ML17312B464
| ML17312B464 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 05/20/1997 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML17312B462 | List: |
| References | |
| 50-528-97-05, 50-528-97-5, 50-529-97-05, 50-529-97-5, 50-530-97-05, 50-530-97-5, NUDOCS 9706020025 | |
| Download: ML17312B464 (40) | |
See also: IR 05000528/1997005
Text
ENCLOSURE 2
U.S. NUCLEAR REGULATORY COMMISSION
.REGION IV
Docket Nos.:
License Nos.:
Report No.:
Licensee:
Facility:
Location:
Dates:
Inspectors:
Approved By:
50-528
50-529
50-530
NPF-51
50-528/97-05
50-529/97-05
50-530/97-05
Arizona Public Service Company
Palo Verde Nuclear Generating Station, Units 1, 2, and 3
5951 S. Wintersburg Road
Tonopah, Arizona
March 23 through May 3, 1997
K. Johnston,
Senior Resident Inspector
D. Orsini, Resident Inspector
D. Carter, Resident Inspector
J. Russell, Resident Inspector, SONGS
D. Acker, Senior Project Engineer
D. Corporandy,
Project Engineer
Dennis F. Kirsch, Chief
Reactor Projects Branch F
Attachment:
Supplemental
Information
9706020025
970520
ADDCK 05000528
8
-2-
e
EXECUTIVE SUMMARY
Palo Verde Nuclear Generating Station, Units 1, 2, and 3
NRC Inspection Report 50-528/97-05; 50-529/97-05; 50-530/97-05
~Oererione
In general, the conduct of operations was good.
Excellent operator response
was
provided for the Unit 2 pressurizer spray valve packing leak, including the
conservative
decision to declare an Unusual Event (Section 01.4).
However,
inspectors observed inconsistent implementation of operations communications
standards:
particularly, the failure to consistently accomplish closed-loop
communications
during certain Unit 3 startup activities (Section 01.2); and
weaknesses
in the thoroughness
of logkeeping, particularly the failure to identify
changes
in major equipment status and plant problems in the logs (Section 01.3).
Operations management
responded
effectively by reemphasizing
their expectations
and assuring that procedures
clearly communicated
expectations.
Control room operations staff performance
during entry into Unit 3 midloop
operations was excellent.
Valve lineups were properly accomplished,
communications were excellent, and the nuclear assurance
organization provided
effective oversight of the evolution (Section 01.1).
Maintenance
~
Formal communications
between the scaffold team and the heating, ventilation, and
air conditioning (HVAC) maintenance
team were not established
to assure the
HVAC maintenance
team maintained adequate
clearance between
platform and plant equipment
in the fuel handling building (Section M4.1).
Encnineering
e
~
Following a water hammer event in the Unit 3 Train A containment spray system,
operations
and engineering
performed thorough actions to assure the operability of
Train A. However, they did not promptly assess
the transportability of-the cause
and assess
the operability of the opposite train (Section M1.1).
~
A violation was identified by NRC wherein el'ectrical maintenance
technicians
violated electrical installation specification requirements
by using adhesive-backed
cable tie bases to anchor cable ties supporting cables in a Unit 3 vital battery
charger.
The anchors were first used in 1994 and again in March 1997, after the
first anchor failed, contributing to a charger breaker failure.
Further, the initial
repairs and subsequent
charger inspections were not documented
on the work
activity sheets
(Section E2.1).
-3-
System design weaknesses
in the automatic makeup to the volume control tank did
not allow the system to function in the last of core life and made the system
unreliable.
As a result, operator actions were required to compensate
for system
problems.
Engineering made little progress
in addressing
these issues, even though
they had, first been recognized
in 1988 and were the subject of both condition
reports and senior management
action plans.
The known system deficiencies were
not well established
in operating procedures
nor well understood
by plant operators
(Section E2.2)
~
A violation of 10 CFR Part 50, Appendix B, Criterion 3, was identified because
design engineering
did not assure that appropriate quality standards
were applied to
in boundaries that served safety-related functions (Section E8.1).
II
1
I
t
Re ort Details
Summar
of Plant Status
Unit
1 remained at essentially 100 percent power throughout this inspection period with
the exception of a short term power reduction to 61 percent on March 25 for repairs to the
2C low pressure
heater.
Unit 2 remained at essentially 100 percent power throughout this inspection period.
On
April 21, Unit 2 pressurizer spray Valve RCE-PV-100F developed
an excessive
packing
leak.
The licensee entered
and exited an Unusual Event (UE) emergency classification
(Section 01.4)
Unit 3 began this inspection period in Mode 6.
On March 31, following completion of a
37-day refueling outage, the unit commenced
a reactor startup and power ascension.
On
April 12, the unit reduced power from 100 to 40 percent to repair a leak on the
2A condenser
hotwell.
Following the repair, the unit returned to 100 percent power and
remained there for the duration of the inspection period.
I. 0 erations
01
Conduct of Operations (71707)
01.1
Reactor Coolant S stem
Reduced Inventor
in Pre aration for Midloo
0 erations
Unit 3
a.
Ins ection Sco
e
On March 24, during the night shift, the inspectors observed the control room staff
make preparations for midloop operations.
