ML20149G279

Decontamination of Selected Ga Science Labs for Release to Unrestricted Use (Group 9)

ML20149G279
Person / Time
Site:	07000734
Issue date:	07/16/1997
From:	Cowan S, Maschka P, Quintana L GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER
To:
Shared Package
ML20149G275	List: ML20149G272 ML20149G279
References
NUDOCS 9707230092
Download: ML20149G279 (43)

Text

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I DECONTAMINATION OF SELECTED GENERAL ATOMICS'

. SCIENCE LABORATORIES FOR RELEASE TO UNRESTRICTED USE

-(Group 9)

. -July.16,1997 Prepared By: Laura Quintana,' Paul Maschka and Scott Cowan lfl *$$$$ $$boh34 ff CENERAL ATORCICS C

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-l TABLE OF CONTENTS i

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LIST OF FIGURES

....I i

LIST OF TABLES.........................

........ ii INTRODUCTION.....

....... 1 i

' SITE DESCRIPTION..................

.1 i

CRITERIA FOR RELEASE TO UNRESTRICTED USE

.2 PREVIOUS ACTIVITIES (HISTORY OF USE).

....... 2 I N STR UM E NTATI ON........................

........... 3 BACKGROUND MEASUREMENTS

....... 4 SURVEYS PERFORMED......

........... 4 l

Removal of items and Equipment..

.. 4 i

L S urvey Plan...........................

.5

- Survey Plan - Detailed Locations of Fixed Measurements and Smears........... 7 RESULTS OF THE SURVEY MEASUREMENTS............

.......... 8 Scanning....................

.......8 Fixed M e as u rem e nts............................................ 8 Removable Contamination Surveys....................................... 8.

Paint Samples and Additional Fixed Measurements on the Walls............... 8 Exposure Rate Measurements..............................

......... 9 Additio n al S u rveys................................................ 9 CONCLUSION....................

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LIST OF FIGURES Page Figure 1:

View of Site...

......... 10 Figure 2:

Laboratory Building Complex. Building 2

. 11 3

Figure 3A: Group 9 labs in Section C of Building 2

..... 12 l'

Figure 3B: Group 9 labs in Section A of Building 2...........

. 13 l

Figure 4:

Final Removable Contamination Survey Locations in Lab 441....

.14 Figure 5:

Final Fixed Measurements in Lab 441...

... 15 Figure 6:

Paint Sample Locations on the Walls in Lab 441

... 16 Figure 7:

Final Removable Contamination Survey Locations in the Mezzanine Above l

Labs 439/441....

17 Figure 8:

Final Fixed Measurements in the Mezzanino Above Labs 439/441

..... 18 Figure 9:

Paint Sample Locations on the Walls in the Mezzanine Above Labs 439/441

.19 Figure 10: Final Removable Contamination Survey (Locations) in Combined Lab 511/513.20 Figure 11: Fixed Measurements in Combined Lab 511/513.............

. 21 i

Figure 12: Paint Sample Locations on the Walls of Combined lab 511/513..

....... 22 Figure 13: Final Removable Contamination Survey Locations in Lab 517............. 23 Figure 14: Final Fixed Measurements in Lab 517.....

.... 24 l

Figure 15: Final Removable Contamination Survey Locations in Lab 645.............. 25 i

Figure 16: Final Fixed Measurements in Lab 645...............

.... 26 Figure 17: Paint Sample Locations on Walls in Lab 645......................... 27 4

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s LIST OF TABLES Page Table 1:

USNRC's Acceptable Surface Contamination Levels..

................. 28 Table 2:

State of CA Acceptable Surface Contamination Levels...............

.29 Table 3:

List of instruments........................................... 30 Table 4:

Background Measurements....

............. 31

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Table 5:

Results of Radiation Scans and Fixed Measurements......

. 32

' Table 6:

Exposure Rate Measurements

. 34 Table 7:

Results of Removable Contamination Surveys....

..... 35

~ Table 8:

Paint Sample Results..........

....... 36 Table 9:

Fixed Measurements on Wall Surfaces Before and After Removal of Paint Sample.........

. 37 l

Table 10: Additional Surveys.........................

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I INTRODUCTION General Atomics (GA) is continuing its efforts directed at decontaminating and obtaining the release to unrestricted use of selected laboratories and associated offices in GA's Bui! ding 2 (also known as the Science Laboratories Building or "L" Building). The building was built in 1958 for purposes of conducting research and development activities. To date, eight (8) groups of labs in this build;ng have been decontaminated and released to unrestricted use.

