ML17056A342
| ML17056A342 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 09/12/1989 |
| From: | Collins T, Laura R, Jun Lee, Loesch R, Pasciak W, Pederson R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17056A341 | List: |
| References | |
| 50-220-89-80, NUDOCS 8910120079 | |
| Download: ML17056A342 (34) | |
See also: IR 05000220/1989080
Text
1
I
C ~
U.S.
NUCXZAR R1KUIAIORY CCNMISSION
REGION I
Docket No.
50-220
Li~No.
Licensee:
Nia
Mohawk Poem
Go
ration
300 Erne
cuse
13202
Facility Name: Nine Mile Point Unit 1
In @ection At: Scriba
Inspection Conducted:
22-28
1989
Inspectors:
T. Collms
Chief
R.
, Rachatxon
Specs ~, RI
9')g9
R. Laura,
RBs1 ent
Mile Point, RI
J. lee, Sr.
Hlys1clst
R., Pedermn
9 f< g'p
Sr. Health Physi,
Appmved by.
W. Pasc,
Team Zea er,
Fac
xtxes
Radiation Protection Section, RI
0
Ins ection
Summar
Ins ection conducted
on Au ust 22-28
1989
Ins ection
Re ort 89-80
Sco
e of Ins ection:
Announced
Augmented
Team Inspection of the circumstances
and safety implications
of the licensee
using the Radwaste
Processing
Building 225'levation
sub-basement
as
a long-term liquid radwaste
storage facility including review of
the history of use
oF the sub-basement,
review of the history of changes
of
radwaste
equipment,
identification of present radiological conditions of the
room and contents,
evaluation of onsite
and offsite radiological safety
consequences,
and review of licensee's
past
and planned corrective actions.
Results:
The 225'levation
sub-basement
of the Radwaste
Processing
Building has
been
used
by the licensee
as
a liquid radioactive
waste storage
holding facility
since July,
1981.
The licensee's
environmental
monitoring program
was 'reviewed
and found to be adequate.
Split sample water analyses
indicated
no detectable
leakage of sub-basement
liquid to perimeter drains.
The radiological safety
impact offsite was negligible
and worker exposures
were within regulatory
guidelines.
The licensee
has initiated the construction of a robot to be used in
the clean-up
and decontamination
of the 225'levation
sub-basement.
Two
problems. were identified as follows: the licensee
(1) did not perform
evaluations
to assess
the acceptability
and consequences
of using the
sub-basement
as
a liquid radwaste
holding facility; and
(2) did not notify the
NRC of flooding the sub-basement,,
of the decision to defer decontamination
of
the sub-basement,
or of the costs
and extent of decontamination
anticipated
(Details,
Section 4).
1.0
Persons
Details
Contacted
8 Present
at Exit
Nia ara
Mohawk
1.2
J.
L.J.
K.
M.
R.
R.
H.
W.
D.
J.
R.
M.
W.
T.
R.
E.
J.
G.
E.
N,
C.
H.
U.S.
Endries,
President
Burkhardt,
Executive Vice President
Willis, General
Superintendent,
Nuc. Generation
Dahlberg,
Station Superintendent,
NMPI
Colomb,
Nuc.
Reg.
Compliance Director
Abbott, Station Superintendent,
NMP2
Remus,
Superintendent,
Chemistry
L Radiological
Master, III, Supervisor
Incident Investigation
Bandla, Assistant
Operations
Supervisor,
NMPI
White, Compliance
& Verification, Tech.
Aldrich, Special Assistant to
NMP1 Supervisor
Randall,
Operations
Supervisor,
NMPI
Dooley, Regulatory
Compliance
Hansen,
Mgr. of gA Audits
Newman,
Supv. of gA Surveillance
Burtch, Jr.,
Public Relations
Gordon, Supervisor Radiological
Support
Duell, Supervisor
Chem.
5 Radiochemistry
Brownell, Nuclear Regulatory
Compliance
Leach,
Generation Specialist
Spagnoletti,
Manager Corporate
Health Physics
Gerber,
Supervisor
Radwaste
Wagner, Assistant
Supervisor
Radwaste
Nuclear
Re ulator
Commission
Management
- R.
R.
- R
J.
- B
- R.
Knapp, Director, Division of Radiation Safety
and Safeguards,
RI
Pasciak,
Chief, Facilities Radiation Protection Section,
RI
Loesch,
Radiation Specialist,
RI
Collins, Section Chief, Sect.
