ML17055E431
| ML17055E431 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/04/1989 |
| From: | Jerrica Johnson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17055E430 | List: |
| References | |
| 50-410-88-21, NUDOCS 8901130159 | |
| Download: ML17055E431 (12) | |
See also: IR 05000410/1988021
Text
'
U.S.
NUCLEAR REGULATORY COMMISSION
REGION I
Report
No.
Docket No.
License
No.
Licensee:
Faci 1 ity:
Location:
Dates:
Inspectors:
88-21
SO-410
Niagara
Mohawk Power Corporation
301 Plainfield Road
Syracuse,
13212
Nine Mile Point, Unit 2
Scriba,
December
3,
1988 to December 21 1988
W.A: Cook, Senior Resident
Inspector
R.A. Laura,
Resident
Inspector
Approved by:
J.R.
Johnson,
Chief, Reactor
Projects
Section
2C,
Date
INSPECTION
SUMMARY
Areas
~Ins ected:
Special
inspection
by resident
inspectors
to review the
events
leading to Division
1
ADS being identified as inoperable
since
initial fuel load
on November 2,
1986.
This inspection
involved 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br />
by the inspectors.
Results:
The licensee
had several
opportunities
to identify and correct
the logic circuit wiring error causing Division I ADS inoperability,
but failed to adequately
investigate
and resolve the surveillance test
'results.
An apparent violation of Technical Specification 3.3.3 is
discussed
in Sections
2 and 3.
An apparent violation of 10 CFR 50,
Appendix B, Criterion XVI is discussed
in Section
3.
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DETAILS
~Pur oae
The purpose
of this special
safety inspection
was to review the
circumstances
leading to Division
1 Automatic Depessurization
System
(ADS) being inoperable
since initial fuel load (November 2, 1986).
Event ~Followu
(93702,
61726)
a.
~Back round and Identification
On December
3, with the reactor
in Cold Shutdown
and the
A Residual
Heat
Removal
System
(RHS) in Shutdown Cooling Mode of operation,
technicians
performed procedure
N2-ISP-ISC-M004 (Monthly Functional
Test
And Trip Calibration Of
ECCS Actuation
On Reactor
Vessel
Level One).
While performing step 7.4 of the test,
a Reactor
Level
One
trip was dialed in and the technicians
noticed while testing
ADS Channel
E, that
an
ADS initiation seal-in signal
was not activated
as evident by
the unlit white indicating light on the control panel.
Investigation
by
the technicians
and the Station Shift Supervisor
(SSS)
also found that
when the
ADS inhibit switch was taken to the
ON position,
the
ADS inhibit
light did not illuminate; however,
the annunciator did activate.
Further investigation
by the licensee
found that relay
K70A (RHS A pump
running permissive relay) failed to pick up causing
the absence
of an
initiation signal.
The
ADS inhibit circuit is supposed
to be independent
of the trip and permissive circuits.
However,
when the low water level
signal
was
removed,
the
ADS inhibit light came
on.
These
symptoms
led
the licensee
to originally suspect
that
a potential wiring defect existed
in the
ADS Division I Channel
E circuitry.
An emergency
Work Request
was generated
to troubleshoot
the potential wiring problem.
The
inspector
noted that the
and
I&C technicians
possessed
a questioning
attitude in identifying the potential for wiring defects
and this is
considered
to be
a positive attribute.
The licensee initiated
a 50.73
reporting to the
NRC.
During troubleshooting
the licensee
found
a wiring error
on relay
Two leads
were
supposed
to be landed
on terminal Ml; however,
Ml only had
one lead
landed
and terminal
Rl (which should
have
been
empty)
had
one lead landed.
This was found when the as-built wiring
scheme
was
compared to the relay termination drawing.
The licensee
speculates
that the miswiring was
a result of personnel
error.
The
termination
screws for the relay coil and auxiliary contacts
are closely
aligned at the relay base.
The termination
screw for Ml is adjacent
to
R1 and because
the termination
numbers
are unreadable
without a
magnifying tool, the initial termination of the wire from the fuse to Ml
may have
been mistakenly
landed
on Rl.
The licensee
commenced
an
evaluation
on
how the wiring error affected the
ADS operability.
On December
8, it was determined
by the licensee that all channels of
Division I ADS were rendered
since initial fuel loading
on
November -2,
1986.
An
ENS call was
made to the
NRC reporting the
inoperability of Division I ADS due to the wiring error.
This miswiring
would have prevented
the manual
or automatic initiation function of
Division I ADS, however the applicable
(SRVs) still
could have
been individually manually operated
from the control
room.
The Division II ADS Trip System
was not affected
by the wiring error.
b.
~Testin
The inspector
reviewed the licensee's
methodology of testing the Division
I ADS trip system circuitry during the Preoperational
Testing
Phase
(final testing prior to initial fuel loading).
The licensee
used
Procedure
N2-POT-34 to test the circuit, and
had it been
performed
as
originally written the wiring error may have
been detected.
