ML19269C192
| ML19269C192 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 11/21/1978 |
| From: | Baird J, Book H, Thomas R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML19269C191 | List: |
| References | |
| 50-312-78-19, NUDOCS 7901290299 | |
| Download: ML19269C192 (6) | |
See also: IR 05000312/1978019
Text
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U. S. ?!UCLEAR REGULATORY COMMISSIO 1
0FFICE OF IMSPECTION AtlD ENFORCEMEflT
REGI0ll V
Report No.
50-312/78-19
Docket No.
50-312
License tio.
Safeguards Group
Licensee: , Sacramento Municioal Utility District
P. O. Box 15830
Sacramento, California 95813
Facility flame: Rancho Seco
Inspection at: Clay Station, California
Inspection Conducted: October 26-27, and 30,1978
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inspectors:
ter
R. D. T.t.'as, Radiation Specialist
/Date Signed
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J. B. 8 ird, Rad'ation Specialist
D' ate Signed
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Approved By:
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H. E. Book, Chief, Fuel Facility and
' Date Signed
Materials Safety Branch
Summary:
Inspection on October 26-27, and 30,1978 (Report No. 50-312/78-19)
Areas Inspected: Licensee Reportable Occurrence of radiation overexposure
including review of job ' planning meetings, job related events, personnel radia-
tion exposures, radiation survey data, conditions requiring enforcement actions,
and reports.
The inspection involved 10.5 inspector-hours onsite by two
inspectors and 4.5 inspector-hr>urs onsite by one inspector.
Results: Of the six areas inspected, no apparent items of noncompliance
or deviations were identified in four areas; three apparerit items of non-
compliance (infraction - personnel overexposure, Paragraph 3.c; infraction -
noncompliance with Technical Specification requirement, Paragraph 3.e;
infraction - failure to perform survey as necessary, Paragraph 3.e) were
identified in two areas.
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790lMe
IE:V Form 219 (2)
DETAILS
1.
Persons Contacted
- R. Colombo, Technical Assistant
R. Miller, Supervisor, Chemical and Radiation Protection
- S. Coats, Plant Health Physicist
W. Wilson, Senior Chemical and Radiation Assistant
- T. Morrill, Senior Chemical and Radiation Assistant
D. Abbott, Associate Maintenance Engineer
J. Hickey, Welder
- P. Oubre, Plant Superintendent
Others
E. Couch, Senior Health Physics Technician, Chem-Nuclear Systems,
Inc.
- Denotes those attending the exit interview.
2.
Licensee Reportable Occurrence (Radiation Overexposure)
On October 24, 1978, the licensee notified an NRC inspector
onsite that an apparent radiation overexposure had taken place on
October 23, 1978. An exposure of 3.45 rems was confirmed to the
inspector onsite on October 24, 1978, after the personnel monitor-
ing data had been evaluated.
3.
~ Licensee Reportable Occurrence Followup
On October 26, 1978, two radiation. specialist were dispatched to
the site in response to the notification.
Interviews were conducted
with the individuals involved. An examination of the conditions
and records associated with the overexposure was conducted. Other
items also reviewed were as follows:
a.
Job Planning Meetings
On October 11, 1978, a plan to remove the pre-filter to the
Miscellaneous Waste Filter, F-688A, was discussed by the
licensee in preparation of the Radiation Work Permit (RWP),78-517. The plan was reviewed by the health physics techni-
cian and a radiation survey was conducted to assess the
radiation levels present in the work areas.
The radiation
levels were not.ed on the RWP.
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_2_
.
On the morning of October 23, 1978, a job planning meeting
was conducted by the licensee.
Those individuals involved
in the removal of the pre-filter housing were briefed by the
Engineer-in-Charge as to the work to be performed. As planned,
two riggers were to disconnect the pre-filter housing from
the plumbing connestions, and a welder was to cut off the . inlet
and outlet pipes, the drain line and associated valve. The
work was to be performed while remaining behind a specially
built protective shield which had been put into place in front
of the pre-filter housing.
The pre-filter housing was to be
placed into a shielded cask and removed from the area.
b.
Job Related Events
At approximately 2:30 p.m. on October 23, 1978, the health
physics technician entered the work area and performed a
radiation survey.
