ML20155B054
| ML20155B054 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 06/01/1988 |
| From: | Harrell P, Reis T, Westerman T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20155B040 | List: |
| References | |
| 50-285-88-15, NUDOCS 8806130065 | |
| Download: ML20155B054 (26) | |
See also: IR 05000285/1988015
Text
__-___ __- __-
_ - _ _ _ _ _ .- _ -
_ _ _ _
. __ __ - -
- _______
_ _ __ __________ _ _-_____ ____ _ ___ ____ _ __
,
..
',
,.
-
.
.
,
APPENDIX A
,
'
U. S. NUCLEAR REGULATORY COMMISSION
REGION IV
NRC Inspection Report:
50-285/88-15
Operating License:
Docket: -50-285
Licensee: Omaha Public Power District (0 PPD)
1623 Harney Street
Omaha, Nebraska 68102
Facility Name:
Fort Calhoun Station (FCS)
Inspection At:
Inspection Conducted: April 6 - May 13, 1988
Inspectors:
.
d
$[1[N
'
'
P. H. Harrell, Senior Resident Reactor
Date
Inspector
bflfff
'
-
.
T. Reis, Resident Reactor Inspector
Date
A
Approved:
6[
T. F. Westerman, Chief, Reactor project
Date
Section B
Inspection Summary
Inspection Conducted April 6-27, 1988 (Report 50-285/88-15)
Areas Inspected:
Routine, unannounced inspection incicding followup on the
status of the instrument air accumulator assemblies and followup on an onsite
event.
Results: Within the two areas inspected, two potential violations (failure to
meet the established design criteria for the instrument air system,
paragraph 3; and the apparent failure to maintain containment integrity,
paragraph 4) were identified.
8806130065 880601
ADOCK0500g5
0
, , , - ,
. ,
.. .
..-
- , _ . . _ .
.__-.
,- .-_ - .
. - . - - ..
. _ . _ _ -
._______- _____.
'
-,
,,
'
. .
,
.
.
'
,
DETAILS
1.
Persons Contacted
- R. Andrews, Division Manager, Nuclear Production
- W. Gates, Plant Manager
- M. Core, Supervisor, Maintenance
- J. Fisicaro, Supervisor, Nuclear Regulatory and Industry Affairs
- J. Gasper, Manager, Administrative and Training Services
- R. Jaworski, Section Manager, Technical Services
- R. Kellog, Acting Manager, Technical Support
- T. Patterson, Supervisor, Technical
- S. Swearngin, System Engineer, Instrument Air System
- C. Simmons, Plant Licensing Engineer
- S. Trausch, Supervisor, Operations
[
- K. Morris, Division Manager, Quality Assurance and Regulatory Affairs
p
- J. O'Connor, Plant Engineer
l
- A. Richard, Manager, Quality Assurance
l
- R. Scofield, Supervisor, Outage Projects
- Denotes attendance at the monthly exit interview.
The NRC inspector also contacted other plant personnel, including
operators, technicians, and administrative personnel.
2.
Plant Status
The reactor was operating at 100 percent power during this inspection
period. The next refueling outage is sched;1ed for September 1988.
3.
Followup'on the Status of the Instrument Air Accumulator Assemblies
This inspection was performed to follow-up on licensee activities for
testing of accumulator assemblies for air-operated, safety-related valves.
This inspection was focused to review the status of the accumulator
assemblies for valves required to function by changing position during
various design basis accidents (e.g., locs-of-coolant accident, seismic
event, er steam generator tube rupture) that require plant shutdown.
Each accumulator assembly is comprised of a check valve, accumulator,
valve operator, and interconnecting tubing.
The valve operator is
normally repositioned by using air pressure from the instrument air
system.
The instrument air system is a nonseismically installed system
supplied by three nonvital air compressors.
The accumulator assemblies
were designed and installed to provide an air pressure storage system to
reposition the valves in the event the normal air supply is lost. The
accumulator assemblies are safety grade installations designed to fulfill
their intended safety function following a design basis accident (DBA).
In the recent past, NRC inspectors have reviewed the installation of the
accumulator assemblies to verify that the assemblies were designed and
installed in accordance with the appropriate regulatory requirements.
l
l
-
.
_
=_-
_ ______._________- - __ ______ - ___________-_ _ _
-
.
.
..
'
.
, .
.,
.
.
2
-
.
Each of the inspections and reviews performed by NRC personnel is
discussed below:
a.
-During a safety system outage modification inspection (SSOMI)
performed by NRC Headquarters personnel in September and October
1985, the SS0MI team ,dentified an apparent deficiency related to the
accumulator assemblies for the component cooling water supply to the
reactor coolant pump containment isolation valves, HCV-4388 and
HCV-4380. The details of the deficiency are documented as
Deficiency 2.2-1 in NRC Inspection Report 50-285/85-22, issued on
January 21, 1986.
The deficiency noted that the licensee had altered the hardware
installation so Valves HCV-438B and HCV-438D were changed from a fail
closed to a fail open mode.
Because the "failed" position was
changed, the licensee relied on the air pressure in the accumulator
assembly to shut the valves in the event containment isolation was
required. The SSOMI team noted that the calculation associated with
Modification MR-FC-81-218, the design document that changed HCV-438B
and HCV-4380 frcm fail closed to fail open valves, assumed zero
leakage from the accumulator assen;bly, and therefore concluded that
the size of the accumulator was sufficient to hold HCV-438B and
HCV-438D shut until an operations individual could manually shut the
valves. The SSOMI team disagreed with the no-leakage assumption made
in the calculation because the licensee had not performed any testing
to determine the actual leakage from the accumulator assembly.
On April 15, 1986, the licensee provided a response to
Deficiency 2.2-1.
The response stated that, "although the system
leakage was not quantified in the original calculation, the amount of
allowable leakage can be inferred from the margin between the minimum
pressure required and the system pressure following actuation of the
,
!
valve. The amount of margin in the original calculation was such
that system leakage was a moot point.
The revised preliminary
calculation, using the correct parameters, indicates that the margin
is approximately 40 percent." The response also stated that a new
revised calculation would be completed and placed in the file.
On August 7, 1986, a working meeting was held in the Region IV
offices between the NRC and the licensee. At this meeting, the
l
correutive action programs provided by the licensee in the response
dated April 15, 1986, were discussed and it was determined that the
response to Deficiency 2.2-1 was inadequate. As a result of the
,
l
discussions, the licensee agreed to submit a revised response to the
l
deficiency.
i
On April 10, 1987, the licensee submitted a revised response.
The
revised response stated that the licensee had initiated a program to
l
l
l
l
u
.
..
'.
'
l
l
3
l
..
,
provide comprehensive evaluation of systems which depend on
accumulator assemblies for proper functioning during an accident
event. The revised response stated that the program would include
the following elements.
