ML092730263
| ML092730263 | |
| Person / Time | |
|---|---|
| Site: | 07000925 |
| Issue date: | 11/02/1989 |
| From: | Rogers W Cimarron Corp |
| To: | Region 3 Administrator |
| Shared Package | |
| ML092720355 | List:
|
| References | |
| Download: ML092730263 (38) | |
Text
Pu Plant Boiler Room The only entrance to this room is from the Pu-plant yard and the yard and boiler room were maintained as clean areas.
The Pu-plant boiler room contains three boilers, air conditioning unit, chiller, two air compressor, hot water tank, and associated piping, conduits and pumps for these systems.
All this equipment was in-stalled before production began and occupies approximately 74 square meters of floor space.
Before we started our release survey, a clean-up crew vac-uumed this area and we surveyed all the tools, spare parts, stools, ect.
Numerous tools were found to exceed Pu-plant release limits.
After this facility was placed in standby a tool box of uranium plant tools were cleaned of all smearable contamination and taken to the boiler room for use.
As we identified these tools during this survey they were sent to LSA trash.
After completion of this ini-tial clean-up we preformed an alpha scan on the floor and found no 2
direct reading greater than 100 dpm/100 cm2.
We then did a grid survey on the first two meters of the wall and on the exposed floor.
Of the 181 direct readings taken all readings were less than 100 2
dpm/100 cm2.
Because of these results I decided that we would take one row of readings next to the ceiling to see if we could identify any contamination that might have came from the room (exhaust fanroom) above the boiler room.
All results from this sur-vey were less than 100 dpm/cm. direct and less than 20 dpm/100 cm smearable.
Because 'of these results and the great difficulty in griding and surveying the rest of the walls and ceiling I decided not to pursue this survey unless other readings indicated a possible problem.
We then preformed a random spot survey on equipment, pipes,
'conduit, and electricial boxes from the floor to approximately two meters above the floor.
Our random spot survey indicated approximately 14 feet of 2" piping. that was added when the lab chiller was replaced, had contamination levels of approximately 2000 dpm/100 cm2 fixed 'and 9 dpm/100 cm2 smearable.
This piping came from the U-plant and was removed.
We also found two pieces of kendorff with approximately 500 dpm/100 cm2 direct that were removed. Excluding these items we identified 2
no spots of greater than 20 dpm/100 cm smearable and five 2
small spots of greater than 100dpm/100 cm direct.
They were:
2
- 1. -
156 dpm/100 cm direct on boiler #2 return 2
line.
Deconed to 72 dpm/100 cm direct.
2
- 2.
144 dpm/100 cm direct on 1 inch copper pipe insulation.
2
- 3.
108 dpm/100 cm direct gas regulator boiler #2 deconed to 60 dpm/100 cm2 direct.
2
- 4.
324 cpm/100 cm on air compress motor platform 2
deconed to 0 dpm/100 cm direct.
- 5.
7008 dom/100 cm2 2" conduit elbow -
line was
~2 less than 100 dpm/100 cm
- line added to get power to dock hoist-elbow from U-plant -
deconed to 60 dpm/100 cm2.
Four of these spots were cleaned and the one on insulation was left since it meets release limits.
I believe this random survey 1290 data points, grid survey of floor, and grid survey of the first two meters of walls are suffi-cient to demonstrate that this clean area meets release limits and no further surveys are planned for this room.
We used a Ludlum 2220 with a Ludlum 43-17 low energy gamma probe to identify areas in cracks and seams that might need decon-tamination.
A Ludlum 2220 with a Ludlum 43-68, 43-4, or 43-27 was used with P-10 gas for all alpha release surveys.
All smears were taken on Whatman smear paper and counted in a Hewlett-Packard 5560 A (low background) automatic sample counter.
W. A. Rogers
Pu PLANT RELEASE SURVEY PLAN
- 1. For initial decontamination all surfaces will be scanned with an Eberline PRM-6 with a Radeco alpha scintillation probe.
Back-ground will be maintained at less than 100 CPM(200 dpm).
All areas greater than twice background will be marked and reading will be taken with a release survey instrument to document cont-amination levels and random large area smears will be taken.
- 2.
After these initial areas are decontaminated, all floor surfaces and the base of each wall will be completely surveyed with a digital readout release instrument and a Ludlum large area gas proportional alpha detector and random smear samples will be taken.
