ML20155K416
| ML20155K416 | |
| Person / Time | |
|---|---|
| Site: | 07000734 |
| Issue date: | 11/02/1998 |
| From: | Finchum S, Gonzales L, Joseph Turner GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER |
| To: | |
| Shared Package | |
| ML20155K414 | List: |
| References | |
| NUDOCS 9811130234 | |
| Download: ML20155K416 (37) | |
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1 FINAL RADIOLOGICAL SURVEY PERFORMED AT GENERAL ATOMICS' BUILDING 21 UNAFFECTED OFFICE AREAS i
)
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Prepared By: John Turner, Laura Gonzales, Stephen Finchum, and Dane McKay November 2,1998
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u Table of Contents INTRODUCTI ON................................................................... I S ITE DESCRI PTION................................................................ I CRITERIA FOR RELEASE TO UNRESTRICTED USE................................... 2 Equipment and Facilities...................................................... 2 Exposure Rate G uideline...................................................... 2 Soil Criteria................................................................ 2 IN STRU MENTATION.............................................................. 2 1
B ACKGROUND M EAS UREMENTS.................................................. 2 Background Measurements for Instruments / Detectors............................... 2 Exposure Rate Background.................................................... 3 FINA L S U RVEY S.................................................................. 3 Objectives and Responsibilities................................................. 3 Classi fication o f Areas........................................................ 4 Removal of Equipment...................................................... 4 Survey Plan............................................................... 4 S urvey S um m ary.......................................................... 4 Results of Final S urvey........................................................... 4 i
Scan n i n g................................................................. 5 Fixed Meas urem ents....................................................... 5 Removable Contamination Surveys............................................. 5 Exposure Rate Measurements................................................... 5 CONC LU S I ON................................................................. 6 List of Tables Table 1:
USNRC's Acceptable Surface Contamination Levels........................
... 7 Table 2:
State of CA Acceptable Surface Contamination Levels......................... 8 Table 3:
Li st o f I nstrum en ts....................................................... 9 Table 4:
Background Measurements (Obtained from Building 13).........................
12 Table 5:
Results of Final Surveys in Unaffected Office Areas of Building 21........
14 List of Figures (unnared)
Figure 1:
Plan View of General Atomics Site
- Figure 2:
Building 21 in Relation to Surrounding Facilities Figure 3:
Building 21 - TRIGA* Reactor Facility Figure 4:
Building 21 - Unaffected Rooms - Prior to Modifications Figure 5:
Building 21 - Unaffected Rooms - Current Status Figure 6: Floor. Large area Masslin Wipe Survey Figure 7: Floor and Walls. Alpha and Beta Sean Figure 8: Floor and Walls. Fixed, and Exposure Rate Measurements Figure 9: Floor and Walls. Removable Contamination Results APPENDIX A " Final Survey Plan for Portions of Building 21: Rooms 100,101,101 A, Restrooms (2),
Hallways and Janitorial Storage Closet" dated June 11,1998 and " Addendum #1" dated July 6,1998.
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Final Radiological Survey for Building 21 Unaffected Offke Areas 4asummasmuseus Introduction General Atomics (GA) is continuing its efforts directed at decontaminating, as appropriate, and
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obtaining the release to unrestricted use of selected facilities. GA has recently completed the Final Survey of the unaffected office areas (and. restrooms) ofits Building 21. Building 21 also houses two TRIGA* non-power reactors. These offices are not used, nor needed, to support the possession of the two TRIGA* reactors located in Building 21. (Both reactors have had their licenses amended a withdraw authorization to operate, and their future decommissioning will be under thejurisdicuon of the Non-Power Reactors and Decommissioning Project Directorate of the Nuclear Regulatory Commission.)
The unaffected offices (and restrooms) which are the subject of this report will be needed to support the project / personnel that will occupy the adjacent Building 27. For that reason, the release of Building 27 is also being requested at this time in a coordinated request.
GA is requesting both the State of California and the Nuclear Regulatory Commission (NRC) to release the unaffected office areas of Building 21. This report documents the results of comprehensive measurements completed in Building 21 and demonstrates that these areas meet the approved criteria for release to unrestricted use. The total area to be released to unrestricted use is 2
~850 ft2 (~80 m ),
Site Description A plan view of the GA site is shown in Figure 1. The location of Building 21, the TRIGA* Reactor Facility in relation to other facilities on GA's Main Site is shown in Figure 2. Building 21, showing the area to be released to unrestricted use, is shown in Figure 3. The unaffected office area of Building 21 is shown in Figure 4.
Building 21 is located adjacent to, and immediately east of, Building 27. The unaffected office areas of Building 21 are located in the southwestern portion of the TRIGA facility (see Figure 3).
The unaffected office areas are of concrete masonry construction. The area is composed of two office rooms (100 & 101), a men's restroom (room M-1), a women's restroom (W-1), one janitorial storage closet, one room which was used as the photographic dark room (101 A) and a hallway. The unaffected oflice areas occupy an area of approximately 850 ft2 (~ 80 m ).
2 a
The exterior of this unafrected office area is composed ofload bearing concrete block walls, as is room 100. The remaining rooms are encompassed by non-load bearing plywood / drywall structures.
Portions of the bathrooms walls are composed of ceramic tiles. Most of the floors are composed of j
tiles installed over the concrete foundation, except for room 100 and a small portion of room 101 which were carpeted.