A,
RSB,
Pederson,
Senior Health Physicist,
Laura,
Resident
Inspector,
Nine Mile Point,
RI
Lee, Senior Health Physicist,
Cook, Senior Resident
Inspector,
Nine Mile Point,
RI
Temps,, Resident
Inspector,
Nine Mile Point,
RI
- Denotes
those individuals who attended
the exit meeting
on
August 28,
1989.
The inspectors
also contacted
other licensee
personnel.
2.0
~Pur ose
The purpose of this augmented
team inspection
was to review and determine
the following matters:
Establish
the circumstances
under which the sub-basement
was initially
flooded in 1981;
Identify the present
condition of the room, including radioactive
material
inventory, radiation
and. contamination levels, isotopic
contents. of the water
and air and leakage
paths;
Determine if the
room has
been
used since its initial flooding for
further material/water
storage
and the circumstances
associated
with
any of these
uses;.
Assess
the radiological
impact of use of this room for water storage
on plant workers
and determine
whether
an evaluation
per
had
been
performed to support
use of the
room for. storage;
Assess
the offsite radiological
impact of the use of this room for
liquid waste storage;
Assess
any radwaste
system design or operational
inadequacies
identified;
Assess
the scope,
extent
and timeliness of the licensee's
corrective
actions;
Determine if NRC was or should
have
been notified of this situation;
Determine environmental
monitoring adequacy;
obtain independent
measurements if possible;
and,
Determine if there
are other places
onsite
where radwaste is being
stored in an analogous
manner.
Enclosure
1 is
a copy of the Hemorandum
from W. Russell
to H. Knapp
establishing
the Augmented
Inspection
Team
and specifying the inspection
objectives
and scope.
3.0
Backcaround
3. 1
Ori inal Facilit
Desi
n
Nine Hile Point Unit
1
became operational
in 1969.
As originally
designed,
the Radwaste
Processing
Building, located
on the east
side
of the Reactor Building, housed
the storage
and processing
equipment
necessary
to properly process,
package
and ship radioactive
wastes
generated
during normal plant operations.
Liquid wastes
and their
related
storage
tanks were segregated
into the following five basic
categories:
-
Low conductivity waste
- High conductivity,
non-chemical
waste
- High conductivity,
chemical
waste
- Filter backwashes
- Spent resins
Waste Collector Tank
Floor Drain Collector Tank
Waste Neutralizing Tank
Waste Building Filter Sludge
Tank
Spent
Resin Tank
Low conductivity wastes
from the Waste Collector Tank were processed
through
a Waste Collector Filter to remove
suspended
solids
and
a
Waste Demineralizer to remove dissolved impurities.
The final
purified water was sent to one of two Waste
Sample
Tanks to allow for
sampling
and chemical
analysis prior to being
added to the Condensate
Storage
Tank for recycling back to the reactor
system.
High conductivity wastes collected in the Floor Drain Collector Tank
were filtered by a Floor Drain Filter prior to storage
in the Floor
Drain Sample
Tank.
After chemical
analysis,
the waste liquid was
either discharged
to the lake or further processed
by the chemical
waste
system.
High conductivity (chemical
waste)
from the Waste Neutralizing Tank
consisted of liquid from the laboratories,
decontamination
operations
and acid
and caustic rinses that resulted
from the regeneration
of
resins.
Upon neutralization,
the waste
was sent to the Ill Waste
which concentrated
the liquid through evaporation.
Some
liquid was evaporated
after which it was condensed
and recycled to the
Waste Collector Tank.
The concentrated
"evaporator
bottoms" were then
processed
through
a Concentrated
Waste Tank,
a Concentrated
Waste
Volume Tank,
mixed with the appropriate solidification chemicals
and
placed into 55-gallon
drums for eventual
shipment to a waste burial
site.
When the various filters became
exhausted,
the filter media were
backwashed
from the filter columns into the Waste Building Filter
Sludge
Tank.
This slurry was then processed
through
a centrifuge to
remove most of the free liquids.
The liquids were routed to the Floor
Drain Collector Tank while the resins
were transported
via
a hopper
for placement into 55-gallon drums for storage
and later shipment
offsite.
Spent resins
from the demineralizers
were transferred
to the Spent
Resin
Tank.
