ML16341E845
| ML16341E845 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/25/1988 |
| From: | Rood H Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML16341E846 | List: |
| References | |
| TAC-55305, TAC-68049, NUDOCS 8811140063 | |
| Download: ML16341E845 (30) | |
Text
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DOCKET NOS.:
50-275 and 50-323 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 October 25, 1988 APPLICANT:
FACILITY:
SUBJECT:
PACIFIC GAS AND ELECTRIC COMPANY (PG&E)
DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1
AND 2
SUMMARY
OF MARCH 28-30, 1988 PLANT WALKDOWN BY THE NRC STAFF OF AS PART OF ITS REVIEW OF PROBABILISTIC RISK ASSESSMENT, DIABLO CANYON LONG TERM SEISMIC PROGRAM (LTSP)
(TAC NOS.
55305 AND 68049)
On March 28-30, 1988 the NRC staff and its consultants conducted a "walkdown" of the Diablo Canyon Nuclear Power Plant as part of the on-going review of the probabilistic risk assessment (PRA) study being performed the plant.
PG&E and its consultants accompanied the staff on the walkdown.
The agenda for the walkdown is given in Attachment l.
Attendees at the pre-walkdown entrance meeting on March 28, 1988 are given in Attachment 2.
Because Unit 1 was down for a refueling outage, it was possible to open several electrical cabinets to examine anchorages and mounting of components inside the cabinets (specific cabinets of interest had been identified by the NRC staff prior to the walkdown).
It was also possible to enter containment and observe several components that could not have been observed during power operation.
In order to facilitate the walkdown, the attendees were divided into four
- groups, as is shown in Attachment 3.
The specific components observed and the location of each is given in Attachment 4.
The selection of systems and components to be observed was established prior to the walkdown based on discussions between the NRC staff and PG&E.
The plant walkdown covered four different areas of the plant, identified as Tours 1 through 4 in Attachment 4.
Also given in Attachment 4 is the starting location for each of the four groups for each tour.
Each group observed all of the components associated with each tour, but start'ed at different locations as indicated in Attachment 4.
P~e't On March 30, 1988; an exit meeting was held, and the NRC staff and its consultants dis'cussed their observations and comments with PG&E.
These observations and. comments, along with PG&E comments where applicable, are given in Attachment 5.
The attendees at the exit meeting are given in Attachment 6.
Detailed comments by the attending NRC consultants are given in Attachments 7,
8, and 9.
In addition to the plant walkdown, at the NRC staff's request, PG&E conducted a
simulator exercise.
The exercise was conducted by two PG8E employees, rather than a full operating crew.
The simulated accident scenario was not meant to POR
+Do 88i025 88glg~oo+>
P cI Osoog27~
)W October 25, 1988 be a detailed investigation of operator actions in an accident.
- Rather, the purpose of the exercise was to allow the NRC staff and its consultants to get a
feel for the type of information available in the control room and the role of emergency procedures in an accident.
The specific accident scenario simulated was selected by NRC consultants from BNL.
After the simulator exercise was conducted, the PGSE operators explained how they interpreted various information, what actions they took based on this information, and how they used specific emergency procedures..
The NRC staff stated that the exercise was very informative and wi 11 facilitate review of specific operator actions and emergency procedures found to be important by the PRA.
PGSE also provided information about the structure of operating procedures, with emphasis on emergency procedures.
In summary, the NRC staff and its consultants found the walkdown to be very well planned and coordinated by PGSE, and therefore very efficient and informative for the staff and consultants.
Attachments:
As stated Harry Rood, Senior Project Manager Project Directorate V
Division of Reactor Projects - III, IV, V and Special Projects cc: w/enclosures See next page
1
October 25, 1988 be a detailed investigation of operator actions in an accident.
- Rather, the purpose of the exercise was to allow the NRC staff and its consultants to get a
feel for the type of information available in the control room and the role of emergency procedures in an accident.