The dedicated midloop team was in the
process of draining the RCS to the reduced inventory elevation.
The inspectors
had
discussions with the midloop team, onshift control room staff, outage management,
and other plant personnel.
In addition, the inspectors verified completion of
required prerequisites,
which included physical plant walkdowns.
b.
Observations
and Findin s
The inspectors
observed the midloop team drain the RCS from 114 feet, the reactor
vessel flange level, to 111 feet, 6 inches,
a stable level prior to entering reduced
inventory.
A decision was made to stop at this level to allow the completion of the
steam generator tube plugging activities before continuing to reduced inventory and
midloop operations.
The inspectors
noted that the Procedure 40OP-9ZZ16, "RCS Drain Operations,"
Revision 6, had been revised as part of the corrective actions for the drain path
misalignment that occurred during the last refueling outage
in Unit 1. Appendix Q
of the procedure
established
a drain path for draining of the RCS.
In two past
events, Valve CHN-V495, normally a locked closed valve, was left in the closed
position although verified to be open.
One of the changes
in the revised procedure
I
)1
-2-
removed Valve CHN-V495'from the body of the drain path alignment checklists and
converted it to a separate
action step with an added independent
verification step.
The inspectors accompanied
the auxiliary operator (AO) who performed the
independent
verification portion of Appendix Q.
The AO was directed by the
midloop control room supervisor
(CRS) to perform the checklist.
The AO performed
the checklist on the first page of Appendix Q and returned to the control room.
The
midloop CRS identified that the AO had performed only the first page of the two
page checklist and directed the AO to complete the checklist.
The AO went back to
the field and completed the second
page, which contained the independent
verification for Valve CHN-V495.
Although the midloop CRS prevented the AO from missing the second
page, the
inspectors
noted that the AO did not realize that there were two pages for valve
lineup and verification.
The inspectors verified that the AO attended the prejob
briefing that discussed
the revised procedure
and concluded that the AO did not
adequately review the contents of Appendix Q prior to performing the job. The
inspectors discussed
the observation with the unit department
leader.
The unit
department
leader stated that the AO's inattention to detail did not meet operations
management
expectations.
The inspectors verified that the makeup and gravity flow paths were aligned
properly.
Communications
between the midloop team and the control room staff
were excellent.
Nuclear assurance
was present for the evolution and provided
additional verification for the valve lineups'.
01.2
Plant Startu
Activities - Unit 3
'.
Ins ection Sco
e
The inspectors observed
portions of the Unit 3 plant startup following the sixth
refueling outage, including closing the main generator output breaker and
transferring steam generator feedwater supply from the downcomer to the
economizer.
b.
Observations
and Findin s
Both the closing of the main generator output breaker and the feedwater swapover
evolutions were conducted successfully.
System transients resulting from these
operations were within expected
levels.
The inspectors did note that the control
room staff did not consistently implement operations standards
for communications
and annunciator response
during the conduct of the main generator output breaker
closing operation.
Operations standards
provide the expectation
of closed loop
communications
(statement,
repeat-back,
acknowledgment).
However,
in some
instances,
communications
between the reactor operators
shift supervisor
(SS) did not include a repeat back and acknowledgment.
-3-
Additionally, operations standards
required ROs to announce
control room alarms
and the CRS to acknowledge the alarm announcements.
The inspectors noted that
there were instances where alarms were not announced
by ROs acknowledging the
alarm and other instances
where announced
alarms were not acknowledged
by the,
CRS.
The inspectors discussed
these observations
with the operations
standards
department
leader, who was observing the startup activities.
He acknowledged that
he had made the same observations
and planned to discuss them with the SS when
the unit was stable following the closure of the generator output breaker.
The
department
leader later confirmed that he had discussed
these communications
standards
with the SS.
The inspectors
did observe that during the subsequent
feedwater swapover activity that communications
were more consistent with
operations standards.
Review of 0 erations
Lo books
Unit 3
Ins ection Sco
e
On a routine basis, the ins'pectors reviewed RO and unit logs.
The inspectors
compared the logs to plant activities and events.
Observations
and Findin s
Section E2.2 of this report discusses
problems experienced
during the automatic
makeup to the Unit 2 volume control tank (VCT). In summary,
an automatic
makeup terminated after adding approximately 2 percent level to the VCT and the
boration flow totalizer did not count.
As a result, operators
did not have board
indication of boron added and ultimately had,to raise control rods to adjust
reactivity.
The inspectors
noted that this event was not discussed
in either the RO or unit logs.
The,issue was turned over to the oncoming shift and discussed
at the operation
director's morning meeting as a reactivity management
issue.
The inspectors
expressed
concern that this event was not logged.
In this case, logging the event
would assure that key.information was captured for an ongoing engineering
investigation.
On March 28, at approximately 4 a.m., with Unit 3 in Mode 4, operations personnel
removed the vital "C" battery charger EPKCH13 from service and placed the "AC"
swing battery charger EPKAH15 in service for corrective maintenance.
This action
complied with Technical Specification (TS) 3.8.2.1, Action B.
On April 1, the
inspectors reviewed the unit logs and determined that a logbook entry had not been
made for this evolution.
