ML18033B669
| ML18033B669 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/26/1991 |
| From: | Kellogg P, Patterson C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18033B667 | List: |
| References | |
| 50-259-91-07, 50-259-91-7, 50-260-91-07, 50-260-91-7, 50-296-91-07, 50-296-91-7, NUDOCS 9104230088 | |
| Download: ML18033B669 (17) | |
See also: IR 05000259/1991007
Text
UNITED STATES
NUCLEAR REGULATORY COIVIMISSION
REGION II
101 MARIETTASTREET, N.W.
ATLANTA,GEORGIA 30323
Report Nos.:
50-259/91-07,
50-260/91-07,
and 50-296/91-07
Licensee:'Tennessee
Yalley Authority
6N 38A Lookout Place
1101 Market Street.
Chattanooga,
TN
37402-2801,
Docket Nos.:
50-259,
50-260,
and 50-296
License Nos.:
and
Facility Name:
Browns Ferry Units 1, 2,
and
3
Inspection at Browns Ferry Site near
Decatur,
Inspection
Conduc
d:
Fe r
r
22 - March 13,
1991
Inspector:
enior
es
ent
nspector
E. Christnot, Resident
Inspector
W. Bearden,
Resident
Inspector
K. Ivey-, Resident
Inspector
G. Humphrey, Resident
Inspector
P.
rnett,
Rea
r Inspec
r
Approved by:
Pau
el
In
e
rog
m,
TYA Projects Division
te
sgne
Date Signed
SUMMARY
Scope:
This
special
inspection
included
those
activities
associated
with the
February
21,
1991
through
March 6,
1991
Fuel
Loading.
Those activities
included
a review of reload design,
on shift coverage activities
and
a review
of the conditions that led to the beginning of fuel load
and loading of one
fuel
assembly
into the Unit 2 reactor core with a fuel load chamber spiking to
alarm conditions.
Results:
One refueling violation was identified for failure to follow the refueling
procedure,
paragraph
two.
Indications of
a fuel
load
chamber
causing
alarm
conditions
due to noise were available prior to commencing fuel load and during
movement of the 'first fuel assembly into the reactor vessel.
Fuel loading was
not stopped until after the first fuel assembly
wa's seated
into its designated
core position.
The
B Fuel
Load Chamber
was
then declared
and fuel
loading
stopped
for approximately
50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />
during maintenance
and eventually
replacement of th~
R
I=
1 Load Chamber.
~lo"~3
soooas9
ADOCN, 050
Q
0
0
1
The, Plant Operations
Review Committee
review of this event contained
several
discrepancies.
The
sequence
of events
was different .from control
log entries
and resident
inspector observations.
After the initial problem with the
8 Fuel
Load Chamber the'emainder
of the
refueling
was
completed
in
a
professional
and
conservative
manner.
Fuel
loading was completed
on March 6,
1991 at 9:49 p.m.
A review of the Reload Licensing Report, reconstitution
program summaries,
and
the
Revised
Reload Technical Specification
by regionally based
inspectors
did
not result in any concerns
with operating Unit 2 with reconstituted
fuels.
o
10
REPORT
DETAILS
Persons
Contacted
Licensee
Employees:
- 0. Zeringue, Site Director
L. Myers, Plant Manager
- M. Herrell, Operations
Manager
J. Rupert, Project Engineer,
R. Johnson,
Modifications Manager
- N. Bajestani,
Technical
Support Manager
R. Jones,
Operations
Superintendent
A. Sorrell, Maintenance
Manager
G. Turner, Site guality Assurance
Manager
- P. Carier, Site Licensing Manager
- P. Salas,
Compliance Supervisor
J.'orey,
Site Radiological
Control Manager
R. Tuttle, Site Security Manager
T. Beu,
BWR Fuel Engineering
Other
licensee
employees
or
- contractors
contacted
i'ncluded
licensed
reactor
operators,
auxiliary
operators,
craftsmen,
technicians,
and
public safety officers;
and quality assurance,
design,
and engineering
personnel.