Identify CQE (safety-related) valve operators that are equipped
.
with air accumulators.
Determine the operating criteria of the valve during each
.
applicable postulated accident.
This will include parameters
such as operating pressure and temperature, time duration after
-
an initiating event when valve operation will commence, and the
length of time that the valve operator must function.
Develop criteria for functional testing each valve operator
.
which was identified according to the above criteria.
Develop appropriate surveillance testing to ensure that tne
.
systems continue to function as required.
The revised response stated that at the comp'.etion of the evaluation
described above, a systematic program would be initiated to perform
testing of the installed accumulator assemblies to verify that the
equipment could reliably perform the required accident function. The
revised response also noted that a schedule for completing air
accumulator testing would be provided by August 1987.
On December 23, 1987, the licensee submitted an update of the
previous response for the items identified by the SS0MI team.
In
this updated response, the licensee stated that because of the
unforeseen requirement to perform more extensive evaluations with
respect to the corrective actions, the date for providing the
schedule for completing air accumulator testing has been extended to
July 1988.
Consequently, at the time of this inspection, the
licensee still has yet to submit a schedule for testing the
This item remains open pending submission of the
required schedule as committed by the licensee in its April 10, 1987,
revised response.
(285/8815-01)
Also, in response to Deficiency 2.2-1 identified by the SSOMI team,
'
the licensee issued Operations Support Analysis Report (OSliR) 87-10
dated April 6, 1988, to determine the following:
The valves serviced by an accumulator assembly that are
.
essential to ensure a safe plant shutdown or to mitigate the
consequences of a DBA coincident with the loss of offsite power.
Describe the function of the essential valves and accumulator
.
assembly following a DBA.
_
._
!
.*
.
..
,
,
4
,
-
4
j
.
Evaluate the need to reposition the essential valves following a
.
DBA.
Determine the postaccident oper iting conditions for the
.
essential valves and ensure tnat the conditions are within the
design basis for the facility.
Establish the maximum time interval the essential valves' must be
.
repositioned and/or the number of times the essential valves
require recycling.
Develop criteria for functionally testing the essential valves
.
to verify the valves will perform their intended safety
function.
Based on the results of OSAR 87-10, the l'censee determined that
various actions would be required to ensure that essential valves
would comply witn their design basis and would be able to perform
their intended safety function. A detailed discussion of the status
of each essential valve is provided later in this inspe +tsn report.
b.
On September 26, 1983, the licensee submitted a 10 year inservice
inspection (ISI) plan for the period of 1983 to 1993. Based'on
concerns identified by NRC personnel in the licensee's submittal, an
onsite meeting was held in October 1987 to resolve the concerns. One
of the areas of concern involved the licensee's inservice
testing (IST) program for the check valves installed in accumulator
assemblies. At tne meeting, the licensee agreed to submit a revision
to the IST program to include the accumulator check valves and on
December 16, 1987, the IST program revision was submitted by the
licensee for NRC review and approval.
This revision has not yet been
approved by the NRC.
Subsequent to the submission of the revised IST program, the licansee
determined, based on the results of the analysis performed by
OSAR 87-10, that additional accumulator check valves should be
included in the IST program.
However, the licensee has not yet
submitted a proposed revision to include the newly identified check
valves in the IST program.
The licensee stated that a new revision
would be made prior to the end of the 1938 refueling outags. This
item remains open pending a submission of a revised program by the
licensee and review and approval by the NRC.
(285/8815-02)
A detailed discussion is provided later in this inspection report
that identifies the valves that have been included in the IST program
and also identifies which valves need to be included in the program.
c.
On July 6,1987, the licensee experienced an event where water from
the fire water system entered the instrument air system. As a result
,
.
.
_
. . .
. . -
-
. .
,
5
-
.
of this event, Emergency Diesel Generator 2 failed to start on demand
during the performance of a surveillance test on September 23, 1987.
The details of the event are provided in NRC Inspection
Report 50-285/87-27.
As a result of the followup inspections performed by NRC inspectors
on the water intrusion event, a Notice of Violation and Proposed
Imposition of Civil Penalty was issued on February 22, 1988.
Subsequent to the issuance of the Notice, a meeting was held at the
NRC Headquarters Office on November 13, 1987. At the enforcement
conference, the licensee made numerous commitments to address the
concerns identified by the NRC inspectors. One concern addressed by
the licensee was the testing of the check valves installed in
accumulator assemblies.
The commitments made by the licensee during
the enforcement conference for testing of check valves were submitted
to the NRC in a letter dated November 20, 1987.
In the letter, the
licensee stated that the accumulator check valves would be tested and
that the IST program would be revised to ensure periodic testing of
the check valves in the future (the status of the IST program was
discussed in paragraph 2.b above and the status of the testing of the
check valves is discussed later in this inspection report. The
status provides a detailed description of which valves have been
tested and the results of the testing).
In addition to the testing of the accumulator check valves, the NRC
identified concerns related to the seismic installation of the
accumulator assembly components that include the accumulator, tubing,
valve operator, and check valve.
In response to this concern, the
licensee submitted a letter, dated November 20, 1987, that provided
the seismic calculations completed by the licensee.
The NRC is
currently reviewing the calculations submitted by the licensee to
verify the adequacy of the calculations (the status of the seismic
qualification for each valve accumulator assembly is provided in a
detailed discussion later in this inspection report).
This item
remains open pending a review of the seismic calculations by NRC
personnel.
(285/8815-03)
The licensee submitted a response to the notice of violation and
proposed imposition of civil penalty, dated April 27, 1988, to the
violations identified in NRC Inspection Report 50-285/87-27.
(At the
time this inspqction was concluded, the response was under review by
the NRC Region IV office.)
l
d.
On April 18, 1988, the licensee issued a Safety Analysis for
l
Operability (SA0).
The licensee issued the SA0 to address conditions
related to specific essential valves for verification that the plant
l
could continue to operate safely. The SA0 issued on April 18, 1988,
was a revision to previous SA0s that had been issued by the licensee.
,
'
The revised SA0 considered all data related to the operability of
l
essential valves that was available at the time, and applies to the
!
valves discussed below.
l
. - .
,
tj;
,
..
.
.
.
,
.
6
.
.
A detailed discussion of the status of each accumulator assembly
installed with essential valves is provided below. The discussion
for each valve includes: (a) a description of the valve and the
function of the accumulator assembly, (b) actions performed to verify
accumulator size, (c) function testing performed on the accumulator
assembly, (d) IST program status for the accumulator assembly check
valve, and (e) seismic qualification status of the accumulator
assembly.
For each essential valve discussed below, a review was performed to
verify that the currently existing conditions did not require entry
into a limiting condition for operability (LCO) as defined by the
Technical Specifications (TS).
This review was performed based on
the current information available with respect to the present status
of each essential valve. Based on this review, it appeared that none
of the conditions of the essential valves described below require
entry into an LCO.