Based upon the radiation levels present
in the area where the welder would be located, a stay time
was established at four minutes t, complete the cutting
operation.
After the radiation survey, the two riggers entered the area
to remove the plumbing connections to the pre-filter. Approxi-
mately two minutes later the two riggers came out of the area
and informed the welder that the plumbing had been disconnected
and there was water in the lines, and the pre-filter housing
appeared to be filled with water.
The pre-filter housing was
supposed tobe empty, since Operations had opened the drain
valve earlier; however, the valve was apparently " plugged"
and the housing did not drain.
At this point, a "klunk" was heard from inside the filter
cubicle. The health physics technician entered the area to
investigate the noise and perform another r~adiation survey.
It was observed by the health physics technician that the
pre-filter housing had fallen over and was wedged between
the wall and the left edge of the protective shield to the
extent that the upper third of the filter housing was ex-
posed outside the protective shield. The radiation levels
around the protective shield appeared to be approximately
the same as recorded previously.
The welder entered the work area at approximately 2:45 p.m.
He immediately verified that the pre-filter housing had moved
from its original location, and had rotated 180 degrees so
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that the inlet and outlet pipes were now located on the left
side of the protective shield in a position which would re-
quire a greater effort for renoval. The welder attempted
to remove the orain line from the housing, but the escaping
water extinguished the torch flame several times.
In order
to facilitate the draining of the housing, the welder up-
righted the housing with his left hand to provide better drain-
age. Approximately twenty seconds later he placed the housing
back in 'he tilted position. The drain line was removed. Work
on the inlet and outlet pipes began.
In order to reach the
pipes with the cutting torch, the welder stated that he had
to expose both hands, his head and upper trunk around the
edge of the protective shield.
He maintaired this position
for approximately two minutes until the health physics techni-
cien entered the room and informed him that the four minutes
stay time had expired.
Both individuals left the work area.
The dosimeters were removed from the welder's helmet and
read by the health physics technician. At this time, it was
determined that the welder had received a radiation exposure
of 3.4 rems to the head and upper trunk. The health physics
staff was notified immediately that the overexposure had
occurred.
The welder's film badge, which was also located on his helmet
was sent in for analysis along with the two wrist film badges.
Some time later, the job was completed by a second welder
using a high temperature cutting torch and mirrors.
c.
Personnel Radiation Exposures
An examination of the film badge and dosimeter records indicated
that the welder had received exposures of 3.45 rams to the
head and upper trunk area, 3.98 rems to the left hand, and 2.47
rems to the right hand. When the 3.45 rems were added to
previous exposures for the quarter, the total exposure was
3.7 rems (whole body) for the quarter which ext.eeded 10 CFR 20.101(b)(1) limitations. This was identified as an item of
noncompliance.
The radiation exposures recorded for the two riggers were 550
mrems and 800 mrams (whole body), respectively.
The health
hysics technician received a total exposure of 180 mrems
p(whole body). The second welder received a total whole body
exposure of 60 mrems to complete the job.
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d.
Radiation Survey Data
The radiation survey records related to the pre-filter removal
were examined.
Based upon the physical radiation surveys
conducted by the health physics technician, the radiation
levels (gamma) in the work area were as follows:
(1)
Behind the protective shield, 1 R/hr.
(2) At floor level, behind protective shield, 2-4 R/hr.
(3) On top of the pre-filter housing, at the surface,10 R/hr.
(4) The bottom and side surfaces of the pre-filter housing,
ranged from 150-200 R/hr.
(5) Distance of 12 inches from the housing, 60-80 R/hr.
(6) Distance of 18 inches from the housing, 4-15 R/hr.
A value of 12 R/hr at 18 inches was used in the stay time
calculation.
An air sample taken in the work area during the cutting
operatgn indicated particulate activity levels in the order
of 10'
uCi/ml. The gaseous activity level was minimal.
e.
Conditions Requiring Enforcement Actions
The existing conditions present at the time of the cutting
operation were reviewed and discussed with the licensee.
Technical Specification 6.13.1.a requires that any individual
entering a high radiation area be provided with a radiation
monitoring device which continuously indicates the radiation
dose rate in the area. During the period of time the riggers
and the welder were in the work area, a monitoring device of
the type specified was not present inside the filter cubicle
area.
