ML20150F008
| ML20150F008 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 03/25/1988 |
| From: | Farrell R, Michaud P, Westerman T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20150F000 | List: |
| References | |
| 50-267-88-03, 50-267-88-3, NUDOCS 8804040236 | |
| Download: ML20150F008 (12) | |
See also: IR 05000267/1988003
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APPENDIX B
U. S. NUCLEAR RECULATORY COMMISSION
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REGION IV
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NRC Inspection Report:
50-267/88-03
License:
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Docket:
50-267.
Licensee:
Public Service Company of Colorado (PSC)
Facility Name:
Fort St. Vrain Nuclear Generating Station
Inspection At:
Fort St. Vrain (FSV) Nuclear Generating Station, Platteville.
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Inspection Conducted:
February 1-29, 1988
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Inspectors:
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R. E. Farrell,"Senior Resident Inspector (SRI)
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F. W. Michaud, Rbsident Inspector (RI)
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Approved:
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T.'F. Westerman, Chief
D6te'
Reactor Projects Section B
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8804040236 890331
ADOCK 05000267
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Inspection Summary
Inspection Conducted February 1-29,1988 (Report 50-267/88-03)
Areas Inspected:
Routine, unannounced inspection of folicwup of licensee
action on previously identified findi;.gs, operational safety verification,
followup of unusual event, engineered safety features walkdown, monthly
surveillance observation, monthly maintenance observation, radiological
protection, and physical security observation.
Results: Within the eight areas inspected, one violation was identified (the
failure to implement and follow procedures for maintenance and operations
activities, paragraph 4).
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DETAILS
1.
Persons Contacted
FSV
- L. Brey, Manager, Nuclear Licensing and Fuels
"M. Ferris, Manager, Quality Assurance (QA) Operations
- C. Fuller, Manager, Nuclear Production
- M. Holmes, Manager, Nuclear Licensing
- F. Novachek, Manager. Technical / Administrative Services
- P. Tomlinson, Manager, QA
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- D. Warembourg, Manager, Nuclear Engineering
- R. Williams Jr. , Vice President, Nuclear Operations
- J. Reesy, Staff Assistant, Nuclear Engineering
- F. Borst, Nuclear Training Manager
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- M.
Deniston, Shift Supervisor
- S. Hofsetter, Nuclear Licensing
- M. Block, Superirtendent, Nuclear Betterment
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- L. Scott, Manager, QA Service
- R. Sargent, Assistant to Vice President, Nuclear Operai1ons
- R. Webb, Maintenance Supervisor
The NRC inspectors also contacted other licensee and contractor personnel
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during the inspection.
- Denotes those attending the exit interview conducted March 8, 1988.
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2.
Followup of Licensee Action on Previously Identified Findings
(Closed) Open Item 267/8507-06: Shorten Time Between Change Notice (CN)
Issue And Notation On Drawing - In some cases, a caution that changes had
been made under a CN was not reflected on the affected drawings for 30
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days or more af ter a CN was issued.
This presented a concern that a
modified system or component could be in service for that amount of time
without adequate drawings.
By utilizing a computerized document update
information system, the licensee has shortened the time involved to mark
all affected drawings to approximately 1 week, with the drawings in the
control room, shif t supervisor's of fice, and records center updated the
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same day a CN issue notification is received. The NRC inspector verified
these activities are taking place by direct observations and a review of
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documentation.
This item is closed.
(Closed) Open Item 267/8507-07: Devcon Epoxy Only Qualified to 200 F.
Epoxy used to attach thermocouples to control rod drive assemblies was
qualified to enly 200*F, while actual operating temperatures can exceed
200 F.
Two tests were performed by the licensee to establish this
adhesive's acceptability.
One test performed under Fuel Handling
Procedure 100-31 involved a visual examination and measurement of force
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required to remove the epoxy from a CRD element, which had been subjected
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to varying power operating conditions in the reactor core between 1979 and
1984.
The second test, T-288, involved subjecting epoxy to greater than
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300 F temperature and then performing a pull test to verify that
thermocouples remained sufficiantly attached. Based on these tests, the
licensee concluded the Devcon ep;xy was acceptable for use in applications
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up to 300 F.
The NRC resident inspectors reviewed the licensee's tests
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and evaluation and found them acceptable.
This item is closed.
3.
Operational Safety Verification
The NRC resident inspectors reviewed licensee activities to ascertain that
the facility is being operated safely and in conformance with regulatory
requirements and that the licensee's management control system is
ef fectively discharging its responsibilities for continued safe operation.