(1) Safety injection and refueling water tank (SIRWT) level control
bubblers (A/FIC-383, B/FIC-383, C/FIC-383, D/FIC-383)
(a) These bubblers are used to detect the level in the SIRWT.
In the event of a loss-of-coolant accident (LOCA) and
safety injection is initiated, the safety-injection pumps
will transfer water from the SIRWT into the react e coolant
system. When the level in the SIRWT reaches approXmately
16 inches, as detected by the level bubblers. a
recirculation actuation signal (RAS) is initiated.
.\\ RAS
will shut the SIRWT outlet valves, open the containmect
sump isolation valves, shut the safety injection and
containment spray pumps recirculation valve to the SIRWT,
and stop the low pressure safety-injection (LPSI) pumps.
The purpose of the RAS is to switch suction of the
high pressure safety-injection (HPSI) and containment spray
(CS) from the SIRWT to the containment sump.
If air system
pressure is lost to the bubblers, the accumulator
assemblies maintain pressure for bubbler operation to
prevent premature initiation of a RAS.
(b) A preliminary calculation has been completed by the
licensee to verify that the accumulators are of sufficient
size to provide a backup source of air pressure in the
event the normal instrument air pressure is lost.
The
results of the preliminary calculation indicate that the
accumulator size is adequate and the licensee is in the
process of issuing a formal calculation to verify the size
of the accumulators is adequate.
This item remains
unresolved pending the issuance of a formal calculation by
the licensee and a review of the calculation by the NRC.
l
(285/8515-04)
lc
.
-
___ _. _ _..
.
,
..
.
.
.
7
.
.
(c) A functional test of the accumulator assembly was performed
in April 1988 to verify that the check valves would
maintain sufficient pressure in the accumulator for a
period of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to ensure proper operation of the
bubblers.
The 12-hour operational period for the
accumulators was established by the analysis done in
OSAR 87-10. When the installed check valves were tested,
the licensee determined that the check valves would not
maintain accumulator pressure for the required 12-hour
period. Upon discovery of the inadequacy of the installed
check valves, the licensee replaced the check valves with
new check valves that had been bench tested and verified to
have zero leakage.
The April 18, 1988, SA0 addressed the
operability of the SIRWT level detectors. The evaluation
concluded.that the detectors were operational based on the
fact that the installed check valves had been replaced with
new check valves and that the prelimina y calculation
inaicated that the accumulators were properly sized. Based
on the conclusions contained in the SAO, the licensee
stated that no action was required at that time. However, a
test to verify that the accumulator assembly will function
for a period of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> has not been performed by the
licensee for any of the SIRWT level detectors. The
licensee stated that the functional test would be completed
during the 1988 r efueling outage. This item remains open
pending a satisfactory functional test to verify the
accumulator assembly will provide a 12-hour supply of air
pressure to the bubblers.
(285/8815-05)
The significance of this issue is that when the licensee
tested the originally installed check valves, it was
determined that the check valves leaked excessively.
The
check valves had not been previously tested.
Based on the
results of the tests, it appeared that the accumulator
assemblies could not perform their intended safety function
in the event that a LOCA occurred in conjunction with the
loss of instrument air pressure.
The worst case scenario
would occur if two or more level detectors lost air
pressure, causing a premature initiation of a RAS.
If a
premature initiation of RAS was initiated, the suction of
the HPSI and CS pumps would be switched from the SIRWT to
,
!
the containment sump.
If the sump did not contain
sufficient water to provide adequate flow through the
pumps, the HPSI pumps would self-destruct due to
overheating.
The loss of the HPSI and CS pumps would
significantly impact the ability to maintain sufficient
core cooling flow to prevent gross fuel damage.
The loss
l
of the CS pumps would impact the ability to lower the
l
containment pressure during a post-LOCA event.
l
I
l
l
l
.--
_
-.
_
.-
,
..
'
a
,
.
8
-
Section 9.12.5 of the Updated Safety Analysis Report (USAR)
establishes the design criteria for the performance of the
SIRWT bubblers and provides an evaluation of the
established design.
Section 9.12.5 of the USAR states, in
cart, that the level controller in the SIRWT requires a
supply of air to function properly. These cortrollers are
required to transfer the suction of the HPSI and CS pumps
to the containment sump after the water supply in the SIRWT
reaches the low-level setpoint.
To make these instruments
independent of the instrument air system during the
accident, each is equipped with an air storage tank which
tioats on the instrument air system.
If the pressure'in
the instrument air system drops, a check valve in the line
to the air storage tank closes which isolates the tank from
the system and prcvides a supply of air to the controller .
,
However, in this case, the accumulator assemblies for the
SIRWT level controllers fe'1ed to meet the established
design criteria in that testing performed on the
accumulator assembly check valves indicated that the valve
leaked excessively and would not perform its intended
design function.
This is one example of a potential
violation of the failure to meet plant design criteria
(285/8815-06).
(This condition was identified and reported
to the NRC as 10 CFR 50.72 report on April 15,1988.)
The NRC inspectors consider this matter potentially
significant, even though the probability of experiencing a
LOCA concurrent with the loss of instrument air is
extremely. low. Systems and components must be installed
and maintained to ensure that they can continue to fulfill
the established design criteria.
(d) The check valves associated with the SIRWT bubbler
accumulators were included in the revised IST program
submitted by the licensee on December 16, 1987.
Inclusion
of these check valves in the IST program will ensure that
the valves are verified to be functional each quarter.
(e) The licensee performed a calculation to verify that the
accumula,or assembly was seismically qualified. The
licensee submitted the calculation to the NRC for review on
November 10, 1987.
(2) Component cooling water to the reactor coolant pumps'
containment isolation valves (HCV-438B and HCV-4380)
(a) Valves HCV-4388 and HCV-4380 are designed to shut to
isolate containment in tha event containment isolation is
required in conjunction with a loss of pressure in the
component-cooling water (CCW) system.
Valves HCV-438B and
-
.
.
'
>
..
,
.-
.
.
,
.
9
.
HCV-4380 fail open on a loss of air pressure and rely on
taeir individual accumulator assemblies to hold the valve
shut, if required, when containment isolation is required.
(b) In response to a deficiency identified by the SSOMI team,
the licensee performed a calculation to verify that the
accumulator was properly sized to perform its intended
safety function.
The SSOMI team subsequently reviewed the
calculation performed by the licensee and determined that
'
the calculation was not adequate to establish that the
accumulator was sufficiently sized.
Based on this rev'ew,
the licensee performed an SA0 to verify that the plant
could continue to operate safely.
The results of the SAO concluded that the valves, as
currently installed, do not represent a significant
degradation of plant safety. The basis for this conclusion
was that the pressure in the CCW system would always be
greater than containment pressure during a LOCA.
