ML17310B447
| ML17310B447 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde |
| Issue date: | 07/12/1994 |
| From: | Perkins K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML17310B445 | List: |
| References | |
| 50-528-94-23, 50-529-94-23, 50-530-94-23, NUDOCS 9407220032 | |
| Download: ML17310B447 (46) | |
See also: IR 05000528/1994023
Text
I
APPENDIX B
U.S.
NUCLEAR REGULATORY COMMISSION
REGION IV
Inspection Report:
50-528/94-23
50-529/94-23
50-530/94-23
Licenses:
NPF-51
Licensee:
Arizona Public Service
Company
P.O.
Box 53999
Phoenix,
Facility Name:
Palo Verde Nuclear Generating Station,
Units 1, 2,
and
3
Inspection At:
Maricopa County, Arizona
Inspection
Conducted:
Hay 28 through June 3,
1994
0
Inspectors:
H. Wong,
Team Leader
A. MacDougall, Resident
Inspector
P.
Eng, Senior Operations
Engineer,
F. Burrows, Electrical Engineer,
Accompanying Persgqnel:
J. Ganiere,
Intern,
Approved:
er ins,
erector
Malnut Creek Field Office
a
e
Ins ection
Summar
Areas
Ins ected
Unit 2
Special,
announced
inspection of the circumstances
regarding
a reactor trip on May 28,
1994, which was caused
by water flow from
the refueling water tank to the containment
spray header.
The licensee's
response
to and assessment
of the event were evaluated;
included were
interviews with the personnel
involved in the reactor trip event.
Areas
Ins ected
Unit
1 and
3
No inspection of Units
1 and
3 was performed.
~R1<<UR
2
~
The licensee's
preliminary event investigation
int'o the root cause of
the event
was thorough
and objective.
The licensee's
review of the
event
had captured
the concerns
and weaknesses
identified by the
inspectors.
Licensee
management
involvement in the review of the event
was clearly evident.
9407iP200
050005ge
gp 9q07aa
ADOC
@DR
Q
,
I
I
1
J
l
I
t
1
0
e
~
The primary cause of the event
was that
an instrument
and control
(I&C)
technician
had
a mindset
and the technicians
failed to follow the
instructions of a work order when they were replacing
a relay in the
wrong cabinet.
Extra material
in the work package left one technician
with the mindset that the work was to be done in Train
B (incorrect
train).
However, there were also several
other contributing factors
which led the technicians
to work on the wrong relay
and the subsequent
~
.
Communications
between
the
I&C technicians
and operations
crew were
poor:
(1) the pre-job briefing in the control
room was inadequate
in
that it did not specifically identify the train which would be worked
on;
(2) during the relay replacement
work,
an
I&C technician
entered
the
control
room to see if the work had caused
any unexpected
response,
but
did not speak with anyone regarding his intentions or the status of the
work;
and (3) when trying to understand
the cause of the containment
sump level increase,
operations
personnel
had
a mindset that,
since
power had
been
removed
from the containment
spray valve, the ongoing
work could not
be the cause,
and they failed to check
on the work being
done
by the technicians
even
though they were just outside
the control
room.
Management
expectations
regarding certain
aspects
of work control
and
conduct of work were not understood:
(1) the
ILC technicians
failed to
carefully review the work order;
one technician did not review the work
order until after the event
and the other technician
had
a mindset that
work was to be conducted
in Train 8;
and
(2) personnel
did not
understand
how to apply the Sensitive
Issues
Manual in the review of
work to be performed
(as
a policy document
implementing procedures
had
been considered
unnecessary).
~
Personnel
failed to maintain
an effective questioning attitude:
(1) the
I&C technicians
worked
on the wrong relay even though the work
instructions clearly specified the proper relay;
and
(2) the operations
crew focused
on the
blowdown line as the source of the
water going to the containment
sump, did not conduct effective
questioning
or perform control board walkdowns to eliminate other
possibilities,
such
as the containment
spray
system,
and did not
investigate
the work bei.ng
done
by the
I&C technicians
although they
were just outside the control room.,
The licensee's
"re-engineering"
program
had
made
changes
to the work
process
which had not been effectively communicated
to plant personnel.
No longer did all work orders require .the workers to verify the train
and component
which was being worked on.
The work order
being performed
in this event did not have this verification step.
The removal of the
verification step
was not known to the operations
crew.
In addition,
the relay work was
moved
up from its original schedule without the
'
f
t
1
I
)
normal
scheduling interface
between
the unit schedulers
and those
on the
"re-engineering" pilot team.
~
The licensee's
preliminary corrective actions,
including department
meetings
which discussed
the event,
review of communication practices,
review of the changes
made in the "re-engineering"
program,
and
counseling of the technicians
involved in the event,
were appropriate.
~
The licensee's
review of the reactor coolant
pump electrical
and other equipment potentially affected
by the containment
spray
system
flow was thorough
and complete.
Other than the
damaged
connectors
and penetration
enclosure
box,
no other components
were found
to be adversely
affected
by the borated water.
Results
Units
1
and
3
Not applicable.
Summar
of Ins ection Findin s:
~
One violation was identified (Section 3.2.3).
t
Attachments:
~
Attachment
1 - Persons
Contacted
and Exit Heeting
~
Attachment
2
'
J
l
)
DETAILS
1
EVENT SUMMARY
On May 28,
1994, at
11: 15 a.m., while Palo Verde Unit 2 was operating
at
86 percent
power,
a reactor trip occurred
as
a result of a trip of Reactor
Coolant
Pump
18.
The cause of the reactor coolant
pump trip was
a phase-to-
phase fault caused
by water getting into the reactor coolant
pump junction box
inside containment.
The water flowed into .junction box when
a containment
spray
(CS) valve was inadvertently
opened
and allowed borated
water
from the
refueling water tank
(RWT) to flow by gravity through the
CS system
piping and auxiliary nozzles
in the lower elevations of containment.
technicians
had
removed
a relay in the wrong train of the engineered
safety
features
actuation
system
(ESFAS) which caused
the opening of the
CS system
valve.
The elevation of the
RWT provided gravity flow from the
RWT through the id
pump, inadvertently opening the
CS system valve,
and through the lower
elevation
CS nozzles.
For approximately
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 45 minutes,
while the
operations
crew was trying to identify the source of water going to the
containment
sump,
approximately
7000 gallons of borated water flowed to the
containment
from the
RWT ~
The reactor trip occurred while operations
personnel
were in the containment
looking for the source of water.
The
personnel
subsequently
identified the water coming through the
CS nozzles.
When alerted to the situation,
control
room personnel
identified the
inadvertently
opened
valve
and closed it at ll:31 a.m.
The licensee
concluded that the plant response
to the reactor trip was
uncomplicated.
