ML16342D875
| ML16342D875 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/13/1997 |
| From: | Richards S NRC (Affiliation Not Assigned) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| Shared Package | |
| ML16342D876 | List: |
| References | |
| 50-275-97-202, 50-323-97-202, GL-89-13, NUDOCS 9712030146 | |
| Download: ML16342D875 (8) | |
See also: IR 05000275/1997202
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 2055&4001
November
13,
1997
Mr. Gregory M. Rueger, Senior Vice President
and General Manager
Pacific Gas and Electric Company
Nuclear Power Generation, NB9
P.O. Box 770000
San Francisco, California 94177
SUBJECT:
DIABLOCANYON UNITS 1 8 2, DESIGN INSPECTION (NRC INSPECTION
REPORT NOS. 50-275/97-202 AND 50-323/97-202)
Dear Mr. Rueger:
From August 4 through September
11, 1997, the staff of the U.S. Nuclear Regulatory
Commission (NRC), Office of Nuclear Reactor Regulation (NRR), Special Inspection Branch,
performed a design inspection at your Diablo Canyon Facility. This inspection reviewed the
design of the auxiliary salt water (ASW) and the containment heat removal systems.
The
containment heat removal system consisted of the containment spray (CS) system and
containment fan cooler unit (CFCU) and their support systems.
The purpose of the inspection
was to evaluate the capability of the selected systems to perform the safety functions required by
their design bases, the adherence of the systems to their design and licensing bases,
and the
consistency of the as-built configuration and system operations with the updated final safety
analysis report (UFSAR).
The findings of the inspection were discussed
during a public exit meeting on September
11,
1997, and are presented
in the enclosed report.
Overall, the team determined that the systems
are capable of performing their safety functions.
However, two issues identified may represent
potential unreviewed safety questions and an additional NRC evaluation is ongoing.
One issue
involves the single failure design of the CCW, ASW, and the residual heat removal (RHR)
systems.
Because of the design of the electrical distribution system, these systems are operated
with both trains cross-tied.
The resultant single train systems are vulnerable to passive failure
when cross-tied and to active failures when the trains are split. The second issue involves the
availability of the containment spray function during containment recirculation.
Both issues were previously identified and evaluated by Pacific Gas and Electric Company
(PG8E) staff. The evaluations resulted in compensatory'administrative
actions, which involved
changing emergency operating procedures
and assignment of manual functions to operating and
emergency response
staff.
Issues were identified with the current ASW pump testing method that results in pump and heat
exchanger unavailability. PG&E staff are pursuing changes to the current test method to improve
system availability..Additionally, the ASW system supply path from the demusseling
line is
credited in the UFSAR since the single ASW intake bay screen is not seismically qualified.
However, this alternate supply line is not being maintained or tested.
PG8 E's
response
to Generic Letter 89-13, "Service Water System Problems Affecting Safety-Related
Equipment" and its actions to implement the maintenance
rule did not resolve this issue.
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Mr. G. M. Rueger
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Some design calculation weaknesses
were identified, although they did not affect the overall
results of the calculations.
They involved updating and control of calculations, and the use of
nonconservative assumptions.
In addition, the team identified discrepancies
and inconsistencies
in the UFSAR, procedures,
design criteria memorandum, calculations, drawings, and other
documents.
Please provide a schedule, within 60 days, detailing your plans to complete the corrective actions
for the open items listed in Appendix A to the enclosed report. This schedule willenable the
NRC staff to plan for the reinspection and closeout of these items.
"As with all NRC inspections, we expect that your staff willevaluate the applicability of the results
and specific findings of this inspection to other systems and components throughout the plant.
In
addition, please evaluate the inspection findings, both specific and programmatic, against your
response to NRC's request (October 9, 1996) for information pursuant to 10 CFR 50.54(f)
regarding adequacy and availability of design bases information.