The inspectors discussed
this observation with the Unit 3
department
leader.
He recognized that major equipment status changes
should be
logged and subsequently
determined that it was an oversight of the crew.
,IJ
-4-
As discussed
in Section E2.1 of this report, maintenance
support personnel
logged
maintenance
rule unavailability of the PK C vital battery charger to the PK A vital
battery charger.
This was the result of weaknesses
in the unit logs which identified
that a Train A charger had been removed from service and did not specify which of
the two chargers
had been removed from service.
The inspectors discussed
these observations
with operations
management.
The
inspectors expressed
concern that operators may not be aware of the different
users of their logs and the importance of complete and accurate information.
Operations management
subsequently
reemphasized
their expectation for
logkeeping with operators.
In addition, they initiated a review of log keeping
procedures to assess
whether their expectations
were clearly communicated.
01.4
Hi h RCS Leaka
e - Unit 2
On April 21, 1997, at approximately 3:16 p.m., with the reactor operating at
100 percent power, operators received
a control room alarm indicating a high
reactor drain tank (RDT) pressure.
Operators observed that the temperature
and
level of the RDT were increasing
and that there was a mismatch between charging
and letdown flow. The inspectors observed
operators
assess
and eliminate
potential sources of RCS leakage to the RDT. They determined that the probable
source was a pressurizer spray valve packing.
At 3:57 p.m., the site shift manager
(SSM) declared
an UE and entered the TS
action for identified leakage greater than 10 gpm.
Emergency plan implementing
procedures
required an UE be declared with 10 gpm of unidentified RCS leakage and
25 gpm of identified RCS leakage.
TS 1.15, the definition for identified leakage,
defines identified leakage
as leakage from closed systems to collecting tanks.
At
the time they declared the UE, the SSM and SS were concerned with temperature
and level conditions in the RDT. Shortly after the declaration, the RDT conditions
were stabilized.
A team of operations,
engineering,
radiation protection, and maintenance
personnel
entered containment at approximately 5:30 p.m. to search for the leakage source.
They identified that the leak was from the packing leakoff line for pressurizer spray
Valve RC-PV-100F.
An operator closed upstream
and downstream
isolation valves
to the spray valve, terminating the leak. At 6:46 p.m., the SSM terminated the UE.
The inspectors observed
excellent operator response
and communications.
Additionally, the decision made by the SSM and the SS for event classification was
conservative.
-5-
01.5
Conclusions
on Conduct of 0 erations
In general, the conduct of operations was good.
Excellent operator response
was
provided for the Unit 2 pressurizer spray valve packing leak, including the
conservative
decision to declare the UE. However, inspectors observed inconsistent
implementation of operations communications
standards,
particularly the failure to
consistently accomplish closed-loop communications
during certain Unit 3 startup
activities, and weakness
in the thoroughness
of logkeeping,
as evidenced
by the
failure to identify a problem and changes
in major equipment status in the logs.
Operations management
responded
by reemphasizing
their expectations
and
reviewing procedures
to assure that these expectations
were clearly communicated.
08
Miscellaneous Operations Issues (92901)
08.1
Closed
Violation 50-528 96013-01 50-530 96013-01:
" ventilation boundary door
control.
This violation concerned
three examples where plant personnel
did not
properly control doors required to be closed to maintain fuel handling building and
auxiliary building ventilation boundary integrity.
The licensee responded
to this violation by letter dated November 21, ]996.
Actions completed at the time the response
was submitted were:
The maintenance
and engineering departments
had performed
a walkdown in
all three units to document field labeling on doors.
During these walkdowns,
temporary door labels were installed to clarify door numbering.
~
Bulletins were issued to inform site personnel
of the door control issues and
the consequences
of inadequate
door control.
~
A multidisciplinary design review team was established
to ensure design
requirements
were implemented for controlled doors.
Door control
Procedure 40DP-9ZZ17 was revised to incorporate their findings.
The inspectors found that each of these items had been satisfactorily completed.
The licensee also initiated the following corrective actions to prevent recurrence.
They planned to implement a design modification to install permanent door
signage
in all units.
They planned to train appropriate station personnel
on changes
to the door
control procedure.
Additionally, all personnel would receive training on
expectations
for door control and door labeling during site access training
and refresher training.
The inspectors found that these planned and completed actions were acceptable.
-6-
Closed
Licensee Event Re ort
LER 50-528 95012
Revision 0: reactor trip
caused
by a high water level in Steam Generator
1. This event was discussed
and
dispositioned
in NRC Inspection Report 50-528/95-21; 50-529/95-21;
50-530/95-21.
No new issues were revealed by the LER.
Closed
LER 50-528 95014
Revision 0: reactor trip following the degradation
of
main feedwater control system {FWCS). This event was discussed
in NRC
Inspection Report 50-528/95-21; 50-529/95-21; 50-530/95-21.
The inspection
report discussed that the 120-Vac control power Bus NNN-D11, which supplies the
FWCS, failed to complete an automatic transfer from its alternate power supply
Bus PBA-503 to the normal nonclass power supply, causing the loss of power to
Bus NNN-D11. As a result of the loss of power to the FWCS, the main feedwater
pumps went to minimum speed
and feedwater control valves closed, causing steam
generator
levels to decrease.