Minor equipment
problems
were identified by the licensee,
such
as
economizer
and
a steam
bypass
control valve not going fully
closed
and
a control element
assembly
rod bottom light not illuminating as
quickly as the others.
These
issues will be addressed
in a routine resident
inspector
inspection report.
2
PURPOSE
OF
INSPECTION
The purpose of this special
inspection
was to review the circumstances
of the
reactor trip and to assess
the licensee's
response
to the event.
The
inspection
included
an independent
evaluation of the licensee's
root cause
evaluation,
interviews of personnel
involved in the event,
evaluation of the
performance of the reactor coolant
pump containment
which was
subjected
to the phase-to-phase
fault,
and evaluation of the inspection
and
repairs to equipment affected
by the
CS flow.
In particular,
the special
inspection
independently
assessed:
~
the cause of the
I&C technicians'emoval
of the relay in the wrong
train,
1
'
~
~
why the operations
crew took
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 45 minutes to identify the source
of the water going to containment
sump,
~
the licensee's
assessment
of the root causes
of the event,
~
the
adequacy
of the licensee's
preliminary corrective actions,
~
the performance of the reactor coolant
pump containment electrical
and
~
the status of other components
potentially damaged
by the
CS flow,
including the licensee's
evaluation of these
components.
3
EVENT FOLLOWUP
(92703)
3. 1
Summar
of Investi ation
NRC personnel
interviewed the 'two
I&C technicians,
the
I&C foreman,
and the
Unit 2 operating
crew that were involved with the event.
All personnel
were
cooperative
and candid during their interviews.
The work package
and other
supporting
information were also reviewed to determine
whether
inadequacies
in
the work instructions contributed to the event.
Based
on the review of the work package
and staff interviews,
the root causes
of the event were determined
to be:
(1)
human error caused
in part by
mindsets
and extra material
in the work package;
(2) inadequate
communications,
including ineffectively communicated
management
expectations
for both operations
and maintenance
personnel;
and
(3) failures to maintain
an
effective questioning attitude.
3.2
Rela
Work b
1&C Technicians
3.2.1
Background
On Hay 21,
1994,
l&C technicians,
who were assigned
to the
I&C "re-
engineering" pilot team, identified
a failed contact
on
an engineered
safety
features
actuation
system
(ESFAS) relay during surveillance testing.
It was
Relay K111, in the Train
A ESFAS,
which is normally energized.
The relay de-
energizes
on
a
CS actuation
signal
and
opens
the Train A CS isolation valve
(SIA-UV-672).
The technicians
identified
a failed contact
on the relay which
provided valve position indication to the quality safety parameter
display
system.
The failed contact did not affect the ability of Relay
K111 to open
the
CS isolation valve.
Prior to the event,
the licensee
had initiated
a program to "re-engineer" its
work processes
and work resources.
As part of this effort, the licensee
had
implemented
several
programs
designed
to increase
the efficiency of performing
maintenance
at the plant.
These efforts included:
(1) streamlining work
instructions,
(2) streamlining the work assignment
process,
and
(3)
implementation of
a "pilot" program
as
a trial of the
new work process
and
I
I
I
J
organization
changes,
which involved re-alignment of maintenance
work crews
by
plant system rather than
by unit.
Implementation of the "re-engineering"
pilot programs
began
in February
1994.
Discussions
with members of the licensee's
staff revealed that instructions
for writing work orders
were being revised
in the "re-engineering"
process.
The changes
were
made
based
on
an evaluation
performed
by four work planners
and were reviewed
by the maintenance
and work control organizations.
Discussions
with members of the licensee's
staff also revealed that work on
"critical" or "sensitive"
equipment
was generally pre-scheduled.
Pre-
scheduling
work on critical components
provided plant staff sufficient time to
assess
how such work would affect the plant co( iguration.
In addition,
the licensee
previously developed
and issued t'e "Sensitive
Issues
Nanual
(SIN)," which identified plant systems,
conditions,
or
activities that
have
a greater
impact
on safety
and, therefore,
need
a higher
level of management
attention.
The SIN states
that
a prejob briefing should
be held for any work involving equipment that may result in actuation of an
ESF system.
However,
because
licensee
management
intended
the
SIN to be
a
policy document,
implementing procedures
for the SIN had not been
developed.
In addition,
no specific training regarding
management's
expectations
of
worker use of the SIN had
been given to the personnel
involved in the event.
The operating
crew on duty during the event
had worked together for over
a
year
and were very experienced.
Although there
were three reactor
operators
(ROs)
on shift, the third
RO was undergoing on-the-job training in
preparation for becoming
an assistant shift supervisor
(SS).
The two
I&C technicians
involved with the event were participating in the
maintenance
department's
"re-engineering" pilot program.
The two technicians
were assigned
to the pilot team
when it was formed in February
1994.
They
worked with each other
on the back shift about
1 week per month
and were
familiar with each other's
work practices.
Both individuals
had extensive
experience
in I&C.
The lead technician's
(Technician
1)
ILC training was
current;
however,
the second technician's
(Technician
2)
I&C training had
lapsed.
Technicians
1
and
2 were also designated
in the Palo Verde
maintenance
organization
as the "independent"
and "dependent"
worker,
respectively.
Discussions
with members of the licensee's
staff revealed that
the designation
of "independent"
and "dependent"
workers
was
common
and only
served to identify whose training was current.
Both technicians
were familiar
with the scope of the relay replacement
work.
Both technicians
knew that the licensee
was evaluating its organizational
structure
and work processes
to increase efficiency in the performance of
maintenance
work.
The technicians
acknowledged
that this "re-engineering"
could lead to downsizing the work force later in 1994.
They also
knew that
the purpose of the "re-engineering" pilot program
was
a t}ial of the proposed
organization
and processes.
Technician
1 had worked
12 days in a row;
',
t
f
however,
he stated
that
he
was not fatigued
and did not feel
an abnormal
level
of stress.
No regulatory limits on worker overtime were exceeded.
Technician
2 had not worked any overtime
and stated that
he was neither
fatigued nor felt overly stressed
prior to working on Relay Kill.
The component designation
convention at Palo Verde generally identifies
components
for Trains
A and
B such that
a lower number is associated
with
Train A.
This would mean that
CS isolation Valves SIB-UV-671 and SIA-UV-672
would be expected
to be in Trains
A and
B, respectively.
However,
Valve SIA-
UV-672 is in Train
A and Valve SIB-UV-671 is in Train B.
Discussions
with
members of the operating staff revealed that experienced
operators
have to
remind themselves
of this inconsistency.
Also, the'elays
that actuate
Valves SIB-UV-671 and SIA-UV-672 for Trains
B and
A are both designated
as
Relay K111.
The controls for Trains
A and
B of the
CS system
are located
approximately
4 feet apart
on the control
room panel.