NRC Personnel
- C. Patterson,
Senior Resident
Inspector
- E. Christnot,
Resident
Inspector
- W. Bearden,
Resident
Inspector
- Y.. Ivey, Resident
Inspector
G. Humphrey,
Resident
Inspector
P. Burnett, Reactor Inspector
M. McCoy,
NRR/SRXB
T. Ross,
NRR/PD2-4
- Attended exit interview
and initialisms
used
throughout this report are listed in the
last paragraph.
Sequence
of Events for Fuel
Load
After an extended
shutdown of over six years
in duration,
Unit
2 fuel
loading
commenced at 6:39 a.m.
(CST)
on February 21,
1991.
The reactor .nuclear
instrumentation
included four
SRM channels
to provide
neutron monitoring during fuel loading.
Two of the
SRM channels,
A and
B,
were electrically wired, using temporary cabling, to FLCs.
The
FLCs were
placed
in the core in the
same
quadrants,
respectively,
as
C and
D.
The
two channels
wi~ed
to the
were
considered
by the
licensee.
can
be declared
when they indicate greater
than
3 cps.
The
SRM channels
attached
to FLCs were reading
100 cps
on channel
8
and
250
cps .on channel
A.
The following events
were
observed,
all
times are approximate
CST.
a.
4:00
p.m.
Wednesday,
February
20,
1991,
two inspectors
attended
a
PORC meeting
chaired
by the Plant Manager.
A')so present
were the
Site Director
and
the Vice President
Nuclear
Operations.
The
decided that adequate
systems
were operable
to support fuel loading.
The
RPS shorting links for the
SRMs would be in the non-coincident
logic pattern.
In this configuration
a single Hi-Hi Set Point Trip
from the
SRMs would cause
a full scram.
b.
2:00 a.m. Thursday,
February
21,
1991.
Hi-8i Set Point Trip from SRM
8 and erratic operation
was
observed
by
a RI.
This
was discussed
with the licensee.
An entry in the operator's
log at 2:50
a.m'.
indicated that
CO 42091
was initiated to troubleshoot
and repair
SRM 8 as
necessary.
The
WR was closed out with no root causes
being
identi fied.
c.
6:30 a.m. Thursday,
February
21,
1991.
An entry in the operators
log
indicated
that 2-SOI-100-1,
Fuel
Load Prerequisites
Checklist,
was
completed;
the prerequisites
for 2-G01-100-3,
Refueling Operations,
were completed;
and that permission
had
been received
from the Plant
Manager to load fuel into the Unit 2 reactor vessel.
d.
6;39 a.m.
Thursday,
February
21,
1991.
Permission
was given to the
refueling bridge
personnel
to
commence
loading fuel
and the bridge
reported
the commencing of step
1 of the fuel loading procedure.
e.
g.
6:41
a.m.
Thursday,
February
21,
1991.
The refueling
bridge
personnel
reported that the fuel bundle
was clear of the spent fuel
pool.
The control
room operator
reported
to the
SOS that
SRM 8 was
spiking.
The control
room RI observed
that the
SRH
8 cps meter
was
ramping
up from a reading of approximately
100 cps to 500 cps.
6:43 a.m.
Thursday,
February
21,
1991.
Refueling bridge personnel
reported
that
the fuel
bundle
was
stopped
at the cattle
chute to
await the completion of a radiation control survey of the drywell.
The control
room
RI observed
that
the
8 cps
meter
was still
reading
approximately
500 cps
and the period meter
was erratic.
The
control
room
RI discussed
this with licensee
personnel
and
was
informed that this
was
not considered
a
problem
because
both
SRHs
were not receiving electronic noise.
The control
room RI noted that
the operator
had
informed the
SOS that the
A count rate
was
steady.
7:05 a.m.
Thursday
February
21,
1991.
Fuel
loading
resumed.
The
control
room
RI noted that the
SRH
8 cps meter
had returned
to
an
indication of approximately
100 cps prior to resuming fuel movement.