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In accordarice with 10 CFR 2.790(a), a copy of this letter and the enclosure will be placed in the
NRC Pdiblic Document Room, where they willbe made available to the public, unless yo'u notify
this office by telephone within 10 days of the date of this letter and submit a written application to
withhold the information contained therein.
Such application must be consistent with the
requirements of 10 CFR 2.790(b)(1). Any enforcement action resulting from this inspection will
be handled by NRC Region IVvia separate
correspondence.
Should you have any questions
'oncerning
the enclosed inspection report, please contact the project manager, Mr. S.
D. Bloom
at (301) 415-1313, or the inspection team leader, Mr. M. W. Branch, at (301) 415-1279.
Sincerely,
Ozlcinal signed. lgc
Stuart A. Richards, Chief
Events Assessment,
Generic Communications,
and Special Inspection Branch
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Docket Nos.: 50-275 and 50-323
Enclosure:
Inspection Report 50-275/97-202
and 50-323/97-202
cc w/enclosure:
See next page
- SEE PREVIOUS CONCURRENCE
DOCUMENT NAME: G:iDC97202.RPT
To receive a copy ofthis document, Indicate in the boiu "C" = Copy without enclosures "E" = Copy with enclosures "N"= No
OFFICE
NAME
DATE
PSIB:DISP*
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11/06/97
PSIB:DISP*
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11/06/97
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Mr. Gregory M. Rueger
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CC:
NRC Resident Inspector
Diablo Canyon Nuclear Power Plant
c/o U.S. Nuclear Regulatory Commission
P. O. Box 369
Avila Beach, California 93424
Regional Administrator, Region IV
U.S. Nuclear Regulatory Commission
Harris Tower 8 Pavillion
611 Ryan Plaza Drive, Suite 400
Arlington, Texas
76011-8064-
Dr. Richard Ferguson, Energy Chair
1100 11th Street, Suite 311
Sacramento,
California 95814
Christopher J. Warner, Esq.
Pacific Gas 8 Electric Company
.
Post Office Box 7442
San Francisco, California 94120
Ms. Nancy Culver
San Luis Obispo
Mothers for Peace
P. O. Box 164
Pismo Beach, California 93448
Mr. Robert P. Powers
Vice President and Plant Manager
Diablo Canyon Nuclear Power Plant
P. O. Box 56
Avila Beach, California 93424
Chairman
San Luis Obispo County Board of
Supervisors
Room 370
County Government Center
San Luis Obispo, California 93408
Telegram-Tribune
ATTN: Managing Editor
1321 Johnson Avenue
P.O. Box 112
San Luis Obispo, California 93406
Mr. Truman Burns
Mr. Robert Kinosian
California Public Utilities Commission
505 Van Ness, Room 4102
San Francisco, California 94102
Mr. Steve Hsu
Radiologic Health Branch
State Department of Health Services
Post Office Box 942732
Sacramento,
California 94232
Diablo Canyon Independent Safety
Committee
ATTN: Robert R. Wellington, Esq.
Legal Counsel
857 Cass Street, Suite D
Monterey, California 93940
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DISTRIBUTION:
/'Docket'Files,50-275,.&',50-323
PUBLIC
PECB R/F
J. Roe, NRR
Inspection Team
M. Branch NRR
S. Bloom, NRR
W. Bateman, NRR
E. Peyton
D. Norkin, NRR
S. Richards, NRR
E. Adensam, NRR
C. E. Rossi, AEOD
D. Proulx, SRI
H. Miller, Rl
L. Reyes,
Rll
A. B. Beach, Rll-
E. Merschoff, RIV
C. Hehl, Rl
J. Wiggins, Rl
A. R. Blough, Rl
J. Johnson,
Rll
J. Jaudon, Rll
D. Collins, Rll
J. Caldwell, Rill
G. Grant, Rill
T. Gwynn, RIV
A. Howell, RIV
R. Scarano, RIV
ACRS (3),
OGC (3)
1S Distribution
L. Marsh, BPBiB, NRR
M. Cunningham, PRAB, RES
J. Rosenthal,
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