ML20196H544
| ML20196H544 | |
| Person / Time | |
|---|---|
| Site: | 07000734 |
| Issue date: | 02/26/1999 |
| From: | Gonzales L, Maschka P, Joseph Turner GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER |
| To: | |
| Shared Package | |
| ML20196H524 | List: |
| References | |
| NUDOCS 9907060372 | |
| Download: ML20196H544 (39) | |
Text
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{
l FINAL RADIOLOGICAL SURVEY
{
PERFORMED AT GENERAL ATOMICS'
{
BUILDING 45
{
Prepared By: John Turner, Paul Maschka, Laura Gonzales, Richard Stowell, Efraim Ramirez, Kevin Busby, Cornelius Stanley & Barbara Lyons.
February 26,1999
- 27ta =*m 09 8
l
,l Table of Contents INTRODUCTION............................................................... 1 SITE DESCRIPTION........................................................... 1 PREVIOUS ACTIVITIES (HISTORY OF USE)....................................... 2 CRITERIA FOR RELEASE TO UNRESTRICTED USE................................ 3 Facilities and Equipment.................................................... 3 Enriched Uranium......................................................... 3 Exposure Rate Guideline.................................................... 3 INSTRUMENTATION........................................................... 4 BACKGROUND MEASUREMENTS............................................... 4 Background Measurements for Instruments / Detectors
............................4 Exposure Rate Background.................................................. 5 FINAL SURVEYS PERFORMED................................................. 5 Objectives and Responsibilities.............................................. 5 Classi fication of Areas..................................................... 6 Final Survey Plans
........................................................6 S URVEY S UMMARY........................................................... 6 RESULTS OF THE FINAL SURVEYS.............................................. 7 Scan ning................................................................ 7 Fixed Measurements....................................................... 7 Removable Contamination Surveys........................................... 8 Exposure Rate Measurements................................................ 8 Soil / Concrete Samples..................................................... 8 CONCLUS ION................................................................. 8 List of Tables Table 1:
USNRC's Acceptable Surface Contamination Levels......................... T-1 Table 2:
State of CA Acceptable Surface Contamination Levels........................ T-2 Table 3:
List of Instruments.................................................... T-3 Table 4:
Background Measurements (Obtained from Building 13)...................... T-5 Table 5:
Results of Final Surveys in Building 45.................................... T-7 g
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l I
List of Figures (unnaged)
Figure 1:
Plan View ofGeneral Atomics Site Figure 2:
Building 45 in Relation to Surrounding Facilities
- Figure 3:
Ground Floor: Masslinn Survey Figure 4:
Office Mezzanine: Masslinn Survey Figure 5:
Basement Shop: Masslinn Survey Figure 6:
Ground Floor: Alpha & Beta Floor Scans & Exposure Rate Measurements Figure 7:
South Hallway of Ground Floor: Alpha & Beta Floor Scans Figure 8:
Office Mezzanine: Alpha & Beta Floor Scans & Exposure Rate Measurements Figure 9:
Basement Shop: Alpha & Eeta Floor Scans & Exposure Rate Measurements Figure 10:
Contractors' Mezzanine: Alpha & Beta Floor Scans & Exposure Rate Measurements Figure 11:
Ground Floor & Walls: Fixed Alpha & Removable Contamination Locations Figure 12:
Ground Floor & Walls: Fixed Beta Measurement Locations Figure 13:
South Hallway of Ground Floor: Fixed Beta Measurement Locations Anpendir
" Final Survey Plan for Building 45" dated August 21,1998.
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- l*ammmera mmuses Building 45 Final Radiological Survey Report Introduction General Atomics (GA) is continuing its efforts directed at decontaminating, as appropriate, and I
obtaining the release to unrestricted use of selected facilities at General Atomics. GA has recently completed the Final Radiological Survey of Building 45 located at GA's Sorrento Valley Site.
GA is requesting both the Nuclear Regulatory Commission (NRC) and the State of California for the release of Building 45 to unrestricted use.
This report documents the results of the radiological measarements completed inside Building 45 and demonstrates that this area meets the approved criteria for release to unrestricted use. The total surface area to be released to unrestricted use is ~ 8456 ft2 (~ 786 m ),
2 l
Site Description A plan view of the GA Site is shown in Figure 1. Building 45 and its location in relation to other facilities at GA's Sorrento Valley Site is shown in Figure 2.
I Building 45 is composed of a ground floor (main ground floor and contractors' area ground floor),
an office mezzanine and a basement. The ground floor of Building 45 is shown in Figure 3, the office mezzanine in Figure 4 and the basement in Figure 5.