12 level decreased
below the reactor
trip setpoint resulting in a reactor trip.
The inspection report also noted that the licensee had determined that aligning
Bus NNN-D11 with its normal supply was preferable to aligning it with its alternate
supply.
Subsequent
to the inspection report, the LER identified that operating
procedures
were revised to reflect alignment of Bus NNN-D11 to the "normal"
power supply and that, prior to the action, the Plant Review Board had reviewed the
change
and concurred.
The inspectors concluded that the licensee's
actions were
acceptable.
Closed
LER 50-529/95001
Revision 0: reactor trip following the degradation
of
main feedwater flow. This event was discussed
in NRC Inspection
Report 50-528/95-14; 50-529/95-14; 50-530/95-14.
The LER also discussed
corrective actions resulting from the licensee's
event review.
Condition
Report/Disposition Request
(CRDR) 2-5-02553 added additional actions to address
other, identified problems associated
with the event.
The inspectors reviewed and verified the licensee's corrective actions and
concluded that the licensee's
completed and planned actions were acceptable.
Conduct of Maintenance (62707)
Containment
S ra
S stem Water Hammer - Unit 3
Ins ection Sco
e
On April 25, 1997, during the first routine surveillance test of the Train A
containment spray pump, operators
heard
a loud noise when the pump was started.
They subsequently
opened system high point vents and vented
a quantity of air
calculated to be less than 10 cubic feet.
The inspectors performed an initial review
of the licensee's
actions in response,to
this event.
0
-7-
Observations
and Findin s
The inspectors determined that engineering
personnel were involved in assessing
the effects of the event on April 25, and had promptly performed
a system
walkdown.
Engineering determined that the event did not damage plant equipment.
Additionally, engineering concluded that the event was less severe than a similar
water hammer event which occurred on the Unit 2 Train A containment spray
system in July 1995.
The Unit 2 event similarly occurred during the first system
test after a refueling outage.
On April 28, the inspectors inquired whether the Unit 3 Train B containment spray
pump had been tested or the system vented following the outage.
The SSM
confirmed that this had not occurred and initiated actions to vent the system.
Operators observed that although there was some air removed from high point
vents, it was considerably
less than the quantity of air removed from the opposite
train.
At the end of the inspection period, the licensee was reviewing the event to
determine root cause.
Specifically, corrective actions from the Unit 2 event were
expected to preclude
a repeat occurrence.
The inspectors will follow up the
licensee's
evaluation in a future inspection (Follow-up-Item 50-530/97005-01).
Conclusions
Following a water hammer event in the Unit 3 Train A containment spray system,
operations
and engineering thoroughly performed actions to assure the operability of
Train A. However, they did not promptly assess
the transportability of the cause
and assess
the operability of the opposite train.
Maintenance Staff Knowledge and Performance (62707)
Scaffold Platform Control in the Fuel Handlin
Buildin
Ins ection Sco
e
On April 9, 1997, the inspectors toured the Unit 2 fuel handling building with the
Office of Nuclear Reactor Regulation project manager.
A freestanding
scaffold
platform had been erected adjacent to the cask loading pit on the 140 foot level of
the fuel handling area.
The inspectors examined whether it had been erected.
according to site scaffolding requirements.
Observations
and Findin s
The scaffold platform was identified as "seismic" on an attached tracking tag.
The
inspectors noted that it was adjacent to the fuel handling building wall and in close
proximity to piping running vertically down the wall. The inspectors determined
l
-8-
that, for this construction,
a one bay, two tier scaffold platform, the construction
specification required
a clearance of 4 inches from safety related equipment.
t
The scaffold team leader walked-down the scaffold and concluded that it was closer
than 4 inches to piping.
However, none of these lines were safety related.
He also
noted that the scaffold was not in its original location.
It had been erected for the
HVAC maintenance
crew to work on air diffusers in a duct running along the west
wall of the fuel handling building.
It had originally been erected at the southwest
corner of the building and moved by the HVAC group to support their work. The
scaffold team leader was confident that, as originally constructed,
they had assured
adequate
clearance from plant equipment.
He had been aware that the HVAC group
intended to move the scaffold to support their work. It appeared that the need to
maintain these clearances
had not been adequately communicated to the HVAC
group.
The maintenance
services section leader responsible for the scaffold group initiated
a CRDR.
He noted that although they had met procedural requirements to maintain
a clearance from safety-related
equipment, this was primarily due to absence
of
such equipment along the path the scaffold was moved.
He recognized that
improved communications,
such as a precautionary step in the HVAC group's work
order, would have been necessary to assure
adequate
control.
C.
Conclusions
Formal communications
between the scaffold team and the HVAC maintenance
team were not established to assure the HVAC maintenance
team maintained
adequate
clearance between
a scaffolding platform and plant equipment in the fuel
handling building.
M6
Maintenance Organization and Administration
M6.1
Re ack of Pressurizer
S ra
Valve - Unit 2 62707
On April 24, 1997, maintenance
personnel
removed and reinstalled the packing in
pressurizer spray valve RCE-PV-100F.