The NRC resident inspectors toured the control room on a daily basis
during normal working hours and at least weekly during backshif t hours.
The reactor operator and shif t supervisor logs and Technical Specification
compliance logs were reviewed daily. The NRC resident inspectors observed
proper control room staffing at all times and verified operators were
attentive and adhered to approved procedures.
Control room
instrumentation was observed by the NRC inspectors and the operability of
the plant protective system and nuclear instrumentation system were
verified by the NRC resident inspectors on each control room tour.
Operator awareness and understanding of abnormal or alarm conditions were
also verified.
The NRC resident inspectors revieved the operations order
book, operations deviution report (0DR) log, clearance log, and temporary
configuration report (TCR) log to note any out-of-service safety-related
systems and to verify compliance with Technical Specification
requirements.
The licensee's station manager and superintendent of operations were
observed in the control room on a daily basis, with the superintendent of
operations frequently in the control room during the day and during
special tests or evolutions.
The NRC resident inspectors verified the operability of a safety-related
system on a weekly basis.
The PCRV overpressure protection system,
120 VAC vital power distribution system, reactor plant cooling water
system, and firewater system were verified operable by the NRC resident
inspectors during this report period.
During plant tours, particular
attention was paid to components of these systems to verify valve
positions, power supplies, and inst umentation were correct for current
plant conditions.
General plant condition and housekeeping were
acceptable.
Shift turnovers were observed at least weekly by the NRC resident
inspectors. The information flow appeared to be good, with the shift
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supervisors routinely soliciting comments' or concerns from reactor
operators, equipment operators, and auxiliary tenders.
No violations or deviations were identified in the review of this program
area.
4.
Followup of Unusual Event
On February 10, 1988, at 3:47 p.m. (MST), "A" helium circulator tripped
due to a low speed signal with the reactor at 75 percent power.
The
circulator trip resulted in a reactor runback to between 50 percent to
60 percent reactor power and then reactor power was further reduced by the
plant operators to 25 percent power. While attempting to balance
feedwater between Loop 1 and Loop 2, an upset in the helium circulator
auxiliaries supplied by feedwater resulted in the tripping of "B"
and "D"
helium circuiators at 4:07 p.m. (MST).
The tripping of two circulators (A & B) in one loop r.;ulted in a loop
shutdown (ESF actuation).
The reactor operators manually scrammed the
reactor from 25 percent power with only one helium circulator running.
At 6:40 p.m. (MST), the licensee identified that an unplanned release was
occurring and an unusual event was declared.
An operator had been
dispatched to vent the surge tank associated with the liner cooling water
system.
The licensed operator dispatched to perform this function
inadvertently opened the wrong valve venting the tank to the plant stack
rather than to the gaseous radwaste system.
The total release over
approximately 200 minutes was small.
(4.26 X 105 microcuries of noble gas
activity)
The plant maintained forced circulation cooling at all timas.
The SRI
responded to the event and was onsite all night.
The Colorado Department
of Health was in contact with the site and was briefed by the licensee as
well as the SRI.
The licensee has subsequently determined that the
"A" helium circulator
trip occurred due to an apparent interchange of speed indication signal
cables during a recent equipment calibration.
The trip occurred when the
"B" helium circulator was placed in manual control for calibration.
a.
Background
The unusual event of February 10, 1988, and associated unplanned
release started with the trip of helium circulator "A".
Helium circulator speed cable daily calibration was in process when
circulator "A"
tripped.
When a circulator's speed cables are calibrated, the circuiator is
taken from auto to manual control to minimize the chances of a trip.
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Helium circulator "A" speed cables had been successfully calibrated
and circulator
"A" returned to auto control.
Helium circulator "B"
was placed in manual control and calibration of the
"B" circulator
speed cables was in process when circulator "A" tripped.
The licensee determined that on February 2, 1988, while calibrating
the speed modules (SM) on circulator "A", SM 2109 could not be
balanced while getting its signal from cable 18194.
The technician
decided to check if the problem was in SM-2109 or in the cable 18194.
The licensee suspected the speed problems were in the cables.
Seven
spare speed cables are available from each circulator's SM.
The
technician unplugged cable 18194 from SM 2109 and plugged in
cable 18133.
With cable 18133 installed, SM-2109 balanced and was
left in this configuration by the technician.
Cable 18133 does not
sense circulator "A" speed but is a spare speed cable from the "B"
circulator,
b.
Design Information
There are two speed indications from each circulator:
a steam
turbine speed indication and a water turbine speed indication. The
water turbine speed indicator is much easier to read than the steam
indicator and generally the one the operators use.