The operator reported,to
the
SOS,
and the control
room RI observed,
a
Hi-Hi Trip on the
B channel.
The
SOS
ordered
the refueling
bridge personnel
to stop moving fuel .
The .control
r oom RI observed
a discussion
among
control
room licensee
personnel
as
to whether
a full scram
should
have
been
received,
and whether
the shorting
links were in the coincidence
or non-coincidence
logic pattern.
The
SOS
asked
the refueling bridge
personnel
where the fuel bundle
was
located.
The refueling
bridge
personnel
replied that
the fuel
bundle
was approximately
2 feet from the top of the grid.
h.
7: 10 a.m.
Thursday February 21,
1991.
The
SOS informed the refueling
bridge personnel
and all control
room personnel
that he
was directing
the refueling bridge personnel
to install the bundle into the reactor
vessel
using the jogging mode.
7:21
a.m.
Thursday,
February
21,
1991.
The
refueling
bridge
personnel
reported that the. bundle
was in the vessel
and upgrappled.
During this eleven
minute time frame
the control
room
RI observed
that the
B cps meter
was indicating between
approximately
800 to
1000 cps,
SRM Channel
A was
steady,
and
B period
meter
was,
erratic.
j.
7:23 a.m. Thursday,
February 21,
1991.
The operator reported
and the
control
room RI observed
another
SRN
B Ki-Hi trip.
The 'control
room
RI observed that the
SRN
B cps meter
was indicating approximately
800
to
1000 cps,
the
A was
steady
and
the
SRN
B period meter
was
erratic.
k.
7:24
a.m.
Thursday,
February
21,
1991.
The
SOS
declared
B
and stopped all fuel movement.
Both the
RO and
SRO logged
this
time
as
when the
B
FLC was declared
and refueling
stopped.
The
inspector
concluded
that the refueling
procedure
was
not followed.
Technical Specification 6.8. 1. 1 requires
that written procedures
shall
be
established,
implemented,
and
maintained
covering
the
applicable
procedures
in Appendix
A of Regulatory
Guide 1.33, Revision 2,
February'978.
Appendix
A of Regulatory, Guide
1.33
includes
procedures
for
refueling.
Refueling Operations
Procedure,
2-GOI-100-3,
implements this requirement
for refueling.
Procedure
step
3. 1,
under
Precautions
and Limitations,.
require that refueling shall
be
immediately halted
upon occurrence
of
unexplained'r
abnormal
increase
in
SRMs or
FLCs readings
(procedure
step
3. 1. 1),
or loss
of neutron
monitoring with less
than
two
SRNs/FLCs
and responding
wi,th one in the fuel handling quadrant
and
one in
an adjacent
quadrant
(procedure
step.3. 1.3).
The inspector
concluded that
a violation of TS
had occurred.
Refueling
was
not
stopped
after
questionable
and erratic
response
of the
B
FLC.
This
is identified
as
VIO 260/91-07-01,
Failure to
Follow Refueling
Procedure.
The '8'LC was
again declared
due to spiking on February 27,
1991,and
remained
inoperable for the remainder of the fuel loading.
When
the spiking occurred this time, the bundle being moved
was returned to the
spent fuel pool.
The licensee
is conducting
an incident investigation of
these
problems
which will be reviewed
by 'the resident inspectors.
The
remainder
of fuel
loading
was carried
out in
a professional
and
conservative
manner.
Fuel
loading
was
completed
at
9:49
p.m.,
on
March 6,
1991.
3.
PORC Review Discrepancies
The
inspector
reviewed
an
event
description
of
B
problem
on
February 21,
1991.
The description
was
approved
by
on February.23,
1991,
and
a copy was given to the inspector.
This
PORC was chaired
by the
Plant Operations
Manager.
Numerous
discrepancies
and inaccuracies
were
noted
as follows:
The licensee's
events
and causal
factor ch'art stated
a high alarm was
received at 2:50 a.m.
The inspector
reviewed the
SRO 'log and the entry at 2:50 a.m.
was for
a high-high alarm and not
a high alarm.