Release instrumentation shall have a minimum detectable level of at least 50 dpm/100 cm2.
- 3.
All hot spots greater than or equal to 100 dpm/100 cm2 ident-ified will be decontaminated.
- 4.
A random survey with a release instrument will be taken on the walls and ceiling to try to identify any other problem areas.
- 5.
If no problems are identified, each room will be gridded off into approximately 2 meter on a side square on the walls and floor and five readings will be taken in each grid.
Readings shall be taken in the center and at the midpoint from the center to each corner.
- 6.
Each ceiling has closely spaced rafters that will not be easily divided into 2 meter squares.
Because of this, we will take readings on the bottom of each rafter at 2 meter inter-vals and one reading centered on the ceiling between rafters.
Readings on each rafter will be staggered one meter.
- 7.
These release readings will be documented on a map that is drawn to approximately scale measurements in meters.
- 8.
Data provided on each map:
- 1. Survey block numbers, identifiable on a scale drawings.
- a.
room or area name or number.
- b. surface surveyed.
- c. type of measurement and units.
- 2.
Name of surveyor taking measurements, date of survey, and location.
- 3.
Type, model number, calibration data, sensitivity limit, background, and source response of instruments used in survey.
- 4.
When a block surveyed is below the sensitivity of the instru-ment, the fact that such a measurement was made should be included as significant data.
- 9. All release survey smears will be taken on Whatman smear paper and counted in the automatic sample counters.
Each smear will cover approximately 100 cm2.
- 10. There will be at least 30 survey blocks in each area to be released.
- 11. Piping and ductwork will be surveyed on all accessable sides at 2 meter intervals.
If more than one line is running parallel in a pipe rack, readings shall be staggered at one meter intervals.
- 12. All readings taken that only cover part of a probe area will be corrected to dpm/100 cm2.
- 13.
No survey block will measure less than one meter on a side.
- 14.
No survey block will measure more than 3 meters on a side.
- 15. All portable release survey instruments will be calibrated quarterly and all instruments in use will be source checked daily.
9 Table 1-1.
Acceptable surface contamination levels NuclidesU Averageb' f
Maximumlli
,J U-nat, U-235, U-238, and 5,000 dpm a/I100 cmo I5,0(O dpm u/1O0 cm2 associated decay products Transuranics, Ra-226, Ra-228, 100 dpm/l00 cm2 300 dpm/1I) cm2.
Th-230, Th-228, Pa-231, Ac-227, 1-125, 1-129 Tb-nat, T"-232, Sr-90 1,000 dpm/100 cm2 3,000 dpm/100 cm2 Ra-223, Ra-224, U-232, 1-126, 1-131, 1-133 Beta-gamma emitters (nuclides S,000 dpm By/100 cm 2 15,000 dpm By/l00 cm' with decay modes other than alpha emission or spontaneous fission) except Sr-90 and other noted above.
Removab I e1, ;7:
-J 1,000 dpm ai/100 cm 2 20 dpm/100 cm?
200 dpm/100 cm2 1,000 dpm 6'y/100 cm2 a Where surface contamination by both alpha-and beta-gamma-emitting nuclides cxi:;ts, the limits established for alpha-and beta-gamma-emitting nuclides should apply independently.
bAs used in this table, dpm (disintegrations per minute) menns the rate of emi-sion by rnrlii,,:itive material as determined by correcting the counts per minute observed by an appropriate detector for background, efficiency, and geometric factors associated with the instrumentation.
C Measurements of average contaminant should not he averaged over more than I square meter.
or objects of less surface area, the average should be derived for each such object.
dThe maximum contamination level applies to an area of not more than 100 cm2.
eThe amount of removable radioactive material per 100 cm2 of surface area should be determin,*d by wiping that area with dry filter or soft absorbent paper, applying moderate pressure, and assessing the amount of radioactive material on the wipe with an appropriate instrument of known efficiency.
When removable contamination on objects of less surface area is determined, the pertinent levels should be reduced proportionally and the entire surface should be wiped.
fThe average and maximum radiation levels associated with surface contamination resultiiip, from beta-gamma emitters should not exceed 0.2 mrad/hr at 1 cm and 1.0 mrad/hr at 1 cm, respectively, measured through not more than 7 milligrams per square centimeter of total absorber.