The specific accident scenario simulated was selected by NRC consultants from BNL.
After the simulator exercise was conducted, the PGSE operators explained how they interpreted various information, what actions they took based on this information, and how they used specific emergency procedures.
The NRC staff stated that the exercise was very informative and will facilitate review of specific operator actions and emergency procedures found to be important by the PRA.
PGSE also provided information about the structure of operating procedures, with emphasis on emergency procedures.
In summary, the NRC staff and its consultants found the walkdown to be very well planned and coordinated by PGSE, and therefore very efficient and informative, for the staff and consultants.
October 25, 1988 Harry Rood, Senior Project Nanager Project Directorate V
Division of Reactor Projects - III, IV, V and Special Projects Attachments:
As stated cc: w/enclosures See next page DISTRIBUTION
~NRC Im Local PDRs PD5 Reading GKnighton HRood OGC EJordan BGrimes NRC Participants ACRS (10)
MJohnson (Region V)
DRSP/PD5 D
- PD5 HRood:dr hton 10/gg/88 0/
/88 OFFICIAL RECORD COPY
f J
Mr. J.
D. Shiffer Pacific Gas and Electric Company Diablo Canyon CC:
Richard F. Locke, Esq.
Pacific Gas 5 Electric Company Post Office Box 7442 San Francisco, California 94120 NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach, California 93424 Janice E. Kerr, Esq.
California Public Utilities Commission 350 McAllister Street San Francisco, California 94102 Ms. Sandra A. Silver 660 Granite Creek Road Santa Cruz, California 95065 Mr.
W. C. Gangloff Westinghouse Electric Corporation P. 0.
Box 355 Pittsburgh, Pennsylvania 15230 Managing Editor San Luis Obispo County Telegram Tribune 1321 Johnson Avenue P. 0.
Box 112 San Luis Obispo, California 93406 Mr. Leland M. Gustafson, Manager Federal Relations Pacific Gas and Electric Company 1726 M Street, N.
W.
Washington, DC 20036-4502 Dian M. Grueneich Marcia Preston Law Office of Dian M. Grueneich 380 Hayes Street, Suite 4
San Francisco, California 94102 Mr. Dick Blakenburg Editor
& Co-Publisher South County Publishing Company P. 0.
Box 460 Arroyo Grande, California 93420 Bruce Norton, Esq.
c/o Richard F. Locke, Esq.
Pacific Gas and Electric Company Post Office Box 7442 San Francisco, California 94120 Dr. R. B. Ferguson Sierra Club - Santa Lucia Chapter Rocky Canyon Star Route Creston, California 93432 Chairman San Luis Obispo County Board of Supervisors Room 270 County Government Center San L'uis Obispo, California 93408 Director Energy Facilities Siting Division Energy Resources Conservation and Development Commission 1516 9th Street Sacramento, California 95814 Ms. Jacquelyn Wheeler 3033 Barranca Court San Luis Obispo, California 93401
Pacific Gas I%
E 1ectri c Company Diablo Canyon CC:
Ns. Laurie NcDermott, Coordinator Consumers Organized for Defense of Environmental Safety 731 Pacific Street, Suite 42 San Luis Obispo, California 93401 Mr. Jack NcGurk, Acting Chief Radiological Health Branch State Department of Health Services 714 P Street, Office Building P8 Sacramento, California 95814 Regional Administrator, Region V
U.S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596 Ms.
Nancy Culver, 192 Luneta Street San Luis Obispo, California 93401 President California Public Utilities Commission California State Building 350 McAllister Street San Francisco, California 94102 Michael N. Strumwasser, Esq.
Special 'Assistant Attorney General State of California Department of Justice 3580 Wi lshire Boulevard, Room 800 Los Angeles, California 90010
cl
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MONDAY MARCH 28, 1988 8:30 a.m. - 11:30 a.m.