GA has recently surveyed additionallaboratories in Building 2 designated as " Group 9". This report summarizes the surveys completed for the " Group 9' laboratories which consist of five (5) labs and one (1) mezzanine and occupy a total area of ~1968 ft GA has no plans for 2

conducting any future activities involving radioactive materials in these laboratories and/or mezzanines. (The offices across the hall from these laboratories have never been used for work involving radioactive materials). It is urgent that these labs and the mezzanine get released to unrestricted use as soon as possible. Radioactive material, including U-235 has been used in some of these labs in the past. Because of this, GA is requesting both the State of California and the Nuclear Regulatory Commission release these labs to unrestricted use.

Contamination was detected in only one lab (Lab 441) and the mezzanine above Labs 439/441.

A chemistry hood and the associated ducting and filter plenum were removed from Lab 441 and the mezzanine above Labs 439/441. Twelve (12) contaminated floor tiles were also removed from Lab 441 where the hood was located. Contamination was not detected in any other " Group 9" lab.

This report documents the results of extensive and comprehensive measurements completed in the " Group 9" laboratories to demonstrate that these laboratories, meet the approved criteria for release to unrestricted use. Accordingly, GA is requesting that these laboratories and their associated offices be released to unrestricted use.

SITE DESCRIPTIOE The location of Building 2 with respect to other facilities on the GA Site is shown in Figure 1. A layout of Building 2 is shown in Figure 2. The building is divided into three Laboratory sections; Sections B, C, and A. Laboratory Section B includes offices and laboratories from 102 through 243. Laboratory C includes offices and laboratories from 300 through 445 and Laboratory Section A includes offices and laboratories from 502 through 651. A total of 5 labs and one mezzaniae are to be released in " Group 9".

Lab 441, and the mezzanine above labs 439/441 are located in Laboratory Section C and are shown in Figure 3A. Labs 511/513 (combined 1

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labs), Lab 517 and Lab 645 are located in Section A and are shown in Figure 38.

j The total area to be released to unrestricted use in the " Group 9" labs is ~ 1968 ft 2 as follows:

Laboratory fL 2

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Lab 441 336 I

Mezzanine above Labs 439/441 448 Labs 511/513 558 Lab 517 288 Lab 645 333 Total 1968 CRITERIA FOR RELEASE TO UNRESTRICTED USE Table 1 is taken from U.S. NRC's criteria for releasing facilities and' equipment to unrestricted use. It has been incorporated into GA's SNM-696 license. The State of California's guidelines, "DHS Criteria for Release of Facilities and Equipment to Unrestricted Use," also known as "DECON-1", are summarized in Table 2.

GA has conducted extensive and comprehensive surveys and sampling to demonstrate that the levels of any residual contamination in the laboratories and mezzanines are below these guidelines.

PREVIOUS ACTIVITIES AND DECONTAMINATION REQUIRED GA's Work Authorization logs were searched in order to review the previous activities i

conducted in each lab and to identify the radionuclides of concern. Although an exhaustive l

t search of the records was not completed, enough information was obtained to demonstrate that '

detailed measurements in each lab were needed. The following is a brief summary of the activities performed in each lab and the radioactive material used.

Labs 511/513 - The only history of use involving radioactive materials in these laboratories was between 1991 - 1996 when the Health Physics laboratory occupied these labs. Only small quantities of radioactive materials were used in these labs, primarily in the form of sealed sources or radiation standards used to test and calibrate standard counting equipment such as low-level alpha / beta counting systems, gamma spectroscopy systems and a liquid scintillation counter. Samples containing small quantities of various radionuclides were counted. The lab was moved to Building 10 in November and December 1996. No radioactive contamination was detected in these labs.

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Lab 517 - A work authorization allowing the use of sealed sources for calibration purpose m existence between 4/78 and 2/81. No radioactive contamination was detecte Lab 441 and the Mezzanine Above Labs 439/441 - There is extensive history involving radioactive materials in this lab and the mezzanine above labs 439/441.

Work Authorizations issued beginning in 1965 (initially for the conduct of permeability tests) through 1986 allowed the storage and use of enriched uranium, depleted uranium, normal (cr natural) uranium and thorium in the form of oxides, carbides, coated particles and uncoated particles and fuel rods.

