
Two separate non-interruptable. instrument air lines branch from the air dryer discharge-header and enter the Reactor Building. These lines form . , two independent loops, each with its own receiver. This redundant piping ' precludes the possibility of a total loss of non-interruptable instrument air to vital instrumentation and pneumatic controls. An automatic standby
air compressor is provided for each loop to maximize reliability.
Non-interruptible instrument air provides air to the containment isolation i valves, G16-F003, -F004, -F019, and -F020.
! ' . ! , h , ! ! . i
i ! , F
i ! i i '
' , I
I i i l E i ! ! ,
i I ! i
!
Appendix 3
l i i
- - -.. - ,,.. _ _,.,. . _ _ _ _... _ _ _, _ _ _ _ _, _. , _, . _ _. - - - -_ -
. . - - _- ._ . . , t >
i APPENDIX 4 , , REVIEW OF INITIAL CONDITIONS AND OUT-OF-SERVICE EQUIPMENT l
A.
Overview of Initial Pcwer Evolutions . Review of these evolutions provided significant insight into the - , licensee's handling of inoperable equipment and the implementation of the , maintenance program and therefore warranted detailed examination. The evolutions, however, did not directly relate to the post-scram primary
containment isolation system (PCIS) valve failures, j At 55 percent power the offgas flow had increased to 150 scfm, and the < (Augmented Offgas System) A0G system bypass opened.
Since the maximum
indicated flow on the combined offgas flow recorder is 150 scfm and the
individ u1 train flow recorders were out of service, Operations personnel l ! could no longer determine total offgas flow rates. At 55 percent power, r the operators removed the "A" reactor feedwater pump from service and at [ approximately 2210 hours, the operators secured the "B" steam jet air r ejector (SJAE) per general procedure GP-05, Unit Shutdown, Rev. 24. At
2215 hours Unit 2 was at 48 percent power and the power reduction , continued through control rod insertion per GP-10, Rod Sequence Checkoff , Sheets, Rev. 6.
At approximately 2240 hours, rod insertion was , temporarily stopped to allow the nuclear engineer to run a computer i program.
} i ! Between the hours of 2220 and 2245, the operators noted a gradual decrease in condenser vacuum from approximately 27 inches (normal) to 25 inches.
i In an attempt to restore condenser vacuum, the operators tried to restore the "B" SJAE, which had previously been secured, to service.
This attempt ! was unsuccessful apparently due to a hydrogen recombiner temperature i recorder which was incorrectly reading below the minimum 300F SJAE j permissive. As an alternative means of restoring vacuum, the operators
increased the load on the "A" train SJAE from 50 to 100 percent but vacuum l
continued to decrease.
l ' At 2226 hours, reactor power was increased to 53 percent with , l recirculation flow in an attempt to restore condenser vacuum.
Following i ' this power increase, vacuum increased to 26.5 inches and appeared to j stabilize. Operators were dispatched into the plant to look for the ' i source of the vacuum leaks.
At approximately 2250 hours, the vacuum began
decreasing again but at a more rapid rate than previously experienced. At
2330 hours, operators in the plant reported a potential source of vacuum ! letkage at the west moisture separator reheater drain tank.
j At 2356 hours the operators again began pulling control rods (per the !
sequence determined by the nuclear engineer) under the supervision of the
Shift Operations Supervisor (505) to increase reactor power and stop the ! j vacuum decrease. At 2359 hours with the reactor power at 56 percent, , vacuum was at 24.s inches and the power increase was stopped.
The 505, j
- .
i ,
Appendix 4 i l l
e - - - - - - -
,- r-nw., . - - - - - - -,.. r-, ., ,,. --vc -. n -.., - - - - - - -, ,
. - _.- __ _ _ _ - _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _
acting Shift Foreman (ASF), and Shift Technical Advisor (STA) discussed the potential course of action should the condenser vacuum continue to decrease toward the 20 inch turbine trip setpoint.
The STA recommended a controlled shutdown by reducing power below the 30 percent power turbine trip / reactor scram setpoint; tripping the turbine; and, utilizing the turbine bypass valves to dissipate reactor steam production.
This method of shutdown had apparently been successfully utilized in a July 1987 power reduction when similar vacuum problems were experienced.
The SOS was reluctant, however, to utilize this method of shutdown due to the increasingly rapid drop in condenser vacuum and the chance that it might result in a turbine trip and Group 1 main steam isolation valve closure.
The SOS considered requesting Maintenance to work on the defective hydrogen recombiner temperature recorder to allow the restart of the "B" trsin SJAE. At this point, however, vacuum was decreasing rapidly and the offgas filter high differential pressure alarm had been received.