Train A is denoted
by
red labels with Train
B identified by green labels.
3.2.2
Planning
and Scheduling of Corrective Maintenance
On May 21,
1994,
Work Order
(WO) 00661592
was written to replace
Relay
K111
(located in the Train
A ESFAS cabinet).
The
WO identified that,
when
Relay
K111 was de-energized,
CS isolation Valve SIA-UV-672 would receive
an
open signal.
As
a precaution,
the
WO had
a step to ensure that power was
removed
from the valve to prevent it from opening.
The
WO was determined
to be Priority 3 (routine work) and
was scheduled for
July 11.
However,
on May 27',
1994,
the
I&C foreman included the job as work
for,the crew for the weekend
and the Unit 2 scheduling organization
was not
informed of the change.
Therefore,
the work was not included in the Unit 2
weekend
schedule.
While the
WO cover page specifically identified the correct relay to be worked
(Train A), the
WO did not have
a step to verify that the workers were working
on the proper equipment prior to starting work as
had
been stated
in the work
instructions
in the past.
The licensee identified that
a revision to the
maintenance
procedure writer's guide
was issued
in February
1994 that removed
the requirement for all
WOs to include such steps
in the
WO to verify the
proper train and equipment prior to starting work.
3.2.3
Sequence
of Events
At about
7 a.m.
on May 28,
1994, the lead
I&C technician
(Technician
1)
arrived in the
I&C shop
and reviewed the list of work for the day.
The higher
priority surveillance tests
available to be done could not be performed
due to
the existing plant conditions,
so the technician
decided to perform the
Relay Kill replacement
work.
The
I&C foreman
had given Technician
1
a list of
work which could
be done over the weekend;
however,
the foreman did not
conduct
a prejob briefing with the technicians prior to the start of the
Relay
K111 replacement
work.
Both
I&C technicians
had previously worked
on
similar jobs
and
knew that bench testing of the relay was required prior to
(
installation.
Technician
1 reviewed the work package.
Then Technician
2 went
to the
IKC shop to bench test the replacement
relay,
and Technician
1 went to
notify Operations
personnel
that the technicians
were going to replace
Relay K111.
During the interviews,
the technicians
stated that they preferred
to split the work with Technician
1 doing the paperwork
and Technician
2 doing
the bench testing
and gathering of equipment
needed
to perform the job.
Technician
1 directed the job activities
and Technician
2 did not review the
work package until after the event.
The work package
described
the replacement
of Relay Kill for Train A.
The
inspector's
review of the work package
revealed that,
although the majority of
the work instructions specifically addressed
Train A components,
the last few
pages
contained
work instructions for Train B.
Technician
1 stated that
he
remembered
looking at the work package
and
was convinced that the work was to
be done
on Train B.
At approximately 8: 15 a.m.,
Technician
1 went to the
control
room to get permission
from the assistant
SS to perform the work.
After, looking over the work package,
the
SS,
the assistant
SS,
and the third
RO noted that work on Relay
K111 could cause
the
CS isolation valve
(SIA-UV-
672) to go open.
They moved to the Train A portion of the control board,
which included the controls for Valve SIA-UV-672, and discussed
the potential
consequences
of Valve SIA-.UV-672 going open.
The
18C technician
was in the
immediate vicinity of the operations staff.
None of the individuals
interviewed
remembered
specifically stating that the component
was
on Train A.
The assistant
SS also noted that the
WO included
a precaution to ensure that
power was
removed
from Valve SIA-UV-672 to ensure
the valve remained
closed.
The assistant
SS realized that removing power from Valve SIA-UV-672 would
prevent the valve from performing its intended safety function if called
upon.
Therefore,
de-energizing
Valve SIA-UV-672 required entering the Technical
Specification Limiting Condition for Operation for one train of CS being
The
SS agreed to remove
power from Valve SIA-UV-672 and enter the
limiting condition for operation just before the technicians
were ready to
start the actual relay replacement.
Technician
1 then obtained
the relay
cabinet
keys, exited the control
room,
opened
the Train
B cabinet in error,
and returned
the keys to the control
room.
During this time, Technician
2 completed
the bench test of the replacement
relay
and proceeded
to the control
room.
Just outside the control
room,
Technician
2 noted that the Train
B ESFAS cabinet
was
opened
and
assumed
that
the work was
on Train B.
At approximately
9 a.m.,
the technicians
were ready
to start the relay replacement.
Both technicians
went into the control
room
and informed the assistant
SS that they were ready to have the power removed
from Valve SIA-UV-672.
The control
room staff determined
the correct power,
supply for the valve
and directed
an auxiliary operator to open the breaker
for Valve SIA-UV-672.
At 9: 12 a.m.,
the
SS declared
Train A of CS inoperable
when power was
removed
from Valve SIA-UV-672.
The assistant
and the
primary reactor operator
(PO) verified that power was
removed
from the correct
valve.
Since the power was
removed
from the valve,
a white safety
equipment
I
,
l
l
0
status
system
(SESS) indication was lighted
on control
room Panel
B02,
indicating that the valve would not open if an actual
CS actuation
signal
was
received.
At approximately
9,: 15 a.m.,
the assistant
SS then gave the
IKC technicians
permission to start work on the Relay Kill replacement.
When the
PO and
assistant
SS observed
the indicator light for Valve SIA-UV-672 go out, they
told Technician
1 that the valve was de-energized
and pointed towards
an
extinguished
valve indicator light.
Neither the Assistant
SS nor the
PO
recall specifically stating that they were de-energizing
the containment
spray
valve for Train A.
Although Technician
1 had received
some
systems training,
he was not familiar wi'th which section of the control
board contained
which
train.
Then the technicians left the control
room to start the relay work.
Both technicians
went to the Train
8 cabinet just outside the control
room
that
was previously opened
and
began
removing Relay
K111 using the work order
instruction.
In Step
3'.3 of the
WO, the technicians
were to document
the
orientation of the Train
A relay mounted in ESfAS Cabinet
However,
the technicians
were in Train
B Cabinet
This was
a violation of
Technical Specification 6.8. 1 for the failure of the technicians
to follow the
work order instructions (Violation 529/9423-01).
The next step in the
WO was to remove the power leads to the relay.
At
approximately 9:36 a.m.,
the technicians lifted the power leads
which de-
energized
Train
B Relay Kill. Technician
1 then entered
the control
room and
conducted
a visual
check for any unusual
operator activity.
The operators
seemed
to be acting normally,
so Technician
1 returned to the relay cabinet
and continued to work on the relay replacements
He did not speak to any of
the control
room personnel.
When Train
B Relay
K111 was de-energized,
the
Train
B valve (SIB-UV-671) opened
and the
RWT began to gravity drain into the
containment
through the Train
B
CS auxiliary (lower) spray nozzles.