The spent resins
were processed
by the
same centrifuge
mentioned
above
and were then loaded into drums for ultimate offsite
disposal.
3,2
The 225'levation of the Radwaste
Processing
Building is
a
sub-basement
of approximately
2400 square feet,
subdivided
by 30"
thick shield walls into five working areas:
the operator's
aisle,
the
fill aisle,. storage
areas
A and
B,
and the east
equipment aisle
(see
Figure 1).
The room is the lowest point in the radwaste
building and
contains
two floor drain
The Ill sump is located in the east
equipment aisle
and the
812
sump is located at the west
end of the
operator's
aisle.
The
were
used for the collection of waste
from routine washdowns/decontaminations
of the processing line.
In
addition, the
sumps received additional
inputs from other sources
within the radwaste building. Both the floor and the lower portions of
the walls were painted with a protective coating to facilitate
decontamination
of the
room,.
The room was designed
to receive
processed
wastes
in the form of dewatered
resins
and sludges,
transfer
the waste material into 55-gallon drums,
provide temporary storage
capability,
and to make final transfer to
a loading dock for shipment
in shielded
casks.
During normal operations,
empty drums were loaded onto
a drum elevator
and lowered to the 225'levation
where they were automatically loaded
onto carriers
which hung from a monorail track.
The drums were routed
into the fill aisle where
a vibrating bed automatically lifted up
under
the carrier.
The vibrating bed facilitated the efficient filling
of the drums.
Waste
from the centrifuge,
located
on the 261'levation
passed
down through
a hopper to the 225'levation
and
was loaded into
drums under control of the radwaste
operators
working from the
operator's
aisle,
Waste from the waste concentrator
stored in the
Waste
Volume Tank was mixed with chemicals
in a mixer
located
on the 236'levation
and
was
used to fill drums at
a
different location in the fill aisle.
The operator
had the capability
to remotely cap the drums.
However, to facilitate the further drying
of the waste product,
the drums were routinely left open,
and capped
only prior to shipment.
The filled drums were routed
by the monorail
conveyor system to storage
locations
in the
A and
B storage aisle.
0 erational
Histor
During the first few years of operation
( 1969-1971),
the licensee
determined that the as-built liquid handIing systems
were undersized
and would have to be supplemented
with additional capacity to
adequately
handle future demands.
Occasionally,
when backlogs of
unprocessed
liquids were experienced,
incoming liquids would back
up
from the two sumps into the sub-basement,
resulting in a few inches of
waste water
on the floor. However,
when the backlog
was corrected,
the
225'levation
would be decontaminated
and returned to operation.
Due
to operational
problems
being experienced
with the centrifuge,
a
flat-bed filter system
was installed in 1972. This unit was
essentially
a shallow container,
the bottom of which was
a movable,
~
~
L
p
1
r 0,
0 ~
l ai
porous belt.
Waste
was forced through the belt; the liquid exiting
from the bottom was recycled.
At the appropriate
time, the belt would
move the filtered waste for transfer through
a hopper to 55 gallon
drums.
Since
bead type resins
from the Spent
Resin
Tank would not hold
together
when dry, they were transferred
and dewatered directly in the
shspping
casks.
After 1973,
use of the Ill waste concentrator
was curtailed
due to
operational difficulties. To continue processing
operations,
an
outside
vendor
was brought in to dewater and/or solidify wastes
from
the Floor Drain Sample
Tank and the Waste Neutralizing Tank. During
the
1973-1974 period,
an addition was built onto the Radwaste
Processing
Building. This addition housed
a
new 812 waste
a concentrated
waste storage
tank and supporting
equipment
and effectively replaced
the inoperable
811 waste evaporator
which was
removed
and scrapped
in 1976.
During the 1977-1979 period,
burial site requirements drastically decreased
the allowable water
content of waste.
Therefore,
the licensee
shifted the dewatering of
sludges
and resins
from the flat-bed filter to predominately
in-cask
dewatering.
After this time, the drum processing
area
on the
225'levation
sub-basement
was not used
except for storage of
approximately
150 previously filled drums.
3.3
Other Radwaste
Stora
e Areas
During the course of the inspection,
the Radwaste
Building was toured
by the inspectors
several
times
and
numerous
licensee
personnel
were
questioned
regarding the likelihood of there
being
an analogous
location onsite
where radwaste
may be stored in a manner not
consistent
with the facility design.