The SOS also considered reducing reactor power to the point where the mechanical vacuum pumps, which have a higher offgas capacity, could be ' started in place of the SJAE. This option was discounted due to the inability to determine total offgas flow and the 5 percent power limitation on the use of the mechanical vacuum pumps.
At 0016 hours, the condenser vacuum had decreased to 22.5 inches, and at 0017 hours the "A" train exhaust hood vacuum alarm was received at 22 inches. Both the "A" train and "B" train low vacuum alarms should have been received at 25 inches of vacuum. At this point, the SOS made a decision to scram the reactor and directed a reduction in recirculation
flow. At 0018 hours, the SOS directed a manual scram of the reactor.
B.
Train A and B Offgas Flow Recorders While still at 69 percent power, prior to commencing the refueling outage shutdown, the operators were experiencing excessive offgas flow of approximately 140 scfm.
This flow is nearly three times the normal offgas flow rate experienced during power operations.
This high offgas flow was attributed to condenser air in-leakage through sources which had not been , identified. As the reactor power was reduced, the offgas flow rates ' increased which was to be expected.
I At 2115 hours, offgas flow had reached 149 scfm. At approximately 2125 hours, offgas flow reached 150 scfm and the offgas bypass flow I automatically opened to bypass excess flow around the offgas treatment system.
150 scfm is also the taximum available reading on the combined offgas flow recorder.
The only way to determine the total offgas flow under these conditions was - to read the individual "A" and "B" train outlet flows on recorders 2-0G-FR-4283 and 4323 and then total the results.
These two recorders , were out of service pending completion of an outstanding maintenance work l request. As a result the SOS could not obtain total offgas flow and could
Appendix 4
- . .- , - _. , .. i
I
< I . not utilize this parameter as an input to his decision whether to scram or ! ~
to attempt a controlled unit power reduction or shutdown.
! ! The augmented offgas (A0G) system was installed in 1984 and turned over to
Operations in 1986 with a number of outstanding deficiencies or punch-list ' items to be resolved. The inspectors reviewed the maintenance history of ! the "A" and "B" train outlet flow recorders (4323 and 4386).
This review
indicated that the recorders had essentially been inoperable since installation.in 1984. Two maintenance work requests were written in f F December of 1984 on the A train recorder but were apparently never worked.
l A maintenance work request was also written in December 1984 on the B t train flow recorders. This maintenance work request was worked but was unsuccessful leaving the blue pen inoperable and the red pen pegged i downscale, , Interviews with Maintenance and Technical Support personnel indicated that ) numerous problems and deficiencies still exist in the Unit 2 A0G system ! and this deficiency is only one example.
Interviews indicate that when l , Maintenance cannot adequately resolve a problem identified by a i maintenance work request on the system, as in December 1984, the i responsibility for resolution is turned over to the Technical Support , Group. Until one year ago, a dedicated system engineer was not assigned . to the A0G system, and the inoperable recorder status was not pursued and i
resolved.
In 1987, a system engineer was dedicated to the A0G system, but [ had not identified these recorders as a priority.
The licensee also ! indicated that the inaccessibility of transmitters in the A0G system [ during power operations may have contributed to the three year outage time i ' of these flow recorders.
i C.
Hydrogen Recombiner Catalyst Bed Temperature Recorder ! When operators experienced a decrease in Unit 2 condenser vacuum between . l 2220 and 2245 hours on January 1, 1988, they tried ur.successfully to [
restart the "B" train steam jet air ejector (SJAE).
The "B" SJAE had been
previously secured at 2210 hours as part of the Unit 2 shutdown under l i GP-5, Unit Shutdown, Rev. 24.
The start "permissive" light for the "B" ! SJAE could not be obtained due to the center (blue pen) hydrogen l , recombiner catalyst bed temperature reading low (recorder 2-0G-TR-4320).
- The start-up permissive for the SJAEs includes a center temperature in the i
recombiner of greater than or equal to 300F,
i Interviews with operators indicate that this temperature recorder read !
approximately 250F during the period of the event, apparently l
out-of-calibration low.
Since the operators indicated that all other SJAE ! permissives were met, it appeared that this out-of-calibration recombiner ! bed temperature prevented the restart of the "B" train SJAE.
The restart !
of the "B" SJAE could have probably helped restore Unit 2 condenser vacuum !
and allowed additional time for determining the source of air inleakage ) and loss of vacuum.