This condition was identified as an item of noncompliance.
10 CFR 20.201(b), requires that surveys (evaluatione.) are to
be made as may be necessary for compliance with all sections of
Part 20. When appropriate, such evaluation includes physical
surveys of the location of materials and equipment and measure-
ments of levels of radiation present. Specifically, a complete
evaluation was not conducted when the pre-filter housing was
found to contain water and the housing and associated piping
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had changed location in relationship to the protection
shield after being disconnected frcm the plumbing connec-
tions.
The lack of a complete evaluation was identified
to the licensee on November 6,1978, by telephone, as an
item of noncompliance.
f.
Reports
The licensee stated that a complete report of the overexposure
will be filed with the NRC in accordance with 10 CFR 20.405(a).
A complete review of the overexposure has been conducted by
licensee management and the Plant Review Committee. All re-
commendations and corrective actions have been documented. A
complete report will be given to the welder in accordance with
4.
Exit Interview
In addition to those individuals denoted in Paragraph 1, the
following individuals were in attendance:
R. Rodriguez, Manager
of Nuclear Operations; C. Martin, Staff Environmental Specialist;
F. Kellie, Nuclear Chemist (representing R. Miller); G. Coward,
Maintenance Supervisor; and J. Mau, Training Supervisor. The
inspector summarized the scope and findings of the inspection.
The items of noncompliance were identified and discussed. The
licensee stated that for future operations of this type, planning
will be more extensive and surveillance by the health physics
staff will be incr msed.
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SACRAMENTO MUNICIPAL UTILITY DISTR:OT
1703 59:h Street. Box 15830. Sxra, ente. Ca .furnia 95813:(916) 452 321
flovember 13, 1978-
,CW
Director of Regulatory Operat.ions
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ATTil:
Mr. R. H. Engelken
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NRC Operations Office, Region V
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1990 N. California Boulevard
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Walnut Creek Plaza, Suite 202
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Walnut Creek, Cal i fornia 94596
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Re:
Operating License DPR-54
e./ M r f -
Docket No. 50-312
Personnel Overexposure
Dear Mr. Engelken:
Th.., report of personnel overexposure is forwarded to you within the
requirements of Ti tle 10 CFR 20.405 and the Rancho Seco Unit 1 Technical Specifications Section 6.9.1.
DESCRIPTION OF SYSTEM
The Miscellaneous Liquid Radwaste System collects drains, leaks and
condensate from all radioactive areas within the plant including the Reactor
Building.
"he liquids are collected in area sumps and are pumped to the
Miscellaneous Wastes Tank for storage prior to processing.
The cleanup process
transfers the liquid from the Miscellaneous Wastes Tank via Miscellaneous
Wastes Tank Pumps to a Miscellaneous Vastes Prefilter, Miscellaneous Wastes
Filters and Oil Absorbers, Miscellaneous Wastes lon Exchanger, Spent Regenerant
. Tanks, Miscellaneous Wastes Filters and finally to the Miscellaneous Wastes
Evaporator.
The condensate f rom the evaporator is recycled to the 31 ant systems
and the evaporator concentrate is stored until shipped off site as waste.
The
Miscellaneous Wastes Prefilters are the first process components and because of
their ef ficiency accumulate considerable radioactive particulate.
The filter
elements were replaced several times and the replacement process was observed
.as an operation that could be improved by replacing the complete Miscellaneous
Prefilter Canister with one designed with access to the top and inlets / outlets
with quick disconnects. The new design had lead shiciding wrapped around the
complete unit to allow access near the filter and minimize radiation exposure
to operating personnel. However, to install the new prefilter the existing
unit had to be removed from the system.
JOB PREPLANNING
The Miscellaneous Wastes Prefilter Canister is a 10 1/?-inch rulind -
standing on end and is 52 inches high
diameter carbon steel and are connect
above the top of the filter. A 1-inc
the fiiter.
The compiete fiiter asse:
DUPLICATE DOCUMENT
. bolted to the floor (see attached figt
was planned to be into a shipping cas!
Entire document previously
The drain, inlet and outlet lines had
entered into system under:
i .i t o rho chinni.n c :, c b
~7. 7/ ? /Z 0 / #
wo
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