Since both drives
are on a common shaft, the speed should be the same regardless of
which turbine is driving the circulator.
There are 12 speed cables coming from the speed modules of each
helium circulator.
Four of these cables are utilized for speed
control.
One cable for steam turbine speed, one cable for water
turbine speed, and two spares.
Eight cables from each circulator are dedicated to the plant
protection system (PPS).
Three of these cables are used at one time
(one for each logic channel).
Five cables are dedicated spares.
c.
Speed Control
The speed control circuitry looks at the water turbine indicated
speed and the steam turbine indicated speed and controls from the
higher of the two indicated speeds (no difference if everything
working correctly).
As long as the "B" circulator speed was less than or equal to the "A"
circulator speed, the control system saw no problem and chose the "A"
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circulator steam turbine speed to control circulator
"A"
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cable 18133 (a "B" circulator speed cable) controlling SM-2109 (the
"A" circulator water turbine SM) the problem arose during calibration
of "B"
circulator speed when the "A" circulator was in auto control
and the "B" circulator speed exceeded the
"A"
circulator speed,
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.When this happened, the control circuit for "A" circulator, selecting
the higher speed indication, selected the "A" circulator water
turbine speed. -This was actually the "B"
circulator speed, since a
"B" cable was feeding this speed module.
This falsely told the
control circuit that the "A" circulator was running faster than the
control circuit required, so the control circuit began closing the
"A" circulator steam speed valve.
Since the control circuit was actually reading "B" circulator speed
it saw no change in the
"A" circulator speed indication and continued
to close down the "A" circulator speed valve. When the
"A"
circulator reached the low setpoint of the circulator
speed-to-feedwater flow program, which forces a limit on primary to
secondary flow ratio, the the PPS which was correctly reading
circulator "A" speed tripped the circulator.
d.
Findings
The technician calibrating the SM was utilizing licensee
Procedure SR-RE-17-W, Issue 10, "Circulator Speed Modifier Weekly
Check."
The procedure did not address cable termination.
When the technician removed the installed cable (18133) he was no
longer performing surveillance activities, but was performing
maintenance activities.
Maintenance activities are governed by the
licensee's Administrative Prosedure P-7, Issue 12, "Station Service
Request Processing." Procedure P-7 as modified by Procedure
Deviation Request 88-0006, dated January 13, 1988, specifically
states, in Section 2.0, that the procedure applies to corrective and
preventative maintenance and not to calibration activities.
Procedure P-7 is the licensee's procedure for controlling maintenance
activities.
Procedure P-7 requires initiation of a Station Service
Request to authorize, document, and control maintenance activities.
Failure to follow Procedure P-7 is an apparent violation of NRC
regulations (267/8803-01).
The operator venting reactor plant cooling water system surge tanks
was guided by System Operating procedure (SOP) 46, Issue 39, "Reactor
Plant Cooling Water System." SOP-46 in Step 3.7, "Venting the Vapor
Space in T-4601 or (T-4602)," details the steps for venting the
reactor plant cooling water surge tank vapor space to the gas waste
system.
The steps call for first opening V-4653 for Surge
Tank T-4601 (V-4654 for Surge Tank T-4602).
Then the operator is to
open V-461691 for Surge Tank T-4601 (V-461692 for Surge Tank T-4602).
Opening these two valves for each surge tank vents the vapor space of
each tank to a common line leading to the gas waste system. When
these steps are completed, the operator opens Valve V-46193, which
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opens the common line from the two surge tanks to the gas waste
system relieving the pressure in the , urge tanks.
All of the valves mentioned in the preceding paragraph are manual
valves. Adjacent to the valves, V-461691 on Tank T-4601 and V-461692
on Tank T-4602, are hand operated valves, V-461634P and k-461635P,
respectively. Opening Valve V-461634P after opening Valve V-4653
vents Surge Tank 1-4601 to the plant exhaust stack. Opening Valve
V-461635P af ter opening Valve V-4654 vents Surge Tank T-4602 to the
plant exhaust tank.
The valves are now clearly marked as to function.
At the time of the
incident, the valves were marked with small stamped metal tags
identifying the valves by number.
Procedure 50P-46 in Step 3.7 clearly listed the valves to be opened.
The valves were identified in the procedure by valve number
corresponding to the valve numbers attached to the valves. The
operator opened either or both Valves V-461634P and V-461635P, rather
than V-461691 and V-461592. This vented the gaseous content of
Tanks T-4601 and/o" T-4602 to the plant stack resulting in an
unplanned radioactive release.