The control
room RI stated
that at approximately this time he observed
the operators
resetting
a
Hi Hi Trip on the
B channel
because
a clear, distinct
Red Light
was
on.
When the
RI discussed
this observation with the licensee
he
was
informed that
a
on the
was
in progress
and this
was
expected.
A later review by the control
room RI indicated that the
SI was
being performed
on an
FLC for the
A SRM and not the
B
SRM at
this time.
b.
C.
The licensee's
events
and causal
factor chart
and event description
narrative
stated
that
the
B
FLC was
determined
to be inoperable at
7: 18 a.m.
and before
a second
high-high alarm
was received
when the
bundle
was placed into the core.
The inspector
reviewed
both the
RO and
SRO log and the
B FLC was not
declared
inoperable until 7:24
a.m. after the bundle
was
placed in
the core
and after several
high-high alarms.
The inspector
in the
control
room also
heard
-the
announcement
that
the 'B'LC was
inoperable after the bundle
was released.
The assessment
of personnel
performance
concluded that the decision
to lower the
bundle into the core
was
made
in accordance
with Step
3.2 of 2-GOI-100-3
which requires
that if core alterations
are
suspended
for any
reason
other
than
a fire alarm
or
medical
emergency,
a fuel -bundle being
moved wi 11
be lowered
and placed in a
safe condition immediately.
,
The inspector
noted that lowering
a fuel bundle into,,the core meets
the, definition of a core alteration
and Step 3.2 is not applicable.
d.
The actions
to
be taken to preclude future occurrences
stated
that
changes
were
being
made to 2-GOI-100-3
and 2-TI-147A to include
a
precaution
that if erratic
or unexplained
SRM/FLC
response
is
obsess ved, fuel, loading shall
be immediately stopped.
The
inspector
reviewed
2-GOI-100-3
procedure
Step
3. 1.1
and
the
precaution already existed in the procedure.
In general,
the inspector
concluded that the
assessment
contained
several
discrepancies.
The
assessment
did not critically assess
operations,
actions,
or troubleshooting of the
MR written.
The assessment
did
not
adequately
assess
the significance
of proceeding
with fuel
handling after
a high-high alarm was received
and
an expected
scram signal
was not received.
Although later it was
learned
from GE that spiking can
result in an alarm without
a scram signal,
the
PORC did not specifically
conclude that this event
was the
phenomenon
described
by GE.
4.
Related Matters
a.
Shift Turnover During Movement of First Fuel Assembly
Refueling
began
during shift turnover of operations
personnel.
The
Plant Operations
Manager
was present
in the control
room during this
time, of the
movement 'of the first bundle into the vessel.
The
oncoming shift relieved the watch during movement of the first fuel
assembly.
The inspector
concluded that during
a major evolution was
not the best time to conduct shift relief.
In .addition, the oncoming
crew
may not have
been fully aware of the spiking problem
on the
B
FLC.
b.
Noise Problem
Known Related to Bridge Movement Prior to Fuel
Load
Planners
who process
WRs were aware of the
FLC spiking problem
and
the relationship to bridge movement prior to beginning fuel movement.
An entry into the
planners
log at 5:00
a.m.
stated
"FLC
B spikes
appear
to be related to bridge work (Ops says they will buy it off)".
Evidently, this
information
was
not fully communicated
to all
management.
co
System
Engineer
Not Notified
During this
event,
the
system
engineer
was
not notified of the
spiking problem.
In the past,
the involvement of the system engineer
in problem resolution
has
been effective.
5.
Fuel Handling Problems at Other Sites
An inspector
reviewed
events
involving failures of the fuel
handling
bridge at other nuclear
plants
to determine if they could
be potential
problems for BFN.
The inspector discussed
these
events with the cognizant
system engineer
and the
SRO responsible for refuel floor activities.
The
events
and the
BFN actions
are addressed
below:
a,
At another facility in early
January,
1991,
a fuel
bundle
was
released
from the main hoist grapple while it was being lowered into
the core
when the refuel bridge electrical
power was lost.