Building 45 has extemal dimensions of~ 82 % fl x 102 % ft (~ 25 lm x 31.2m) and encompasses an area of~ 8456 ft2 (~ 786 m ). Individual areas within the building are as follows:
2 I
Location Area-ft2 Area-m2 Main Ground Floor 4991 464 Contractors' Ground Floor 3465 322 I
Contractors' Mezzanine 1482 137.5 Basement 1653 153.5 Office Mezzanine IXd 126.5 Totals 12,954 1,203.5 The floor surfaces of the ground floor and the basement are composed of unpainted, reinforced concrete. The floor of the office mezzanine is composed of reinforced decking overlaid with carpet or linoleum tile. The floor of the contractors' mezzanine is composed of wood. The restroom floors 1of8
y-- mouses Building 45 Final Radiological Survey Report are composed of ceramic tiles. The graphite machine shop's floor is composed of non-slip, rubberized tile sheets over concrete.
The exterior walls of the building are composed of conugated (standard stock) sheet metal. All of the exterior walls are attached to a stmetural steel framework and adjoin the edge / footing of the concrete floor. The walls of the basement are composed ofpainted, reinforced concrete.
The interior wall separating the main floor machine shop from the contractors' area is composed of gypsum wall board / sheetrock (see Figure 11). The south wall (of the ground floor hallway) as well as the east wall of the substructure for the office mezzanine are composed of concrete blocks (see Figure 11). All of the entry / exit doors and roll-up doors are composed of metal.
The roofconsists of ribbed steel sheet decking. The ribbed steel sheets span supporting rafters and I-beams to which they are fastened.
Previous Activities (History of Use)
Building 45 is currently being used for non-radioactive work. It is being used mainly as the site facility machine shop with supporting storage and office areas. It also contains office space for contractors and their collective storage areas (i.e., ofrices, building and maintenance supplies and materials). The building is occupied by personnel and equipment involved with these operations. In the past the building was used for various projects, but none of these projects were known to involve the use of radioactive material.
The only history of radioactive material being in the building occurred during 1987 when a properly packaged fission chamber was temporarily stored on the ground floor (in the south hallway) as shown in Figures 6 & 7. The fission chamber was an integral component of an In-core Flux Monitoring Unit (IFMU) that was to be installed in the Fort St. Vrain, Colorado Project.
The entire fission chamber device was approximately 20 feet long, and the fission chamber itself was located at one end and was 5.5 inches long and 0.41 inches in diameter. The fission chamber was a totally sealed canister with highly enriched uranium inside. The box, in which the fission chamber was stored, was approximately 20 feet long x 8 inches wide x 8 inches in height. The exterior surface of this package was checked for contamination before being moved into the building and it was well below the release criteria. To our knowledge, the package was never opened while it was stored in Building 45.
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- je - - - m am a Building 45 Final Radiological Survey Report friteria for Release to Unrestricted Use Facilities and Equioment U.S. NRC's criterion for releasing facilities and equipment to unrestricted use is shown in Table 1.
The State of Califomia's guidelines, "DHS Criteria for Release of Facilities and Equipment to Unrestricted Use," also known as "DECON-1," is sho vn in Table 2.
Enriched Uranium I
The approved guideline values for residual contamination for release to unmstricted use for enriched uranium are provided as follows:
I 2
2 5,000 dpm/100 cm (averaged over a 1 m area) 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 activity)
In Building 45, the alpha surveys were sufficient to determine compliance with the release criteria, although beta monitoring was also perfonned. Alpha measurements are satisfactory for the following reasons:
1.
In " highly" enriched urantim (uranium used in the fission chamber was typically ~ 90%
enriched); alpha monitoring is the method of choice. At this enrichment, the U-234 activity present has increased significantly. The alpha to beta ratio is approximately 116:1.8 Because of this, alpha monitoring was the measurement of choice for enriched uranium.
2.
Alpha surveys are accurate if the surface is clean and free of dust and debris. All surfaces were cleaned before scanning or fixed measurements were performed.
Exoosure Rate Guideline The guideline value for exposure rates measured at I m above the surface, is 10 R/hr above background levels.
'I
' From Table 5-4 of" Health Physics Manual of Good Practices for Uranium Facilities" Prepared for DOE by Idaho National Engineering Laboratory, document EGG-2530, UC-41, dated June 1988.