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u Final Radiological Survey for Building 21 Unaffected Office Areas f emmmmm mmmmmer There is no history of use of radioactive materials in these rooms, therefore, the area was classified as an "unafTected area" and surveyed accordingly.
Criteria for Release to Unrestricted Use Equipment and Facilities U.S. NRC's criteria for release of facilities and equipment to unrestricted use is shown in Table 1.
The State of California's guidelines,"DHS Criteria for Release of Facilities and Equipment to Unrestricted Use," also known as "DECON-1," is shown in Table 2. Based on the previous history of work conducted in this building (reactor facility), the possible radiological contaminations include mixed fission products and mixed activation products, therefore, the guideline values for release to i
unrestricted use for these beta / gamma emitters are:
l 5,000 dpm/100 cm (averaged over 1 m )
l 2
2 2
2 2
15,000 dpm/100 cm (maximum in a 100 cm area if the average over 1 m is met) 2 1000 dpm/100 cm (removable contamination)
Exnosure Rate Guideline The guideline value for exposure rates measured at I m above the surface, is 10 R/hr above background levels.
Soil Criteria No soil sampling was required in these areas since they were " unaffected" offices, restrooms and hallways and no radioactive contamination was detected on any of the concrete floor surfaces or walls.
Instrumentation A list ofinstruments used during the radiological surveys is shown in Table 3. The table includes: (1) a description of the instrument and its serial number, (2) a description of the detector (if applicable) and its serial number, (3) instrument ranges, (4) calibration due dates (5) typical efficiencies (if applicable) and (6) typical background readings. All of the instruments used were calibrated semiannually and after repair except for exposure rate meters which were calibrated quarterly.
Background Measurements Background Measurements for Instruments / Detectors Building 13 on GA's main site was used for conducting background measurements due to: (1) there is no history involving radioactive materials or storage of radioactive materials in Building 13, (2) the various surfaces found in Building 21 (unaffected office areas) could also be found in Building 13 and (3) the age of the building closely approximates the age of Building 21. A list of the instruments 2
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Final Radiological Survey for Building 21 Unaffected Office Areas 4 -~ memaus with detectors (if applicable) and their background measurements are shown in Table 4.
Backgrounds for the ceramic tile found on the floor and walls in the restrooms at Building 21 were taken in the unaffected area restrooms of Building 30. This tile exhibited alpha activity typical of natural background radionuclides which make up the tile. These results are also provided in Table 4.
For the fixed background measurements, shown in Table 4, the mean and standard deviation for each 2
surface surveyed with the 100 cm gas flow proportional detector were calculated using equations 8-11 and 8-12 from the draft version of NUREG/CR-5849' as shown below:
Equation (8-11) 7 1D,1, n,
Equation (8-12) p ;_,,,
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h Minimum detectable activities (MDA's) for each type of surface were calculated using equation 5-2 from the NUREG/CR-5849 as shown below:
Equation (5-2) 2.71 +4.65/B,xt 2
MDA=
(dpm/100cm )
j fxEx 100 Where:
B = background rate (cpm) g t = count time (min)
E = efficiency 2
A = area of the detector (cm )
Exoosure Rate Background Typical exposure rate background for this site is about 15 pR/hr at 1 m from the surface, measured i
south of Building 15 (an office building). Measurements taken offsite in 10 different locations over a period of a year also give an average of about 15 R/hr (at I m from the surface). Normal background exposure rates increase to about 22 R/hr at I m from the surface in small rooms with concrete floors and walls.
Final Surveys Ob_iectives and Resoonsibilities The final survey was performed for the purpose of demonstrating that the radiological conditions in 3
Manual for Conducting Radiological Surveys in Support of License Termination (Draft for Comment), NUREG/CR-5849, ORAU-92/C57, Oak Ridge Associated Universities, June 1992.
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Final Radiological Survey for Building 21 Unaffected Office Areas
+ -- meness l
Building 21 (unaffected office areas) satisfy the NRC and State of California guidelines for release to unrestricted use.
Surveys were taken only by qualified Health Physics Technicians having a minimum of three years l
Health Physics experience in accordance with approved Survey Plans. Samples were counted in GA's Health Physics Laboratory which maintains a QA program.
Classification of Areas Each of the rooms and the hallway were classified as " unaffected areas."
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Removal of Eauioment Prior to the start of the final survey, all of the office items (i.e., equipment, supplies, furniture, copier, etc.) and various other materials contained within this area were surveyed and released to unrestricted l
use including the removal of non-structural walls (drywall / plywood), tile and carpeting. All of the j
above items were surveyed with a Ludlum Model 3 instrument and corresponding 44-9 (15 cm )
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pancake detector for p activity.
l No radiological contamination was found, except on a small section of carpet located in room 101 l
which exhibited very low levels of contamination. It was removed, properly packaged and disposed of as radioactive waste.
Survey Plan l
Figure 5 shows the " unaffected" areas surveyed, after the removal of several of the non-load bearing l
structural walls. The survey plan (and addendum #1)is provided in Appendix A.
Survey Summary A summary of the number of fixed measurements, smears and uR/hr measurements is provided below:
l
- Survey:
Fixed-Smearv
? R/hr
' Measurements.
'(100 cm )
Measurements -
t l
Final Surveys 59 49 62 l
Resnits of the Final Survey Results of Final Survey Measurements Table 5 provides the results of scanning, fixed measurements, smears and exposure rate measurements taken after the Final Survey. Figures 6 through 9 provide the locations and, in some cases, the results of various measurements.