If CCW
system pressure is lost concurrent with a LOCA,
Valves HCV-438B and HCV-4380 would be held shut by the
accumulator assemblies for 30 minutes.
(The valves were
tested during the 198/ outage and verified to be operable
for 30 minutes.) When CCW system pressure is lost, the raw
water (RW) system, the backup cooling water source for CCW,
will automatically initiate to provide cooling to the
components normally supplied by the CCW system.
However, in the event of a CCW line break inside
containment Valves HCV-4388 and HCV-4380 would shut for
30 minutes, as verified by the licensee's tests, and would
then potentially reoper due to the unverified adequacy of
the accumulator assembifes.
Further, if a line break
occurred, the valves car.not be manually shut due to the
high radiation levels at the valve location during a LOCA.
If Valves HCV-4388 and HCV-4380 reopened, RW would be
pumped into containment, causing the boric acid solution in
the containment sump to become diluted. The diluted boric
acid solution could potentially cause the reactor to become
critical when pumped into the vessel by HPSI pumps
When questioned by the NRC inspectors, the licensee stated
that the original design basis for the plant did not
require that an analysis be performed for a LOCA concurrent
with a CCW line rupture in containment. This matter will
be discussed with NRR to verify that such an analysis is
not required.
Therefore, this item remains unresolved
(285/8815-07).
(This condition was identified and reported
by the licensee as a 10 CFR 50.72 report on April 6, 1988.)
.--
- . . - . . _ .
_.,
_
l
-
,
,,
.
.
10
-
(c) During the 1987 refueling outage, the accumulator
assemblies for Valves HCV-4388 and HCV-438D were
functionally tested and verified to be operable for
30 minutes.
Subsequent to the testing, the licensee
established, during preparation of OSAR 87-10, that the
design criteria for the accumulators required that
Valves HCV-4388 and HCV-438D be held shut for a period of
1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />.
The licensee could not verify that the
accumulator assemblies could meet this new design criteria,
so an SA0 was issued. The discussion provided above
references the results of the SA0 evaluation, and the NRC
inspector's concerns.
(d) The check valves associated with Valves HCV-438B and
.
HCV-438D were not included in the revised IST program
submitted by the licensee on December 16, 1987.
These
check valves will be included in a revision to the IST
program which the licensee stated will be completed prior
to the end of the 1988 refueling outage.
(e) The licensee performed a calculation to verify that the
accumulator assembly was seismically qualified.
The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
(3) Loop injection valves from the discharge of the charging pumps
(HCV-238 and HCV-239)
(a) Valves HCV-238 and HCV-239 are normally open valves that
provide a path for continuous makeup water flow from the
volume control tank to the reactor coolant system via the
charging pumps.
The valves are required to be shut in the
event a LOCA occurs and hot-leg injection is required. The
valves are shut to divert flow from the charging pump
through the pressurizer auxiliary spray line. The valves
fail open on a loss of air pressure and are required to be
held in the shut position by the accumulators in the event
hot-leg injection is initiated.
(b) The licensee has not performed any calculations to verify
that the accumulators are properly sized to perform their
intended safety function.
An SA0 has been issued to
address the indeterminate status of the size of the
accumulators. A discussion of the SA0 is provided below.
(c) The licensee performed functional testing of the
accumulator assemblies during the 1987 refueling outage.
The test performed by the licensee verified that the
accumulator assemblies would perform their design functions
for a period of 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />.
However, during the preparation
of OSAR 87-10, the licensee established a design criteria
. - - - - - - - -
-
- . -
-
-
,- - ,
. - ,
--
_ _ _ .
_
'
v
..
<
.
11
that required the accumulator assemblies to operate
indefinitely. Based on the newly established criteria, the
licensee determined that the accumulator assemblies could
not be considered operable.
(This condition was identified
and reported by the licensee as a 10 CFR 50.72 report on
April 6, 1988.)
The licensee issued an SA0 to address the inoperability of
Valves HCV-238 and HCV-239. The conclusions of the SA0
indicate that Valves HCV-238 and HCV-239 cannot-meet the
established design basis. Therefore, the licensee has
established an alternate means of establishing hot-leg
injection by using the path through SI-186, HCV-347, and
HCV-348.
Valve SI-186 is a normally closed, locked manual
valve.
Valves HCV-347 and HCV-348 are motor-operated
valves. The licensee has established interim measures to
ensure that hot-leg injection is established as soon as a
LOCA occurs by having the auxiliary. building operator open
Valve SI-186. An operations memorandum was issued to
instruct the operator to open Valve SI-186 as soon as
possible because the valve is inaccessible in a post-LOCA
situation due to high radiation levels.
(d) The check valves associated with tho accumulator assemblies
were included in the revised IST program submitted by the
licensee on December 16, 1987.
In the revised IST program,
the licensee proposed that the check valves would be tested
quarterly.
However, the check valves are located inside
the bioshield inside containment, so it is not apparent how
the licensee intends to test the check valves quarterly
when the plant is at 100 percent power.
This item remains
-open pending a review of this apparent discrepancy in the
licensee's IST program submittal.
(285/8815-08)
(e) The licensee has not performed calculations to verify the
accumulator assemblies are seismically qualified.
For this
reason, an SA0 was issued, as described above, to address
the inoperability of the valves. The licensee stated that
calculations would be performed during the next refueling
outage to seismically cualify the accumulator assemblies.
This item remains onc., pending completion of the
calculations and a review of the calculations by the NRC,
(285/8815-09)
(4) Auxiliary spray isolation valve (HCV-240)
(a) Valve HCV-240 is used to provide a hot-leg injection path
into the reactor coolant system via the auxiliary spray
line for the pressurizer.
Valve HCV-240 is normally shut
5
. .
..
..s
12
and fails shut on the loss of air pressure.
The
accumulator assembly was installed to hold the valve open
during hot-leg injection.
(This condition was identified
and reported as a 50.72 report on April 6,1988.)
(b) The licensee has not performed a calculation to verify that
the size of the accumulator is. adequate.
For this reason,
the licensee issued an SA0 to address the inoperability of
the valve. A discussion of the SA0 is provided below.
(c) The licensee performed functional testing of the
accumulator assembly during the 1987 refueling outage and
verified the accumulator assembly would function for a
period of 25 hcurs. However, during the preparation of
OSAR 87-10, the licensee established a design criteria that
required the accumulator assembly to operate indefinitely.
Based on the newly established criteria, Valve HCV-240 was
declared inoperable. The licensee issued an SA0 to address
the inoperability of the valve. The conclusions of the SA0
are the same as those discussed above for Valves HCV-23P
and HCV-239.
In addition to the conclusions made by the
SA0 for HCV-238 and HCV-239, a solenoid-operated valve,
HCV-249, is installed in parallel with Valve HCV-240.
Valve HCV-249 can be used to provide hot-leg injection.