The work involved conducting various evaluation tests on these fuels such as particle and coating density measurements, radiography, and microscopic observation. Samples for irradiation capsules were handled and included the splitting, compositing, weighing and packaging of coated particles and weighing, dimensioning and observation of fuel rods.

' Microscopic observation of pyrophoric uranium containing resin kernels was also performed in this lab.' At various times, mixed fission products were also authorized to be possessed and used in the lab.

A hood in lab 441 and the associsted ducting and exhaust plenums containing pre-filters and HEPA filters in the mezzanine above the lab were removed along with twelve (12) contaminated i

floor tiles from the area around the hood. Gamma spectroscopy analyses of various samples showed the contamination to be primarily Cs-137. After vacuuming the area, a post-survey showed levels were below the release criteria.

Labs 645 - No record of radioactive materials being used in this lab could be found. This room has a concrete pit in the southeast corner that is approximately 2 feet by 3 feet by 10 feet deep There are a number of pipes that extend from the top of the pit to within about one foot from the bottom of the pit. We have no knowledge or record of the use of this pit or the piping for work involving radioactive materials. No contamination was detected in the pit or any other area within this lab.

INSTRUMENTATION Table 3 is a list of instruments used during the radiological surveys, The table includes: (1) a description of the instrument, (2) the model and serial numbers of the rate meters and detectors, (3) instrument ranges, (4) calibration due dates, (5) typical efficiencies, and (6) typical background count rates.

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BACKGROUND MEASUREMENTS Eight (8) different surfaces exist in the Group 9 laboratories. These surfaces are made of

-cement block, tile, plasterboard, wood, concrete, drywall, metal and/or metal grating. Building 13 was selected for conducting background measurements because there has never been radioactive material used in this building, the age of the building (building 2 was built in 1958 and building 13 was built in 1960), and because the various surfaces found in the Group 9 laboratories could also be found in building 13.

For background fixed measurements, shown in Table 4, the mean and standard deviation for each surface surveyed with the 100 cm' detector was calculated using equations 8-11 and 8-12 in draft NUREG/CR-5849 as shown below:

(8-11)

Average of 5 measurements (8-12)

E;'., 6-rf 83 Background measurements and minimum detectable activities (MDA's) for each type of surface j

and for various counting times are provided in Table 4. Minimum detectable activities (MDA's) for each type of surface, were calculated using equation (5-2) from draft NUREG/CR-5849 as shown below:

(5-2) 2.71 4.65 /B,xt 2

MDA=

(dpm/l00cm )

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txEx Where:

100 Ba = backgroundrate (cpm) t = count time (min)

E = effciency 2

A = area ofthe detector (cm )

EURVEYS PERFORMED Removal of items and Eauloment in each laboratory, all items and equipment were surveyed prior to removal. The only i

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contaminated equipment found was in lab 441 and the mezzanine above labs 439/441. A l

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contaminated hood and associated ducting and plenum was removed from lab 441 and the mezzanine above labs 439/441. In addition, twelve (12) contaminated floor tiles around the l.

chemistry hood in lab 441 were removed. Gamma spectroscopy analyses of various samples showed the contamination to be primarily Cs-137. All contaminated materials were disposed of l

as radioactive waste.

l The rest of the floor tiles in lab 441 were surveyed for both fixed and removable radioactive contamination and the results showed only natural background levels.

Floor tiles were also removed from the other " Group 9" laboratories and the concrete surfaces were then scanned and fixed measurements obtained in accordance with a Survey Plan.

l Survey Plan After all items and equipment were removed, a survey plan was developed based on the previous history of the lab, the radionuclides of concern, the various types of surfaces and the potential for contamination. The physical characteristics of the lab and mezzanine (ducts, painted surfaces, unpainted surfaces, overhead structures, etc.) were inspected in determining the number of locations and types of surveys to be performed.

Labs 441 and mezzanine 439/441 were categorized as "affected" areas because the history of use indicated that radioactive materials were used or could have been used in these labs. Labs 511/513 and lab 517 were categorized as " unaffected" because only trace quantities of radioactive materials were used in labs 511/513 and only sealed sources were used in lab 517.

In addition, no contamination of the labs was detected during the surveys. Lab 645 was categorized as an " unaffected" araa because a historical search of past records did not reveal work involving radioactive materials w is conducted in this lab. However, extensive final surveys were still performed in labs 511/513, lab 517 and lab 645.