By the
original procedure,
the "boiler" level detectors
were to be varied
locally at the detector
through the use of an externally applied test
rig.
This method of testing would have
been
the most conservative
approach.
The procedure
was revised to trigger the Level I signal
by
installing
a General Electric test switch in the circuit rather than
direct stimulation locally at the detector.
The test switch was
installed in
a less conservative
manner than the previously intended
method.
The
K3E relay is considered
to be the boundary
between
the
reactor level
and
ADS circuits.
The licensee
is reviewing other similar
preoperational
tests for a similar misapplication of the test switch
where portions of a circuit may not be tested.
Surveillance
procedure
N2-ISP-ISC-R104 is performed
on
a refueling outage
periodicity to verify the proper function of the entire
ADS trip logic.
This procedure
was performed
on July 16,
1986,
May 6,
1988,
and
May 11,
1988.
Each time this procedure
was performed,
step 7.8.3 identified a
test
anomoly associated
with the wiring error.
However, this anomoly was
not properly resolved
by the licensee.
The inspectors
determined that
the technicians
involved notified their first line supervisors
of the
surveillance test
problem and annotated
the problem in the test
procedure.
On July 16,
1986 the licensee
decided that further testing
and
investigation
was not necessary
to resolve the anomoly because
the
monthly surveillance test would verify this logic function.
(This was
an
incorrect assumption
by the reviewers.)
On May 5,
1988 the performance
of step 7.8.3
was "N/A'd" and deferred for further technical
resolution.
The procedure
was reperformed
on
May ll after the testing
anomoly was
addressed
by a Temporary
Change
Notice (TCN) to the procedure
to verify
proper
logic function via
a different test method.
This
TCN unknowingly
changed
the intent of the surveillance
test procedure.
The inspector
determined that this
TCN was reviewed
and approved
by the Site Operations
Review Committee.
3.
~Inx ector ~Findin
e (93702,
61726)
Operation of the unit in Modes 1,2 and
3 with Division I ADS
is an apparent violation of Technical Specification 3.3.3.
(50-410/88-21-01)
The inspector
noted that the licensee
had
two opportunities to properly identify the logic circuit wiring
deficiency, but did not adequately
pursue technical
resolution of
the problem.
(A summary of the surviellance testing chronology is
provided in Attachment 1.)
Failure to take timely and appropriate
corrective action to correct
an identified condition adverse
to
quality is an apparent violation of 10 CFR 50, Appendix B, Criterion
XVI, "Corrective Action". (50-410/88-21-02)
b.
A meeting
was conducted with the licensee
station
management
on
December
20 to summarize
the findings and concerns
and the licensee
stated
the following issues will be evaluated
as part of their
corrective action:
1.
Investigate
why the installation
and preliminary testing did
not identify the wiring error.
2.
Evaluate
why the pre-operational
test procedure did not
adequately
test this portion of the
ADS logic function.
3.
Review of technical
errors
made in the review and analysis of
surveillance test data including all last performed
surveillance tests that contain Logic System Functional
Tests
(LSFTs).
4.
Establish policies
and revise test procedures
to include
acceptance
criteria specific to varying plant conditions.
5.
For interim corrective acti'on, all surveillance test results
containing
LSFT will be reviewed
by an independent
member of
the Technical
Department Staff.
4.
Persons
Contacted
Dave Flood, Technical
Department Staff
Rick Abbott, Unit 2 Superintendant
Jim Willis, General
Superintendent
Nuclear Generation
George
Moyer, Station Shift Supervisor,
Unit 2
Mike Falise,
Site Superintendent
Maintenance
Bob Smith, Operations
Superintendent,
Unit 2
5.
Exit ~Meetin
(30703)
At the conclusion of the inspection
on December
21,
1988,
a meeting
was
held with station
management
to discuss
the
scope
and findings of this
inspection.
Based
on the
NRC Region
1 review of this report and discussions
held
with licensee
representatives, it was determined that this report does
not contain
Safeguards
or
10 CFR 2.790 information.
ATTACHMENT 1
ADS WIRING PROBLEM CHRONOLOGY SUMMARY
A monthly surveillance test is perfomed regularly, which is in addition to the
tests listed below.
The monthly test is not intended to test the subject
circuitry.
Early 1986
May 1986
July
1986
May 6,
1988
May ll, 1988
December
3,
1988
December 8,
1988
Preliminary Testing,
Control Circuit Verification
Preoperational
Testing
Surveillance
Test (performed
on refuel
outage
periodicity)
Surveillance
Test
Surveillance
Test (performance
ADS portion only)
Initial identification during Monthly Surveillance
and
a 50.73 Report was initiated.
The licensee
located
and corrected
the wiring error and began
an
investigation to determine
the effects of the wiring
error.
Determined
the wiring error caused
Division
1 ADS to
be inoperable
since initial fuel load.
A four
hour'0.72
notification was
made to the
NRC.
l
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