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Final Radiological Survey for Building 21 Unaffected Office Areas famummasmummer Scanning Concrete floor surfaces were scanned 100%, for beta only, using the 434 cm gas-flow proportional 2
detectors (floor monitors). Concrete floor surfaces were scanned 10%, for alpha only, using the 434 2
cm probe. Wall surfaces (< 2 m) were scanned 10% for both alpha and beta with the 434 cm probe.
2 The results of these scans are provided in Table 5 and the approximate locations (and results) are i
shown in Figures 6 through 9. No evidence of contamination was found during scanning.
The electrical conduit trench was scanned (100%) with a 15 cm pancake GM counter and no 2
readings above background were discovered.
The items remaining in the restrooms (i.e., urinals, toilets, sinks, paper towel dispensers, partitions and doors, mirror, soap dispensers, etc.) were also scanned (100% ) with a 15 cm pancake probe and 2
no readings above background were discovered.
Fixed Measurements Fifty-nine (59) fixed measurements were performed using a beta gas-proportional counter having a 2
100 cm detector. The counting time for a fixed measurement was for one (1) minute. For fixed measurements, an appropriate background was determined for each type of surface and subtracted from the survey readings. The readings were converted to dpm/100 cm using the efficiency of the 2
detector and the geometry of the detector. The results are provided in Table 5 and the approximate locations (and results) are shown in Figure 8. All results were < MDA of the instrument used. The maximum result was <448 dpm/100 cm, well below the release criteria.
2 Removable Contamination Surveys Forty-nine (49) removable contaminat on measurements (100 cm smears) were performed on all i
2 walls (< 2 m) and floors. Smears consisted of using a Whatman Filter Paper (4.7 cm diameter) and 2
wiping an area of~ 100 cm. The smears were counted in GA's Health Physics Laboratory using a 2
Canberra 2400 low level alpha / beta counting system. The maximum smear result in dpm/100 cm for 2
both alpha and beta is provided in Table 5 and the approximate locations (and results) are shown in Figure 9. The maximum smear results were < 10 dpm/100 cm for both a and p; well below the 2
release criteria of 1000 dpm/100 cm,
2 Masslin smears were also taken on the concrete floors and measured with a 15 cm pancake probe. All 2
readings were less than background (background < ~100 cpm).
Exnosure Rate Measurements Sixty-two (62) direct radiation exposure rate measurements were taken at I meter above the surface using a exposure rate ( R/hr) meter at various locations inside the unaffected office areas. Exposure 5
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n Final Radiological Survey for Building 21 Unaffected Office Areas femmamammeness rate measurements inside the facility ranged from 14-17 R/hr. The results are provided in Table 5.
1 Conclusion Final contamination and radiation surveys as provided in this report for the unaffected areas of Building 21, demonstrate that these areas meet the approved guidelines for release to unrestricted use.
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. Table 1:1USNRC'S ~ ACCEPTABLE SURFACE CONTAMINATION LEVELS 2 i LNuclidcsf
~
, ' Average 6d.
Maximum '#
Removdle #
6 be 2
2 2
< (dpm/10 Gem ) -
(dpm/100 cm )
- (dpm/100cm )
J-nat, 235U, 23:U, & associated decay products 5,000 a 15,000 a 1,000 a Transuranics,226Ra,22Ra,23 Th, 22:Th, 23'Pa, 100 300 20 Ac, 25g, n91 227 Th-nat, 232Th, "Sr, 223Ra, 22*Ra, 232U,i261,"'I, 1,000 3,000 200 nig Beta / gamma emitters (nuclides with decay modes other than alpha emission or 5,000 15,000 1,000 spontaneous fission) except "Sr and other noted above.
j Where surface contamination by both alpha-and beta / gamma-emitting nuclides exists, the limits a
established for alpha-and beta / gamma-emitting nuclides should apply independently.
I b
As used in this table dpm (disintegrations per minute) means the rate of emission by radioactive material as determined by correcting the counts per minute observed by an appropriate detector for background, efficiency, an geometric factors associat<:d with the instrumentation.
Measurements of average contaminant should not be averaged over more than I square meter.
c For objects ofless surface area, the average should be derived for each such object.
2 d
The maximum contamination level applies to an area of not more than 100 cm,
2 e
The amount of removable radioactive material per 100 cm of surface area should be 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 instrurnent of known efficiency. When removable contamination on objects ofless surface area is determined, then pertinent levels should be reduced proportionally and the entire surface should be wiped.
f ne average and maximum radiation levels associated with surface contamination resulting from 2
2 beta-gamma emitters should not exceed 0.2 mrad /hr at I cm and 1.0 mrad /hr at I cm,
l respectively, measured through not more than 7 milligrams per square centimeter of total I
absorber.
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Table 2: STATE OF CA ACCEPTABLE SURFACE CONT' AMINATION LEVELS 8!
