ML20032B045
| ML20032B045 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 10/15/1981 |
| From: | Baker K, Connaughton K, Gildner M, Peschel J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20032B038 | List: |
| References | |
| 50-295-81-22, 50-304-81-18, NUDOCS 8111040324 | |
| Download: ML20032B045 (10) | |
See also: IR 05000295/1981022
Text
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U.S. NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
REGION III
Reports No. 50-295/81-22; 50-304/81-18
D<,cket Nos. 50-295; 50-304
Licensee:
Commonwealth Edison Company
Post Office Box 767
Chicago, IL 60690
Facility Name: Zion Nuclear Power Station, Units I and 2
Inspection At: Zion, IL
Inspection Conducted: September 15 and 21-24, 1981
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Inspectors:
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gR. Baker, Chief
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Approved By:
Management Programs Section
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Inspection Summary
Inspection on September 15 and 21-24, 1981 (Reports No. 50-295/81-22;
50-304/81-18)
Areas Inspected: The inspection at Zion was a special inspection conducted
to followup on the Preliminary Notification - PNO-III-81-79 of September 15,
1981, (LER 50-304/81-20) and to review modifications M22-1-80-24 and M22-2-80-24.
The inspection involved 56 inspector-hours onsite and 22 inspector-hours in
office by three NRC inspectors.
Results: One item of noncompliance was identifed by the inspectors'; failure
to develop test criteria in accordance with Quality Procedure 3-51 of the
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Commonwealth Edison Quality Assurance Program.
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DETAILS
1.
Persons Contacted
- K. Graesser, Plant Superintendant
- E. Fuerst, Operating Assistant Superintendant
R. Budowle, Operating Engineer
- E. Campbell, Technical Staff
S. llazelrigg, Technical Staff
P. LeBlond, Assistant Technical Staff Supervisor
A. Miosi, Technical Staff Supervisor
T. Lukens, Quality Control Supervisor
- J. Murphy, Quality Control
- B. Harl, Quality Assurance
J. Deress, Station Nuclear Engineering Department
- Denotes those attending the exit interview of September 23, 1981.
The inspectors also interviewed other licensee employees including
members of the Technical, Operations, and SNED staffs.
2.
Review of Modifications M22-1-80-24 and M22-2-80-24
The inspectors reviewed the modification packages to determine whether
or not the proposed modification had received proper review in accord-
ance with 10 CFR 50.59; 10 CFR 50, Appendix B, Criterion III, " Design
Control;" the licensee's approved Quality Assurance Program and other
licensee commitments. The inspectors also reviewed design drawings
and specifications to assess what additional impact, if any, the mod-
ification may have had on the operability of affected components from
the time of installation until corrective action was taken following
the September 14, 1981 event (PNO-III-81-79) later reported as
LER 50-304/81-20.
a.
Background
on May 15, 1980, during performance of safeguards testing at
Zion 1; the 1A Service Water pump failed to automatically start
on command. The cause was determined to be a faulty Westinghouse
Type W-2 control switch. The switch's contacts, in the neutral
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(automatic) position did not provide electrical continuity for
the automatic start signal path. Subsequent tests revealed that
contact closure was intermittent. Westinghouse, manufacturer of
the switch, was notified of the problem and they performed a
review. The results of the review were transmitted in NSD
Technical Bulletin No. 80-9 to all utility owners of Westinghouse
operating plants. The technical bulletin recommended that all
switches be tested for continuity in the neutral position initially
and subsequently after each manipulation (removal from the neutral
position). As an alternative Westinghouse also proposed that the
green breaker position indicator light be rewired to monitor contact
status in the neutral position. Subsequently the NRC Office of
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Inspection and Enforcement issued IE' Bulletin No. 80-20 which
directed licensees of operating plants using Type W-2 switches in
safety-related systems to test the switches fo+ continuity in the
neutral position within ten days of the date c. wae bulletin
(July 31, 1980), at least once every 31 days after the initial
test and after each manipulation of the switch. Furthermore, the
bulletin required long term corrective action consisting of as a-
minimum, the design change described in Westinghouse Techncial
Bulletin No. 80-9.
Licensees were required to submit a description
of plans for longer term corrective measures within forty-five days
of the date of receipt of the IE Bulletin.
Commonwealth Edison, in a response letter dated September 15,
1980, stated that a modification had been initiated to rewire the
indicator lights so both the red and green lights would be used
for checking continuity of the neutral contacts. At that time,
no further oetail concerning the modification was provided.
Commonwealth Edison performed the modification on approximately
fourty-six switches between October 2 and October 16, 1980.
Figure 1 shows a simplified, typical control circuit before and
after modification.
(NOTE: Refer to Table 1 for an explanation
of schematic symbols and nomenclature). After the modification
it was observed that in the trip and' pull-to-lock switch positions
both the red and green breaker position indicating lights were
dimly lit. A sneak power path was discovered at that time which
is shown in Figure 2.
The sneak path was confirmed and was con-
sidered merely a nuisance. A Modification Training Summery was
written that described the new manner of indicator light operation,
including the dimly lit re6 and green lights in the trip and
pull-to-lock positions.