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4====== mrammes Building 45 Final Radiological Survey Report Instrumentation A list ofinstmments used during the radiological surveys is shown in Table 3. The table includes:
(1) a description of the instrument, model number and its serial number, (2) a description of the detector (if applicable) and its serial number, (3) instmment ranges, (4) calibration due dates, (5) typical background readings and (6) calibration efficiencies (if applicable). All of the instruments used were calibrated semiannually and after repair, except for exposure rate meters which were calibrated quarterly.
Background Measurements Backcround Measurements for Instmments/ Detectors Building 13 on GA's main site was used for conducting background measurements on instmments used for the final survey because: (1) there is no history involving radioactive materials or storage of radioactive materials in Building 13, and (2) the various surfaces found in Building 45 could also be found in Building 13.
For the fixed background measurements (6own in Table 4) the mean and standard deviation, for each 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:
2 Equation (8-11) pl a,
n, Equation (8-12)
Us(A-#)*
s;)
n-1 Minimum detectable activities (MDA's) for each type of surface (see Table 4), were calculated using equation (5-2) from the NUREG/CR-5849 as follows:
2 Manual for Conducting Radiological Surveys in Support of License Termination (Draft for Comment), NUREG/CR-5849, ORAU-92/C57, Oak Ridge Asaciated Universities, June 1992.
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eb - - mensues Building 45 Final Radiological Survey Report Equation (5-2) 2.71 +4.65/B,xt
-MDA-(dpm/100cm*)
^
t Eu Where:
Ba=backgmund rate (cpm) t = count time (min)
E = efficiency 2
A = area of the detector (cm )
Exnosure Rate Backaround Typical exposure rate background for this site is about 15 R/hr measured at I m from the surface.
This value caa be measured south of Building 15 (an office building on the eastern portion of the GA site). Measurements taken offsite in 10 different locations over a period of a year also give an average of about 15 R/hr (measured 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, and up to 28 R/hr inside concrete lined trenches or concrete lined pits (background measurements inside a concrete pit near Building 2 confirmed this).
Final Surveys Performed Obiectives and Reana==ibilities The objectives of the final survey plan were (1) to demonstrate that the average surface contamination level for each survey unit was below the approved release criteria, (2) to show that the maximum residual activity did not exceed three times the average value in an area up to 100 cm, (3) 2 that a reasonable effort was made to clean removable contamination and fixed contamination (if necessary) and (4) that the expositre rates in occupiable locations are less than 10 R/hr above background measured at I meter above the surface.
l Surveys were taken only by qualified Health Physics Technicians having a minimum of three years Health Physics experience in accordance with approved Survey Plans. Samples (100 cm wipes) r 2
were counted in GA's Health Physics Laboratory which maintains an effective QA program.
Every survey conducted was documented on a daily basis to a worksheet or drawing showing the approximate locations surveyed. The documentation included the results of the measurements 5 of 8
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- l* *""""" mensues Building 45 Final Radiological Survey Report (including units), the technician's signature, date, instrument (s) used (including the model and serial number of both the ratemeter and detector), calibration due date, % efficiency, background readings I
(if applicable) and any other pertinent information.
l C1===htion of Areas l
Unagected Areas The ground floor (i.e., a main floor machine shop, welding shop, graphite machine shop, tool crib and the south haliway), except for the contractors' area in the north portion of the building, was classified as " unaffected" due to the temporary storage of the fission chamber along the south hallway (see Figure 6). This area measures ~ 4991 ft2 (~ 464 m ),
2 Non-Impacted Areas: The basement shop, office mezzanine and the north portion of the ground floor (i.e., contractors' offices, storage facilities and mezzanine) have no known history of radioactive material usage or storage. Therefore, they were classified as "non-impacted" areas and require no radiological surveying. However, a/p scans with the 434 cm floor monitors, large area 2
masslinn smear surveys and exposure rate measurements were conducted in these areas.
Final Survey Phne Survey plans were developed based on the previous history of the building, the radionuclide(s) of concem, the various types of surfaces, the potential for contamination and the classification of the area (unaffected or non-impacted).
The surveys included scanning of the floor and wall surfaces, large area masslinn smear surveys, 2
collection and analyses (by gross alpha / beta counting) of 100 cm wipes, the taking of fixed measurements and exposure rate measurements ( R/hr).
The surveys were completed in accordance with approved written Final Survey Plan. A copy of the Survey Plan is provided in the Appendix as follows:
Appendix:
" Final Radiological Survey Plan for Building 45" dated August 21,1998.