The technicians
continued their work and
began to lift all the wires from the
various parts of Relay K111.
The technicians
had lifted about
50 wires
and
were about
75 percent
complete
when the reactor trip occurred at 11: 15 a.m.
During this time, the technicians
were not aware of the problem iy the control
room with containment
sump alarms.
3.3
Res
onse to Containment
Sum
Level
Increase
3.F 1
Background
At approximately
9:30 a.m.,
both the
and the shift technical
advisor
(STA)
left the control
room.
The Assistant
SS,
a licensed
senior
RO,
and three
reactor operators
(one with a senior reactor operator license)
remained
in the
control
room.
At approximately
9:35 a.m.,
upon completion of the
blowdown
evolution, the secondary
operator
(SO) initiated
a high rate
blowdown on Steam
Generator
(SG)
1.
Approximately
1 minute later,
the
IKC technicians
incorrectly removed the power from Train
B Relay K111, which caused
the
Train
B
CS isolation valve to open.
A Train
B
SESS
alarm was not generated
-10-
because
the valve responded
as expected
on the removal of power to Relay KI11.
The only indication available to the control
room operators
of the change
in
valve position
was the valve position indicator on control
room Panel
B02 that
went from closed
(green)
to open (red).
The
PO was entering
new constants
for
the computer
program that calculated
secondary
power due to performing the
high rate
blowdown in
1
and did not notice the momentary blue
SESS light or
the change
in valve position indication for the Train
B
CS isolation valve.
3.3.2
Sequence
of Events
At approximately 9:44 a.m.,
the east
containment
sump high level alarm
on
control
room Panel
B07 was received.
The
SO appropriately
responded
to the,
alarm.
Approximately
3 minutes later,
upon completion .of the
blowdown
evolution,
the
SO secured
the high rate
blowdown on
1
and returned to
a
normal rate
blowdown.
At about 9:52 a.m.,
the operators
received
an east
containment
pump excess
alarm.
Control
room personnel
followed the alarm
response
procedure
and
began to evaluate
primary plant parameters
to determin~
if there
was
system
(RCS) leak.
The operators
believed
there
was not
an
RCS leak since all the primary system
parameters
were nor%
~
Because
the
SG high rate
blowdown was the last evolution performed before
receipt of the
sump alarm,
the
SO believed the source of the leak to be the
blowdown system.
Both the
PO and the
SO were focused
on blowdown
manipulations
and limited their investigations of plant status
to the primary
and secondary
systems.
Control
board walkdowns of neither the
ESFAS control
board,
which includes the
CS system,
nor the electrical control
boards
were
performed.
The Assistant
SS agreed with the SO's initial assessment
of a
probable
blowdown system leak
and
began to monitor containment
humidity,
temperatur'e,
and
sump levels.
The assistant
SS then
asked
the
PO whether the
CS system could
be the source of the leak
and the
PO responded
that
Valve SIA-UV-672 had
been de-energized
in the closed position.
Both
individuals glanced
over to the
CS system
panel
and noted that the indicator
for Train
A CS isolation Valve SIA-UV-672 was not lighted.
Neither of these
individuals looked at the indicator for Train B, which showed that
isolation Valve SIB-UV-671 was open.
The assistant
SS then directed
the third
RO to monitor containment
parameters
and to determine
the leakage rate,
At approximately
10 a.m.,
the
and the
STA returned to the control
room.
The assistant
SS informed the
SS of the excess
containment
leakage
and that
he
believed the source of the leak to be the
SG blowdown system.
While being
briefed
by the assistant
SS,
the
asked
about the status of the
CS system
and
was told that Valve SIA-UV-672 had
been verified de-energized
and shut.
No one questioned this statement
and
no further investigations
regarding
the
CS system
were performed.
The assistant
SS then directed the
STA to assist
with the trending of containment
parameters.
The
SS also directed his
attention to future actions with other systems,
such
as dealing with the
liquid radwaste
from the containment
sump.
Inspector interviews revealed that
the operators
did not perform any control
board walkdowns after this point.
No further discussions
regarding
the containment
spray
system were held until
after the reactor trip.
It is significant to note that the operations
crew
1
I
j
-11-
did not investigate
the work being performed
by the
18C technicians
even
though they were just outside the control
room.
At approximately
10:07 a.m.,
the
SO isolated
the
1 blowdown line.
At this
time, the operators
did not observe
a change
in the rate of increase
in the
containment
sump level.
The third reactor operator
determined that the leak
rate
was about
50 gallons per minute
(gpm).
At approximately the
same time,
the assistant
and the
SS again verified that they did not have
any
indication of an
RCS leak.
The Assistant
SS then decided to make
a
containment entry to determine
the source of the leak.
At approximately
10: 16 a.m,,
the
SO isolated
blowdown from
2 and the
operators
observed
sump level rising more rapidly.
Based
on this information,
the
SO reasoned
that isolation
oF the blowdown increased
system pressure,
thereby increasing
the leak rate.
As
a result,
the control
room operators
decided
to open the
blowdown isolation valves
and align the blowdown system
for normal operation.
At approximately
10:35 a.m.,
the Assistant
SS exited the control
room to
participate
in the briefing for the containment entry.
Prior to entering the
containment,
the assistant
SS returned to the control
room and
was
informed
that the leak rate remained
at about
50 gpm.
The sssistant
and three other
personnel
entered
the containment
at approximately
11:08 a.m.
occurred
at approximately
11: 15 a.m., shortly after the
team entered
the
containment.
At the
same time, the personnel
in containment
heard
a loud
bang,
which was the failure of the Unit 2 Reactor
Coolant
Pump
1B electrical
enclosure
box.
When the assistant
SS called the control
room
seeking further directions,
the
SS directed
him to continue looking for the
source of the leak.
The personnel
in containment
then identified that water was coming out of the
at the
120 foot elevation
and notified the control
room.
Approximately the time that the source of the leakage
was identified by
personnel
in containment,
Unit
1 operators
arrived in the Unit 2 control
room.
The Unit
1 operators
noted that the Train
B CS isolation valve (SIB-UV-671)
was
open
and
announced
that fact to the Unit 2 crew.
Simultaneously,
the
personnel
in containment notified the Unit 2 control
room of the source of the
leak.
At 11:31 a.m.,
the third reactor operator
closed Train
B
CS isolation
Valve SIB-UV-671.
With only minor exceptions,
all other plant systems
responded
as expected
and
the operators
followed the emergency
operating
procedures
in order to maintain
the plant in hot standby conditions.
3.4
NRC Investi ation of Human Performance
As ects of the Event
3.4. 1
Analysis of Human Performance
During the Event
The licensee
was in the process
of "re-engineering" its organization
and
had
implemented
several pilot programs
to evaluate
changes
in both work and
f
J
I
-12-
resource
allocations.