, , i i l
l
Appendix 4 ! ! . -. -. - - - - -. - - -. -... - - - . - - - -. - - -. - - _. - --
__ ~ , { ! ,
A review of the maintenance history for this temperature recorder in 1986 l and 1987 indicated several maintenance work requests.
In some cases these maintenance work requests were associated with all three temperatures on
the recorder including top bed temperature (green), center bed temperature ! (blue), and bottom bed temperature (red). A maintenance work request , issued on July 14, 1986 indicated that the green pen was failed downscale,
the blue pen was reading low and the red pen was reading upscale. The , , green pen was repaired by replacing the transmitter and the red pen was '
repaired under another maintenance work request.
The blue pen which was reported as reading low was noted on the maintenance work request as "SAT" and no work was completed. Additional maintenance work requests on the recorder were generated on April 5 and November 15, 1987.
Interviews with i Operations personnel indicated that the recorders had been a continuing source of inaccurate or erratic readings since the system had been e installed in 1984 and turned over to Operations in 1986.
A maintenance work request completed on January 7, 1988 determined that ! oxidation of the controls on the temperature transmitter which feeds the SJAE had caused the transmitter to read downscale. The contacts were cleaned and the temperature' recorder and transmitter appeared to be ' reading correctly.
, D.
Effect of Inoperable Offgas Instrumentation on Unit 2 Operation and Scram l ! Due to apparent increasing air in-leakage and loss of condenser vacuum and the 5 percent power limitations on use of the mechanical vacuum pumps; the inaccessibility of the "B" SJAE and total offgas flow information may not , have ultimately affected the SOS's decision to scram the reactor. On the > other hand, the SOS was not provided with all the equipment ("B" SJAE) l > necessary to attempt to recover condenser vacuum or the necessary r
information (total offgas flow) to cletermine whether to perform a scram or ! controlled shutdown.
I ' !
E.
Unit 2 Condenser Vacuum Leak (Air Inleakage History and Out of Calibration ' Low Vacuum Alarms)
! l Unit 2 had experienced previous vacuum leaks and air inleakage in recent ! ) months.
In July 1987, power had to be reduced to 5 percent to hold vacuum l and allow location and repair of vacuum leaks.
Since that time the unit j
air in-leakage and offgas flow rates had increased from approximately 4U
' scfm to 140 scfm on the evening of January 1, 1988.
During this period l the licensee indicated that there was an ongoing effort to locate and [ ' repair the source of this leakage.
Following the event on January 2, , 1988, a leak was located in a turbine steam extractor line, a leak which t
probably contributed to the loss of Unit 2 vacuum.
! i t As noted in the sequence of events, the Exhaust Hood "A" low vacuum alarm was received by operators at 22 inches of vacuum. The "B" low vacuum was
, never received before scraming the reactor.
The normal setpoint for this i instrumer.tation is 25 inches one inch. A scheduled surveillance and i ' calibration of these two low vacuum alarms during the inspection [ ' !
Appendix 4 , - - _ -.. -- .- - .. . . - -. . -
determined that both were out-of-calibration low.
The "A" alarm was set at 22.3 inches and the "B" alarm at 21.5 inches.
Since the manual scram was initiated at 22 inches vacuum, this explains why the "B" alarm was never received.
Although the low vacuum alarms are considered balance-of plant instrumentation, the lower setpoints could have reduced the time for corrective action to prevent a low vacuum trip, particularly if the operators had not been constantly monitoring the dropping vacuum levels.
!
Appendix 4
, _ _ _ _ _ _ _ _ _ _ _. APPENDIX 5 DETAILED SEQUENCE OF EVENTS FOR BRUNSWICK UNIT 1 General Status of Subsequent to the shift turnover at Unit 1, prior to 2000 hours on 1/1/88, Unit I was at 100 percent event on Unit 2 power.
on 1/2/88 Time (EST hours) Data Source Item JANUARY 2, 1988 1200 I&C Super-Four PCIS containment sump valves for visor Unit 1 (1-G16-F003, -F004, -F019 and -F020) Statement manually cycled CLOSED and OPEN to assure closing capability.
JANUARY 4, 1988 1400 I&C Super-18 month special surveillance test visor SP 88-003 completed on Unit 1 to verify Statement operability of 1-G16-F003, -F004, -F019 and-F020 valves.
Each valve was cycled twice.
Test was successful.
JANUARY 5, 1988 1431 CO Log Closed 1-G16-F003, -F004, -F019 and -F020 valves due to concern with solenoid stem clearances and undetermined valve failure root causes on Unit 2.