Survey Summary A summary of the number of fixed measurements, smears and exposure rate measurements ( R/hr) taken during the Final Survey is provided as follows:
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4 ammamem.mysemes Building 45 Final Radiological Survey Report I
Building 45 Final Survey Summary Survey
- of Fixed
- of Fixed
- of Smears
- of Exposure Rate Measurements Measurements Measurements a
p
( R/hr)
Final Survey 17 34 6
76 Results of the Final Surveys The results for the Final Surveys are provided in Tables 5 and locations are shown in Figures 3 through 13.
Scannine 2
Scans with the 434 cm a:pha gas-flow proportional detectors (floor monitors) were conducted in order to identify elevated areas of activity. Areas with elevated readings would then be further investigated with hand-held a instruments / detectors to determine if the levels were above the release criteria. No areas were discovered that displayed elevated levels of a activity. The results of these scans are provided in Table 5 and the approximate locations are shown in their respective figures.
2 Scans with the 434 cm beta gas-flow proportional detectors (floor monitors) were also conducted in order to identify elevated areas of activity. Areas with elevated readings would then be further investigated with hand-held instruments / detectors to determine if the levels were above the release criteria. No areas were dircevered that displayed elevated levels of p activity. The results of these scans are provided in Table 5 and the approximate locations are shown in their respective figures.
Fixed Measurements A total of 17 fixed alpha measurements were performed during the final survey in the unaffected 2
areas (i.e., floors and walls). The final measurements were taken using a 50 cm alpha scintillator ZnS(Ag) detector. The applicable background for the 50 cm alpha detector was subtracted from 2
2 the survey readings and these readings were converted from cpm to dpm/100 cm using the appropriate count time, the efficiency of the detector and the geometry of the detector. The results are provided in Table 5 and their approximate locations are shown in Figure 11. All the fixed alpha 2
measurements were < 140 dpm/100 cm,
A total of 34 fixed beta measurements were performed during the final survey in the unaffected areas 2
(i.e., floors and walls). The final measurements were taken using a 100 cm gas-proportional beta 7 of 8
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i 4 anamam m aanes Building 45 Final Radiological Survey Report I
detector. The applicable background for the 100 cm beta detector was subtracted fmm the survey 2
readings and these readings were converted from cpm to dpm/100 cm using the appropriate count 2
time, the efficiency of the detector and the geometry of the detector. The results are provided in Table 5 and their approximate locations are shown in Figures 12 & 13. All the fixed beta 2
measurements were < 540 dpm/100 cm.
Remnvable Contaminatian Surveys
- A total of 6 smears were taken during the final survey. These removable contamination measurements (smears) were taken from the concrete floor surfaces.
2 Smears consisted of using a Whatman Filter Paper (4.7 cm diameter) and wiping an area of~ 100 2
cm. The smears were counted in GA's Health Physics Laboratory using a Canberra 2404 low level alpha / beta counting system. The smear results are provided in Table 5 and their approximate locations are shown in Figure 11. The maximum smear results were < 10 dpm/100 cm for both a 2
andp.
Masslinn surveys were also conducted on all floors by wiping the surfaces with masslinn cloths and 2
measuring the activity on the masslinn cloths with a hand-held 15 cm GM pancake detector and a 2
hand-held 50 cm alpha detector. All readings were less than or equal to natural background levels.
No decontamination was required.'
)
Frnosure Rate Measurennents A total of 76 direct radiation exposure rate measurements were taken at various locations inside the building. 'Ihe measurements were taken at ~1 meter above the surface using a microR meter. The exposure rate measurements are provided in Table 5 and in the respective figures for each location.
Measurements taken throughout the building's ground floor ranged from 8 to 15 R/hr.
~ Measurements taken in the basement ranged from 15 to 20 R/hr. Measurements on the office mezzanine ranged from 12 to 13 R/hr.
Soil / Concrete Ramnles
' No sampling of the concrete or soil beneath the concrete was required in any areas of Building 45, since they were classified as either "non-impacted" or " unaffected," and no radioactive contamination was detected on any of the floor surfaces or walls.
Conclusion Final contamination and radiation surveys provided in this report for Building 45, demonstrate that the building meets the approved guidelines for release to unrestricted use.
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Table 1: USNRC'S ACCEPTABLE S' URFACE CONTAMINATION LEVELS Nuclides*
' Average W
Maximum #
RemovableW 6
8 2
- (dpm/100cm )
(dpm/100 cm')
' (dpm/100cm )
U-nat,235U,23sU, & associated decay products 5,000 a 15,000 a 1,000 a Transuranics,226Ra, 22sRa, 230Th,22sTh,23:Pa, 100 300 20 227Ac, 225,129g 1
Th-nat, 232fh, "Sr, 223Ra, 224Ra, 232U, i261, '33,
1,000 3,000 200 1
(
isig 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.