The inspectors attended the prejob briefing
and reviewed the work package.
The inspectors noted that appropriate personnel
attended the prejob brief. The briefing, conducted
by the radiation protection team
leader and the Unit 2 SS, was thorough and in accordance
with the licensee's
guidance for prep'aration for risk significant work. Briefing attendees
actively
participated
in the discussion
and demonstrated
a questioning attitude.
The SS
emphasized
the need to perform the job correctly the first time and to be sensitive
to safety.
e
-9-
III. En ineerin
E2
Engineering Support of Facilities and Equipment (37551)
E2.1
Failure of Class
1E Batter
Char er C Unit 3
a
~
Ins ection Sco
e
On March 21, 1997, during Train A integrated safeguards
(ISG) testing, the PK C
battery charger AC input breaker tripped open.
A work request was written to
troubleshoot
and repair, as necessary,
and
a CRDR was written to document the
failure. The inspectors observed
portions of the corrective maintenance
performed
by electrical maintenance
and had several discussions
with the personnel involved.
Observations
and Findin s
On March 22, electrical maintenance
technicians were in the process of performing
a load test to restore the charger to service.
The inspectors discussed
with the
electrical maintenance
engineering section leader, present in the field, the cause of
the PK C battery charger AC input breaker trip. The engineering
section leader
stated that the troubleshooting
efforts were unable to duplicate the problem;
however, the as-found condition indicated that the incoming 480-Vac cables had
come into contact with the high voltage shutdown (HVS) card which may have
induced
a trip signal to the AC input Breaker, CB-1.
The engineering section leader stated that the incoming 480-Vac cables had been
supported
by a cable tie anchored to an adhesive-backed
cable tie base.
The cable
tie base subsequently
became detached
from the cabinet wall, allowing the cables
to fall closer to the HVS card.
The inspectors noted that the corrective actions
were to place the cables back to their original position, supported
by a new
adhesive-backed
cable tie base.
The load test was performed satisfactorily and the
charger was returned to operations.
The inspectors were concerned that the same problem could recur.
The engineering
section leader stated that the cables had been adjusted
in such
a manner that, if the
cable tie base were to fail, the cables would not come in contact with the HVS
card.
The inspectors were, also, concerned. that the same configuration, i.e, the
cables supported
by adhesive-backed
cable tie base, could exist in the other onsite
PK battery chargers.
The engineering section leader stated that they would inspect
the other chargers.
The licensee inspected the other units and determined that only the Unit 3 PK C
battery charger had the cables tied back with this adhesive
cable tie base.
A similar
configuration existed in the Unit 1 PK B battery charger, except that the cables
were supported
by nylon cable ties strapped to bigger cables.
The licensee had
removed the Unit 3 PK C battery charger from service to allow the electrical
-10-
maintenance
technicians to perform corrective maintenance.
The incoming 480-Vac
cables were rerouted and the adhesive
cable tie base was removed.
Similar problems had been identified in the past.
A 1986 engineering
evaluation
report and
a 1994 CRDR had been written in response
to similar events.
The 1986
engineering
evaluation report (EER) described
a problem that was discovered during
troubleshooting
efforts of the Unit
1 PK A and C battery chargers.
The 480-Vac
input cables were too close to the HVS card which caused the AC input breaker to
open from the shunt trip circuit. The corrective actions included the movement of
the incoming cables from the immediate vicinity of the HVS card for all PK battery
chargers.
The 1994 CRDR was written for the failure'of the Unit 3 PK D battery
charger.
During the performance of integrated safeguards
testing, the AC input
breaker tripped open during the simulated loss of offsite power.
As corrective
actions, electrical engineering determined that a distance of a minimum of 2.5
inches be maintanined between the 480 ac cables and the HVS card for all PK
battery chargers.
The inspectors
examined Specification 13-EN-306, Revision 5, "Installation
Specification for Cable Spacing
and Termination of Cable Systems at the Palo Verde
Nuclear Generating Station."
The specification clearly defines and lists the supports
that are allowed to be used to relieve stress on cable terminations or splices due to
cable weight and to prevent movement of cables to maintain minimum separation
and minimum bend radius requirements.
The inspectors determined that the 1994 corrective action to the Unit 3 PK C
battery charger was not in accordance
with electrical installation Specification
13-EN-306, in that adhesive-backed
cable tie bases were not allowed by the
specification.
Also, the corrective maintenance
on March 22, 1997, to the Unit 3
PK C battery charger was not in accordance
with the electrical installation
Specification 13-EN-306.
The two examples of inappropriate
use of the adhesive
cable tie base are a violation; specifically, the failure to follow approved
specifications (Violation 50-530/97005-02.)
The inspectors determined that the corrective maintenance
work package for the
initial troubleshooting
and repairs to the Unit 3 PK C battery charger did not
adequately document the work activity. The work activity sheet, which documents
the work/testing activities, did not contain the as-found condition, nor did it
describe the corrective action.
The inspectors discussed
this with the electrical
maintenance
engineering section leader.
The engineering section leader agreed with
the inspectors'bservation.