(This condition was identified and reported as a 50.72
report on April 6, 1988.)
(d) The check valve associated with the accumulator assembly
was included in the revised IST program submitted by the
licensee on December 16, 1987.
Inclusion of the check
valve in the IST program will ensure that the valve is
i
verified to be functional each time the plant is placed in
the cold shutdown mode.
(e) The licensee has not performed a calculation to verify that
the accumulator assembly was seismically qua~ified.
The
accumulator assembly was seismically qualified based on
'
engineering judgement.
The licensee stated that a
calculation would be performed during the next refueling
outage to verify that the accumulator assembly is
seismically installed.
This item remains open pendin0 the
preparation of a seismic calculation for the accumulator
assembly and a review of the calculation by the NRC.
(285/8815-10)
(5) SIRWT cutlet valves (LCV-383-1 and LCV-383-2)
(a) Valves LCV-383-1 and LCV-383-2 are used to isolate the
SIRWT from the safety-injection and containment spray pumps
suction header when pump suction is switched from the SIRWT
to the containment sump upon receipt of a RAS. These
, , . - -
__ ,__
_
._
. . '
,
s
-
.
,
13
valves shut to minimize the possibility of contaminated
'
water in the containment sump from entering the SIRWT.
The
valves fail open on a loss of air pressure and are held
shut by the-accumulator assemblies.
s .
(b) The licensee has not performed a calculation to verify that
the accumulator size is adequate to operate
Valves LCV-383-1 and LCV-383-2.
In this case, both valves
share a common accumulator.
Section 6.2.5 of the USAR states, in part, th:t the
safety-injection system has been designed to meet the
single-failure critarion. However, the accumulator
assembly for Valves LCV-383-1 and LCV-383-2 does not meet
the single failure criterion'in that one accumulator
supplies backup air pressure for both valves. This is
another example of a potential violation of the failure to
install a component that complies with the established
design criteria.
(285/8815-06)
The NRC inspectors noted that the licensee identified the
need to install an additional accumulator during the
preparation of OSAR 87-10, and that the licensee is
currently planning to install the additional accumulator in
the near future.
(c) The licensee did not functionally test the accumulator
assembly for Valves LCV-383-1 and LCV-383-2. Although the
licensee had not previously established a duration criteria
for accumulator assembly operation during the preparation
of OSAR 87-10, the licensee determined that the design
criteria for the accumulator assembly was to hold
Valves LCV-383-1 and LCV-383-2 shut for a period of
1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />. When the licensee determined that design
criteria, a modification was installed to provide a
nitrogen supply system to the valve operators to supplement
the accumulator assembly.
When the nitrogen system was installed, new check valves
that had been bench tested and verified to have zero
leakage were installed in the accumulator assembly.
The
nitrogen bottles were located within the plant such that
the bottles would be accessible during a LOCA.
By placing
the bottles in this location, operations personnel could
always replace depleted bottles to ensure that a continuous
source of pressure is available to hold Valves LCV-383-1
and LCV-383-2 shut for 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />.
By installing the nitrogen supply system, the licensee had
established a method for ensuring that Valves LCV-383-1 and
LCV-383-2 met the newly established design criteria.
(This
..
.
t
.
.>.
'
. .
j
14
-
LCV-383-2 met the newly established design criteria.
(This
7-
condition was identified and reported as 10 CFR 50.72
report on April 6, 1988.)
(d) The check valves associated with the accumulator assembly
were included in the revised IST program submitted by the
licensee on D.cember 16, 1987.
Inclusion of these check
valves in the IST program will ensure that the valves are
verified to be functional each quarter.
(e) The licensee performed a calculation to verify that the
accumulator assembly was seismically qualified. The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
(6) Safety-injection and containment spray pumps' recirculation
isalation valves to the SIRWT (HCV-385 and HCV-386)
(a) Valves HCV-385 and HCV-386 are normally open to allow water
being pumped by the safety-injection and containment spray
pumps to recirculate back to the SIRWT to prevent
deadheading the pumps. When a RAS is generated, the valves
shut to prevent the contaminated water in the containment
sump from being pumped into the SIRWT.
The accumulator
assemblies installed on these valves are intended to hold
the valves shut during the containment recirculation mode
of operation of the safety-injection system.
(b)
In response to Deficiency 2.2-1 identified by the SSOMI
team, the licensee evaluated the accumulator installation
for Valves HCV-344 and 345.
During the evaluation, the
-
licensee noted that both valves shared a common
Because the installation did not meet the
design requirement to satisfy the single-failure criteria,
another accumulator was installed.
The modification
provided one accumulator for each valve. After the
modification was completed, the licensee performed a
calculation to verify the size of the accumulators for the
valves was adequate. The csiculation verified that
sufficient accumulator capacity existed.
(The modification
completed by the licensee is detailed in Licensee Event
Report (LER)87-018, dated August 28,1987.)
(c) A functional test was performed on the accumulator
.
assemblies during the 1987 refueling outage.
The test
verified that the accumulator assemblies would function for
'
a period of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
However, during the preparation of
OSAR 87-10, the licensee established that the accumulator
assemblies are required to maintain prersure for a period
of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, then shut the valves and hold them shut for a
period of one hour.
The one hour period was established to
allow the auxiliary building operator sufficient time to
-
( ~,
- .
.
,
15
manually shut the valves.
To ensure that operations
personnel are aware of the need to shut the valves, a
change was-made to Procedure E0P-20, "Functional Recovery
Procedure." This change directs operations personnel to
shut the valve as soon as a RAS is initiated.
By manually
shutting t.he valve, the licensee meets the design criteria
that states the valves must be held shut for a period of
1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> following the initiation of a RAS.
(d) The check valves associated with the accumulator assemblies
were included in the revised IST program submitted by the
licensee on December 16, 1987.
Inclusion of these check
valves in the IST program will ensure that the valves are
verified to be functional each quarter.
(e) The licensee performed a calculation to verify that the
accumulator assembly was seismically qualified. The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
(7) Radiator exhaust dampers for the emergency diesel generators
(YCV-871E and YCV-871F)
(a) Dampers YCV-871E and YCV-871F are normally shut to prevent
outside air from entering the emergency diesel generator
(EDG) rooms. When the EDGs are started and reach 100 rpm,
"
the air-operated motors open the dampers to provide air
flow across the radiator.
The air flow provides cooling
for the EDGs. Once the dampers are open, they will remain
open without the presence of air pressure. On a loss of
air pressure, the dampers will remain in the normally
closed position. The accumulator assemblies were installed
to provide a backup source of air pressure to ensure that
the dampers are opened when the EDGs are started.
If the
dampers did not open, the EDGs would overheat and could
potentially cause damage to the engines.
(b) The accumulators were supplied by the manufacturer of the
air-operated motors and were sized by the manufacturer to
ensure that a sufficient volume of air was available to
l
operate the motors.