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.
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.
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.
d The maximum contamination level applies to an area of not more than 100 cm,2 The amount of removable radioactive material per 100 cm of surface area should be determined 2
e 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 ofless surface area is determined, 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-gamma emitters should not exceed 0.2 mrad /hr at I cm and 1.0 mrad /hr at I cm,
2 2
respectively, measured through not more than 7 milligrams per square centimeter of total absorber.
f T-1
c l
l Table 2: STATE OF CA ACCEPTABLE SURFACE CONTAMINATION LEVELS I l
W -
- Maximum ^f Removable d Nuclides*
Average b
b 2
2 2
(dpm/100cm )
(dpm/100cm )
. (dpm/100cm )
U-nat,235U,23sU, & associated decay products 5,000 15,000 1,000 l
Transuranics, 226Ra, 22sRa, 23*Th, 22sTh, 23 Pa, 100 300 20 227Ac, 25,1291 1
Th-nat,232Th, "Sr, 223Ra, 224Ra, 232U, i261, 331, 1,000 3,000 200 isig 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 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.
g 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, l
an geometric factors associated with the instrumentation.
e 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.
2 I
d The maximum contamination level applies to an area of not more than 100 cm,
c The amount of removable radioactive material per 100 cm of surface area should be determined by wiping that I
2 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 ofless surface area is determined, then pertinent levels should be reduced proportionally and the entire j
surface should be wiped.
l f The avemge and maximum radiation levels associated with surface contamination resulting from beta-gamma I
2 2
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.
8 Guidelines For Decontamination of Facilities and Equipment Prior to Release for Unrestricted j
Use or Termination of Licenses For byproduct, Source, or Special Nuclear Material, also known i
as "Decon-1" incorporated into GA's State of CA Radioactive Materials License.
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~ Ludlum Model 2221 Rate Meter s/n 97817 With Model 43-37 Probe s/n 147965
- Alpha Floor Monitor Bahkground Scan Resultsi 434 cm Detector (Emciency =22.37%)-
2
. Background Material::.
1 Alpha Scan Range (cpm)
Concrete 6-26 Concrete Block 6-23 Linoleum over Concrete 0-18 Carpet 5-13 Wood 4 16 Ludlum Model 2221 Rate Meter s/n 84459.With Model 43-37 Probe s/n 086213
. Beta Floor' Monitor Background Scan Results': 434 cm Detector (Efficiency = 22.04%)
2 Background Material
~ Beta / Gamma Scan Range (cpm) -
Concrete 1400-1570 Concrete Block 1174-1409 Linoleum over Concrete 1188-1462 Carpet 1030-1166 Wood 1061-1262 Ceramic Tile 2067-2207 Ludlum Model 3 Rate Meter s/n 138880 With Model 44-9 Probe s/n 145963 2
15 cm Beta Detector (Emclency = 22.05%)' _
LBackground Material.
Beta / Gamma Scan Range (cpm)
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l RTable:4:! Background 4 Measurements (Obtained frontBuilding;13) l
-l Ludlum Model 2221 Rate Meter s/n 86332 With Model 43-68 Probe s/n 142540 l
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2
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' Background Material 2
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- 56 381 Metal 281
- 44 280 Drywall / Sheetrock 287
- 44 283 Concrete Block 447 56 350 Ceramic Tile 540
- 54 372
@ 29.80% Efficiency l
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Figure 1: Plan lew of General Atomics Site
Figure 2: Building 45 in Relation to Surrounding Facilities 3j f
l
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'Al 45 tr GUARD FLINTCOTE AVE.
i Building 45 4 STA.10
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N Figure 3: Ground Floor: M*sslinn Surv:y.
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[ Figure 6: Gr:und Floor: a / p floor scans & Exposure R:t3 M::sur:m:nts. N [ %@%E s d. 'j O ) [. [ N- .* Contractors' ofRoos, supplist & storspo, area '- .f D -}* L] g (. l l
- Jhpa h
-- e, ~. 3 4 + _ ~.- -. -+ A m ~ i M + y, m'. H' I I I a. l Main floorinachine sho.p + l l l l .l l L H I I I [" " ' Package.Contafning Fissier) .Gouth Halfway ( Obamber
- h IIIII Welding
'. Shop. . Graphite M.d ' Mine *
- Shop
_.~ oc. mA,lo i l l l l I I I I l Tool Crib l J ] ,l ] l l l i Notes.