.Nu' lides* ~
. Average L
' Maximum
- Removablew' W
c (dpm/100cm') -
(dpm/100cm ) -
(dom /100cm ) -
8 8
U-nat, 225U,23'U, & associated decay 5,000 15,000 1,000 products i
Transuranics,226Ra,22'Ra,2Th 2 'Th, 100 300 20 Pa, 227Ac, '25g, i29g j
22 Th-nat,222 h, "Sr,22'Ra, 224Ra, 232U, i261, 1,000 3,000 200 T
n3g, mg Beta / gamma emitters (nuclides with decay modes other than alpha emission or 5,000 15,000 1,000 j
spontaneous fission) except "Sr and other noted above a Where surface contamination by both alpha-and beta / gamma-emitting nuclides exists, the limits established for alpha-and beta / gamma-emitting nuclides should apply independently.
b As used in this table dpm (disintegrations per minute) means the rate of emission by radioactive material as determined by correcting the counts per minute observed by an appropriate detector for background, efficiency, an geometric factors associated with the instrumentation.
c Measurements of average contaminant should not be averaged over more than I square meter. For objects ofless surface area, the average should be derived for each such object.
2 d The maximum contamination level applies to an area of not more than 100 cm 2
e The amount of removable radioactive material per 100 cm ofsurface area should be determined by wiping that area with dry filter or sof1 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 ofless surface area is detennined, then pertinent levels should be reduced proportionally and the entire surface should be wiped, f The average and maximum radiation levels associated with surface contamination resulting from beta-2 2
gamma emitters should not exceed 0.2 mrad /hr at I cm and 1.0 mrad /hr at I cm, respectively, measured through not more than 7 milligrams per square centimeter of total absorber.
l Guidelines For Decontamination of Facilities and Equipment Prior to Release for Unrestricted Use or Termination of Licenses For byproduct, Source, or Special Nuclear Material, also known as "Decon-1" incorporated into GA's State of CA Radioactive Materials License.
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Q Table 3: List ofInstruments Meter Detector Detector -
Calibration Efficiency Range
' Background L Description '
S/N S/N Due Date (cpm)
' (cpm) l Ludlum Rate Ludlum S/N 086238 07-08-98 20.00 %
Four Linear See Table 4 The instmment is a gas-flow propertional counter with 2
Meter Model S/N 086238 08-27-98 20.00 %
Ranges 0-an active probe area of 434 cm. The detector and rate Model 2221 43-37 S/N 086238 09-16-98 21.83 %
500,000 &
meter are combined and mounted on a roll around r
2 S/N 97287 434 cm S/N 083265 11-19-98 21.69 %
One Log 50-cart. He instrument features a static-flow system, Alpha S/N 083265 11-24-98 21.69 %
500,000 i
quick connects, a ponable gas bottle and a means to S/N 086238 11-27-98 21.90 %
adjust the height of the detector from the floor for S/N 086238 01-19-99 21.40%
optimum performance.
l Ludlum Rate Ludlum S/N 086236 09-09-98 21.15 %
Four Linear See Table 4 He instmment is a gas-flow proportional counter with 2
Meter Model I l-09-98 21.15 %
Ranges 0-an active probe area of 434 cm. The detector and rate Model2221 43-37 500,000 &
meter are combined and mounted on a roll around 2
S/N 84734 434 cm One Log 50-can. The instrument features a static-flow system, Alpha 500,000 quick connects, a portable gas bottle and a means to adjust the height of the detector from the floor for optimum performance.
Ludlum Rate Ludlum S/N 083293 06-04-98 21.14 %
Four Linear See Table 4 He instrument is a gas-flow proportional counter with 2
Meter Model S/N 094120 10-29-98 21.85 %
Ranges 0-an active probe area of 434 cm. The detector and rate Model 2221 43-37 S/N 086213 01-07-99 22.04 %
500,000 &
meter are combined and mounted on a roll around 2
S/N 84459 434 cm One Log 50-cart. The instrument features a static-flow system, Beta 500,000 quick connects, a portable gas bottle and a means to adjust the height of the detector from the floor for optimum performance.
I Ludlum Rate Ludlum S/N 083265 01-06-98 20.30 %
Four Linear See Table 4 De instrument is a gas-flow proportional counter with 2
Meter Model S/N 083265 07-08-98 21.85 %
Ranges 0-an active probe area of 434 cm. He detector and rate Model 2221 43-37 S/N 094119 11-03-98 21.85 %
500,000 &
meter are combined and mounted on a roll around 2
S/N 73701 434 cm S/N 094119 12-17-98 21.85 %
One Log 50-cart. The instrument features a static-flow system, Beta S/N 093600 12-30-98 24.13 %
500,000 quick connects, a portable gas bottle and a means to i'
S/N 093600 02-17-99 23.26 %
adjust the height of the detector from the floor for optimum performance.
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- Table 3
- List ofInstruments ~
Meter..
Detector L Detector :
_ Calibration.
Efficiency..
. Range l Backgre nd
'.- Description'
'S/N.
1S/N Due Date -
(cpm)j
- (cpm):
~
Ludlum Rate Ludlum S/N 120477 11-03-98 27.06 %
Four Linear See Table 4 he instrument is a gas-flow proportional counter with 2
Meter Model Ranges 0-an active probe area of 100 cm.
Model2221.