Survey measurements for surface activity consisted of a combination of surface scans, direct measurements, and measurements of removable activity. The following survey plan summarizes the surveys performed.

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" Group 9" Survey Plan (March 18,1937)

Lab 441 Labs 511/513 Lab 517 Lab 645 Type of Survey Mezzanine 2

g 448 ft History of Use Extensive History of Use Extensive History of Use On!y samples Only sealed sources None involving Radioactive involving Radioactive containing trace were used in this tab.

Material Material quantities of radioactive materials.

Category Affected Area Affected Area Unaffected Area Unaffected Area Unaffected Area Floor 100% a scan Yes Yes Yes Yes Yes Floor 100% D scan Yes Yes Yes Yes Yes Lower Walls (bottom 2m)

Yes Yes Yes Yes Yes 100% S scan Upper Walls -10% p scar:

Yes Yes Yes Yes Yes

1. of Fixed Measurements 7

36 24 9

6 (see list)

(5 minutes each)

(5 minutes each)

(5 minutes each)

(5 minutes each)

(5 minutes each)

1. of Smears (see ust) 44 82 72 41 61

1. of Paint Samples 8

4 4

None (new or 4

1. 9-16

1. 17-20

1. 5-8 unpainted walls)

(#1-4)

1. of MicroR Readings 8

Entire Surface 16 8

8 Are there Floor Drains?

Yes No No No No Floor Surface Concrete Wood Concrete Concrete Concrete (Tile removed)

(Tile removed)

(Tile removed)

(Tile Removed)

(Tile removed)

Underground Pit in Comer of Room (-2* x 3' and 10' deep)

Total # of Measurements 51 118 96 50 67 (Fixed Measurements & smears)

Note:

Total area is 1968 ft2 6

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" Group 9" Survey Plan - Detailed Locations of Fixed Measurements and Smears Laboratory Fixed Measurements Smears Lab 441 Fixed Measurements (7)

Smears (44) j 5

Floor 16 Floors 1

Top of Drain 17 Walls 1

Service Core 4

Lights 6

l-beams 1

Exhaust Vent Mezzanine above Fixed Measurements (36)

Smears (82)

Labs 439/441 30 Floor 30 Floors 6

Metal plate 16 Blinds 1

10 l-Beams 8

Lights 6

Metal Plate 6

Walls i

4 Window ledge l

1 Exhaust vent 1

inlet vent Labs 511/513 Fixed Measurements (24)

Smears _ (72) 10 Floor 40 Floor 8

Lights 20 Walls (5/ wall) 1 Inside a large duct 3

Ducts 4

l-beams 4

Lights j

1 Service Core 5

l-beams Lab 517 Fixed Measurements (9)

Smears (41) 5 Floor 16 Floor 4

Walls (1/ wall) 21 Walls 4

l-beam Lab 645 Fixed Measurements (6)

Smears (61) 6 Floor 16 Floor 37 Walls 2

Railing 1

Old light 2

Upper l-Beams 2

Piping i

inside Drain Line in Service Core Note.

Fixed measurements were also obtained before and after paint samples from the wall

. were collected (see Table 9).

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RESULTS OF THE F NAL SURVEY MEASUREMENTS Scannina Scanning was performed in each lab using floor monitors having a 425 cm gas-flow 2

proportional detector. In all areas where there was floor tile, the tile was scanned over 100% of the surface. All radiation measurements of the tile were at or near background levels except for the twelve (12) contaminated tiles found in lab 441. These 12 tiles were removed and disposed of as contaminated waste. In each lab, the tile was removed from the floor.

The concrete floors and lower walls (lower 2 m) were scanned over 100% of the surface for both alpha and beta contamination. Upper walls (above 2 m) received about 10% coverage for I

both alpha and beta radiation. The results of the scans on the floors, upper walls and lower walls are provided in table 5. Readings were at or near background levels (see table 4 for background levels).

Fixed Measurements Fixed measurements were performed using a beta gas flow proportional counter having a 100 2

cm detector. The counting time for each fixed measurement was five (5) minutes. For fixed measurements, an appropriate background was determined for each type of surface and subtracted from the survey readings and the results converted to dpm/100 cm 2

The fixed measurements on the floor and other surfaces were taken in accordance with the survey plan and are provided in figure 5 for lab 441, figure 8 for the mezzanine above labs 439/441, figure i l for combined labs 511/513, figure 14 for lab 517, and figure 16 for lab 645.