In the case of the replacement
of Relay Kill, the work
instructions,
the method of work allocation,
and the areas of work assignments
had all recently
been revised.
However,
management
expectations
regarding
the
responsibilities of plant staff related to these
changes
were not effectively
communicated
to the individuals involved in the event.
Interviews revealed
that both operations
and maintenance
staffs were unclear
as to their
responsibilities
in the conduct of maintenance activities.
Specific areas of
confusion
included the
use of the SIN, duties
and responsibilities
of the
dependent
and
independent
workers,
and which department
was responsible
for
notifying management
of rescheduled critical work.
Both the maintenance
and operations staff made erroneous
assumptions
and
became
locked into them.
I&C Technician
1 was'convinced
that
he was to work
on Train "B" and the operating
crew believed the leak was associated
with the
SG blowdown lines.
In both cases,
a questioning attitude
and independent
verification of assumptions
could have prevented
the inadvertent
opening of
the
CS isolation valve and subsequent
3.4. 1. 1
Work Scheduling
In the area of work allocation,
the licensee's
expectation
was that the unit
scheduling staff should
be informed when the work group supervisor
moved
up
previously scheduled
work.
Therefore,
the
I&C foreman's decision to move
up
the scheduled
date
from the original date in July without informing the unit
scheduling organization
was not in accordance
with the licensee's
expectatio'n.
Discussions
with members of the maintenance staff indicated that the
guidelines for rescheduling critical work are not well understood.
, Additionally, the re-engineering
group
has
a scheduler
who must interface with
the existing unit scheduling organization during the transition to the
new
organization.
Confusion regarding
the
scope of the re-engineering effort and
responsibilities
for the individuals participating in the pilot program
may
also
have contributed to the improper handling of the change
in schedule for
the Relay
K111 replacement
work.
3.4. 1.2
Work Order Weaknesses
A contributing factor to the
I&C technicians
working on the wrong relay was
the inclusion of Train
8 specific'instructions
in the work package,
although
only Train A work was to be done.
Technician
1 stated that
he was convinced
that
he would be working on Train
B in part because
some of the pages
specifically addressed
components
in Train B.
The inspector
noted that
equipment identifiers at Palo Verde contain both the unit and train of the
component;
however,
the information is imbedded in an alpha-numeric
character
string.
The train is not readily apparent.
Work package
cover sheets
do not
specifically highlight which unit or train is involved and color coding is not
used
in the
WOs to designate
the affected train,
as is the practice at
some
facilities.
The
WO did not include instructions to verify that work was being
done
on the
correct piece of equipment
as
was the licensee's
previous practice.
The
I
f
0
1
-13-
technicians
were aware that the instructions
were not included in the work
package;
however,
members of the operating
crew stated that they thought
equipment verification was still included in the work package.
The operations
crew involved in this event were unaware of the revision to the maintenance
work instructions
which changed this requirement.
One of the technicians
involved in the event stated that the event might have
been
avoided
by the
inclusion of the verification step in the work instructions.
Operations
personnel
also noted that previous work involving critical or
sensitive
equipment
sometimes
had
a step
on the
WO to conduct
a prejob
briefing with specified
members of the operations staff such
as the
STA.
The
work package for replacement
of Relay
K111 did not require
such
a prejob
briefing with operations'n
this case,
the
STA first became
aware of the
work on the containment
spray
system after the reactor trip.
Therefore,
his
ability to function in an oversight role was compromised
by his lack of
knowledge regarding
the Relay
K111 replacement.
3. 4. 1. 3
S IM Use
0
In February
1993,
the licensee
issued
the
SIM and,
although the personnel
involved in the event were
aware of the existence
of the SIM, none of them had
a clear idea of the purpose of the SIM. 'nterviews
revealed that the Unit'2
operating
crew did not understand their responsibilities
regarding the SIM,
and the
I&C technicians
were
unaware of the existence of the document.
The
inspectors
noted that the
SIM defined evolutions that may, if incorrectly
conducted,
cause
an
ESFAS actuation
as sensitive
issues.
These evolutions
would require plant management
approval
and
a detailed prejob briefing prior
to starting the work.
Licensee
management
stated that the operations staff
were expected
to question
any work on critical systems
that was not
prescheduled
and to discuss
such work with plant management
before authorizing
this type of work activity.
This expectation
was not understood
by the
licensee staff involved in the event.
No one
on the operating
crew notified
senior plant management
about the replacement
of Relay
K111 prior to work
authorization,
Interviews revealed that the operations
crew relied
on the
step in the
WO to determine if the work was
a sensitive evolution and,
therefore,
required
a formal prejob briefing.
In this case,
the operations
crew did not check whether
an evolution was covered in the SIM, and relied
on
the
WO to call it to their attention.
3.4. 1.4
Work Package
Review
Licensee
management
expected
both
IKC technicians
to review the work package
and independently verify the work and actions of the other.
This expectation
was not met by the two ILC technicians
involved in the event.
The work was
divided between
Technicians
1
and 2,
and Technician
2 did not review the work
package until after the reactor trip.
A clear definition of the work order
review responsibilities of an "independent
worker" and
a "dependent
worker"
was not effectively communicated
to the two ILC technicians
in this case,
l
-14-
3.4. 1.5
Communications
Communications
between
the
members of the operating
crew and the two
technicians
were not detailed
enough to identify the misunderstanding
of which
train was to be worked on.
The inspectors
noted that communications
among
operations staff were
much more detailed
than those
between operations
and
maintenance
personnel
during the event.
Both groups
understood
that they were
working on Relay Kill for a
CS isolation valve,
but
no one specifically
mentioned
the affected train.
A contributing factor was the understanding
on
the part of the operators
that the work instructions
included
a step to verify
what equipment
would be worked on.
Another contributor to the confusion
was
the inconsistency
in identifying
CS Valves SIB-UV-671 and SIA-UV-672, with
regard to train designation with lower numbers usually associated
with
Train A, except
in this case.
During the initial stages
of the event, briefings of the control
room staff,
similar to those routinely conducted
in the plant specific simulator during
training sessions,
were not held.
Interviews revealed that,
when control
room
briefings were held in the latter stages
of the event,
the content
included
assumptions
as well
as facts.
The assertion
that there
was
a leak in
containment
apparently
due to manipulations of the
SG blowdown system
reinforced the crew's conviction that the leak was related to the
blowdown
system.,
This may also
have contributed to the operators
not walking down the
other control panels.
It was not until the call from the personnel
in
containment,
simultaneous
with the identification of the open valve by
individuals from Unit 1, that the control, room staff became
aware that the
Train
B
CS isolation valve was open.
When asked
whether they had
been trained
on the identification of leaks in containment,
several
Unit 2 operators
stated
that they had
been
and that it had always
been
a precursor to either
a main
steam, line break or
a loss of coolant accident
in containment.