43-68 500,000 &
2 S/N 148436 '
100 cm One Log 50-Beta 500,000
' Ludlum Ludlum S/N 145967 04-15-98 23.34 %
Four Ranges concrete 80-140 The instrument is used for beta / gamma surveying. He 2
Model3 Model S/N 145967 07-13-98 23.34 %
0-100,000 detector has an active probe area of 15 cm.
concrete Block S/N 143349 44-9 S/N 145967 10-21-98 23.24 %
60-Ho 2
15 cm Beta / Gamma Metal 40-100
- Ludlum Ludlum S/N 145963 04-15-98 23.24 %
Four Ranges concrete 80-140 The instrument is used for beta / gamma surveying. He 2
Model 3 Model S/N 145963 10-08-98 22.05 %
0-100,000 detector has an active probe area of 15 cm,
g,,,,,,,g,,,,
S/N 138880 44-9 S/N 145963 11-02-98 22.05 %
60-140 2
15 cm S/N 145963 12-28-98 22.05 %
Beta / Gamma Metal 40-100
. Ludlum Ludlum S/N HP-210 08-11-98 20.36 %
Four Ranges concrete 80-140 The instrument is used for beta / gamma surveying. He 2
' Model 3 Model 11-25-98 20.36 %
0-100,000 detector has an active probe area of 15 cm.
g,,,,,,, g,,,g S/N 74220 44-9 60-no 2
15 cm Beta / Gamma Metal 40-100 Ludlum Ludlum S/N 076230 09-02-98 21.22 %
Four Ranges 0
Alpha scintillator ZnS(Ag) with an acuve probe area 2
6 Model 12 Model 0-500,000 of 50 cm,
S/N 73920 43-65 2
50 cm Alpha 10
4 JTable 3i; List ofInstruments4 m
- . Mete'r.
Detector ?
Detector iCahlmationi
? EfReiency Range.
Background)
Description-w
- S/N
':S/N.-
i Due Datel
- -(cpus)}
i(cpan);
' Ludlum RCA 6199 N/A 06-04-98 N/A Five Ranges 10-18 Used for measuring external dose rates on the surface
. Model 19 ?
coupled to a 07-14-98 0-5 mR/hr R/hr and at one (1) meter from the surface (i.e., initial.
i Micro-RE Nal(TI) 10-06-98 ground floor surveys). The scintillator [1" x 1" NaI '
. Meter J Scintillator (TI)]is mounted internally.
S/N 144022 i
Canberra.
Gas Flow N/A As needed
~ 26-30%
- N/A Varies with Canberra Model 2400 Low Level a/p gas proportional Low Level '-
Proportional Sample counting system used to count wipes for removable
. a/$ Counter :
Detector contamination. Results are usually reported as
' '~
dpm/100 cm,
2 r
n
)
[
T f
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I Table'4i Background Measurements (Obtained from Building 13) -
l Ludium Model 2221 Rate Meter s/n 148436 with Model 43-68 Probe s/n 120477
(
100 cm Beta detector -
2 l
Average of10 Measurements /
. MD A -
l Background Material -
'l minute each (cpm
- 2 o)
(dpm/100cm )-
2 (Efficiency = 25.04%)1 Concrete 554 56 448 Concrete Block 437 36 399 l
Drywall 273
- 40 318 l
- Background Material
' Average of10 Measurements -
MDA-1 l
(tile backgrounds from-
.1 minute each (cpm
- 2 o) :
(dpm/100cm )'
2
- Building 30)
(Efficiency = 27.06%)
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Ceramic Tile - Floor 621
- 54 438 Ceramic Tile - Wall 687 60 460 i
' Background Material Average of 10 Measurements.
MDA; 2 minutes each (cp2m
- 2 'o).
(dpm/100cm ).
2
- (Efficiency = 27.06%):
Concrete 933
- 38 268 Concrete Block 802 28 249 Metal 575 i 28 213 Drywall 510*30 199
- Ludlum Model 2221 Rate Meter s/n 73701 with Model 43-37 Probe s/n 083265 '
2 Beta Floor Monitor Background Scan Results: 434 cm ' detector (Efficiency = 21.85%)
Background Surface Material Beta / gamma Scan Range (cpm)
Concrete 1795-2030 Concrete Block 1281-1554 Metal 1151-1425 Drywall 906-1050 i
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Table 4 Background Measurements (Obtained from Building 13) -
- Iludium Model 2221 Rate Meter s/n 84459 with Model 43-37 Probe s/n 083293 --
Beta Floor Monitor Background Scan Results: 434 cm ' detector (Efficiency = 21.14%).
~8 1Backgro'und Surface MaterialL Bet'a/ gamma Scan Range (cpm)
Concrete 1400-1570 Concrete Block 1174-1409 Ceramic Tile (at Building 30) 2067-2207 Drywall 770-937 Metal 816-1047 Ludlum Model 2221 Rate Meter s/n 84734 with Model 43-37 Probe s/n 086236 :
2 Alpha Floor Monitor Background Scan Results: 434 cm detector (Efliciency = 22.15%).
Background Surface Material'
- Alpha Scan Range (cpm)-
~
Concrete 0-2G Concrete Block 0-20
. Ludium Model 2221 Rate Meter s/n 97287 with Model'43-37 Probe s/n 086238 '
2
! Alpha Floor Monitor Background Scan Results: 434 cm detector (Efficiency = 20.00%)
. Background Surface Material' Alpha Scan Range (cpm).
Concrete 0-20 Concrete Block 0-20 Drywall 0-15 Ceramic Tile (at Building 30)87-115 Metal 0-20 13
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' Table 5r Resmits hf Final Surveys in Building 21 Unaffested OfBee Areas L
- of1 min Fixed Maximum 1 Scan Results::!
4 Scan Results Maximum L b==e E 2
2.
iRadRange "434 ' m p.