The inspectors reviewed the Unit 3 operations
logbook and determined that the
logbook did not contain an entry for the PK C battery charger that had been
removed from service for corrective maintenance
on March 28 to reroute the
incoming cables and remove the nylon cable tie adhesive
base.
This is discussed
in
Section 01.3.
-1 1-
The inspectors discussed,
with the system engineer and maintenance
support
personnel,
how the battery charger problems would be addressed
with res'pect to
maintenance
rule implementation.
They had concluded that the out-of-service time
of the PK C battery charger should be logged as unavailability time in the computer
data base.
The inspectors reviewed the unavailability data base for a PK C battery
charger and noted that no entry was logged for the March 21 occurrence.
The
maintenance
support engineering section leader stated that the unavailability was
entered,
in error, on the PK A battery charger.
The error was attributed to the
maintenance
support review of the operation unit log (see Section 01.3).
The error
was subsequently
corrected.
At the end of the inspection, the CRDR that had been initiated following the
March 21 event was still being evaluated
by the licensee.
The inspectors reviewed
the condition reporting section of the CRDR and noted that information which could
have been useful for a review had not been included.
The CRDR origination form,
did not discuss the previous occurrences
of this event.
Additionally, the CRDR did
not discuss that a walkdown of other chargers was recommended
or had been
performed, nor the immediate corrective actions to the resecure the cables.
c.
Conclusions
Electrical maintenance
technicians violated electrical installation specification
requirements
by using adhesive-backed
cable tie bases to anchor cable ties
supporting cables in a Unit 3 vital battery charger.
The anchors were first used in
1994 and again in March 1997, after the first anchor failed, contributing to a
charger breaker failure. The inital repairs and subsequent
charger inspections were
not documented
on the work activity sheets.
E2.2
Unit 2 VCT Blended Makeu
E ui ment Failure Resultin
in an Unknown Amount of
Boric Acid Addition
Ins ection Sco
e 71707
37551
On March 18, 1997, at approximately 4 a.m., the Unit 2 VCT decreased
in level,
due to identified charging system leakage,
and an automatic, blended makeup to the
VCT was initiated.
The Unit was at 100 percent power.
The makeup stopped
before the high level setpoint was reached
and the borated water totalizer had failed
to count the gallons added.
As a result, operators did not know how much boron
had been injected and waited for a system response
to adjust reactivity.
The
inspectors examined the circumstances
surrounding this situation and reviewed
procedures,
design documehts,
interviewed cognizant operations
and engineering
personnel,
and reviewed plant monitoring data.
-1 2-
Observations
and Findin s
S stem Descri tion
VCT level can be controlled automatically or manually.
In automatic, the operators
set a blend of borated water, from the refueling water tank, and pure water, from
the reactor makeup water tank, to correspond to the necessary
RCS concentration.
Operators adjusted the blend in the control room by setting the controllers for
Valve 210X (for reactor makeup water) and Valve 210Y (for borated water).
The
VCT automatic level setpoints
are 34 percent for initiation of makeup and
44 percent for termination of the makeup.
When automatic makeup occurs, the
borated water and reactor makeup water totalizers count the total amount of each,
in gallons, that are added.
Operators can, also, manually add water and/or boric
acid to the VCT, with Valves 210X and 210Y controlled either automatically (by a
totalizer counting down to a preset amount) or manually.
In automatic control a
boric acid pump will start and
a reactor makeup water pump, if not already running,
will start.
Valves 210X and 210Y will open fully, then throttle to match actual
flow to demand flow.
Event Review
Following the event on March 18, the inspectors reviewed logs, trends of reactor
power, cold leg temperature,
and makeup flow, and interviewed operators to
determine the plant impact.
The inspectors found there had been no impact on RCS
temperature.
Operators had determined,
based
on flow rates and times, that the
automatic makeup had contained too much borated water, and had withdrawn
control rods to compensate
for the negative reactivity addition.
The inspectors observed that there were no control room log entries concerning the
event, although the oncoming day SS was aware of the specifics.
The absence
of
log entries was discussed
in Section 01.3.
Subsequently,
the inspectors interviewed the cognizant system engineer.
The
system engineer noted that it appeared
that two problems had contributed to the
the event.
First, historically, Units 1, 2, and 3 had occasionally experienced
the
automatic cessation of the VCT makeup, before reaching the VCT high level
setpoint for makeup termination.
Operators
had termed this to be a "short cycle."
The system engineer did not know what caused
VCT makeup to short cycle.
The
second problem was that the totalizers would not register flow below 17 gpm.
The
circuitry used to sum the output from the flow detectors provided
a zero output if
the input was less than or equal to approximately 17 gpm.
The inspectors noted
that the operators
had set in 14 gpm for borated water flow during the activity
described
above and were not aware that the totalizer would not function with this
flow. There was a "temporary note" on the control board that indicated that the
system could short cycle.
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-1 3-
I
On April 24, the inspectors met with the system engineer to discuss the results of
the engineer's
investigation into the cause of the short cycle events.
The system
engineer had determined that the system had responded
as designed.
He found
that Valve 210Y would respond quickly to a makeup demand by fully opening.
However, the valve would not then quickly throttle to a low flow position.