- 1. Scan results are provided in Table 5.
- 2. a / p scan in cross hatched area.
- 3. Exposure Rate Measurements were taken. General area pR/hr results were 8 to 15 pR/hr.
l
jl I
- I I
1 ~ E NA%wv 4W ~ a.e r a y., de a h .. lw c ta la h s H.. so ~ h rc . t e u l o, b y S.. uo m d u n n i c l is a l.- a r w e s .W b r m o a a e o h r l C a f ~ n d r o e m h ~- is c m la is t l a a w F h e s p h s t s / o u g r in c m a e u d in lb m r a t u o lo a n o o d c F e n + d 5 n g a d o i le a n b k a c e u s + a r a o s T p a r i~ s G F + i h e n e d m ~ d t h f g e f c u o nr. id o ta y ie v n h ni o o a t p it s r s i sm w am + a o e c r t u l r o c n a., s l a l a a oh + s o in H C. C m lt t a s u s m n h a t e o e i c x u g r o s o a n r a p p S k' c p / S A. a. g s 7 a e 2 3 P + 1 w to e N r u g b iF m r 2 w >l
a \\ y nocla B E N&hj 4W / [- / mo I o R h" ec r. .s n h t / e R n e r e c e f m m n 3 O o 1 e C o r t u I 2 s 1 a e r e e M ws [ lt e u t I s a e R r r e h r /R u p s a o e e p ic ra x f la f E O ,u r a m e ne s G na n. c \\ e s M ka r t 5 e o r o le e a l b e w f e a r g p T a s a t t in d n r / o e e a Ss d h m /m e c e t n no id a u r e eo v h s o r s a oR i h p s e na I p o M e r W e TN s a r c z le a e z t M lt in e s R u n e NF s a r e c u e r s s ic n f a p op f c / x O S a E s 2. 3 e 1 g t nl o a 8 it c N aim e e n r Hao ho u - cR g Ce /M i A U 1 i
IIlI Ii ltIilI ll! i I E
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4W tne en s mip h o r tn ech h e saS / m I aM R B p e 0 r 2 wM u o t sa 5 1 e e re e w wR lt t s a use e r r r u h / s R o p y m p a s x e r mu E la a re s n n e a G c .n s e r ka o t o 5 e l r f le e a p b e w a r / T a s t a i d n n e e d h m
- p e
c e t o d a u r h iv h s o S r s a p s e t o M e r n r c e a e n t s a me lt i R s u n e s a r s e c u a r s s B I c / x na p op S a E 9 s 2 3 e 1 e to r N ug i F Ii!
s r ia Y tS E N&A'Wvs W / .s tne m r e h u r /R u s a 9 e o t M 8 e e r t e a w R s e ltu r s e u r r s o h / p R x E ae r a s la n re a n c e s G r n o o e k t l a 5 e f p e r l e / c b e w a a f T a s t n in d n e e e d h m in e c e t d a u r a w h s z o z r s a p s e e o M e r M r c a e 's lt in t s a r s R o u n e s a r t e c u c r s s a n r a S o p t c 1 x n S u. E o s C 2 3 e 1 to N
- 0 1
s r i e a T r t u S g iF
I' I l Figure 11: Ground Floor & Wdis: Fixed a and R:mr.vable Csnt;mination Locations. 1 W*@* E i l f li D 3g I ~ j l I N)" d Contractors' offices, supplies & storage ares D ] Df 1 j I I e -+- (sR) (SR) Lg Jyj T r-H I T I r I I_ Main floor machine shop ^ p I I $I ) ) I E m l l l ^ azi H I I I H y / ll III Graphite (' Machine Dd 8 n c m ra o l l l l l (ce) Tool Crib E j, (SR) I I I I I Notes.
- 1. Fixed a and Removable Contamination results are provided in Table 5.
l
- 2. The squares with cross hatches provided are the approximate locations of fixed a measurements taken.
- 3. The numbers circled are approximate locations of wipes taken.
- 3. M concrete floor surfaces unless noted. (SR) = Sheetrock-Wall, (M) = Metal-Wall, (CB) = Concrete Block-Wall.
l
Figure 12: Ground Floor cnd Walls: Fixed p M;asur;m nt Locations. N W*@* E 0 ]O I l I D) Contractors' ofnces, supplies & storage ares D B[ _] ] ~ .+ (sn> ~ s ~ 7 H I L I I l m"fE E E. E E Main floor g i machine shop y H I I I L Ri "; y ath c45 ,y a w mm g W id G hite N 2 ~ D{. O N g a I \\ l l 9 ToolCrib a W B 2 k 9 Y"2 cs ~j l l l kl l / R2 Notes:
- 1. Fixed p measurement results are provided in Table 5.