No such areas
were found by
inspectors
nor were any identified by the licensee
or their staff.
4.0
Summar
of the
1981 Floodin
Event
The inspectors
reviewed operations
and waste logs for the period of July 4,
1981, to July 20
1981,
in order to determine
the sequence
of events
leading to the f)ooding. During the Unit
1 startup
on July 5,
1981, higher
tha'n normal conductivity was noted in the low conductivity (high purity)
waste water process
stream
(Waste Collector Tank).
The higher than normal
conductivity in the process
stream
caused
a more rapid depletion of the
resins
in the waste demineralizer.'he
licensee therefore
began
a changeout
of the waste demineralizer.
The evolution of demineralizei
changeout
halts
low conductivity stream processing.
At the
same time, this evolution
creates
large
volumes of high conductivity waste
because
of the resin
.
regeneration
and resin transfers
involved.
During this period (July 5-7), the
812 waste concentrator
in the high
conductivity process
stream
was out of service for extended
periods.
Since
the waste concentrator
is the only means for reducing conductivity to
a low
enough level that the water can
be transferred
to the low conductivity
'tream, all high conductivity waste is stored in holdup tanks whenever the
waste concentrator
is out of service.
Therefore,
during this period when
'the demineralizers
were being changed
out and the waste concentrator
was
out of service,
both the low and high conductivity process
streams
were
unavailable
and large
amounts of waste water were being generated.
By July 7, all radwaste
tanks
were full. However, the very process
needed
to return the low conductivity processinq
system to operation
would also
generate
additional
waste water.
In particular, regeneration
of the
demineralizer
was essential
for establishing
low conductivity stream
rocessing.
Since
no additional
waste storage
tanks were available,
the
icensee
elected to overflow the radwaste
storage
tanks with the intention
of using the 225'levation
sub-basement
area
as
a temporary storage
area.
Apparently, consideration
was not given at the time of this decision to the
potential
impact of room flooding on the drums of solid waste which were
stored at that location. Further,
the licensee
did not perform
a safety
evaluation of using the sub-basement
as
a liquid radwaste
holding facility
under the requirements
of 10 CFR 50.59.
The overflow in the waste building
flooded the sub-basement
area to just above the 229'levation.
At the time
of the flooding, there were approximately
150,
55 gallon drums in the area,
most of which were filled with radioactive waste
made
up mostly of filter
sludges
and spent resins.
As was discovered
in October,
1981, the water
floated
many of the waste storage
barrels off of their carriers,
resulting
in tipping and spilling of the contents of many into the water.
Late
on
July 7, the waste concentrator
was returned to service
and processing
of
the high conductivity stream started.
Processing
of the high conductivity
stream
was not successful
however,
because
the transfer point between
the
high and low conductivity streams
is the equipment drain
sump located
on
the flooded 229'evel.
The flooding at the 229'evel
allowed flow from
the high conductivity to the low conductivity process
streams
and thus
recontaminated
the low conductivity processed
water.
The occurrence of the
recontamination
problem is further evidence that
a safety evaluation
had
not been
performed prior to the flooding event.
In order to reestablish
separation
between
the high and low conductivity streams, it was first
necessary
to reduce
the water level to below the 229'levation.
On July 8,
the licensee
therefore
began
a controlled discharge of water to Lake
Ontario from the 50,000 gallon Waste
Surge
Tank at
a rate of 30 gallons per
minute in order to make the surge tank available for storage of the water
currently flooding the 225'nd 229'levations.
The licensee notified the
NRC of this discharge
by letter dated
October 30,
1981,
but did not
describe
the flooding of the 225'levation or its consequences
(Reference
9. 1).
By July 10, level recovery in the radwaste
tanks
had begun.
On
July 16, decontamination
of the 229'levation
was initiated.
In August
and September,
1981,
attempts
were
made to decontaminate
the 225'evel.
These efforts were discontinued
in October,
1981,
based
upon radiation
protection priorities. Decontamination efforts are
more fully discussed
in
Section 7.1.
In October,
1981, after the licensee
terminated their initial
decontamination effort of the July,
1981, flooding event, it was decided
10
5.0
that the sub-basement
area
would be left flooded at about
a depth of one
foot until decisions
on ultimate clean
up were made.
A depth of one foot
was maintained to help control potential
airborne contamination.