The system engineer also determined that system logic would terminate automatic
makeup if the mismatch between demanded flow and actual flow exceeded
5 percent when the VCT low level switch for automatic makeup reset.
The reset
occurred at approximately 36 percent VCT level, or about 82 gallons.
During an
automatic makeup, the reset typically occurred in less than 30 seconds.
Valve 210Y had not been setup to throttle from full open to low flow in this time
frame.
The inspectors reviewed Procedure 42OP-2CH01, Revision 23, "Chemical and
Volume Control System Normal Operations."
Sections 7, 8, and 9 of the procedure
discussed
automatic makeup to the VCT, reactor coolant makeup borate mode, and
reactor coolant makeup dilution mode.
Each section included a note stating that the
flow controllers were not reliable at flow rates less than 20 gpm.
However, each
section allowed a minimum flowrate of 10 gpm.
The inspectors were concerned
that the procedure
allowed operators to control the system in a region where it was
not reliable, requiring operator intervention when it failed. Although both the
procedure
and established
expectations
required that operators closely monitor
makeup evolutions,. the latitude provided by the procedure
appeared
to provide
unnecessary
challenges to operators.
Procedure
was subsequently
revised to provide a minimum flowrate of
20 gpm.
Consequently,
Unit 2 placed their VCT makeup controller in manual.
Problem Histor
The inspectors reviewed the history of problems with VCT makeup control.
In 1988, EER 88-CH-145 was initiated, documenting that the makeup flow
controllers could not reliably gain flow control in the time necessary
to
prevent
a short cycle event.
The EER proposed four possible resolutions and
some system modifications were drafted.
In 1991, EER 88-CH-145 was closed without implementing any system
changes.
The proposed
changes
were determined not to be cost effective.
In 1993, engineering initiated EER 93-CH-002, noting that Unit 3 was
experiencing flow control problems and had requested
that the resolution of
EER 88-CH-145 be revisited.
In this evaluation, engineering
discovered the
low signal cutout of the flow controllers.
-14-
~
In 1994, all open
EERs were rolled into the CRDR program when the EER
process was discontinued.
In late 1994, CRDR 9-4-800 was initiated to
address
the issue discussed
in EER 93-CH-002.
CRDR 9-4-800 included
actions to perform system testing and provide recommendations
by October
1995
~
The inspectors found that the actions for CRDR 9-4-800 were still open at
the time of the inspection.
Although the CRDR database
did not show it, the
inspectors was informed that the action plan had been rolled into a
significant (Level 1) action plan for engineering.
The inspectors was informed that initially the Level
1 action plan had
belonged to system engineering.
It was subsequently
transferred to design
engineering.
In early 1997, it became
a Vice President,
Engineering,
Level 1,
and was listed as one of the "Top 5 Customer Issues."
At the time of the March 18, 1997, event in Unit 2, both Units
1 and 2 had
"Temporary Notes" recognizing makeup problems.
Shortly following restart,
Unit 3 added
a Temporary Note reflecting similar problems.
In summary, the issues of makeup to the VCT had
a long history where
performance
issues were recognized.
However, no corrective actions had been
implemented
and at the time of the March 18, 1997, event, the causes
were not
well understood
by engineering.
However, engineering
did understand
system
limitations.
These limitations were not implemented
in operations
procedures
and
practices.
Safet
Anal sis Re ort Review
The chemical and volume control system was described
in detail in the Combustion
Engineering Standard Safety Analysis Report, Chapter 9.3.4.
The chapter discussed
all modes of VCT makeup.
However, it did not identify any limitations to the
automatic mode, other than to state that near the end of core life, it becomes
inefficient and the deborating demineralizer must be used to reduce boron
concentrations.
It did not identify that the automatic mode would be unreliable
during the last third of core life due to control system limitations.
Conclusions
System design weaknesses
in the automatic makeup to the VCT did not allow the
system to function in the last of core life and made the system unreliable.
As a
result, operator actions were required to compensate
for system problems.
Engineering
had made little progress
in addressing
these issues,
even though they,
had first been recognized
in 1988 and were the subject of both condition reports
and senior management
action plans.
The known system deficiencies were not well
established
in operating procedures
nor well understood
by plant operators.
-15-
E8
E8.1
Miscellaneous Engineering Issues (92903)
Closed
Follow-u
Item 50-529 96012-01
a
~
Backcaround
As discussed
in Inspection Report 50-528; 50-529; 50-530/96-12, the inspectors
found an unsealed
in the essential auxiliary building ventilation (EHA)
system boundary.
The EHA system was aligned with the essential fuel handling
building filtered exhaust trains during a safety injection actuation signal.
In this
mode, the EHA was required to be maintained at a negative pressure.
The
inspectors was concerned that the unsealed
could impact the ability of
the system to be maintained at a negative pressure.
The inspectors found that the licensee had previously identified a significant number
of flood, high energy line break (HELB), and EHA barrier penetration deficiencies.
These penetrations,
as well as sealed penetrations with these functions, were
identified in plant drawings as "nonquality related (NQR)." The inspectors
questioned
this classification because
the licensee had established that design basis
flood and HELB mitigation were safety-related functions.