It is unclear
whether this also contributed to the operators
overly focusing
on the blowdown
system.
3.4. 1.6
Lack of Effective guestioning Attitude
Members of the operations staff were overly focused
on the blowdown system
as
the source of the containment
sump level increase.
Since the last evolution
conducted
immediately before receiving the
sump level high alarm involved the
blowdown system,
they suspected
a leak in one of the blowdown control valves.
Convinced that the
IKC technicians
had disconnected
Train A Relay
K111
20 minutes before receiving the
sump alarm,
and that the Train A CS isolation
valve was de-energized
in the closed position,
the operations
crew did not
verify the status of equipment
on that portion of the control board,
Hembers
of the operating
crew did not maintain
a questioning attitude
and did not
reassess
the condition of all plant systems.
Hembers of the operations staff
offered that they
may have
checked
the status of the containment
spray
system
if they
had
been notified at the time Relay
K111 was disconnected.
No member
of the operating
crew noticed Technician 1's entry into the control
room
immediately after Relay Kill was disconnected.
Further,
the operations
crew
'
I
-15-
did not investigate
the work being done
by the technicians
even
though they
were just outside
the control
room.
3.4. 1.7
"Re-Engineering" Considerations
The inspectors
noted that the streamlining effort included in the licensee's
re-engineering
program
had resulted
in removal of work instructions
deemed
to
be unnecessary,
provision for assignment
of work by shop foremen,
and
reassignment
of work crews.
In the case of the work package,
the step to
verify that work was being perFormed
on the correct
equipment
was not
included.
The inspectors
noted that,
although
the, licensee
is conducting
a site-wide
"re-engineering" effort, additional attention
should
be taken in revising
instructions,
procedures,
and work processes.
It's important to understand
how and
why the instructions,
procedures,
and work processes
were developed
before deleting or modifying specific items.
Specific procedural
steps
may
have
been
included
as
a result of previous incidents,
and removal of these
steps
may remove
a barrier to failure.
Similarly, for work practices
the
requirement
to notify management
of schedular
changes
for work on critical"
equipment
may have
been the result of a prior event at the plant.
There
should
be
a careful consideration
of the balance
between facilitating greater
work process efficiency and assuring that work quality is maintained.
In
addition,
the licensee
should assure
that the expectations
for plant staff
have
been effectively communicated.
This should include
a method to determine
whether these
expectations
are in fact being met.
3.5
Evaluation of the Licensee's
Investi ation
The licensee classified
the event
as serious
and initiated
a formal Category
2
investigation.
The station operating
experience
department
formed
an
investigation
team that included
management
personnel
from the operations,
maintenance,
and engineering
organizations.
The team gathered
the relevant
facts of the event, identified pertinent restart
issues,
and conducted
several
management
review team meetings to review the event
issues
and findings of the
investigation.
Although the licensee's
event investigation
was not complete at the
end of the
inspection,
the licensee's
event
and causal
factors diagram
was reviewed to
assess
the scope
and findings of the licensee's
investigation.
The inspectors
found that the licensee's
investigation
was thorough
and objective.
Almost
all of the concerns identified by the inspectors
had been'aptured
in the
licensee's initial investigation
summary.
The investigation
team
had also
captured
many of"the recommendations
and lessons
learned
suggested
by the
individuals involved in the event.
The licensee
took immediate corrective actions
as
a result of the
investigation,
which included:
J
i
I
I
I
'0
-16-
Conducting
Maintenance
Department
stand-down
meetings
which emphasized
communications
and prejob briefings,
Initiating a formal communications
standards
team to evaluate
the
communication
problems
and develop
a standard
practice,
~
Writing Operations
department
night orders
and conducting briefings,
Initiating a re-assessment
of the "re-engineering"
process,
and
~
Counseling
and issuing positive discipline to the
I&C technicians.
The licensee
stated that it intended to closely scrutinize its current plans
for "re-engineering"
to assess
whether the
scope of the effort should
be
modified.
4
ELECTRICAL PENETRATION ASSEMBLY PERFORMANCE
4.1
RCP Electrical Penetration
Assembl
The Unit 2
18 electrical
(2ENANZ44) is
a medium voltage
manufactured
by Conax
and is located
on the
100 foot level of the
containment.
The electrical
assembly
contains three
1500
MCM bus
bars for the three-phase
13.8 kilovolt (kV) power to
RCP 18.
These
bus bars
are connected,
via 1500
MCM connectors
and ceramic terminal bushings,
to bare
terminal lugs.
The attached electrical
power cables that go to the
18
motor are three-conductor,
250
MCM, shielded
cables
rated for 15 Kv.
A
termination junction/enclosure
box is attached
to the
end of the electrical
assembly
inside containment.
The power cables
run From the
terminal
lugs
up through holes in the top cover of this enclosure
box'.
1. 1
Event Circumstances
and Assembly
Damage
As
a result of the inadvertent
opening of the
CS isolation valve
and the
partial
CS inside containment,
borated water leaked into the, enclosure
box and
onto= the bare terminal lugs.
This caused
arcing inside of the enclosure
box
and eventually resulted
in
a Train
A phase-to-ground
fault followed by a
phase-to-phase
fault.
18 tripped
on overcurrent
as
a result of the phase-
to-phase fault.
The maximum asymmetrical fault current
was 34,890
amperes
(amps).
The enclosure
box blew open
and suffered extensive
damage
as
a result
of the temperature/pressure
increase
caused
by the arcing
and the fault.
There were
no missiles
developed
as
a result of the explosion;
however,
many
of the enclosure
box cover fasteners
were missing
and the cover panels
had
significantly separated
along th'e'edges
from the
box frame.
Upon inspecting
the penetration
aFter the fault, the licensee
noted extensive
damage to the enclosure
box and its internals.
The enclosure
box frame was
bent
and the front and side covers of the
box were
bowed outward, with over
70 percent of the fasteners
missing
as
a result of the explosion.
The top and
,
J
'
f
1
e
-17-
bottom covers of the enclosure
box were also
bowed.
The entire enclosure
was
carbonized,
including the melamine insulating spacer
and the heatshrink tubing
over the ceramic terminal
bushings of the penetration
assembly.
The power
cables
inside the enclosure
box exhibited
damage
ranging from carbonized
stress
cones
to splitting of the stress
cones.
In addition,
the )500
HCH
connectors
and the cable connectors
were damaged.
4. 1.2
Evaluation of Original Design Adequacy of the
During the inspection,
the inspectors
reviewed the original design of the
electrical
enclosure
boxes
and of the Class
IE electrical
enclosure
boxes.
The termination enclosure
boxes for the
electrical
are not environmentally qualified.
However,
the
enclosure
was originally designed
to be drip-tight
(NEHA type 4) to prohibit
direct spray
impingement
and water intrusion into the
box and onto the
conductors.
