ML092730255
| ML092730255 | |
| Person / Time | |
|---|---|
| Site: | 07000925 |
| Issue date: | 11/02/1989 |
| From: | Rogers W Cimarron Corp |
| To: | Region 3 Administrator |
| Shared Package | |
| ML092720355 | List:
|
| References | |
| Download: ML092730255 (31) | |
Text
PU PLANTCHEM.
MAKE-UP While in production, Chem. make-up contained Nitric acid,
- ammonia, and D.I. water make-up tanks.
It was also used for storage and in the approximate center of the room two sets of intermediate and final absolute filters were installed for exhaust fans 79 and 80 (glovebox ventilation fans).
These two fans (79 & 80) were mounted on the north roof section of the building and discharged to the Pu plant stack..
After equipment removal our initial surveys indicated as much 2
as 7,500 dpm/100 cm direct on the tops of the lights,",and 10,000 2
dpm/100 cm direct in isolated spots on the floor.
We grit blasted the floor and wall and deconed the lights and conduit in this area.
After this initial depon, we identified two spots on the floor (350 and 215 dpm/100 cm2 direct) that were reblasted to less 2
than 100 dpm/100 cm2.
We also found ten spots on the conduit that were deconed and resurveyed.
We used a Ludlum 2220 with a Ludlum 43-27 (large area detector for scan),
43-4 with P-10 gas (conduit and. ladder rails), and a 43-68 (floor, walls, ceiling, and other large flat areas) for this release survey.
All smears were taken on Whatman smear paper and counted in a Hewlett Packard 5560A (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.
Table I-I.
Acceptable surface contamination levels Nuclides a Averageb'
,f Maximum T7 Recmova hee, J
U-nat, U-235, U-238, and 5,000 dpm a/100 cm2 15,000 dpm r,/IOU cmr2 1,000 dpm (a/100 cm 2 associated decay products Transuranics, Ra-226, Ra-228, 100 dpm/l0O cm2 300 dpm/ll)) cm2 20 dpm/lOU cm2 Th-230, Th-228, Pa-231, Ac-227, 1-125, 1-129 Th-nat, Th-232. Sr-90
.1,000 dpm/lO0 cm2 3,000 dpm/lOO cm2 200 dpm/l00 cm2 Ra-223, Ra-224, U-232, 1-126, 1-131, 1-133 Beta-gamma emitters (nuclides 5,000 dpm By/l00 cm2 15,000 dpm By/l00 cm 2 1,000 dpm By/1O0 cm2 with decay modes other than alpha emission or spontaneous fission) except Sr-90 and other noted above.
a Where surface contamination by both alpha-nnd beta-Ramma-emitting nuclides exi..ts, the limits established for alpha-and beta-gamma-emitting nuclides should apply independently.
bAs used in this table, dpm (disintegrations per minute) means the rate of emi-nion by rndio:*ctive material as determined by correcting the counts per minute observed by an appropriate detector for backgroinnd, efficiency, and geometric factors associated with the instrumentation.
C Measurements of average contaminant should not be averaged over more than I Square meter.
For 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.
0The amount of removable radioactive material per 100 cm2 of surface area should he determined 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 resulting 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.
I-A