The loss
of power to the bridge
removed
the air from the grapple
and
the
grapple
opened.
The grapple is designed
to remain closed
upon
a loss
of air, but the
licensee
discovered
that the grapple air lines
had
been reversed
during previous work.
At BFN the refuel grapple is designed to.fail in the closed position.
Procedure
EPI-0-079-CRAOOl,
Refueling
Platform
and
Jib, Crane
Inspection,
includes
a main grapple failsafe check.
This procedure
is conducted
within 30 days of fuel
movement.
The check includes
opening
the= grapple
and
removing
power to verify that the grapple
fails closed,
and using test weights to determine if the grapple will
open while in a loaded condition.
The licensee
stated
there
had been
no recent maintenance
on the grapple airlines or switch.
No problems
were identified during the performance
of the EPI prior to beginning
Unit 2 fuel load.
b.
At another facility the refuel bridge main hoist emergency
and motor
brakes failed while lowering
a bundle into the core.
This resulted
in the bundle being put into the core in an uncontrolled. manner.
At BFN the Unit 2 refuel bridge main grapple hoist
has
a double set
of brakes
which are the disc type.
An inspection'as
pe~formed
on
the brakes
and extensive
wear
was noted.
The brake
was
reassembled
using
a
new coil
and operating
assembly
and the original pressure
plate
and fiber brake disk.
In addition,
MMI-34, Refueling Platform
and
Grapple
Assembly
Inspection,
includes
inspection
of the
main
hoist grapple
and
EPI-0-079-CRA001
includes
checking the electrical
and mechanical
integrity of the brakes
using test weights.
Both of
these
procedures
are
performed within 30 days of fuel movement.
No
problems
were identified during the performance of these
inspections
prior to beginning Unit 2 fuel load.
The inspector
concluded that the licensee
had adequately
addressed
both of
these
events
prior to beginning
Unit
2 fuel
load.
No violations or
deviations
were identified in this area.
6.
Browns Ferry Unit 2, Cycle 6,
Fuel Selection
and Core Load (60710,
61702)
a.
References
(I)
TVA-BCD-906,
SUMMARY REPORT
FOR
THE
BROWNS
FERRY
NUCLEAR PLANT,
UNIT 2,
CYCLE 6,
INSPECTION
AND RECONSTITUTION
PROGRAM, August
1988 (Revision 0).
{2)
TVA-RLR-002,
BROWNS
FERRY
NUCLEAR
PLANT,
RELOAD
LICENSING
REPORT,
UNIT 2,
CYCLE 6.
(3)
REVISED
RELOAD TECHNICAL SPECIFICATIONS
(TS254)
BROWNS
FERRY NUCLEAR PLANT, UNIT 2, September
13,
1989.
b.
Introduction
Reconstitution of
BWR fuel
by replacing
damaged
or failed fuel pins
with pins of like initial enrichment;
similar exposure,
and similar
residual
enrichment
from a donor fuel'assembly
is not new.
Prior to
reconstituting
fuel
at
Browns
Ferry,
successful
reconstitution
programs
had
been
conducted
at least
three
other
BWR facilities.
However,
the
program
conducted
at
Browns Ferry
was
much larger in
the
number
of fuel
assemblies
and
fuel
pins
affected
than
the
earlier
programs.
Consequently,
when the
program
was
proposed,
initiated
a dialogue
and
exchange
of technical
documents
with TVA.
That exchange
culminated
in issuance
of new Technical Specifications
(Reference
a.(3)) with conservatively
reduced
'MAPLHGR limits for the
reconstituted
fuel.
TVA submitted
both Reference
a.(1)
and Reference a.(2) in support of
TS
amendment
172,
but
the
NRR review of the neutronic
analyses
presented
by TVA was limited to confirmation that approved
computer
codes
were used in the an'alyses.
The
analyses
described
in Reference
a.(1)
were
reviewed
in the
Region II office
and
discussed
by
Region II personnel
with the
responsible
TVA analyst.