The
inspectors
did not find evidence that the
NRC had
been notified of the
decision to defer decontamination
of the sub-basement.
Current Status of Room
The inspector
reviewed radiological
survey data
and analyses
performed
by
the licensee
to support three decontamination efforts of the 225'levation
(1981,
1985,
and 1986),
video tapes
recorded during
a remote-robotic
survey
>in September
1986,
and recent
surveys of the area,
to determine
the
radiological conditions of the 225'levation.
These decontamination
efforts
and
surveys narc described
in detail in Section
7.
An exact
accounting of the barrels
and their contents
is difficult due to the loss
of the operating
log for. the system.
It is believed that the log book- was
disposed of as radioactive
waste during the
1985 decontamination effort
(see
Section
7. 1). However,
based
on the licensee's
knowledge of the system
and review of a status
board within the 225'levation
sub-basement,
the
licensee
estimates
there
are
no more than
150 barrels (their best estimate
is that there
are
130 barrels) of expended
powdered filter/ion exchange
resin
and filter sludge.
The video recording
by the
SURVEYOR robot of the
drum storage
areas
in September,
1986,
shows 55-gallon drums in disarray.
Hany of these
drums were off the conveyor system
and lying in various
orientations.
Several
drums were lying on their sides without their tops
and with their contents spilled out.
The practice
when the system
was in
operation
was to leave the tops off the drums until just before shipment to
promote drying of the contents.
The video recording indicated
some
corrosion
had occurred
on the drums.
The extent of damage to the drums
was
not clear in the recording.
Based
on the contact
dose rates
measured
on the
drums
when they were initially filled, it is believed that the present
contact
dose rates
associated
with some of these
drums is as high as
500
R/hr. This is the estimated
dose rate at the surface of some
drums within
the shielded walls of the room.
Dose rates at the entrance
to the locked
gate were less
than
10 mR/hr. Contamination levels are discussed
below.
In November,
1985,
an isotopic analysis
and
a dose rate survey were
performed
on
an accessible
barrel
in preparation for the
1986
decontamination effort.
Based
on the results of this analysis
(and the
assumption
of 150 barrels in the area)
the licensee's
"best estimate" of
the total radioactive material
in the area is 7570 Curies. Currently, the
licensee
is maintaining
10 to
18 inches of water on the floor of the
225'levation
to minimize the drying of the resin/sludge
material
and reduce
the potential for radioactive particulates
from becoming airborne.
During
this inspection,
the licensee
sampled water from the area at the bottom of
the stairs leading to the operator's
aisle.
The isotopic analysis of the
sample indicated concentrations
of cesium-137,
and manganese-54
of 5E-3 uCi/ml, 3E-4 uCi/ml and 3E-5 uCi/ml, respectively.
However,
since
the majority of the spilled resins
are located in the rear of the
sub-basement,
the sample
obtained
may not be representative
of actual
concentrations
in the storage aisles.
Assuming that the water at the bottom
11
of the stairs is representative'of
the water throughout the room, these
results indicate that less
than
4 Curies (less
than 0.05 .percent of the
radioactive material
in the area)
is dissolved
in the water standing
on the
floor. Samples of the water in the area at the bottom of the stairs leading
to the, operator's
aisle were also analyzed
by the
NRC (see
Section 6.0)
and
results
were in agreement
with those of the licensee.
6.0
The inspector
reviewed airborne contamination
surveys
performed during
periods of access
to the area.
These
surveys
indicated levels from 4-8% of
the maximum permissible
concentration
(MPC) of 10 CFR 20 for restricted
areas.
An airborne survey taken in the operator's
aisle during this
inspection
(Augu'st 24,
1989) indicated
4.8% of MPC.
In addition to'irborne
contamination,
the licensee
also performed
an area radiation survey
and
a
removable
surface
contamination
(smear)
survey of accessible
areas of the
225'levation
and the 229'levation
access.
Dose rates just'bove the
surface of the water in the operator's
aisle
and the fill aisle were
measur'ed
at up to 200 mR/hr and
up to 2500 mR/hr respectively.
The dose
rates
in the operator's
aisle were measured
by means of'n extendable
probe
survey instrument (teletector)
extended
from the area of the stairs,
and
the dose rates
in the fill aisle were measured
with a teletector
extended
down the elevator
shafts
from the floor above.
