ML16341D943
| ML16341D943 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/26/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16341D944 | List: |
| References | |
| TAC-59802, TAC-59803, NUDOCS 8611050015 | |
| Download: ML16341D943 (8) | |
See also: IR 05000275/1985036
Text
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UNITED STATES
NUCLEAR REGULATORY COMMIS ION
WASHINGTON, D. C. 20555
SAFETY EVALUATION BY THE OFFICE
OF NUCLEAR REACTOR
REGULATION
RELATED TO FIRE
DAMPER INSTALLATION
PACIFIC GAS AND ELECTRIC COMPANY
DIABLO CANYON NUCLEAR POWER PLANT, UNITS I AND 2
DOCKET NOS.
50-275
AND 50-323
I.
INTRODUCTION
In November
1985,
an Appendix
R team inspection
was conducted
by the
NRC
staff at the Diablo Canyon Nuclear
Power Plant, Units
1 and
2 (Ref. I).
During the inspection,
the team observed that in a number of plant locations
fire damper assemblies
were not installed in accordance
with the manufacturer's
installation requirements.
This finding was
documented
in Region
V Inspection
Report Nos.
50-275/85-36
and 50-323/85-04
as
Unresolved
Item 50-275/85-36-04
(Ref. I).
The
NRC staff met with representatives
of Pacific
Gas
and Electric Company
(PG&E), the licensee for the Diablo Canyon Plant,
on March 20,
1986 to discuss
the fire damper installations in further detail
and requested
additional
information (Ref. 2).
By letter dated
May 13,
1986, the licensee
provided its
response
to this issue
(Ref. 3).
An industry-wide concern that many fire rated
damper assemblies
had not been
installed in accordance
with manufacturer's
recommendations
had
been identified
in Bechtel
Problem Alert M-82-06 and
NRC IE Information Notice 83-69.
To
determine if such situation existed at the Diablo Canyon Plant, the licensee
conducted
an examination of all as-built installation details.
This examination
indicated that the manufacturer's
installation instructions
were not explicitly
adhered to for certain fire damper assemblies.
In its response
to the above
examination,
the licensee
categori'zed
these installation discrepancies
into
the following four groups:
1.
Damper assemblies
installed within ducts protected
by a fire rated
barrier material.
2.
Damper assemblies
installed in concrete walls with less
than the
manufacturer's
specified
gap between the damper
assembly
and wall.
3.
Damper assemblies
installed in stud walls and suspended
ceilings with
less that the manufacturer's
specified
gap between the damper assembly
and wall or ceiling opening.
4.
Damper assemblies
in areas without safe
shutdown
components
installed
at variance with the manufacturer's
recommendations.
8611050015
861026
ADOCK 05000275
In accordance
with its procedures
for evaluating potential
nonconformances,
the licensee
stated that two nonconformance
reports
were generated
to address
the cause
and safety significance of the identified discrepancies.
On the
basis of its review, the licensee
determined that the variances
from the
manufacturer's
recommendations
would not prevent the safe
shutdown of the
plant.
II.
EVALUATION
GROUP I:
Fire Dampers in Fire Protected
Ducts/Sleeves
In Attachment
A to the
May 13,
1986 letter, the licensee identified 42 fire
assemblies
installed outside the plane of the wall.
The ductwork and
containing these
damper assemblies
are protected
by an approved material
that affords
a I-hour fire resistance
to the ducts
and damper
assembly
By letter dated
November
13,
1978 (Ref. 4), the licensee
committed to protect
the ducts in several
rooms in this manner.
In Supplement
8 to the Diablo
Canyon, Units I and
2 Safety Evaluation Report,
the staff found these fire
damper installations
acceptable
(Ref. 5).
As stated
(Ref.
6 ), if a fire area
boundary
was described
in the fire hazards
analysis
and
was evaluated
and accepted
in a published Safety Evaluation,
then the
boundary
remains
acceptable,
and it need not be reviewed
as part of the
licensee's
reanalysis for compliance with Appendix R.