The licensee has performed a
calculation to verify that the accumulator size is adequate
to open the dampers.
(
(c) Repairs and a functional test of the accumulator assemblies
was performed by the licensee when a damper failed to open
l
during a routine surveillance test performed on September
j
23, 1987. The subsequent functional test indicated that
the accumulator assemblies were capable of performing their
l
l
l
l
l
7
$.
' .>
,
,
,
16
intended design function.
(The failure of the damper to
open was previously reported in LER 87-25, dated
November 30, 1987.)
(d) The check valves associated with the accumulater assemblies
were in-luded in the revised IST program submitted by the
licensee on December 16, 1987.
Inclusion of these check
valves in the IST program will ensure that the valves are
verified to be functional each quarter.
(e) The licensee performed a calculation to verify : hat the
accumulator assembly was seismically qualified. The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
(8) HPSI header isolation valve used for initiation of long-term
core cooling (HCV-2987)
(a) Valve HCV-2987 is used to divert a portion of HPSI flow
from the cold leg, when the valve is open, to the charging
pump header for hot-leg injection, when the valve is shut.
The valve is normally open and will fail as-is on a loss of
air pressure. Air pressure is required to open and to shut
,
the valve.
The opening and shutting of the valve is
accomplished by the use of an air accumulator.
(b) A calculation to verify the size of the accumulator has not
been performed. The accumulator was supplied by the valve
manufacturer and was specifically designed for use with
this valve type.
(c) Functional testing of the accumulator assembly has not been
performed. During performance of a test to verify
accumulator assembly adequacy, the licensee identified a
problem with the air intensifier installed in the
accumulator assembly. The air intansifier is a mechanism
that boosts the instrument air pressure from approximately
90 psig to 300 psig for valve operation. Since no spare
parts were available to repair the intensifier, the
licensee disconnected the instrument air supply line to the
accumulator assembly and connected a temporary nitrogen
supply system. The nitrogen system supplies the 300 psig
motive force to the valve actuator. This temporary
modification will ensure that the valve can perform its
intended safety function. During the next refueling
outage, the licensee intends to return the valve to its
normal configuration and perform tests to verify valve
operability (the details of the problems with HCV-2987 and
the actions taken by the licensee are provided in LER
88-002, dated February 5, 1988.)
o
,
,
-
.
17
(d) The check valve associated with the accumulator assembly
was included in the revised IST program submitted by the
licensee on December 16, 1987.
Inclusion of the check
,
valve in the IST program will ensure that the valve is
verified to be functional each time the plant is placed in
e cold shutdown mode.
(c) TFe licensee performed a calculation to verify that the
accumulator assembly was seismically qualified.
The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
(9) HPSI heac'er isolation valves (HCV-304, HCV-305, HCV-306, and
HCV-307)
(a) These valves are used to establish hot-leg injection flow
to the reactor coolant system (RCS).
By shutting or
throttling the valves, flow is diverted into the RCS
hot-leg.
The valves are normally open ard require air
pressure for operation.
On a loss ofJair pressure, the
accurrulator assembly will open the valve, if the valve is
shut. Once the valve is open, the position cannot be
changed by the accumulator assembly.
These valves are not
accessible for manual operation during a LOCA due to the
high radiation levels.
When aeviewing the status of the accumulator asserblies for
these valves, the licensee identified that, in the current
design configuration, the valves cannot be shut by the
accumulator assemblies once air system pressure is lost.
Without the capability to shut the valves, no assurance can
be provided that the proper amount of hot-leg injection
flow can be obtained. The valves are required to be shut
only if one diesel generator fails to operate or,1f one
loop motor-operated injection valve fails to shut.
(Details of this matter are provided in OSAR 87-10.)
The nuclear steam supplier, Combustion Engineering,
recommended in 1978 that the licensee provide a remote
manual means of operation for the valves to ensure that the
valves can be operateci, if required.
However, these
modifications have not been pursued by the licensee. The
licensee is now in the process of obtaining an evaluation
from Combustion Engineering to determine whether or not
hot-leg injection can be achieved with the currently
installed system configuration. This item remains
unresolved pending the completion of the evaluation by
Combustion Engineering and the completion of licensee
actions identified in the evaluation.
(285/8815-11)
i
.
J
L
- , _ _
_
_
_
..
,-t
,
8 '
.
,
18
(b) A calculation to verify that the accumulator has sufficient
capacity has not been performed by the licensee.
However,
a functional test has been successfully performed, and
based on the results of the test, the licensee stated that
the accumulators could perform their intended safety
function.
(c) The licensee performed a functional test of the accumulator
assemblies during the 1987 refueling-outage to verify that
the assemblies operated properly.
The test confirmed that
the assemblies were fully operable.
(d) The check valves associated with the accumulator assemblies
were included in the revised IST program submitted by the
licensee on December 16,_1987.
Inclusion of these check
valves in the IST program will ensure that the valves are
verified to be functional each time the plant is placed in
the cold shutdown mode.
(e) The licensee performed a calculation to verify that each
'
accumulator assembly was seismically qualified.
The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
j
(
eupply valves to the turbine-driven auxiliary feedwater
l
- u.., s.CV-1045A and YCV-10458)
(a) Valves YCV-1045A and YCV-1045B are installed to provide
steam to the turbine-driven auxiliary feedwater pump from
Steam Generators A and B, respectively.
The valves are
normally shut and fail open on a loss of air pressure.
The
'
accumulator assemblies were installed to shut the valves in
the event of a loss of air pressure concurrent with a steam
generator tube rupture to prevent the release of
radioactive material to the environment.
(b) The licensee performed a calculation on accumulator sizing
in response to a deficiency identified by the SS0MI team.
The calculation indicated that the accumulator sizing was
adequate.
Subsequent to the performance of the
calculation, the SSOMI team reviewed the results and
determined that the calculation was inadequate.
The
licensee revised the calculation to incorporate the
comments noted by the SSOMI team.
Currently, the
accumulators are considered to be adequately sized to
perform their intended safety function.
(c) Functional testing of the accumulator assemblies was
performed during the 1985 refueling outage. During this
testing, the licensee determined that the accumulator
assemblies could hold Valves HCV-1045A and HCV-1045B shut
'
.
'
-
..
19
for 30 minutes. The design criteria states that the valves
should be held shut indefinitely.
To ensure the valves
stay shut, the licensee has provided instructions in
E0P-04, "Steam Generator Tube Rupture," to direct
operations personnel to manually shut the valve within
30 minutes of the initiation of a steam generator tube
rupture.
(d) The check valves associated with the accumulator assemblies
were included in the revised IST program' submitted by the
licensee on December 16, 1987.
Inclusion of these check
valves in the IST program will ensure that the valves are
verified to be functional each quarter.
(e) The licensee performed a calculation to verify that the
accumulator assembly was seismically qualified.