Smear
samples
on the
229'levation
were measured
at
up to 94,000
dpm/100
cm"2 on the landing inside
the locked access gate,'p
to 30,000
dpm/100
cm"2 outside the locked access
gate,
and
up to 450,000
dpm/100
cm
2 on the stairs leading to the
225'levation.
These
dose rates
and contamination levels are not inconsistent
with what would be expected
in areas of a radwaste
processing
building.
Environmental
and Onsite
Im acts
The inspector
reviewed results of the licensee's
Environmental
Monitoring
Program,
plant layout and design,
plant system drawings
and records of
effluent discharges
to determine if radioactive material spilled
on the
225'levation
area is being or has
been inadvertently released
to the
environment.
Possible
means of radioactive release
from the 225'levation
include release
of water to the surrounding
ground through
some
in the room or
a release
to the air of any airborne
radioactive material
from the room.
The inspector
noted that the
225'levation
was originally designed
as
an area of high potential for airborne
activity.
As such,
the ventilation was designed
so that air from the
225'levation
is taken into the exhaust ventilation system.
This air is
exhausted
through
a High Efficiency Particulate Air (HEPA) filter into the
plant's stack.
An alarming Continuous Air Monitor is provided in the flow
path before the
HEPA filter.
There
have
been
no indications of radioactive
materials
being released
other than what is normally expected
by this path.
Surveillance of the stack radiation monitors to assure operability is
routinely performed in accordance
with plant Technical Specifications
and
reviewed
by the
NRC during routine transportation
and effluent inspections.
12
As-noted in Section
5, air concentration
measurements
in the
room are
generally
below
10% of NPC.
In reviewing the possible
pathways for release
of liquid radioactive
material
from the 225'levation
sub-basement,
the inspector noted that the
lower levels of the plant are recessed
into the bedrock underlying
the'acility.
A drain system
has
been provided surrounding the plant buildings
at the bottom of the back fill area 'between
the plant walls and the bedrock
walls.
This perimeter drain system consists of a perforated collecting
, pipe that channels
water to
a sump.
At the exterior of the radwaste
building, this piping is at the 225'levation.
Any groundwater flowing
into the channel
would be collected in the
and
pumped to the plant
Storm Drain System.
Similarly, any leakage
from the Radwaste
Building
would be collected
and
pumped into the storm drain.
In response
to an
NRC
Information Notice, the licensee
has
been monitoring the discharge
at the
storm drain system
on
a weekly basis
since August,
1981.
Between June,
1979,
and August,
1981, it was monitored
on
a monthly basis.
The results of
this monitoring program do not indicate
any leakage of radioactive material
from the Radwaste
Building or any other buildings onsite.
The inspector
requested
that the licensee
draw
a sample
from the perimeter drain
sump;
however,
there
was not enough flow in the discharge
header with the
pumps running to get flow out of the sample point at the top of the
discharge
pipe.
The licensee did, however,
manage to obtain
a water sample"
and
smear
samples
from the internals of the
pump located
in the
by
partially disassembling
the system.
No detectable activity was found, which
further indicates
no leakage
from the 225'levation
sub-basement.
It is
the conclusion of the inspection
team that leakage of radionuclides
from
the
room is negligible.
The inspectors revisited
an issue of offsite environmental
contamination
raised
in the second half of 1981.
The public concern
expressed
over
detected
in milk samples
in the area of the plant (Reference
9.2)
and
a related report of anomalous
environmental
water sample results
(Reference
9.3) were reviewed with the licensee
in terms of whether the
contamination of the 225'evel
could have contributed to these
concerns.
No pathway of radioactive material
from the 225'evel
to the environment
was identified; therefore, 'the conclusions
drawn in References
9.2
and 9.3
remain valid.
During the inspection, liquid samples
from the floor of the operator's
aisle of the 225'levation
and the plant storm drain were split between
.the licensee
and the
NRC for purposes
of intercomparison.
The. samples
were
analyzed
by the licensee
using normal
methods
and equipment.
The
NRC
samples
were sent to the
NRC reference
laboratory,
Department of Energy,
Radiological
and Environmental
Sciences
Laboratory
(RESL),
Idaho Falls,
Idaho, for analysis.
These
samples
were analyzed for strontium-90,
gross
alpha,
and by gamma spectroscopy.
0
13
The results of these
sample
measurements
indicated that all of the
measurements
were in agreement;
The results of this comparison
are listed
in Table
1.