On this basis,
those
fire damper assemblies
that are installed in this manner
and that are
explicitly identified in the licensee's
November
13,
1978 letter, are
acceptable.
However, this approval applies only to those fire damper assemblies
that were
explicitly identified and not to any other assembly.
The staff could not
establish,
on the basis of the licensee's
May 13,
1986 letter, whether or not
each of the
42 damper assemblies
identified in the letter was subject to this
previous staff approval.
Therefore,
the licensee
should review the fire
damper assemblies
and evaluate
those that were not subject to this previous
staff approval in accordance
with Interpretation
4, "Fire Area Boundaries," of
the interpretations
document attached
In accordance
with the Generic Letter,
an additional
licensee
submittal
on these fire damper
assemblies
is not required.
Therefore,
the staff considers
the concerns with
Group I dampers
resolved.
GROUPS
2 and 3:
Fire Dampers in the Plane of the Wall or Ceiling
Fire damper assemblies
in Groups
2 and
3 are installed in the plane of the
wall or ceiling, but with less
than the manufacturer's
specified expansion
gap
between
the damper
assembly
and the wall or ceiling.
In Attachments
B
and
C to the
May 13,
1986 letter (Ref. 3), the licensee identified 43 such
fire damper assemblies.
The licensee
also provided
a summary engineering
A
IP
evaluation for each of the individual dampers.
On the basis of these
evaluations,
the licensee
concluded that the
43 fire damper assemblies
are
acceptable.
In summary,
the licensee
has justified these
damper assemblies
on
one or more of the following basis:
A.
The fire load in each of the fire areas
separated
by the damper
assemblies
yields
an equivalent fire severity less
than the
ASTM E-119
standard
time-temperature fire used to test the fire damper assemblies.
B.
Failure of the dampers
would not adversely affect safe
shutdown
capability because
the dampers
do not- separate
redundant
safe
shutdown
components.
C.
An automatic fire suppression
system
has
been installed
on one or both
sides of the damper assembly.
GROUP 4:
Fire Dampers without Safe Shutdown
Components
The fire damper assemblies
identified above
as
Group
4 dampers
were not
installed to protect the safe
shutdown capability, but to minimize property
damage in the event of fire.
Therefore,
the staff has not evaluated
these
fire damper assemblies.
CONCLUSION:
The staff has
reviewed the licensee's
summary engineering evaluation
and finds
them acceptable.
The staff concurs with the licensee's
assessment
that the
subject fire damper assemblies
provide an adequate
level of fire safety for
the areas
in which they are installed.
In the staff's judgement, modification
of the damper assemblies
would not significantly increase
the level of plant
fire safety.
Use of the fire damper assemblies
identified in the licensee's
May 13,
1986 letter is, therefore,
acceptable.
PRINCIPAL CONTRIBUTOR:
S.
West
1
4
REFERENCES:
1.
U.S. Nuclear Regulatory
Commission,
Region
V Inspection
Report
Nos.
50-275/85-36
and 50-323/85-34,
dated
December
24,
1985, transmitted
by
letter from D. Kirsch
(NRC) to J.
D. Shiffer (PGSE)
by letter dated
December
30,
1985.
2.
3.
U.S. Nuclear Regulatory
Commission,
"Meeting Summary - Fire Protection",
by H. Schierling,
dated April 30,
1986.
Letter from J.
D. Shiffer
(PGSE) to S.
A. Varga
(NRC), "Fire Dampers",
dated
May 13,
1986.
4.
Letter from P.
H. Crane
(PGSE) to J.
F. Stolz
(NRC), dated
November
13,
1978.
5.
6.
U.S. Nuclear Regulatory
Commission,
"Safety Evaluation of the Diablo
Canyon Nuclear
Power Station,
Units
1 and 2", NUREG-0675,
Supplement
8
(SSER-8),
November,
1978.
4
U.S Nuclear Regulatory
Commission,
"Generic Letter 86-10:
Implementation
of Fire Protection
Requirements",
Letter from D.
G. Eisenhut
(NRC) to
Licensees
and Applicants, dated April 24,
1986.
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