The
Region II staff concluded that the
strategy
of using
the
codes
to confirm that replacement
pins
had
neutronic characteristics
similar to the replaced
pins
was
sound.
A
similar conclusion
was that the strategy for analyzing
the current
neutronic
characteristics
of
the
reconstituted
bundles
and
predicting, their future behavior
was also sound.
No concerns
or caveats
about operating
Browns Ferry Unit 2 with the
reconstituted
fuels
described
in Reference a.(I)
were identified.
It was also
noted that the
use of reconstituted
fuel
has
placed
no
special
or additional
surveillance
requirements
on
the facility
staff.
c.
Core, Design Predictions-
Calculations
for Cycle
6
show that
the
lead fuel
assembly will
produce
from 1.35 to 1.45 times the core
average
power at any point
in the cycle.
The relative
power
production for R2/R3 fuel will
. range
from 1.2 to 1.05 at any time in the cycle.
During parts of
the cycle,
the leading
R2/R3 bundle will be
a reconstituted
bundle,
but many of the reconstituted
bundles will operate at less
than core
average
power throughout the cycle.
The effects of the long shutdown
on fission product
and transuranic
isotope
concentrations
were
calculated
fo'r the
unreconstituted
core.
Bundle
power distributions
were essentially
unchanged.
At
BOC,
SDM increased
by approximately
0.5% dk/k, but that effect burned
out by mid-cycle.
These results
are consistent
with those
reported
for Sequoyah.
The
ana lyses did not identify a need for any special
core monitoring
as
a result of the fuel reconstitution.
Two conservatisms
were
intr'oduced
into
the
plant
computer
to
provide
conservative
monitoring of the reconstituted
fuel.
MAPLHGR curves
were lowered
3.2".
The R-factors
to be
used
in
CPR determination
were increased
by 0.02.
d.
Corrective Actions
Changes
in feedwater .chemistry
have
been instituted to prevent the
recurrence
of the
CILC observed
in
U2C5.
The
condensers
were
retubed
with stainless
steel
to eliminate
the copper
in the brass
tubes.
The system
has
undergone
considerable
flushing to eliminate
residual
'The method of precoating
the demineralizers
may be
changed
to
improve
removal
by
the
demineralizers.
Previously,
the demineralizers
were ineffective in removing copper.
There will be
online monitoring of the
content
in the
Plant activities to reduce 'CILC will be inspected
during
the
power ascension
phase of plant activities.
7.
Exit Interview
The inspection
scope
and findings were summarized
on March
15', 1991, with
other
persons
indicated in paragraph
1 above.
The inspectors
described
the areas
inspected
and discussed
in detail the inspection findings listed
below.
The licensee
did not identify as proprietary
any of the material
provided
to or
reviewed
by
the
inspectors
during this
inspection.
Dissenting
comments
were not received
from the licensee.
Item Number
Descri tion and Reference
259, 260; 296/91-07-01
VIO, Fai lu're to Follow Refueling
Procedures,
paragraph
2.
8.
and Initialisms
CFR-
CILC
CPR,
EPI
GOI
MAPLHGP
NRC
RI
SOI
SOS
SRXB
TI
TS
Beginning of Cycle
Browns Ferry Nuclear
Boiling Water Reactor
Code of Federal
Regulations
Crud Inducted Localized Corrosion
Critical Power Ratio
Counts
Per Second
Central
Standard
Time
Electrical Preventive Instruction
Fuel
Load Chamber
Final Safety Analysis Report
General
Operating Instruction
General
Electric
Maximum Average Planar
Heat Generation
Rate
Nuclear Regulatory
Commission
Plant Operations
Review Committee
Resident
Inspector
Reactor Operator
Reactor Protection
System
Surveillance
Instruction
Special
Operating Instruction
Shift Operations
Supervisor
Source
Range Monitor
Senior Reactor Operator
Reactor
Systems
Branch,
Technical
Instruction
Technical Specification
Valley Authority,
Violation
Work Request
0'