In addition, the inspector
performed
surveys of the general
area radiation levels
and removable contamination,
from accessible
areas
outside the locked gate
access
to the 225'levation
sub-basement
room,
that confirmed-.the licensee's
survey results.
7.0
Corrective Actions
7.1
Past Corrective Actions
Subsequent
to the spill that occurred in July,
1981, the licensee
attempted
a manual
cleanup.
At. this time, the water level in the
room
was
3 to 4 feet deep.
The
811
was unclogged
and the water level
was lowered.
The water/sludge
mixture was being
pumped to
a cask liner
for shipment.
During October,
1981, while the licensee
was conducting
decontamination
of the operator's
aisle,
currents,
wh'ich were caused
by a decreasing
water level in the room,
caused
a barrel to float
around the east
corner of the room.
The barrel
had
a dose rate of
approximately
300 R/hr- on contact.
Prior to this, the licensee
apparently
was not aware that the flooding had caused
barrels to float
off their carriers.
The cleanup effort was terminated,
at which time
approximately
1.3 person-rem
had
been
expended.-
Host of the sludge in
the operator's
aisle
had
been
removed.
The room water level
was
pumped
down to about
a one foot depth
and maintained that way to minimize
airborne contamination.
No further cleanup actions
were taken until
July,
1985,
nor was
any additional solid radioactive waste put in the
room for storage. It was stated
by the licensee that in the years
following the July,
1981, fl'ooding event,
on occasion
the room was
used to accommodate
slight overflows, but there were
no significant
additional flooding events like the
one that happened
in July,
1981.
During July and August,
1985,
the licensee
again
attempted
to clean
up
the
room and sent
a crew into it to initiate desludging.
The
decontamination effort initially involved setting
up plywood dams
on
both sides of the stairs in the operator's
aisle.
Sludge
was
vacuumed
off the floor in the area
between
the dams:
The decontamination
of the
room was not completed
since it was clear from the experience
in the
operator's
aisle that the level of effort and person-rems
that would
have
been incurred to complete the decontamination
were significantly
underestimated.
The licensee
then decided that,
because
of the high
dose rates,
manual
decontamination
was not feasible
and that robotic
decontamination
was necessary.
The licensee
began actively pursuing
robotic methods for decontaminating
the area.
In the spring of 1986, the room was entered to desludge
and remove
two
drums in the west aisle.
This was done to allow access for a robot the
licensee
was planning to bring onsite to survey the room.
The licensee
I
Radionuclide
Split Sample Analysis Comparison
225'ub-basement
Water
Sam le
uC ml
RESL
uC ml
Cesium-134
2.39 +/- 0.09
7.51 +/- 0.39
5.35 +/- 0.17
3.02 +/- 0.21
E-4
E-5
E-3
E-5
2.49 +/- 0.13
6.3
+/- 0.6
5.41 +/- 0.19
2.8
+/- 0.4
E-4
E-5
E-3
E-5
Gross Alpha
NAF
NAF
(3.15 +/- 0.14)E-5
(3
+/-
5
)E
9
Radi onuc1 ide
Potassium-40
Gross
Alpha
Gross
Beta
Perimeter
Drain Water
Sam le
uC ml
ND
ND
NAF
NAF
RESL
uC ml
~
~
1.5
+/- 2.1 )E-8
9
+/- 3
)E-7
(2.8
+/- 0.5 )E-9
(1.4
+/- 0.4 )E-8
NOTE:
NHP
- Nine Hile Point
RESL - Radiological
and Environmental
Sciences
Laboratory,
NAF
- Not analyzed for
ND
'
Not detected
Table
1
0
15
obtained
a robot
(SURVEYOR) in the early
summer of 1986 for video
surveying the room.
The robot was sent into the 225'levation
sub-basement
in September,
1986.
A videotape of the conditions
was
made.
As noted previously in this report, the videotape
indicated
many of the drums
had floated off their carriers
and were spread
in
disarray
around the storage aisles.
Some of the drums were lying on
their sides with their contents spilled out.
7.2
Planned
Corrective Actions
The licensee's
plan is to clean,
decontaminate
and repaint the entire
225'levation
sub-basement.
As noted
above,
there
are approximately
150 barrels of filter sludge in this area,
some of which have tipped
over and spilled their contents.
The licensee
estimated
that if the
area
was
c'1eaned
using manual
methods
approximately
150 person-rem
would be expended.