By design,
each entry point into the
box is sealed
to
prevent moisture intrusion,
and all of the covers
have gaskets.
The enclosure
box for RCP
18 has cable entering
from the top.
Although the cable
hubs
located at the top of the enclosure
box should
have
been
sealed,
there is
evidence that borated water
may have leaked
by the hubs.
However,
upon
inspecting
the enclosure
box, the licensee
determined that the root cause of
the water intrusion
was
due to field installed,
ground strap cable clips that
were bolted through the top cover of the enclosure
box without any sealant.
The lack of sealant
around
these
bolts negated
the manufacturer's
drip tight
qualification of the enclosure.
The inspectors
questioned
whether or not the
same type of water intrusion
could occur within Class
IE electrical
The licensee
confirmed
that all non-Class
IE,
as well as all of the Class
in
containment,
have drip-proof,
NEHA Type
4 enclosures
in order to prevent
faults caused
by water intrusion,
and that the Class
assemblies
~are environmentally qualified without taking credit for the waterproof
enclosure
box.
The Class
lE penetrations
are environmentally qualified with
Raychem splices
covering the terminal
lugs
and other connections
and were
tested without enclosure
boxes.
As
a extra measure,
the enclosure
boxes
are
designed for bottom cable entry only with no holes in the top or sides.
Starting in June
1992,
the licensee
performed
a complete
walkdown of these
environmentally qualified penetrations
and verified that the configuration of
the enclosure
boxes
was in compliance with the qualification requirements.
The inspectors
concluded that the Class
lE and non-Class
lE penetrations
were
designed, not to be susceptible
to faults caused
by water intrusion into the
enclosure
box and, therefore,
properly installed penetrations
should not be
adversely
affected
by containment
spray.
The licensee's
design of electrical
assemblies
conforms to
Regulatory
Guide 1.63,
Revision 2, "Electric Penetration
Assemblies
in
Containment Structures for Light-Water-Cooled Nuclear
Power Plants,"
which
endorses
IEEE Standard
317-1976,
"IEEE Standard for Electric Penetration
Assemblies
in Containment Structures
for Nuclear
Power Generating Stations."
The regulatory guide states
that the electrical
should
be designed
t
i
-18-
to withstand,
without loss of mechanical
integrity, the maximum fault current
versus
time conditions that could occur
as
a result of single
random failures
of circuit overload devices.
As
a result, this electrical
is
provided with redundant
(primary and backup)
conductor overcurrent protective
devices.
Primary protection is provided
by the individual
1B load circuit
breaker
(2E-NAN-S02L) and
backup protection is provided
by the main bus feeder
breaker
(2E-NAN-S02A or 2E-NAN-S04B).
Additional industry guidance
concerning
the coordination
between
the primary and backup overcurrent protective devices
is contained
in ANSI/IEEE Standard
741-1986.
The licensee
has followed the
guidance
in Regulatory
Guide 1.63
as amplified in ANSI/IEEE Standard
741-1986.
Proper primary and
backup penetration
protection device coordination
and
response
times
has
been
demonstrated
by the licensee
per Bechtel
Calculation
13-EC-NA-220 and the corresponding 'coordination
curves for the
primary and backup protection devices.
During the event,
the fault was picked
up by the primary overcurrent
protection device.
The fault current energized
the instantaneous
element of
the
250/251M phase
overcurrent relay which has
an instantaneous
trip setpoint
of 6000
amps.
As
a result,
Breaker
2E-NAN-S02L relayed out within five
cycles.
The relay/breaker
response
time of five cycles
was within the rated
timing characteristic
of this combination.
The breaker coordination for the
event
was evaluated
by licensee
engineering
personnel
and concluded to be
adequate.
The maximum symmetrical fault current of approximately
24,000
amps
that existed for a short time was below the current/time
thermal capability
curve for the penetration,
indicating that the fault did not damage
the
The inspectors
were concerned
that the fault might have
reduced
the qualified life of the penetration.
However,
Conax confirmed that the
fault experienced
was within the penetration
test values
and
was under the
damage
curve.
Therefore,
the licensee
and
Conax concluded that the event
would not have
an impact
on the 40-year qualified life of the penetration.
4.2
Evaluation of Testin
and Corrective Actions
4.2. 1
Electrical Penetration
Assembl
The licensee
performed
a local leak rate test
on the electrical
and determined that the containment
pressure
boundary integrity was not
breached
as
a result of the fault and explosion.
The leak rate
was less
than
10 standard
cubic centimeters
per second
and, therefore,
met the leak test
acceptance
criteria.
In order to verify the electrical integrity of the
the vendor technical
manual
recommended
performing
a megger test
at
a minimum value of 500 volts with a minimum acceptance
value of
1,000
megaohms.
The licensee
performed
a
5
kV dc megger test
on the
and obtained
a resistance
reading of 100,000
megaohms.
Based
on
the results of the local leak rate test
and the megger test,
the licensee
concluded that the penetration
was not degraded
as
a result of the fault and
resulting explosion.
Due to the visible damage of the
Raychem stress
cones,
the licensee
also
performed
a dc high potential test of the cable
from the penetration
to the
)
l
1
t
-19-
18 motor.
Components
in the enclosure
box such
as the bushings
and
terminals
were cleaned,
and the
damaged
stress
cones
were replaced.
4.2.2
1B Motor
The licensee
performed
a visual
examination of the
RCP motor and completed
a
doble test at the
The licensee
compared
the doble test
results
to previous doble results
and found no evidence of degradation.
Other
tests
included
a
5 Kv dc megger test of the
RCP motor with the motor power
disconnected,
a polarization
index test of the motor,
and
an over-
voltage test of the
1B surge capacitors.
A 5 Kv dc megger test of the
cables
between
the penetration
and the
1B motor was also completed.
The
results of these tests
met all of the acceptance
criteria
and the licensee
concluded that the motor
and leads to the motor from the penetration
were not
degraded
or damaged
as
a result of the event.
4.2.3
Breaker
The licensee
inspected
the circuit breaker/switchgear
cubicle that tripped
on
and
found
no evidence of degradation
or damage.
A 5 Kv dc megger
test of the cables
between
the penetration
and the switchgear cubicle was also
completed, with satisfactory results.
4.2.4
Walkdowns
and
Ins ections
Engineering
performed
a complete
walkdown of the electrical
components
in
containment that appeared
to have
been
subjected
to the inadvertent
CS.
The
components
that were identified during the walkdowns were inspected for
internal
leakage
and
damage.
There
was evidence of water leakage
into one
junction box and into one nozzle
dam panel
located
in the affected
area;
however,
there
was
no evidence of damage
found.
During an inspection of the other
RCP enclosure
boxes,
the licensee
found that
the
1A electrical
enclosure
box also
had ground strap cable
clips bolted through the top cover.