- 2. The squares with cross hatches provided are the approximate locations of fixed p measurements taken.
- 3. All concrete floor surfaces unless noted. (SR) = Sheetrock Wall, (M) = Metal-Wall, (CB) = Concrete Block-Wall.
ill i J l A,, 3g E >hI NA 4W ]f 3[, n.e ka t s tne me ru s s a n e o m ]f S it wL lo 3 a d c e o ix f f t o n s e no m ita e c rus e t a a r e m M imxo u p r p 5 p m i }A le a d e b e r x a h T t m F j n e r a i a r d o e d o id e s l v d F o iv m r o u p r n d p e n r s u a e s h o j lt c r w t u a G j s h [ e f r s o t s n o y e rc a y m e h e m llw a e it c m w ru w a f i a l s r l H a a s u e e s H m a e r h u t t h p q e u t r d s c o u e e n S o i T C x h o S F s 3 e 2 3 1 t 1 oN e ]y r j u g iF .y v 1
c Appendix to i Final Radiological Survey Performed at General Atomics' Building 45 Unaffected and Non-Impacted Areas dated February 26,1999 " Final Radiological Survey Plan for Building 45" dated Augnot 21,1998
I I 3 + _ _ INTERNAL CORRESPONDENCE I From: L. Gonzales / J. Tumer In Reply Refer To: LQG:98:138 To: Distribution Date: August 24,1998
Subject:
Issuance of the Final Survey Plan for Building 45 I The Final Survey Plan for Building 45 has been completed. The Plan was reviewed and discussed with the following HP Technicians: Comelius Stanley and Barbara Lyons. I Ia cc: K. Asmussen I F. Dahms P. Maschka B. LaBonte I D. Keesting D. McKay C. Stanley B. Lyons B. Noren I I
- I I
g> t
7 Date: August 21,1998 Prepared by: John Turner 8f4'/96 nuza bhlha) Approved: Laura Gonzales Date v r y Final Radiological Survey Plan for Building 45 Purpose The purpose of this survey is to demonstrate that the radiological conditions in Building 45 satisfy the NRC and State of CA guidelines for release to unrestricted use, and to ensure that the radiological conditions are below the approved release criteria specified in GA's Site Decommissioning Plan. This final survey will encompass the internal surfaces of the building structure only.
Background
Building 45 is currently being used for non-radioactive work. Presently it is being used mainly as the site facility machine shop with supporting storage and office areas. It also contains office space for contractor usage and their collective storage areas (i.e., building and maintenance materials). It is occupied by personnel and equipment involved with these operations. In the past the building was used for various projects, but none of these projects were known to involve the usage of radioactive material. During the year of 1987 it was used for storage of a properly packaged (radioactive) fission chamber, but no residual radioactivity is expected to be encountered in this facility. The fission chamber was stored in the hallway as noted by the " hatched" area on the Figure that follows. ~ Classification of Building 45 (see Figure that follows ) " Unaffected Area"- The main floor area is an " unaffected arer.". Only a small portion of the main floor of Building 45 was used in the past to store radioactive material (i.e., a fission chamber), it was properly packaged and stored only after surveys were conducted to demonstrate that contamination levels on the container's exterior were below the release criteria. 'Iherefore, the first floor of the building is classified as i " unaffected"; no contamination is expected to be present. I "Non-impacted Area"- The basement shop, office mezzanine and north area (contractor's offices and supplies) have no known history of use with radioactive materials. Limited surveying will be performed in i these areas to check far contamination. J Descrintion (see Finure for details) Main Floor-Machine Shop Areas Basement - Machine Shop Area Main Floor, Mezzanine - Oflices { North Area, Floor Space and Mezzanine - Contractor's OfTices and Supplies IIallway - Storage of Fission Chamber l The total " unaffected" floor space is ~ 9860 ft' (~911 m 3. Presently, all of the floor spaces are somewhat restricted (imaecessible) due to the equipment contained in these areas by the ongoing enterprises. ) cumsvrxro l l l
4 August 21,1998 Page 2 of 5 n"---- f.1=t+= (ner GA site D=