All fixed measurement results are summarized in table 5. The results show that radiation levels were well below the release criteria and in all cases were below 1000 dpm/100cm,

2 Removable Contamination Surveys Removable contamination measurements (smears) were performed on all surfaces including the floors, walls, wall cabinets, and overhead structures including ducts, lights and I-beams in accordance with the survey plan. An area of ~ 100 cm 2 was wiped with a filter paper and counted in GA's Health Physics Laboratory using a low level alpha / beta gas flow proportional i

counting system.

The locations where smears were collected on the floors of the labs are shown in figure 4 for lab 441, figure 7 for mezzanine 439/441, figure 10 for combined labs 511/513, figure 13 for lab 517, and figure 15 for lab 645.

Smears were also collected on the ducts, vents, lights, I-beams, walls, and other structures in accordance with the survey plan. The results of all removable contamination surveys are provided in Table 7. All radiation levels were below the release criteria (the highest result was 43 dpm/100 cm a beta).

Paint Samo_ les and Additional Fixed Measurements on the Walls Many of the walls of the labs had painted surfaces, therefore, paint samples were collected at approximately 1 m up from the floor. The paint was collected in an area ~ 100 cm The 2

approximate locations where paint samples were collected are provided in figure 6 for lab 441, j

figure 9 for the mezzanine above labs 439/441, figure 12 for combined labs 511/513, and figure 17 for lab 645.

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l Paint samples were not collected from the walls of lab 517 because each wall had original or unpainted wall surfaces.

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' The paint samples were analyzed using a low-level alpha / beta gas flow proportional counting

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system.' The results, which are all below the release criteria, are provided in Table 8. All gross i

alpha results were <10 dpm/100 cm. The highest gross beta result was 32 dpm/100 cm 2

2 In each location where paint samples were collected, a five (5) minute fixed measurement was i

taken before and after removal of the paint. The results were converted to dpm/100 cm and 2

l are provided in Table 9. The results of the "before" measurements were all sMDA (for that -

l particular surface). The highest result of the "after" measurements was 202 dpm/100 cm 2 beta on a wall in lab 511/513.

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Exoosure Rate Measurements Direct radiation exposure rate measurements using a microR meter were taken in every lab at j

one meter above the floor surface at approximately evenly-spaced intervals throughout the lab.

The radiation levels were at or close to normal background radiation levels (see Table 6).

In addition, measurements were taken in the pit located in lab 645. Radiation levels ranged from 28-30 R/hr at various levels within the pit from the surface down to about 10 feet. For comparison, measurements were taken in an electrical pit located outside of Building 2 (the location is shown in Figure 3B). Radiation levels in this pit, also taken at various levels within the pit (from the surface dow1 to about 10 feet) ranged from 27-30 uR/hr demonstrating that levels in the pit inside lab 645 were at normal background levels. Exposure rate results are provided in Table 6.

Additional Surveys After all final surveys were completed, spot check " confirmatory" surveys were conducted by another Health Physics Technician (who was not responsible for conducting any of the finet surveys). These surveys included scans and spot checks of the floors and walls using a floor monitor, a microR meter and a geiger counter, in addition, smears were collected in biased areas (areas where the highest smear results were obtained during the final surveys) and debris samples on lab 441 were collected and analyzed by gamma spectroscopy. One debris sample showed very low levels of Cs-137 contamination in lab 441 but the levels, as determined.by both the direct (fixed measurements) and removable contamination surveys, were well below the release criteria.

The geiger counter readings, the exposure rate ( R measurements) and the removable contamination survey results collected from these additional surveys are provided in Table 10.

The results of the exposure rate surveys were also provided in Table 6. The results show levels below the release criteria.

_Q.QNCLUSION Final contamination and radiation surveys provided in this report for the labs and mezzanine designated as " Group 9" demonstrate that these laboratories meet the approved guidelines for l

release to unrestricted use.

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Fibure 3B: Group 9 labs in Section A of Building 2 9

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Figure 4: Final Removable Contamination Survey Locations in Lab 441 Hallway 4

~12' 11" a

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7 10 15

~24' 3

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-14'4" Service Core Values provided are the approximate locations where smears were taken on the floors. The number is smear identification number. 'See Table 7 for results.

Other Smear Locations:

l Smear locations #17-44 taken on walls, light fixtures,1-beams and the exhaust vent as

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described in the Survey Plan.