The licensee
has contracted
with an outside
vendor
to build and deliver
a Tethered
Remote Operating
Device
(TROD}.
The
use of the
TROD will result in the expenditure of approximately
10
person-rem
as
compared to 150 person-rem
estimated for manual
decontamination.
The
TROD is
a teleoperated,
el.ectro-hydraulic
system which will ride
on the overhead
conveyor present
in the area
and will be operated
remotely from the 261'levation
of. the building.
Niagara
Hohawk
Radwaste
Department will operate
the
TROD and is in charge of the
cleanup effort,
The licensee
is in the process
of developinq
an
(As Low As Reasonably
Achievable)
Plan for the cleanup activ)ty.
The
ALARA Plan will contain the methodology
and detailed instructions
on
the cleanup operation.
Although"the ALARA Plan
was not available for review, the inspector
discussed
with radwaste
supervision
the cleanup
methodology.
The
operator's
aisle will be decontaminated
manually because
the monorail
barrel carrying system
does not go through this aisle.
The
TROD will
be lowered to the 225'levation
throuqh the west elevator
and then
connected
to the monorail track.
It w>ll be used to decontaminate
all
areas
except the operator's
aisle
and the east
equipment aisle.
Two
drums located in the fill aisle will first be desludged
and removed.
Next, the west aisle will be decontaminated
using the
TROD,
and the
east
equipment aisle will be decontaminated
manually.
The
TROD will
then
be used to clean out the drum filling aisle
and then the 'A'nd
'8'torage
areas.
Other equipment in the area,
such
as control
16
7.3
8.0
Exit
panels
and the conveyor system, will then
be removed.
Final
decontamination
of all surfaces
and removal of all equipment
associated
with the earlier drumming operation will be completed
and
then the area will be repainted.
The schedule of the planned decon/cleanup
has
been developed; it is
planned to begin the last week in September,
1989,
and to take
seven
months.
The licensee
stated that the effort will cost between
$ 1.5
and
$2.0 million;
The inspectors
did not find evidence that the
NRC had
been notified of this estimate
or the, cleanup
plans prior to this
inspection.
Timeliness of Licensee's
Corrective Actions
The flooding of the 225'levation
sub-basement
occurred in July,
1981,
which caused .barrels of filter sludge to tip over and spill
their contents.
The radioactive material
was contained
and the
room
was monitored for leakage.
The licensee
considered
the spill not to
be
a safety concern
since it was contained.
While initial
decontamination
was attempted
and terminated
in October,
1981,
no
further work was initiated until. August,
1985.
Work was not
reinitiated until August,
1985,
because
station
management
assigned
a
low priority to the cleanup
and diverted financial resources
to other
projects.
These other projects
included of the Unit
1 recirculation
pipe replacement
outage,
the Austerity Program developed to deal with
the increasing
cost of building Unit 2,
and major radwaste
processing
system modifications.
As described
in Section
7. 1, in August,
1985,
the licensee initiated
a second
manual
cleanup,
which was terminated
soon after starting.
At that point, the licensee
decided to approach
the cleanup with robotic methods.
In March,
1988,
a "Request for
Proposal"
was let for a robotic system.
In July,
1988,
a "Purchase
Order" to initiate design
was issued,
and in July,
1989,
a design
was
selected
and system ordered.
In summary,
the team found the licensee
did not pursue, cleanup of the
sub-basement
for approximately
a four year time span
between
1981 to
1985.
The team did not find an adequate justification for not dealing
with the situation in the
room during that period.
Interview
The team met with licensee
representatives
(denoted
in Section 1.0) at the
conclusion of the inspection
on August 28,
1989.
The team summarized
the
purpose
and
scope of the inspection
and the findings.
17
9.0
References
9. 1
Letter from Niagara
Hohawk Power Corporation to R.C.
Haynes
(NRC)
dated
October 30,
1981
(describes
controlled release
of 50,000 ga/lons
of Waste
Surge
Tank water to Lake Ontario).
9.2
Letter from Victor Stello, Jr., 'then Director of OIE to Hr. Peter
Dalton, Sierra Club Radioactive
Waste
Campaign,
dated October
19,
1981.
9.3
Preliminary Notification of Event or Unusual
Occurrence,
PN01-81-130
(Anomalous Environmental
Water Sample Heasurements),
dated
December
1 1,
1981.