There
was evidence of moisture intrusion
into the
1A enclosure
box and of minor arcing inside the box.
The
2A
and
2B electrical
enclosure
boxes did not have field installed
bolts in the top cover
and did not show signs of moisture intrusion.
Corrective actions
included sealing the cable
hubs in the top cover of all of
the
RCP electrical
enclosure
boxes
in each unit and sealing
around
the bolts that were installed in the two enclosure
boxes.
The licensee
performed
walkdowns of all other electrical penetration
enclosure
boxes in all three units to verify that there
were
no bol'ts or other objects
protruding through the top of any penetration
enclosures,
The inspections
revealed that there
were
no other non-Class lf enclosure
boxes that
had cable
entrances
through the top cover.
However,
some of the boxes did have
conditions that indicated that they may not
be completely drip-tight.
The
licensee identified and replaced
missing screws
on the top cover of three
non-
-20-
Class
1E enclosure
boxes
in Unit
2 and sealed
other components
that protruded
through the top cover in three other non-Class
1E enclosures.
4.3
Conclusions
The inspectors
concluded that the licensee
adequately
tested
the electrical
assembly
and all of the other separate
components
in the
1B
power circuit that could have potentially been
damaged
or degraded
as
a result
of the fault.
In addition,
a final megger test of the entire circuit from the
switchgear cubicle
up to and including the
1B motor provided additional
assurance
that the integrity of the entire
power circuit was not
compromised'he
licensee will perform
a doble test
and polarization
index test
from the
switchgear cubicle to the
1B motor during the next Unit 2 refueling
outage.
The doble test results will be compared
to historical test data in
order to further evaluate
any possible degradation
to the power circuit.
The inspectors
also concluded that the licensee
promptly and adequately
inspected
and evaluated
the effect of the inadvertent
containment
spray
on all
other components
in the affected
area.
The licensee
performed
a detailed
walkdown
and inspection of the electrical
enclosure
boxes
in all
three units
and completed
the necessary
corrective actions in order to assure
water tightness of the boxes.
5
OTHER CONPONENTS
POTENTIALLY AFFECTED
5. 1
Licensee
Walkdowns
and
Ins ections
As
a result of the partial containment
spray,
licensee
personnel
performed
walkdowns of the areas
inside containment
which had
been wetted
down on the
80,
100,
and
120 foot elevations
~
They noted for followup action
and
evaluation
those
components
(electrical
and mechanical)
which had indications
of being
sprayed
by the borated water from the
RWT (boric acid crystals
evident).
The components
inspected
and reviewed included junction boxes,
emergency lights, instrument racks,
valves,
cable pull boxes,
cable,
Thermo-
Lag, snubbers,
and pipe insulation.
The licensee
used the evaluations
of a
previous containment
spray actuation
event
(EER 91-SI-088)
in Unit 3 in 1991,
which occurred while the unit was operating
at
100 percent
power.
In certain cases,
equipment
enclosures
were opened to determine
the extent of
water entry.
If signs of water or boric acid crystals
were evident,
licensee
personnel
dried
and cleaned
the equipment.
The licensee
evaluated
the various
components
affected
and documented their evaluation
in
a memorandum
dated
June
1,
1994.
The licensee
concluded that,
except for the
1B
electrical
connections,
no damage to containment
components
had
occurred
as
a result of the containment
spray event.
In a few cases,
some
boric acid crystals
were cleaned
and removed,
but in no case
was there
a need
for replacement
of components.
j
I
I
l
I
l
-21-
5.2
Conclusions
The inspectors
conducted
tours of containment
on the day of the spray event
and also during the week following the event.
The inspectors
observed
the
area
which had
been wetted
by the spray,
the equipment that was potentially
affected,
and licensee
personnel
performing walkdown inspections.
The items
identified to be potentially affected
by the licensee
were in agreement
with
the inspectors'bservations.
The licensee's
evaluation of the negligible
affects
from the spray
was reviewed
and the evaluation
appeared
appropriate.
It was noted that there
have
been
no indications of any equipment
problems
following a Unit 3 inadvertent
containment
spray actuation
event in 1991.
l
j
,
I
ATTACHMENT 1
1
PERSONS
CONTACTED
1.1
Licensee
Personnel
I
t
- R
- J
- R
M.
- D
- R.
- B
M.
- D
- J
- D
- G
- J
- R
- G
- p
D.
Adney, Plant Manager,
Unit 3
Bailey, Vice President,
Nuclear Engineering
Flood, Plant Manager,
Unit 2
Friedlander,
Manager,
Unit
2 Work Control
Garchow, Director, Site Technical
Support
Gouge, Director, Plant Support
Grabo,
Supervisor,
Nuclear Regulatory Affairs
Hypse, Acting Manager, Electrical
and
IEC Engineering
Kanitz, Senior Engineer,
Nuclear Regulatory Affairs
Levine, Vice President,
Nuclear Production
Mauldin, Director, Maintenance
Overbeck, Assistant to Vice President,
Nuclear Production
Reynoso,
Incident Investigator,
Nuclear Assurance
Roberson,
Senior Engineer,
Nuclear Regulatory Affairs
Rogalski,
Engineer,
Nuclear Regulatory Affairs
Seaman,
Director, Nuclear Assurance
Shanker,
Department
Leader,
Nuclear Assurance
Wiley, Manager,
Unit 2 Operations
Withers,
Primary Discipline Engineer,
Electrical
Engineering
1.2
Other Personnel
.* F. Gowers, Site Representative,
El
Paso Electric Company
- R. Henry, Site Representative,
Salt River Project
1.3
NRC Personnel
F. Burrows, Electrical
Engineer,
- P.
Eng, Senior Operations
Engineer,
J.
Ganiere,
Intern,
- K. Johnston,
Senior Resident
Inspector
- A. MacDougall, Resident
Inspector
- H.
Wong, Chief, Reactor Projects
Branch
F
- Attended Exit Meeting
on June
3,
1994
2
EXIT MEETING
An exit meeting
was conducted
on June
3,
1994.
inspectors
summarized
the scope
and findings of
acknowledged
the inspection findings documented
did not identify as proprietary
any information
the inspectors.
During this meeting,
the
the report.
The licensee
in this re'port.
The licensee
provided to, or reviewed by,
,
I
I
ATTACHMENT 2
ACRONYHS
amps
dc
gpm
IKC
kv
PO
SESS
SIN
~
amperes
containment
spray
direct current
engineered
safety features
engineered
safety features
actuation
system
gallons per minute,
instrument
and control
kilovolts
primary operator
pump
system
reactor operator
refueling water tank
safety
equipment
status
system
Safety
Issues
Nanual
secondary
operator
shift supervisor
shift technical
advisor
work order
'
l
l