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l Figure 5: Final Fixed Measurements in Lab 441 Hallway

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Notes:

1. Fixed measurements values are provided in dpm/100 cm2.

2. Each measurement was 5 minutes.

3. Contamination was detected on 12 floor tiles which were disposed of as radioactive waste. All tiles were removed. Final measurements taken on concrete surface.

4. All scans and fixed measurement results are provided in Table 5.

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Figure 6: Paint Sample Locations in Lab 441 Hallway 4

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-14'4" i

Service Core i

l I

Paint Sample Locations and Identification Numbers tI.

Notes:

1.

Paint sample results are provided in Table 8.

2.

Fixed measurements on wall surfaces before and after removal of paint samples are provided in Table 9.

f6.vsd i

l 16

Figure 7:

Final Removable Contamination Survey Locations in the Mezzanine Above Labs 439/441 4

~28' 4

14' 57 62 Open to Lower Floor gl 58 61

$l 7'2" 59 60

-- N 4 Metal Plates 6:

15 16 25 26 5

~24' 6" 4

7 14 17 27 24 i

3 8

13 18 23 28 174" 2

9 12 19 22 29 t

1 10 11 20 21 30 v

v 4

-26'

?

Values provided are the approximate locations where smears were taken on the floors. The number is smear identification number. See Table 7 for results.

Other Smear Locations:

Smears #31-56 and 63-78 were taken on ventilation ducts, blinds, window ledges, lights, 1-beams, walls and metal plates as described in the Survey Plan.

rr.ve 17 l

l l-

Figure 8:

Final Fixed Measurements in the Mezzanine Above Labs 439/441 4

-28' 4

14'

^

^

<99

<99 P'"**"'

N Open Open Area

<99 Area 7,2" Metal Plates -

<99

<99

' 99 a

<109

<109

<109

<109

<109

<109

<109

<109

<109

<109

<109

<109

~24' 6"

<109

<109

<109

<109

<109

<109 1N Wood Floor j

<109

<109

<109

<109

<109

<109.

<109

<109

<109

<109

<109

<109 l

v u

4

-26' l

Notes:

i

1. Fixed measurements results are provided in dpm/100 cm2

2. Each measurement was 5 minutes long.

3. All scans and fixed measurement results are provided in Table 5.

i f8.vsd I

'18-ll'

m___.

Figure 9:

Paint Sample Locations on the Walls in the Mezzanine Above Labs $39/441 0

-28' 4

14' h

n u d

20 open

'2" open Open to Lower Floor area area N4 a

a 9

-24' 6" 17 18 17'4" Windows 4

-26' Paint Sample Locations and Identification Numbers Notes:

1. Paint sample results are provided in Table 8.

2. Fixed measurements on wall surfaces before and after removal of paint samples are i

provided in Table 9.

l.

f9 vsd 19 I

Figure 10:

Final Removable Contamination Survey (Locations) in Combined Labs 511/513 Service C

~22' 6" -

> N

+

1 2

3 4

5 6

7 8

9 10 11 12 13 14 15 16 17 18

-24' 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 c

36 37 38 39 40 v

~24' 7" Hallway Values provided are the approximate locations where smears were taken on the floors. The number is smear identification number. See Table 7 for results.

Other Smear Locations: Smears #40 - 72 were collected on the walls, duct, lights, and I-beams as described in the Survey Plan.

f10.vsd 20

i I

i l!'

l Figure 11: Fixed Measurements in Combined Labs 511/513 l

- Service Core

<135 (In Service Cora)

~22' 6" t

4

^

<99 On Large Duct l-be(

Lights l

5

<135 I

<135_

/

<135

/

o

<99 l-beam A

,gg

<99

/

<99 hs

<99

,gg

~24'

<135

<135

<135 i

.I

<135 j

<99

<99

<gg c99

<99

<135

<135

<135 i

u 4

-24'7a Hallway Notes:

1. Fixed measurements results are provided in dpm/100 cm2-N l~

2. Each measurement was 5 minutes long.

3. All scans and fixed measurement results are provided in Table 5.

f11.vsd i

21

s L

Figure 12: Paint Sample Locations in Labs 511/513

)

l Service Core

~22'6" N

a n

7 i

1

~24' e

6 8

i 5

l l

)

i U

1r

~24' 7" Hallway Paint Sample Locations and Identification Numbers Notes:

1.