The failure to follow
Procedure 50P-46 is second example of Violation (267/8803-01).
5.
Engineered Safety Features (ESF) Walkdown
The NRC resident inspectors performed a walkdown of all accessible
portions of the prestressed concrete reactor vessel (PCRV) overpressure
protection system to verify its operability.
Sections 4.3.6 and 6.8 of
the FSAR and Technical Specifications 3.2, 3.3, 4.2.7, and 5.2.1 were
reviewed by the NRC resident inspectors to ensure familiarity with the
system and requirements.
The as-found system configuration was compared
with drawing PI-11-5 to check their agreement. Valve positions and
labeling were verified to be correct by the NRC resident inspectors,
including the installation of lotking devices on valves where required.
All cortions of the system were physically inspected, w th the exception
of the internals of the PCRV safety valve tank T-1101 which contains the
relief valves and rupture discs.
These components will be inspected
during the next outage when T-1101 is opened.
During this inspection,
attention was paid to equipment conditions, housekeeping, and any items
which could degrade performance.
The overall condition of this system was
considered good.
No violations or deviations were identified in the review of this program
area.
6.
Monthly Surveillance Observation
The NRC resident inspectors observed the licensee's performance of
selected surveillance activities as listed below. The surveillance
procedures were reviewed for conformance with Technical Spe;ification
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requirements and to ensure they had been properly reviewed and approved
prior to commencing any tests.
The NRC resident inspectors witnessed
portions of the preparations, conduct, and v/ stem restoration for each of
these surveillance tests.
Test results were independently reviewed by the
NRC resident inspectors to ensure they met applicable Technical
Specification requirements.
Surveillance activities observed during this
reporting period included:
SR 5.4.1.1.8.b-M, "Reheat Steam Temperature Scram Test," performed on
February 1,1988.
This surveillance tests each hot reheat steam
temperature scram channel to verify alarms, actuations, and
indications.
The as-found values were measured and recorded,
acceptance values calculated and independently verified, and
calibration of the bystable amplifiers and thermocouple amplifiers
was checked at 600 F, 900 F, and 1200 F utilizing test signals.
These amplifiers were adjusted as required in accordance with this
procedure and the as-left values were recorded.
No discrepancies
were noted.
SR 5.10.8-M, "Monthly Check of Fire Hose Stations," performed on
February 2, 1988.
This surveillance verified the condition of each
fire hose station in the reactor and turbine buildings, and was
independently versfied by the NRC resident inspectors.
Each
station's hose valve was verified shut and not leaking, hoses and
nozzles properly connected, and general equipment conditions
observed.
No discrepancies were noted.
E3R 8.1.lbc-M, "Radioactive Gaseous Effluent Systein Test," performed
on February 25, 1988.
This surveillance test verifies the operation
of the gaseous waste release system automatic functions.
Instruments
which provide inputs to cause automatic isolation and ventilation
system realignments were tripped using a test signal, then each
associated damper or valve which was repositioned by the automatic
signal was verified to be in its proper position.
The instruments
and equipment were then restored to their normal lineup.
No
discrepancies were noted.
No violations or deviations were identified in the review of this program
area.
7.
Monthly Maintenance Observation
On February 4,1988, the licensee noticed the pressure in the emergency
feedwater supply to the Loop 1 helium circulator Pelton wheel drives was
equal to the feedwater header pressure (approximately 3000 psia).
This
condition indicated a problem with Pressure Control Valve PV-21243, which
should reduce the pressure to approximately 1700 psi. The licensee took
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the emergency feedwater header out of service at 5:57 a.m. (MST), on
February 5, 1988, to perform repairs on PV-21243 and entered Technical
Specification Limiting Condition for Operation (LCO) 4.0.3, since the
conditions of LCO 4.3.4, "Emergency Condensate and Emergency Feedwater
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Headers LCO," were no longer satistted-
LCO 4.0.3 requires the reactor to
be ;hutdown in an orderly manner within a 24-hr Jr period. Also c' :icaale
and providing a 24-hour grace period was LCO 4.2.2.a, "Operable C. culator
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LCO."
Repairs were made to valve PV-21243, which included replacement of
the valve trim. The associated pressure controller, PIC-21243, was
calibrated in accordance with Procedure RP-EQ-16, Issue 2, dated
October 15, 1986.
The NRC resident inspectors observed the repairs and
calibration, which were completed satisfactorily.
No aiscrepancies were
noted.