On September 14, 1981 during normal cooldown on Unit 2, with RHR
in' service to control temperature, Steam generator level was
allowed to fall below the 10% low low level resulting in an auto
start signal to the Auxiliary Feedwater Pumps (AFP). The opera-
tors placed the AFP Control Switches in the pull-to-lock position
as allowed by procedure, to avoid excessive cooldown. The pumps
tripped as restired. Subsequently, the operators attempted to
restart one of the motor-driven auxiliary feedwater pumps. The
pump motor could not be started. Attempts to start the other
motor driven auxiliary feedwater pump also failed. An unrelated
problem prevented the steam supply valve to the turbine driven
auxiliary feedwater pump from opening upon demand rendering the
turbine driven pump inoperable. One motor driven auxiliary
feedwater pump was successfuly started after the four KV supply
breaker had been racked out and then returned to service. The
motor drivea auxiliary feedwater pumps' failure to start was
determined to be a result of the modification to the W-2 type
control switch +s.
Figmre 3 for the following discussion)
(NOTE:
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The modification resulted in the preseace of an additional sneak
circuit, when an automatic start signal was present, that carried
sufficient current to the lockout relay (Y) coil of the breaker
to prevent lockout relay contacts from changing status if the
breaker was tripped.
The lockout relay contacts must change status when the breaker
is tripped to allow the iatch release (X) coil to be energized
and reclose the breaker on demand. With the breaker tripped in
the presence of an auto start signal, reclosure can be achieved
if the sneak circuit is temporarily interrupted, allowing the
lockout relay contacts to change status. Racking out and return-
ing to service the auxiliary feedwater pump breaker accomplished
this and restored the pump-to operable status.
Upon determination of the sneak path which affected the motor
driven auxiliary feedwater pumps, the licensee removed local
breaker position indicator light bulbs which were part of the
sneak path. Local breaker position indicator light bulbs were
removed from all control circuits affected by the modification,
thereby eliminating the possibility of any similar occurence
until a new modification to permanently resolve the problem is
accomplished. Caution tags were hung to prevent inadvertant
installation of local breaker position indicator light bulbs in
the interim.
b.
Findings
Noncompliance (50-295/81-22-01) (50-304/81-18-01)
The modification received re sw by the required station
personnel and was sent to the Station Nuclear Engineering
Department, (SNED), with a transmittal letter, dated July 30,
1980, requesting modification review per Quality Procedure 3-51
(QP 3-51).
According to QP 3-51 SNED has the responsibility for preparing
required detailed engineering design documents including the
safety analysis required by 10 CFR 50.59, necessary drawings,
quality requirements and other supporting documentation require-
ments. Also SNED is required to provide all test criteria,
functional descriptions and engineering information necessary te
prepare the required test procedures.
SNED was provided with functional descriptions by Sargent and Lundy,
by a letter 4:ted August 18, 1980, documenting Sargent and Lundy's
review of the ptcpose modification.
SNED documented it's modification review as having been performed
in accordance with QP 3-1 in a letter dated August 19, 1980. The
letter also made a recommendation that every affected circuit be
functionally tested before it is placed in service. However no
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test criteria was provided. The failure of SNED to provide
specific test criteria in accordance with Quality Procedure 3-51
is an item of noncompliance identified in Appendix A.
c.
Discussion
(1) The Zion Technical Staff chose not to follow the SNED re-
commendation and performed the modification with a step by
step wiring procedure followed by a continuity check which
constituted the test. The licensee stated that a recom-
mendation from SNED does not have to be followed and sound
engineering judgement and experience was used in the pre-
paration of the modification. The licensee also maintained
that Performance Tests were probably run on each item of
equipment af ter the modification, but could not produce any
documentation to substantiate the belief.
The inspectors prescated their position that SNED should not
be making recommendations, but should be following QP 3-51
and supplying criteria for testing. They stated that had a
functional test been performed to demonstrate as a minimum,
conformance with the functional descriptions, the glowing
red and green indicator lights in the trip and pull-to-lock
position would have met the definition of a Discrepant Item,
defined in Quality Procedure 15-53.
" Nonconforming Materials,
Parts and Components for Operation - Inspection and Test."
A Discrepat:. Item is defined as an item that does not
conform to its inspection'and testing requirements defined
in the engineering and design specifications. Corrective
action for a Discrepant Item is initiated by the issuance
of a Discrepancy Record.
Since there was no test failure, a Discrepancy Record was not
required to be written in this case. The Licensee closed the
Action Item Record on the modification on October 16, 1980 and
did not show docmentation of act on on the dim lights until
January 7, 1981, when a new modriication designated ' low
priority' was initiated. The new modification was not con-
sidered vital for the Operation of the plant so an Action Item
Record (AIR) was not initiated for the new modification and
consequently the corrective action was not accomplished in a
timely manner.
The inspectors stated that had a Discrepancy Record been
initiated upon the discovery of the nonconforming condition
the event of September 14, 1981, could possibly have been
prevented since the stated purpose of the Corrective Action
System is to accomplish corrective action in a timely manner
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and the operationa? implications of the sneak circuit may
have been identified and corrected prior to causing an
operational event such as reported in the LER.
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'(2) SNED personnel stated that the modification had been
reviewed by both QP 3-1 and QP 3-51 as is their normal
procedure and the ommission of QP 3-51 in their letter
was a typographical error which would be corrected.
The inspectors had no further questions at this time.
3.
Exit Interview
The inspectors met with licensee representatives denoted in Paragraph 2
at the conclusion of the inspection on September 24, 1981. The inspec-
tors summarized the purpose, scope and findings of the inspection.
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TABLE 1
' Legend for" Figures 1-3
CS-
-Control Switch
Y
Y,
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Lockout Relay Contacts
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Iuxilliary contacts:
a, b
A.S.
Safeguards Contacts -(Closed for Auto-Start)
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Contacts
x4
Latch Reicase Coil
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Lockout Relay Coil
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Resister
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. Indicator Light
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