Room 109, Training Building ll:30 a.m. - 12:00 noon Room 109, Training Building 12:00 p.m. - 12:30 p.m.
12:30 noon - 1:00 p.m.
Security Building Attachment 1
NRC/PGSE PLANT WALKDOWN MARCH 28-30, 1988 Radiation Protection Training and Whole Body Counts Introduction Lunch (Training Bldg.
Lunchroom)
Security Check-in 1:00 p.m. - 4:00 p.m.
Turbine Building, Auxiliary Building 4:00 p.m. - 6:00 p.m.
TUESDAY MARCH 29, 1988 8:00 a.m. - 8:15 a.m.
. Security Building 8:15 'a.m. - 12:30 p.m.
Auxiliary Building, Penetration
- Areas, Outdoor Storage Tanks 12:30 p.m. - 1:00 p.m.
Cafeteria 1:00 p.m. - 4:00 p.m.
Containment 4:00 p.m. - 5:00 p.m.
~ >>
5:00 p.m. - 5:30",p.m.
Room 109, Training Building Visit Non-Radiologically Controlled Areas (Tour 1)*
Operations discussion (Training Bldg. 109)
Security Check-in Visit Radiologically Controlled Areas (Tour 2)*
Lunch (Canyon Cafe)
Visit Inside Containment (Tour 3)*
Visit Intake Structure (Tour 4)*
.... Intake Structure.
Meeting
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'4 WEDNESDAY MARCH 30, 1988 8:00 a.m. - 9:30 a.m.
Room 109, Training Building 9:30 a.m. - 12:00 noon 12:00 noon - 12:30 p.m.
Meeting Plant Walkdown, as necessary Lunch (Training Bldg.
Lunchroom) 1:00 p.m. - 2:00 p.m.
Exit meeting
- See ttac ment 4 or explanation of different tours.
ATTACHMENT 2 ATTENDEES 03/28/88 Entrance Meeting for the Plant PRA Walkdown Diablo Canyon Long Term Seismic Program K.
P.
G.
K.
M.
G.
J.
E.
N.
T.
R.
M.
J.
T.
M.
P.
D.
P.
J.
D.
J.
M.
B.
B.
D.
M.
S.
W.
NAME Aliefendi eg lu Antiochos Bagchi Bandyopadhyay P.
Bohn Bozoki
- 0. Bradfute
'Chelliah Chokshi L. Grebel Heinberg Hug J.
Johnson R. Kipp R.
Khan Kohut E. Naaf Narbut Nystrom Ovadia Portney K. Ravindra Sarkar D. Smith Tateosian Tresler D. Wilson Wogsland ORGANIZATION BNL (NRC)
Sandia (NRC)
BNL (NRC)
NRC/NRR/PDV NRC/RES/DRAA NRC/RES/PRAB PG&E PG&E REG COMA/NLPP EQE NRC)
NTS PG&E)
PG&E NRC/Resident Inspector PG&E/ELECT WPL PG&E PG&E EQE (NRC)
Bechtel (PG&E)
r
Attachment 3
Visitors List
~Grou 1
ESCORT:
Steve Milson G. Bagchi K. Bandyopadhyay J. Johnson D. Ovadia M. Khan
~Grou 2
PG&E NRC BNL/NRC Consultant E(E/NRC Consultant PG&E PG&E ESCORT:
~Grou 3
ESCORT:
~Grou 3A ESCORT:
Bruce Smith N. Chokshi M. Bohn R. Ravindra B. Sarkar T. Kipp David Tateosian E. Chelliah K. Aliefendioglu G. Bozoki P., Kohut M. Tresler M. Hug J. Bradfute P. Antichos J. Portney PG&E NRC Sandia/NRC Consultant E(E/NRC Consultant PG&E NTS/PG&E Consultant PG&E NRC BNL BNL BNL PG&E
'G&E NRC PG&E PG&E
Attachment 4
Tour 1 - Turbine Building and auxiliary building.
non radiological controlled areas of the Tour Sequence:
Group 1
Group 2
Group 3 + 3A a ~
b.