The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
(11) CCW isolation valves to the containment air cooling and
filtering units (HCV-400A, B, C, and 0; HCV-401A, B, C, and D;
HCV-402A, B, C, and D; and HCV-403A, B, C, D)
(a) These are isolation valves for CCW flow to the containment
air cooling and filtering units.
Valves HCV-400A and C,
HCV-401A and C, HCV-402A and C, and HCV-403A and C also
func+. ion as containment isolation valves.
The valves can be normally open or normally shut, depending
on the containment cooling requirements. lne valves
require air pressure for operation. The accumulator
assemblies were provided;to ensure that all valves open in
the event that a containment isolation actuation signal is
initiated concurrent with a loss of air system pressure.
(b) The licensee has not completed calculations to verify that
the accumulators are properly sized. A functional test has
been performed, as described below, that verified the
accumulator sizing was adequate.
(c)
Functional testing on the accumulator a.,sembly for each
valve has been completed.
The testing verified that the
accumulator assembly would move the valve to the open
position.
Based on the testing, the licensee determined
that the accumulator assemblies were operational.
The licensee has not performed functional testing to verify
that the valves can be shut in the event containment
isolation is required. A discussion of whether or not an
analysis is required to be performed to address a CCW line
rupture in containment concurrent with a LOCA was provided
.-
--
_
_
e
.,
,.
,
.
,
a-
y
i .
20
in paragraph 3.d of this inspection report.
The status of
these valves will be revie.wed by NRC when the review is
performed for Valves HCV-438B and HCV-4380. Accordingly,
the review of these valves will be tracked under the
unresolved item (285/8815-07) issued to track the review of
HCV-4388 and HCV-4380.
(d) The check valves associated with the accumulator assemblies
were included in the reri sed IST program submitted by the
licensee on December lo, 1987
Inclusion of these check
valves in the IST program will ensure that the valves are
verified to be functional each time the plant is in the
cold shutdown mode.
(e) The licensee performed a calculation to verify that the
accumulator assembly was seismically qualified.
The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
(12) Spent fuel pool charcoal filter bypass valve (HCV-712A)
(a) Valve HCV-712A is normally open to bypass the charcoal
filter during normal plant operations. Whenever spent fuel
'
movement is performed at the spent fuel pool,
Valve HCV-712A is shut so that the ventilation air flow
passes through the charcoal filter to prevent contamination
from being released to the environment. The valve fails
!
as-is on a loss of air system pressure. The accumulator
assembly *s designed to provide motive force to shut the
valve if the valve is in the open position. Once the valve
.
has been shut, it will remain in the shut position.
'
(b) The licensee has not performed a calculation to verify that
the sizing of the accumulator is adequate. A functional
test was performed, as described below, which verified the
adequacy of the accumulator size.
(c) During the 1987 refueling outage, the licensee performed a
functional test of the accumulator assembly.
The test
'
involved shutting Valve HCV-712A under full-flow conditions
and verifying that the valve remained closed for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Based on the results of the testing, the licensee
established the operability of the accumulator assembly.
(d) The check valve associated with the accumulator assembly
was included in the revised IST program submitted by the
licensee on December 16, 1987.
Inclusion of this check
valve in the IST program will ensure that the valve is
!
verified to be functional each quarter.
-
l
_
.g
,
,
-
.
21
(e) The licensee performed a calculation to verify that the
accumulator assembly was seismically qualified.
The
licensee submitted the calculation to the NRC for review on
November 20, 1987.
The SA0 issued by the licensee for these specific essential valves
has been forwarded to the NRC for review.
In addition, the seismic
calculations submitted on November 10 and 20, 1987, to verify that
the specific accumulator assemblies described above were seismically
qualified are under review by the NRC.
Therefore, these matters will
be considered an open item pending completion of the review by the
NRC.
(285/8815-11)
4.
Followup on an Onsite Event
On April 19, 1988, the licensee identified a situation that represented a
loss of containment integrity. At the time of discovery, the plant was at
100 percent power and had been operating at power since the last refueling
outage that ended June 6, 1987.
During a walkdown being performed by a maintenance engineer to verify the
adequacy of Procedure ST-CONT-3, "Containment Isolation Valves Leakage
Rate Test-Type C," the engineer noted that a tubing cap was not installed.
The cap should have been installed on one leg of the test tee for Pressure
Transmitter PC-743, a pressure transmitter used to annunciate a
containment high pressure condition in the control room.
PC-743 is
connected to containment penetration M-38 via a 1-inch line which is
reduced to 3/8-inch tubing for connection of the transmitter.
The
engineer identified the problem while performing a walkdown in response to
Violation 285/8710-07 cited by the NRC resident inspector in NRC
Inspection Report 50-285/87-10, issued in May 1987. The violation was
related to Procedure ST-CONT-3 not accurately reflecting the as-built
installation of the piping and valves connected to containment
Procedure ST-CONT-3 provides instructions for the local
leak rate testing of mechanical penetrations.
Without the cap installed on the test tee, containment integrity was
violated in that the 3/8-inch tubing connecting PC-743 and
Penetration M-38 provided an unrestricted path from inside to outside
containment. The licensee performed a preliminary calculation to
determine the leak rate through the 3/8-inch tubing, at a containment
pressure of 52 psig, the maximum containment pressure experienced in a
post-LOCA event. The leak rate was determined to be approximately
4.1 cubic feet per minute (cfm). The leak rate calculation was performed
based on a mixture of air water, and steam. This is the mixture that
would be expected after a loss-of-coolant accident occurred.
The licensee also performed a preliminary calculation to determine whether
or not the radiation levels at the site boundary would exceed the levels
established by 10 CFR Part 100 at a calculated leak rate of 4.1 cfm.
The
results of the preliminary calculat;on indicated that the radiation levels
ll
.
.
22
would not exceed the established Part 100 limits. The preliminary
calculation indicated the thyroid dose over a 2-hour period would be
258.6 Rem. The Part 100 limit is 300 Rem. The preliminary calculation
also indicated that the whole body dose would be 6.4 Rem over a 2-hour
period.
The Part 100 limit is 25 Rem.
Based on the results of the
preliminary calculation, it appears that the radiation levels would not
exceed the established Part 100 limits.
The licensee stated that the
preliminary calculation would be formally issued in the near future. This
item remains open pending completion of the calculation and a review of
the calculation by NRC personnel to verify its adequacy.
(285/8815-13)
The licensee performed a calculation to determine the value of the leak
rate through the test tee to determine whether or not containment
integrity was violated as defined by the TS. The flow rate calculation
was performed based on the leakage of dry air from containment, through
the piping and tubing, and out the test tee.