1630 C0 Log Reopened 1-G16-F003, -F004, F019 and -F020 valves due to vendor supplied information.
JANUARY 6, 1988 1730 Licensing Licensee committed to NRC to close valves Supervisor 1-G16-F003, -F004, -F019 and -F020 on Unit 1 while operating except to pump sumps out.
2049 CO Log Valves 1-G16-F003, -F004, -F019 and -F020 were closed to ensure Unit I containment integrity.
The valves will be opened only for pumping out the drywell equipment and floor drain sumps.
Appendix 5
APPENDIX 6 DETAILED SEQUENCE OF EVENTS OF LICENSEE INVESTIGATION Time (EST hours) Data Sour _c_o Item JANUARY 2, 1988 0500 Operations Unit 2 floor and equipment drains were Engineer pumwd do,<n through 2-G16 F003 and -F004 Interview and 2-G16-F019 and -F020, respectively.
0625 AO Log A0 placed air supply to 2-G16-F003, -F004, -F019 and -F020 under clearance #2-0089.
0930 Operations All Unit 2 floor and equipment drain sump Engineer valves (2-G16-F003, -F004, -F019 and -F020) Interview had been successfully manually cycled open and closed to pump nut sump.
1140 I&C Super-Operations conducted PT-11.3 on Unit 1 visor drywell floor and equipment drains.
Interview 1251 SF Log Follow-up Red Phone report to the NRC.
1400 I&C Super-A limited walkdown of the wiring and relays visor was conducted by the licensee.
Interview 1420 A0 Log Clearance No. 2-0089 on 2-G16-F003, -F004, -F019, and -F020 air supplies was removed.
1655 SF Log Unit 2 reached Cold Shutdown conditions.
1900 SF Log Completed maintenance surveillance test 2MST-CAC41R to verify operability of 2-G16-F003, F004, F019 and F020.
Test satisfactorily completed.
1730-I&C Super-Modified 18-month surveillance test , 1930 visor procedure utilized to de-energize each t Statement relay and PCIS valves closed.
Each valve successfully cycled twice.
2400-I&C Super-Performed monthly surveillance test of RPS 0300 visor low level "1" and Group 2 isolation ' Statement (2MST-RPS24M).
Test modified to utilize test switch to cause two valves (2-G16-F003 , and -F019) to actually close.
!
Appendix 6
_ _ _. , JANUARY 3, 1988 0700 Mgmt Mtg Solenoid from valve 2-G16-F019 removed from system for inspection and troubleshooting.
1130 I&C Super-2-G16-F019 solenoid valve bench tested at visor 36 psi air pressure (normal) and 5 psi air pressure.
2-G16-F019 solenoid valve - operated normally at both pressures.
1230 I&C Super-2-G16-F019 solenoid valve disassembled - visor darkened area on face of one valve stem and light oil film in solenoid body.
The bottom disc travel was + 7 mils out-of-tolerance, I&C Super-2-G16-F019 valve solenoid re-installed visor without adjustments to support additional testing under original conditions.
2330 I&C Super-2-G16-F019 tested and cycled successfully, visor JANUARY 5, 1988 1400 AIT Entrance Meeting with licensee.
JANUARY 6, 1988 1610 Observation Special Test SP-88-004 conducted to by AIT duplicate event conditions on Unit 2 to test Group 2 isolation signal simulated at Rosemount transmitter for low level "1" on all four channels at once.
2-G16-F003, -F004, -F019 and -F020 all closed.
The red (OPEN) light on 2-G16-F003 was slow to extinguish (approximately 10 seconds and was illuminated concurrently with green CLOSED light).
JANUARY 7, 1988 1130 I&C Super-Bench test of 2-G16-F003 solenoid valve ' visor was completed successfully.
Disassembly Interview of 2-G16-F003 showed some small amount of foreign matter.
Appendix 6
_ _ _ _ _ _ _ ._ 1600 I&C Super-Reassembly of 2-G16-F003 was completed and visor bench tested successfully.
Test of air Interview supply pressure to 2-G16-F003 completed successfully.
1630 I&C Super-Air cleanliness test of 2-G16-F003 was visor completed at air supply line to 2-G16-F003 Interview successfully.
JANUARY 8, 1938 0400 I&C Super-Removed 2-G16-F020 solenoid valve from l visor system and conducted air pressure test at Interview air supply line to 2-G16-F020.
JANUARY 9, 1988 ' 1100 ASCO The licensee and members of the AIT met Interview with ASCO representatives, t
Appendix 6
_ _ _ _. _____ __ _ ___-____ _ ___ ______- _____ _ ______ _ _ -______.