===' '-- Pl== for Unam-t.: Areas) Facility Structure Criteria ne primary contaminant of concern for this site is enriched uranium. He applicable guidelines for residual contamination on building surfaces for enriched uranium are: Enriched Uranium 2 5,000 dpm ot/100cm2, total, averaged over a 1 m area 2 2 15,000 dpm cm/100cm, total, maximum in a 100 cm area 1,000 dpm ot/100cm, removable activity 2 In Building 45, the alpha surveys are sufficient to determine compliance with the release criteria, although some beta monitoring will also be performed. Alpha measurements are satisfactory for the following reasons: 1. In " highly" enriched uranium (uranium used in the fission chamber was typically ~ 90% enriched); alpha monitoring is the method of choice. At this enrichment, the U-234 activity present has increased significantly. The alpha to beta ratio is approximately 116:1.' Because of this, alpha monitoring is the measurement of choice for enriched uramum. 1 2. Alpha surveys are accurate if the surface is clean, free of paint or other coverings and free of dust and debris. All surfaces will be clean before scanning or fixed measurements are performed. ~ ) -3. It is GA's goal to decontaminate the building structure to levels < 2000 dpm ot/100cm. 2 Alnha Alert Levels If the following " alert levels" are exceeded, notify IIP Managet at so an evaluation can be performed to determine ifincreased survey coverage is required or to evaluate f decontamination is required. 2 > 200 cpm alpha using the large area (434 cm ) probe 2 > 130 cpm using a hand-held alpha probe (~ 1500 dpm/100cm ) Beta Alert Levels If the following " alert levels" are exceeded, notify HP Management so an evaluation can be performed to determine ifincreased survey coverage is required or to evaluate if decontamination is required. 2 > ~ 300 cpm beta above background using the large area (434 cm ) probe j 2 > ~ 200 cpm above backaronad using the 100 cm probe Exposure Rate Level The guideline value for exposure rates measured at I m above the surface is 10 pR/hr above background. ' From Table 5-4 of" Health Physics Manual of Good Practices for Uranium Facilities" Prepared for DOE by Idaho National Engineering Laboratory, document EGG-2530, UC-41, dated June 1988. ) suussur.WPD
August 21,1998 Page 3 of 5 Exposure Rate Alert Background is typically ~15 pR/hr (but may vary with type of facility & location). Alert Level is 20 pR/hr. l Docuanentation 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 read.ngs (if applicable) and any other pertinent information. l ) suussurxro
August 21,1998 Page 4 of 5 l Planned Final Surveys for Building 45 - August 21,1998 Surveys to be Performed in S s to dM Type of Survey Unaffected Areas in Non-Impacted Areas {. Masslin Surveys Yes Yes Concrete Floor '" 10% a,10% p G8 Spot check areas and l (scan w/ 434 cm' probe) Hallway (where fission chambers Record readings of a and were stored) p scans as follows: ") 20% a,20% office Mezzanine 6 each Basement Shop 6 cach Contractor 1st floor 10 each Contractor - Mezzanine 6 each Lower Walls Scan (bottom 2 m of 10% a,10% p None Required south hallway wall) 8 (Scan w/434 cm probes) Walls Scan (above 2 m) None Required None Required Number of Planned 30 Total as follows: Measurements ") id' Alpha fixed on Floor 8 (at least 1 in hallway) Nonc required unless Beta fixed on Floor 4 (at least I in hallway) elevated areas above the Alpha fixed on Walls 8 (at least 1 in hallway) background range are found ] Beta fixed on Walls 4 (at least i in hallway) by scanning. / Removable (wipe) 6 (at least I in hallway) pR/hr Readings I every - 3 m office Mezzanine 6 @ l m from surface Basement Shop 6 Contractor -1st floor 10 Contractor - Mezzanine 6 f Clean all surfaces to remove debris or dirt (wash, mop and/or vacuum, as needed). If contamination above background is detected on any of the floor surfaces, Ilealth Physics will evaluate the need for additional survey coverage. Survey coverage will be increased if contamination levels above 75% are detected (the Site Plan requires reclassification if levels >75% are detected). For the fixed measurements: For a measurements; use the hand held alpha counter (-5-10 second count). Document all readings in epm. For measurements; take a 1 minute count using the 100 cm gas flow proportional detector 2 (beta) with the Model 2221 ratemeter. Document all readings and mark on a drawing where the readings were taken. l Take fixed measurements on wall -1 meter from floor surface. Fixed measurements should be taken as evenly distributed in the room as possible (accessible locations). id) For removable measurements, take a 100 cm wipe at select locations; count using a low level al counter. 2 i BLD4.15UV.WPD ]'
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