C.
d.
e.
Location 85'evel
-Diesel fuel oil transfer
- system, CCW heat exchanger, instrument air receivers, Diesel Generator 1-2 control cabinet and excitation cubicle 119'evel - Vital 4 kV switchgear (Potential transformer drawer and a 4 kV cubicle)
'40'evel
-Control Room (back of a vertical board and PANS panel),
SSPS cabinets 128'evel - Auxiliary relay racks, safeguards relay rack, protection rack, control room pressurization relay panel 115'evel
- Instrument inverter IY-14, battery
- charger, DC switchgear, batteries, instrument inverters, battery chargers 100'evel
-Hot shutdown panel, 480 v NCC, switchgear, and transformer Tour 2 - Radiologically controlled areas of the auxiliary building Tour Sequence:
Group 1
Group 2
Group 3 + 3A Tour 3 - containment a ~
b.
c ~
d.
e.
Location 64'evel -
RHR pump room 73'evel - CCPs and RHR HX 85'evel - Safety injection pumps 100'evel - Auxiliary feedwater pumps 115'evel - Penetration Area (GE-GW) Outside Tanks (RWST,
Tour Sequence:
Group 1
Group.
2 Group 3+3A
'a ~
b.c:
d.
e.
Location RHR suction sump RHR yalyes.(701 and 8702 Reactor Coolant Pumps'ressurizer PORV, block valves, CCW to CFCUs Accumulator check valves CCW system (CFCUs)
P
Tour 4 - Intake Structure Tour Sequence:
Groups I and 2
Groups 3 and 3A Location a.
Intake gates b.
ASM Pumps Note:
Each group visited all of the above locations but started at different designated location.
h
Attachment 5
Comments and Observations Discussed at Exit Neetin On Narch 30, 1988 A question was raised whether the loss of off-site power (LOSP) frequencies included earthquake (earthquakes in the region of interest, not specifically at plant site) induced losses?
PGSE indicated that PGLE system data was used for the LOSP frequencies which included earthquake induced LOSP events.
(2)
(3)
(4)
(5)
During the walk-down it was observed by some members that there may be physical differences between units 1 and 2 auxiliary feed water (AFM) turbine supports (most of the groups visited Unit 2 AFM pumps);
- however, the PG5E staff pointed out that the differences are in the missile shields around pumps because of maintenance access considerations and, basically, there are ro differences in pumps or supports.
il A discussion was held regarding simultaneous test/maintenance schedule for components affected by LOSP initiators.
The PG&E staff briefly discussed the administrative procedure for control of removal of equipment from service.
It was further indicated.that test/maintenance data base has been reflected in the PRA. It is expected that these issues will be further explored during the detailed review of the PRA.
Based on a walk-down observation, an issue was raised regarding how the
.security system (access governed by a card reader) will affect the accessibility to equipments during earthquake.
The PGKE staff indicated that there are emergency overide keys.
However, further examination of this issue is required to verify that access required for human intervention following an earthquake initiated event is not hindered.
A question was raised regarding the consideration of seismic event in the maintenance procedure (e.g. erection of temporary structures such as scaffolding).
The PGLE staff indicated that there is a procedure to address seismic induced systems interactions (SIP) which considers all modes of operations.
(6) "It was"noted that fire conduits: are. not separ ated by. physical separation but protected by conduit walls.
The 'PGSE staff indicated that in the same fire zone (Appendix R zones) pyrochem was used for the fire protection.
In some areas, the existence of fire detection was observed but not specific suppression systems was seen.
A question was raised regarding leak testing procedure for RHR suction NOVs. It was indicated that these valves are leak tested at outages, and test lines were shown to the staff on a drawing.
However, confirmation of the leak test procedure, acceptance criteria and test interval and
applicable reference to the licensee's in service test program should be provided.