Dry air was used because the
TS limit for La, where La is defined as the design basis leakage rate of
0.1 percent weight of the containment atmosphere per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at a
pressure of 60 psig, is based cn the leakage of dry air. The licensee's
calculati'n of the leakage via the instrument line indicates the TS limits
for B&C +,pe leakage was exceeded by a factor of approximately seven
(418,000 standard cubic centimeter (SCCM) calculated as compared to TS
limits of 62,451 SCCM). This item represents a potential violation of the
containment integrity requirement of TS LCO 2.6. (285/8815-14)
Upon discovery of this problem by the licensee, the test tee cap was
immediately reinstalled. The licensee immediately instituted a walkdown
of all other penetrations to verify that no other problems existed. No
other problems were identified. The licensee reported the loss of
containment integrity to the NRC Headquarters duty officer on April 19,
1988, via the emergency notification' system in accordance with the
requirements of 10 CFR Part 50.72. The licensee also immediately notified
.the NRC resident inspector.
Licensee management stated that a licensee
event report would be submitted within 30 days of the discovery of the
event in accordance with 10 CFR Part 50.73.
In followup to this event, the licensee also determined that additional
plant instrumentation was affected by the failure to install the test tee
cap.
Three other pressure instruments are also connected to
penetration M-38 via the common piping that connects to PC-743. The
licensee determined that the three instruments were also inoperable
because the open-ended tubing would prevent a pressure increase in the
piping and thus would prevent the three pressure instruments from sensing
a pressure increase in containment.
Two of the instruments, A/PC-742-1
and A/PC-742-2, are used to initiate safety injection, containment
isolation, and steam generator isolation signals in the event of a high
pressure condition in containment.
The two instruments provide redundant
initiation for one of the four channels installed to detect a containment
high pressure event. There are an additional six pressure instruments
which perform the same function as A/PC-742-1 and A/PC-742-2. A third
instrument, A/PC-765, is used to initiate a reactor trip via the reactor
ls
-
,
.
23
protection system in the event of a high containment pressure. An
additional three instruments are provided at other containment
penetrations to initiate the same reactor trip signal.
Because additional
instrumentation remained functional to initiate automatic response to a
j
containment high pressure condition, the required redundancy for the three
inoperable instruments connected to Penetration M-38 was maintained as
defined by the TS.
To establish when the cap may have been removed, the licensee performed a
documentation search. The results of the search indicated that the local
leak rate test was perf;rmed on Penetration M-33 in March 1987 in
accordance with Procedure ST-CONT-3 and that no other work had been
performed on the pressure transmitter since then.
The search also
revealed that Maintenance Order (MO) 872526 had been issued in May 1987 to
verify that all caps associated with local leak rate testing activities
had been reinstalled. MO 872526 was issued for verification of cap
installation as a result of a loss of containment integrity identified by
the licensee in September 1974.
(The licensee submitted Licensee Event
Report (LER) 50-285/74-14 to provide details of the loss of containment
ntegrity.)
followup inspection was performed by the NRC inspectors to review the
actions taken by the licensee and to verify that the actions were
completed. The NRC inspectors noted that the program established by the
licensee to verify that all penetration assemblies were returned to normal
prior to exiting the cold shutdown mods was not a commitment made in
LER 50-285/74-14, but instead was a program established by licensee
self-initiative. However, the cap that was found not to be installed had
not been included on the M0 as an item for verification.
Therefore, based
on the documentation review performed by the licensee, it appeared that
the cap had not been reinstalled when the local leak rate test was
performed in March 1987.
The NRC inspectors then performed a followup of this event.
The followup
included a tour of the plant to verify that selected penetrations were
properly sealed to prevent a loss of containment integrity, a review of
Procedure ST-CONT-3 to verify that appropriate instructions had been
provided for testing of Penetration M-38, and a review of M0 872526 that
provided instructions for a verification that all test caps were
installed.
During this review, the NRC inspectors noted that the selected
penetrations inspected during the plant tour were in an acceptable
condition.
A review of Procedure ST-CONT-3 indicated that the instructions provided
to the technicians were inadequate in that Procedure ST-CONT-3 requires
that the cap on the test tee be removed prior to performance of the leak
rate test; however, no instructions are provided to the technician ta
ensure the cap is replaced. A review of MO 872526 indicated that the
technicians were instructed to verify that the test fitting used inside
containment to perform the local leak rate test had been removed; however,
no instructions were provided for verification that the normally installed
i
,
- ,,
..
_
"
r
- . ,;.
24
test caps had been replaced. The licensee could not determine why a
verification of cap installation had not_ been provided on M0 872526.
Since Violation 285/8710-07 has already been issued to address the
inadequacies of Procedure ST-CONT-3, no additional violation will be
issued to cite the specific problems associated with the instructions
provided for testing of Penetration M-38.
Licensee management stated, in
response to Violation 285/8710-07, that Procedure ST-CONT-3 would be
upgraded prior to the next refueling outage.
It is expected that the
upgrade of Procedure ST-CONT-3 will include revision of the instructions
for testing Penetration M-38.
Further, licensee management stated that an
in-depth raview would be performed to ensure that the instructions
provided for verification of normal penetration assembly status prior to
startup from a refueling outage would be performed.
In addition, during a review of this event, the NRC inspector noted that
the containment isolation valve, A/HCV-742, for Penetration M-38 was an
air-operated valve and that the valve did not have an accumulator assembly
installed.
In an event where containment isolation of Penetration M-38 is
required, concurrent with the loss of instrument air pressure, it is not
evident how Valve A/HCV-742 could be shut, considering the valve fails
open on a loss of air pressure. The licensee stated that the NRC had
previously approved the installation and failure mode of Valve A/HCV-742.
The NRC inspector will forward the information discussed above to
personnel in NRC Headquarters for review to verify that the installation
and failure mode complies with established design criteria appropriate to
the Fort Calhoun Station. This item remains' unresolved pending a review
i
by NRR. (285/8815-15)
4.
Exit Interview
The NRC inspectors met with Mr. R. Andrews, Division Manager, Nuclear
Production, and othee members of the licensee's staff on April 22, 1988,
and obtained supplemental information until May 13, 1988, at the end of
this inspection. At this meeting, the NRC inspectors summarized the scope
of the inspection and the findings.
l
l
l
[
t
1
)
2:; Ofr;
.
's:~
,- ,
!=
APPENDIX B
- PROPOSED ENFORCEMENT CONFERENCE AGENDA
~
CMAHA PUBLIC POWER DISTRICT-
'
June 8, 1988
- , L
I.
Introduction and Purpose of Meeting
L. J. Callan
Adequacy of Accumulator Assemblies and
Associate Analysis-Justifying
Continued Plant Operation
Containment Integrity
.II.
Licensee Presentation
OPPD Staff
-III. NRC Comments
L. J. Callan
IV.
Licensee Response-
OPPD Staff
V.
Closing Comments
L. J. Callan
L
i
f
.
I
e
+-v
i ,.
s.