The emergency feedwater header was retu ned to service at
1 a.m. (MST), on February 6, 1988, and LCO 4.0.3 and 4.2.2.a were formally
exited at 5:15 a.m. (MST), after allowing the system to run following its
return to service.
The NRC resident inspectors also followed the licensee's actions to
correct the problems in the helium circu'ator speed cables.
The
circulator speed signals to both the indicators and the plant protective
system had been exhibiting erratic behavior at the elevated temperatures
associated with operation at higher power levels.
Troubleshooting
following the February 10, 1988, event, described in paragraph 4 of this
report, indicated a problem with the twinax cable "Cannon" connectors at
the helium circulators.
These special connectors have the male end
attached to the circulator housing and the female end attached to the
cables.
These female pin connectors have a spring-like device which in
some cases had relaxed, allowing a slight gap in the pin connection at the
elevated temperatures. The connectors on each of the four helium
circulators were disassembled and both the nale ar.d fema'e pins were
checked with a micrometer to ensure their size was within a tolerance of
0.060 inch to 0.064 inch.
A number of female pins were replaced, and the
connectors reassembled.
Since returning to power on February 12, 1988,
the licensee has experienced no significant problems wish the helium
circulator speed cables or the associated indications and protective
circuitry.
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At 10:40 p.m. (MST), on February 25, 1988, the license 4 experienced a
turbine trip from approximately 50 percent power due to a <=lse low main
steam pressure signal.
On investigation, the licensee discovered the root
valve to Main Steam Pressure Transmitter PT-5220 was nearly shut.
This
valve had been repacked on February 11, 1988, and was left in a nearly
shut position following this work.
The valve was open enough to allow the
main steam pressure to equalize across it before the turbine was placed in
service.
The valve's new paa,ing shifted, evidenced by the fact that the
valve developed a packing leak about the time of the turbine trip, which
allowed the pressure downstream of the ,alve to be relieved.
This re6fced
pressure was sensed by PT-5220, which then caused a turb'ne trip.
The NRC resident inspectors found no instructions in Maintenance
Procedure MP-2115 to return a valve to its as-found pcsttion following
maintenance.
Although this is not safety-related equipment, the lack of a
step to return the equipment to service following maintenance is of some
concern.
The licensee considers the potential probiers associated with
this significant and will revise all m.iintenance precedures fo valves to
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record the as-found position before commencing maintenance and to return
the valve to that position or leave it in another position with the shift
supervisor's knowledge and consent following completion of the maintenance
activity.
The NRC resident inspectors will monitor the licensee's
implementation of these measures.
No violations or deviations were identified in the review of this program
area.
8.
Radiological protection
The NRC resident inspectors observed the licensee's activities in this
area to verify their conformance with policies, procedures, and regulatory
requirements.
Health physics professionals were observed on all shifts, performing plant
tours, area surveys for radiation levels and radit. .ive contamination,
and checking the operability of area radiation man, toes and continuous air
samplers.
The NRC resident inspectors verified tha the results of area
surveys were posted at entrances to radiation areas and in other
appropriate locations.
Health physics supervisors and personnel were
aware of the plant status and activities which involved potential
radiological concerns.
The NRC resident inspectors observed that health physics personnel were
present and available to provide astistance whenever workers are required
to enter a radiologically controlled area.
No violations or deviations were identified in the review of this program
area.
9.
Physical Security Observation
The NRC resident inspectors vcrified that there was a lead security
officer (LS0) on duty authorized by the facility security plan to direct
security activities onsite for eac's shif t.
The LSO did not have duties
that vould interfere with the direction of security activi+1es.
The NRC resident inspectors verified, randomly and on the backshift, that
the minimum number of armed guarcs required by the facility's security
plan were present.
Search equipment, including the X+ ray machine, metal
detector, and explosive detector, were operational or a 100 percuat
hands-on search was being utilized.
The protected area barrier was surveyed by the NRC resident inspectors.
The barrier was properly maintained and was not compromised by erosion,
openings in tl.. fence fabric or walls, or proximity of vehicles, crates or
other objects that could be used to scale the barrier.
The NRC resident
inspectors observed tne vital area barriers were well maintained and not
ccmpromised by obvious breaches or weaknesses. Th NRC resident
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inspectors observed that persons granted access to the site were badged
indicating whether they had unescorted or escorted access authorization.
No violations or deviations were identified in the review of this program
area.
10.
Exit Meeting
An exit meeting was conducted on March 8, 1988, attended by those
identified in paragraph 1.
At this time, the NRC resident inspectors
reviewed the scope and findings of the inspection.
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