.7434,,2pj
.fy org:
.. JResults
' Location' iSurface :
. Measurementsi (Resultsf e
"(100'..cm2 p){
(dpm/l00 cm );l
- (cpm range) f(cpm range)
- Smearsi l(dpm/100 cm );
(pR/hr) :.
l j:
lp t
1 Room 100 - Floor Concreie 4
< 448 5 - 10 1800 - 2000 4
< 10
< 10 14 - 15 Room 100 - Walt Drywall 4
< 318.
5 - 10 1100 - 1200 4
< 10
< 10 N/A
-i Room 101,101A - Floor Concrete 9
< 448 10 1800.%0 6
< 10
< 10 15 - 17 f
Room 101,101 A - Walls Drywall 5
< 318 5 - 10 u. 00 4
< 10
< 10 N/A Restroom Floors Concrete 6
< 448 10
- 1. " '.000 14 - 16 8
< 10
< 10 Restroom Floors Ceramic Tile 2
< 438 15 2000 - 2600 16 Restroom Walls Drywall 5
< 318 5 - 10 1200 - 1600 Restroom Walls Concrete Block 1
< 399 10 1600 8
< 10
< 10 N/A l
f Restroom Walls Ceramic Tile 2
< 460 100 - 110 2600 Janitorial Closet - Floor Concrete 1
< 448 10 1800 - 1900 1
< 10
< 10 15 Janitorial Storage - Walls Drywall 4
<318 5 - 10 1200 - 1400 3
< 10
< 10 N/A Hallways - Floor Concrete 6
< 448 5 - 10 1800 - 2000 5
< 10
< 10 14 - 16 l
l Hallway Walls Drywall 6
< 318 5 - 10 1100 - 1300 6
- < 10
< 10 N/A Hallway Walls Concrete Block 4
< 399 10 1400 - 1600 See Figures 6 through 9 for locations.
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All 8 masslin were checked for p and y radiation using the 15cm2 detector, Ludlum 3 geiger counter,
3.
No activity above background was found.
4.
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1.
~100% of the concrete floor was scanned for beta. Scan results (in cross hatched area) ranged from 1800 cpm to 2000 cpm and -100% of the ceramic tile floor was scanned for beta.
Scan results (also in cross hatched area) ranged from 2000 cpm to 2600 cpm.
2.
-10% of the concrete floor was scanned for alpha. Scan results (in cross hatched area) ranged from 5 cpm to 10 cpm.
-10% of the ceramic tile floor was scanned for alpha, result was 15 cpm. All measurements were taken with a 434cm detector.
8 I
3.
- 10% of the walls (not shown on map) were scanned for alpha and beta. Alpha ranged from 5 cpm to 10 cpm for concrete wall and drywall.
Alpha scan for ceramic wall file ranged from 100 cpm to 110 cpm. Concrete block beta scan ranged from 1400 cpm to 1600 cpm,
drywall ranged from 1100 cpm to 1400 cpm, and caramic wall tile was 2600 cpm.
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1.
The values provided are the approximate locations of measurements taken. One minute (cpm) fixed beta readings were taken (total of 59 readings) using a 100 cm2 detector, All readings were <MDA (dpm/100 cm2) on all respective surfaces.
2.
62 exposure rate measurements were takon. Results ranged from 14 pR/hr to 17 pR/hr.
3.
All concrete, drywall, concrete block & ceramic tile surfaces.
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l-l Wipe results, All p were <10 dpm/100cm2 & All a were <10 dpm/100cm 2
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All concrete, concrete block & drywall surfaces.
4
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J
Appendix A to Final Radiological Survey Performed at General Atomics' Building 21 Unaffected Office Areas dated October 31,1998
" Final Survey Plan for Portions of Building 21: Rooms 100,101,101A, Restrooms (2), Hallways and Janitorial Storage Closet" dated June 11, 1998 and " Addendum #1" dated July 6,1998
1
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June 11,1998 John Tur Approved by:
hh18 Laura Gonzales:
bun)
Date:
Paul Maschka:
- M# >>#la aMM Date:
G
'/ ' - f f Final Survey Plan for Portions of Building 21: Rooms 100,101,101A, Restrooms (2), Hallways and Janitorial Storage Closet
Purpose:
The purpose of this survey is to ensure that no residual contamination is present by performing a final survey demonstrating that the radiological conditions satisfy the NRC and the State of California guidelines for release to unrestricted use.
Classification:
Certain portions of Building 21 are classified as " unaffected" areas. See figure 1 for the site description. They were used for either administrative purposes only (rooms 100 and 101), as " clean" area restrooms (men's and women's), egress / ingress to the building and rooms (hallways) or as ajanitorial storage closet. See figure 2 for the location of these areas. Room 101 A was used in the past as the Photographic Dark Room. All areas
)
mentioned above are expected to be radiologically " clean" and therefore are classified as
" unaffected". If radiological contamination exceeding 75% of the guideline value is encountered in any of these areas, they will be reclassified.
Note 1: Due to the close proximity of these " unaffected" areas to the other portions of the TRIGA facility, the possibility that these " unaffected" areas may have been inadvertently contaminated (at some point in the past) necessitates they undergo close radiological
- scrutiny, 1
Note 2: All office furniture and other items / materials in these areas have been removed to facilitate the radiological measurements to be conducted. The toilets, sinks and associated plumbing were also removed.