It was observed that the Diesel Generator Contral Panel is mounted on isolator shims.
As these shims relax, bolts may loose pre-tension and may affect dynamic charcter istics of the panel.
This item meeds to be addressed in the fragility calculations with applicable documentation from seismic tests.
(9)
Safety related conduits were noted to traverse (vertically) the seismic joints between the anxiliary.and turbine buildings.
This issue needs further examination, and should be further investigated by PGImE.
The support system for SSPS cabinet for A - train was clearly visible (clip angles welded to embedded plates),
- however, the support system for B-train cabinets was not clearly observable from the outside or inside of the cabinet.
The PGIIE staff further investigated this issue and took photographs to show details of anchorage system.
These photographs were shown at the exit meeting, and it appears that anchorage system for both cabinets is similar (but not identical).
(12)
During the walk-down, it was difficult to see the transformer coil supports for the CV potential transformer, photographs of the support systems were shown at the exit meeting.
These photographs will serve to clarify assumptions used regarding supports in the fragility calculations.
It was requested that fragility calculation for the CCW Heat Exchanger be provided when they are completed.
Additioral RHR heat exchanger calculations (based on the staff comments made during the fragility audit of February 25, 19SS) were discussed briefly.
The staff will further review these calculations at a later date.
(15)
To supplement the previously provided calculations, it was requested that a sketch indicating the weakest element which governs the fragility of the main control board be provided.
It was observed that the safeguard relay/cabinets were anchored by plug welds only.
Considering the inferior reliability of these welds, critical examination of fragility calculations for this component may. be necessary.
Similar considerations may also apply to the DC Switchgear lEL.115')'hich is supported;by four fillet welds only.
It was noted that the 414 potential transformers and switchgears are very close to each other and potential seismic induced interactions between them need to be addressed.
This concern may also apply to other similar components.
Issue of the as-built verification of anchorages was briefly discussed and it was indicated that this information is available.
\\
'A (18) It was noted that. in the RHR pumproom, a monorail hoist was parked properly but its chain was hanging loose.
The PGSE indicated that its examination of the area did not identify this chain as a source for impact on tubing, and generically, such issues are addressed in the seismic induced systems interaction procedure (SIP, see item 5 above).
( 19) For the turbine driven auxiliary feed water pump some of the feed water line valves operators were observed to be either resting on supports or next to supports steel (Photographs were shown to the PGSE).
Possible interactions for these situations need to be addressed.
(20) It was noted that the turbine drive for the auxiliary feed pump can be tripped during earthquake.
Such trips will require manual resetting at the pump site.
This issue needs to be addressed either procedurally or explored further to determine the likelihood of tripping by the seismic evert.
(21)
Some mineral deposits were noted on the outside of some of the tanks.
Source and reasons for these deposits need to be identified.
(22) It was observed that some of the safety systems have been exempted at the Diablo Canyon from the two over one seismic considerations (e.g. control room pressurization system).
PGKE indicated that no credit for such systems was taken in the PRA.
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ATTACHMENT 6 ATTENDEES 03/30/88 Exit Meeting for the Plant PRA Walkdown Diablo Canyon Long Term Seismic Program NAME K. Aliefendieglu P. Antiochos G. Bagchi K. Bandyopadhyay G. Bozoki
- 0. Bradfute N. Chokshi S. Fridley M. Hug J. J.
Johnson T.
R. Kipp M. R.
Khan P.
Kohut P.
Narbut D. Ovadia J. Portney M. K. Ravindra B. Sarkar B. D. Smith D. Tateosian M. Tres 1er W. H.
Wa 1 lace ORGANIZATION BNL (NRC)
BNL (NRC NRC/NRR/PDV NRC/RES/PRAB PG&E REG COMA/NLPP EQE (NRC)
NTS (PG&E)
NRC/Resident Inspector PG&E PG&E EQE (NRC)
Bechtel (PG&E)
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