_ _ - _ - - - _ _ _ _ _ _ _ - __ - _ _ - _ _ _ _ _ _ _ - _
r i ! , t APPENDIX 7 i EMERGENCY RESPONSE FACILITY INFORMATION SYSTEM (ERFIS) . In the process of trouble-shooting the source of the four primary containment isolation system (PCIS) valves to close on a valid Group 2 isolation signal, it was desirable to (1) ensure an automatic isolation signal had been generated by the low level "1", and (2) the closure signal had been received at each of the four valves.
The process computer was utilized by the licensee to verify the automatic isolation signal at low level "1".
Closure of the other Group 2 isolation valves including transversing incore probe (TIP) and residual heat removal (RHR) radwaste and sample isolation valves would have provided an indication that the isolation signal was received at the valves.
Unfortunately, these valves were already in the closed position during the ', scram and isolation.
< , The only remaining method of verifying the automatic isolation signal was i received at valve 2-G16-F003,-F004, -F019, and -F020 would have been the first out from the Emergency Response Facility Information System (ERFIS). Although t this system was not fully operational or turned over, it was in service at the time of the event.
Four of the only seven monitoring points which are t operational are connected to the valve actuation circuit through a recent plant ! modification.
The licensee had determined prior to the AIT arrival that the i ERFIS modification did not contribute to the valve failure event. The l remaining three operational ERFIS monitoring points are connected to the reactor vessel narrow range water level instrumentatio1. The ERFIS printout i from these vessel level monitoring points was utilized by the licensee to - explain why the High Pressure Coolant Injection (HPCI) system did not automatically initiate following a January 5, 1987, scram and low level "2" initiation of other ESF equipment. The ERFIS information indicated that the water level just "brushed" the low level "2" setpoint, and due to allowable , tolerances in initiation setpoints, only some of the low level "2" ESF actuations occurred.
! In this particular event involving the four PCIS valves, the ERFIS information was not retrievable. When fully operational in mid-1988, the ERFIS system " information will be retrievable for a minimum of 14 hours following an event.
In the present testing status, however, the ERFIS information retrieval period varies, and is much less than 14 hours.
If information is not obtained within the existing retrieval period, the system will print over itself, erasing the previous data.
On the morning of January 2,1988, the existing retrieval ' period was only 52 minutes.
Since operators were not trained on ERFIS data i retrieval and the ERFIS personnel were not called in within 52 minutes, the
information was lost and could not be utilized to verify the automatic valve closure signal.
The scram occurred at 0018 but the ERFIS personnel were not contacted until 0230 and did not arrive on-site until approximately 0310.
Attachment 1 of Operating Instruction 01-22, Post Trip Investigation, requires
obtaining ERFIS traces from Technical Support if available.
The STA who was , assigned to complete Attachment I following the scram indicated he did not know l
Appendix 7 l r
_.
, who to contact from Technical Support, particularly at that time of the morning and skipped over this step of the procedure.
The STA was apparently unaware of an Operations memorandum requesting notification of ERFIS personnel within 60 , ' minutes following a reactor trip.
This memorandum includes the names and telephone numbers of the Technical Support staff to be contacted.
Instead of being attached to 01-22, however, the memorandum was tied to Administrative r Instruction AI-84, Scram Incident Investigation Team (SIIT).. Since AI-84 did not require a SIIT team for every scram and the scram team was not onsite until nearly three hours after the event, the memorandum did not accomplish the l intended function.
The ERFIS system was not fully operational or turned over at the time of this event. The licensee commitment is to have the system fully operational within e three months of the end of this refueling outage or about July 22, 1988. On the other hand, the system was in operation the morning of the event, and the
information would have been valuable to the event investigation.
, The licensee indicated that several changes would be made to ensure that the i.
ERFIS information would be retrievable following any future unit trip. AI-84 will be revised to require SIIT team actuation following every unit trip.
Since ERFIS personnel are assigned to the SIIT team, this should help ensure ! timely data retrieval.
In addition, the licensee planned to install a computer l terminal for ERFIS in the control room the week of January 12, 1988. This ' terminal will allow operators to determine the available ERFIS data retrieval time following a unit trip and then to stop the data gathering in time to i prevent system print-over.
These measures should help ensure retrievability of ' available ERFIS post trip data until the system is fully operational with a 14 i hour data capability.
! i I I ! ! I ! l ! ! ! I I
! l
1 ! i i
Appendix 7 ! !
i ! r - . - - -,. -,__. - -. _ - _. ..-__.,,,..-. .. - ., - . ... }}