Note 3: The interior, non-structural walls (drywall, plywood) enclosing these areas have been removed (except for the north walls of Room 101 and Restrooms, as well as the east i
walls of Room 101 and the women's restroom and a small portion of the hallway wall used to access Room 102). The building's exterior structural walls involving these areas have been left in place. See figure 3 for details of the resulting area created after the non-structural walls have been removed. Room 100 is encompassed by concrete walls and retains its integrity.
i l
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==
Description:==
A total of two (2) rooms are now included in the " unaffected " area of Building 21. The total area to be released to unrestricted use is - 830 ft, delineated as follows:
i 2
2 Room ft 101 167 101A 52 Closet 33 Hallway 204 Men's Room 100 Women's Room 103 Sub-Total 644 100 166 Total 830 Survey Oblectives and Resnonsihility l
The purpose of performing a final survey is to demonstrate that the radiological conditions satisfy the NRC and State of CA guidelines for release to unrestricted use. The objectives include (1) to show that
' the average surface contamination levels for each survey unit are within the authorized value, (2) to I
show that the maximum residual activity (" hot spot" area) do not exceed three times the average value 2
in an area up to 100 cm and (3) that a reasonable effort has been made to clean removable
]
contamination and fixed contamination and (4) that the exposure rates in occupiable locations are less than 10 pR/hr above background measured at 1 meter above the surface. Samples will be counted in GA's Health Physics laboratory. Surveys will be taken only by qualified Health Physics Technicians having a minimum of 3 years Health Physics Technician experience following approved Health Physics procedures and this Plan. The survey and final report documenting the survey will be performed by GA's Health Physics group.
Delease Criteria (per GA Site Decommissionino Plan)
- Facility Structure Criteria Mixed fission products and mixed activation products are the primary contaminant in this facility. The applicable guidelines for residual contamination on building surfaces for beta / gamma emitters are:
2 2
5,000 dpm/100 cm, averaged over a 1 m area 2
2 15,000 dpm/100 cm, total, maximum in a 100 cm area 2
1,000 dpm/100 cm, removable activity Surveys for alpha contamination are being done to confirm that no alpha contamination is present.
l Frnosure Rate Measurements L
The guideline value for exposure rates measured at I m above the surface, is 10 R/hr above i
background.
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Soil Criteria No soil sampling is required in these rooms since they were " unaffected" offices, restrooms and hallways only. No soil contamination underneath the building is likely or expected at these locations.
Alert Levels (Based on release criteria for beta /gnmma emitters)
If the following " alert levels" are exceeded, notify HP Management so an evaluation can be performed to determine ifincreased survey coverage or decontamination is required.
On Concrete Surfaces INote: Alert levels for other surfaces can be estimated as the background cpm plus the epm value provided below for each instrument type).
Alpha Monitoring 2
> 100 cpm alpha using the large area (434 cm ) probe. (If >100 cpm, check with hand-held a
]
meter.)
> 60 cpm using a hand-held alpha probe, notify Health Physics Management.
2 Beta Scanning using the 434 cm probe 2
> ~1900 cpm beta using the large area (434 cm ) probe (#84459) 2
> ~2300 cpm beta using the large area (434 cm ) probe (#73701) 2
> ~300 cpm above background of another 434 cm probe - make sure the background determination has been completed at Building 13 (or other HP management approved location)
)
2 Beta Measurements using the 100 cm probe 2
> ~1300 counts in 1 minute using the beta 100 cm gas flow proportional counter (s/n 84423) 2
> ~1150 counts in 1 minute using the beta 100 cm gas flow proportional counter (s/n 86332) 2
> ~400 cpm above background for other beta 100 cm gas flow proportional counter or if probe calibration has changed or of other changes to the meter have been made --make sure the background determination has been completed at Building 13 (or other HP management approved location).
Decontamination Required - When (1) GM measurements > 250 cpm or (2) after an 2
evaluation of the data obtained using the 100 cm probe shows that levels exceed the re' ease criteria.
Exnosure Rate Measurement - Alert Levels Exposure rate measurement measured at I m above the surface. A typical background around G A n about 15 pR/hr. Therefore, a value above 25 pR/hr could be over the limits (a higher background would have to bejustified). Notify Health Physics of any readings > 20 pR/hr.
Final Surveys To Be Performed 1.
Gridding is not required.
2.
Conduct masslin surveys of all concrete floor surfaces (for beta only).
2 3.
Scan 100% of the concrete floor surfaces (for beta only) using the 434 cm probe.
)
l 3
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4.
Scan 100% of the surfaces of the trench in the hallway (all sides) using the 100 cm probe (beta only). If contamination is found, alpha surveys will be performed.
2 5.
Scan 10% of the concrete floor surfaces (for alpha only) using the 434 cm probe.
6.
Scan 10% of the remaining walls (for both alpha and beta)- at < 2 meters in height from the 2
floor using the 434 cm probe.
7.
Take measurements - subdivided as:
[A] Rooms 101.101 A. Restrooms. Hallways. Trench in Hallway and Janitorial Closet Take 50 measurements (evenly spaced) in this Area, as:
2
[a] 14 direct on the concrete floors (beta only, I minute) using the 100 cm probe,
[b] 4 direct on the floor and each of 3 walls inside the concrete lined trench (beta only, I 2
minute) using the 100 cm probe, 2
[c] 8 direct, one on each wall (beta only, I minute) using the 100 cm probe,
[d] 14 smears on the floor, and 2 inside the bottom of the concrete lined trench,
[e] 8 smears, one on each wall.