Additionally, the EHA was
identified as a safety-related
system with the primary function of preventing
unfiltered release paths.
Civil engineering
had concluded that the nonconforming penetrations
did not impact
the safety-related functions and, therefore, did not need to be classified as other
than "nonquality related."
b.
Observations
and Findin s
In February 1997, the licensee provided the inspectors
an assessment
that
concluded that the nonconforming penetrations
with HELB, flooding, and pressure
differential boundary functions should be classified as "quality augmented
(QAG)."
They referenced
CRDR 9-1-0208 as supporting this conclusion.
Engineering
added
an action to CRDR 9-6-0691 to revise their Q-list to change
appropriate penetrations
to QAG.
The inspectors reviewed CRDR 9-1-0208.
The CRDR identified that the barrier
function list, established
as a result of the penetration
seal project, had not assigned
quality classifications.
Two memos, responding to the CRDR, dated September
1992 and March 1993, identified that penetrations
with HELB, flooding and
pressure differential functions should be classified as QAG.
Both memos indicated
that changes to appropriate documentation
should be made.
A subsequent
memo
concluded that appropriate
changes
had been made.
However, the changes
were
not made and as of March 1997, none of the penetrations,
either conforming or
nonconforming, which serve HELB, flooding, or pressure differential boundary
'I
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-1 6-
functions had been classified as QAG.
In response to this finding the licensee
initiated CRDR 9-7-0590.
QAG was defined in UFSAR Chapter 17.2 as: "Items that do not perform a
safety-related function but which, as a result of regulatory commitment or
management
directive, require the application of certain quality assurance
program
elements."
10 CFR Part 50, Appendix B, Criterion 3, requires that appropriate
quality standards
are specified and included in design documents.
Failing to assure
that the QAG quality standard was specified for the penetrations
with HELB,
flooding, and pressure differential boundary functions was a violation of 10 CFR Part 50, Appendix B, Criterion 3 (Violation 50-528; 50-529; 50-530/97005-03).
Conclusions
'
Design engineering
did not assure that appropriate quality standards
were applied to
in boundaries that served safety-related functions.
V. Mana ement Meetin s
X1
Exit Meeting Summary
The inspectors presented
the inspection results to members of licensee management
at the conclusion of the inspection on IVIay 7, 1997.
The licensee acknowledged
the findings presented.
The inspectors
asked the licensee whether any material examined during the
inspection should be considered
proprietary.
No proprietary information was
identified.
Ir
ATTACHMENT
PARTIAL LIST OF PERSONS CONTACTED
Licensee
P. Brandjes, Department Leader, Electrical Maintenance
Engineering
R. Flood, Department Leader, System Engineering
R. Fullmer, Director, Nuclear Assurance
M. Hypse, Section Leader, Electrical Maintenance
Engineering
W. Ide, Vice President,
Nuclear Engineering
K. Jones,
Section Leader, Design Engineering
D. Kanitz, Engineer, Nuclear Regulatory Affairs,
A. Krainik, Department Leader, Nuclear Regulatory Affairs
J. Levine, Senior Vice President,
Nuclear
D. Mauldin, Director, Maintenance
G. Overbeck, Vice President,
Nuclear Production
T. Radke, Director, Outages
F. Riedel, Department Leader, Operations Standards
C. Seaman,
Director, Emergency Services
M. Shea, Director, Radiation Protection
D. Smith, Director, Operations
J. Taylor, Unit 3 Operations Department Leader
M. Windsor, Section Leader, Mechanical Maintenance
Engineering
h
C
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-2-
INSPECTION PROCEDURES
USED
71707
92901
62707
92902
37551
92903
Plant Operations
Plant Operations Follow up
Maintenance
Observations
Maintenance
Follow up
Onsite Engineering
Engineering Follow up
ITEMS OPENED
CLOSED
AND DISCUSSED
~Qened
50-530/97005-01
IFI
containment spray water hammer
50-530/97005-02
failure to follow approved electrical cable specifications
50-528; 50-529;
50-530/97005-03
failing to assure that quality standards
were specified for
the penetrations
boundary functions
Closed
50-528;50-
530/9601 3-01
50-528/9501 2
50-528/95014
50-529/95001
50-529/9701 2-01
ventilation boundary door control
LER
reactor trip caused
by a high steam generator water level
LER
reactor trip following degradation
of main feedwater control
LER
reactor trip following degradation of main feedwater flow
IFI
unsealed
in the essential auxiliary building
ventilation system boundary
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-3-
LIST OF ACRONYMS USED
ABT
CRDR
EHA
gpm
HVS
LER
PK
PMUX
QAG
RDT
SSM
automatic bus transfer
auxiliary operator
condition report/disposition
request
control room supervisor
engineeering
evaluation report
essential auxiliary building ventilation
feedwater control system
gallons per minute
high energy1ine break
heating, ventilation, and air conditioning
high voltage shutdown
licensee event report
Class 1E125-Vdc Power system
Plant Multiplex
quality augmented
reactor coola'nt system
reactor drain tank
reactor operator
shift supervisor
site shift manager
Technical Specifications
Unusual Event
Updated
Final Safety Analysis Report
volume control tank
I