[B] Room 100 2
Room 100 is enclosed by concrete walls. It encompasses an area of ~ 166 ft. Take 16 measurements (evenly spaced) in this Room, as:
2
[a] 4 direct on the floor (beta only,1 minute) using the 100 cm probe, 2
[b] 4 direct, one on each wall (beta only, I minute) using the 100 cm probe,
[c] 4 smears on the floor,
)
[d] 4 smears, one on each wall.
7.
Exposure rate measurements (micro R):
Floor areas only -Take a measurement - every 3 meters (at I meter above the surface)
Documentation Every radiological survey conducted must be documented on a daily basis to a worksheet/ log book and on a drawing showing the appropriate locations surveyed. The documentation must include the results of the measurements (including units), the technician's printed name and signature, date, instrument (s) used (including the model and serial number of both the ratemeter and the detector), calibration due date, % efficiency, background readings (if applicable) and any other pertinent information.
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Approved by:
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M Date:
John Tumer:
3d M-Date:
7 - (o - 9 8 Q
Addendum #1 to the " Final Survey Plan for Portions of Building 21:
Rooms 100,101,101A, Restrooms (2), Hallways and Janitorial Storage Closet"
Purpose:
This addendum was prepared as a supplement to the " Final Survey Plan for Portions of Building 21" dated June 11,1998. It was generated to encompass several of the changes made in the demolition / construction plans, whereby several of the non-structural walls and the restrooms were to remain "in place".
New Descriptiom The non-structural walls enclosing rooms 101 A and portions of 101 were removed. A total of five (5) new areas (rooms) are now included in the " unaffected " area of Building 2
- 21. The total area to be released to unrestricted use is ~ 830 ft, delineated as follows:
2 Room h
)
101,101 A & Hallways 430 Men's Room 100 Women's Room 109 Janitorial Storage Closet 25 100 166 Total 830 Final Surveys To Be Performed 1.
Gridding is not required.
2.
Conduct masslin surveys of all concrete floor surfaces (for beta only).
2 3.
Scan 100% of the concrete floor surfaces (for beta only) using the 434 cm probe.
2 4.
Scan 100% of the surfaces of the trench in the hallway (all sides) using the 100 cm probe (beta only). If contamination is found, alpha surveys will be performed.
2 5.
Scan 10% of the concrete floor surfaces (for alpha only) using the 434 cm probe.
6.
Scan 10% of the remaining walls (for both alpha and beta)- at < 2 meters in height from the 2
floor using the 434 cm probe.
l I
-.. -.- ~. --
i 7.
Take measurements - subdivided as:
l (A) Room 100 l
Room 100 is enclosed by concrete walls. It encompasses an area of ~ 166 ft, Take 16 2
measurements (evenly spaced) in this Room, as:
l
[a] 4 direct on the floor (beta only, I minute) using the 100 cm probe, 2
l
[b] 4 dimet, one on each wall (beta only,1 minute) using the 100 cm probe, 2
l
[c] 4 smears on the floor,
[-
[d] 4 smears, one on each wall.
(B) Men's Restroom 2
The restroom encompasses an area of ~ 100 ft. Take 16 measurements (evenly spaced) in this Room, as:
2
[a] 4 direct on the floor (beta only,1 minute) using the 100 cm probe, 2
[b] 4 direct, one on each wall (beta only, I minute) usinF the 100 cm probe, l
[c] 4 smears on the floor,
[d] 4 smears, one on each wall.
(C) Women's Restroom 2
The restroom encompasses an area of ~ 109 ft. Take 16 measurements (evenly spaced) in this Room, as:
]
[a] 4 direct on the floor (beta only, I minute) using the 100 cm probe, 2
2
[b] 4 direct, one on each wall (beta only,1 minute) using the 100 cm probe,
[c] 4 smears on the floor,
[d] 4 smears, one on each wall.
(D) Janitorial Storage Closet 2
The closet encompasses an area of ~ 25 ft Take 10 measurements (evenly spaced) in this
- Room, as:
2
[a] I direct on the floor (beta only, I minute) using the 100 cm probe, 2
[b] 4 direct, one on each wall (beta only,1 minute) using the 100 cm probe,
[c] 1 smears on the floor,
[d] 4 smears, one on each wall.
l (E) Former Rooms # 101.101 A and Associated Hallways 2
This large section of Building 21 encompasses an area of ~ 430 ft. Take 56 measurements (evenly spaced)in this Room, as:
2
[a] 14 direct on the floor (beta only, I minute) using the 100 cm probe, 2
[b] 14 direct, evenly spaced, on the walls (beta only,1 minute) using the 100 cm probe,
_ c] 14 smears on the floor,
[
[d] 14 smears, evenly spaced, around the walled areas.
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7.
Exposure rate measurements (micro R):
Floor areas only -Take a measurement - every 3 meters (at I meter above the surface).
Documentation l
Every radiological survey conducted must be documented on a daily basis to a worksheet/ log book and on a drawing showing the appropriate locations surveyed. The l
documentation must include the results of the measurements (including units), the technician's i
printed name and signatun:, date, instrument (s) used (including the model and serial number of both the ratemeter and the detector), calibration due date, % efficiency, background readings (if applicable) and any other pertinent information.
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