Paint sample results are provided in Table 8.

2.

Fixed measurements on wall surfaces before and after removal of paint samples are provided in Table 9.

f12.vsd -

I 22

Figure 13: Final Removable Contamination Survey Locations in Lab 517

~10'11"

- Service Core a

'1 8

9 16 2

7 10 15

~24' 3

6 11 14-4 5

12 13-

.N v

Hallway c

~11' 7" Values provided are the approximate locations where smears were taken on the l -..

floors. The number is smear identification number. See Table 7 for results.

Other Smear Locations;

1. 17-41 taken on walls and I-beams as described in the Survey Plan.

4 f13.vsd 23

[

l j

l 1

1 i

Figure 14: Final Fixed Measurements in Lab 517 j

l.

l i

4

-10'11" j

Service Core

<123 on wall-

^

i

<207

<207 t'

<94 on wall 132 on wall 1

~24,

<207 l

i

)

l

<207

<207 N

154 on wall j

Hallway i

~11' 7a Notes.

i 2

1. Fixed measurements results are provided in dpm/100 cm

2. The underlined values are measurements taken on the wall ~1m up.

3. Each measurement was 5 minutes long.

4. All scans and fixed measurement results are provided in Table 5.

i f14.vsd 24

(s.

i l

Figure 15: Final Removable Contamination Survey Locations in Lab 645 l

Hallway 4

~12' 10" 1

dk 1

8

.9 16 2

7 10 15

~24' l

I 3

6 11 14 a

concrete 4-2' +

N f

Lined Pit 4

5 12 3'

ir 13 j

4

~14 3"

?

Service Core Values provided are the approximate locations where smears were taken on the floors. The number is smear identification i

number. See Table 7 for results.

Other Smear Locations:

1. 17-61 taken on walls, railing, light, upper I-beams, piping and inside drainline in the core as described in the Survey Plan.

I f15.vsd 25 l-

\\

I l

Figure 16: Final Fixed Measurements in Lab 645 Hallway l-1

~12' 10" 26

<135

<135 l

i

~24'

<135

<135 i

JL 1

+ 2' +

N

<135 t

Pit 3'

<135 I

+

u Service Core Metal Grate

~14' 3" l

Notes:

1. Fixed measurements results are provided in dpm/100 cm2

2. The underlined values are measurements taken on the wall ~1m up.

i

3. ' Each measurement was 5 minutes long.

4. All scans and fixed measurement results are provided in Table 5.

f16.vsd 26

1 l

l Figure 17: Paint Sample Locations in Lab 645

)

1 Hallway -

~12' 10" JL 26 l

1 1

~24' 4

-2 h

+ 2' +

3 N

3 ir 1P i

9F

~14'3" Service Core l

4 PaintSample Locations and Identification Numbers l..

Notes:

1.

Paint sample results are provided in Table 8.

c 2c Fixed measurements on wall surfaces before and after removal of paint j

samples are provided in Table 9.

l f17.vsd 27 l

\\

f l

Table 1: USNRC'S ACCEPTABLE SURFACE CONTAMINATION LEVELS '

i l

Nuclides*

Average *^'

Maximum **'

Removable"^'

8 2

2 (dpm/100cm )

(dpm/100cm )

(dpm/100cm >

j U-nat,23sU,23aU, & associated decay products 5,000 a 15,000 a 1,000 a Transuranics, 22 era, 22sRa, 234h, 2"Th, 2 'Pa, 100 300 20 22rAc,12sj,in; Th-nat, 232Th, "Sr, 223Ra, 22*Ra, 2 2U,12sg, 533;, i3'l 1,000 3,000 200 Beta / gamma emitters (nuclides with decay l

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.

l 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.

)

I c Measurements of average contaminant should not be averaged over more than 1 square meter. For objects of less surface area, the average should be derived for each such object.

8 d The maximum contamination level applies to an area of not more than 100 cm.

8 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 instrument of known efficiency. When removable contamination on objects of less surface area is determined, then pertinent levels should be reduced proportionally and the entire surface should be wiped.

f The average and maximum radiatiorilevels 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.

Guidelines For Decontamination of Facilities and Equipment Prior to Release for Unrestricted Use or Termination of Licenses For byproduct, Source, or Special Nuclear Material, USNRC, July 1982, incorporated into GA's SNM 696 license.

i l

l 28

Tcbis 2: STATE OF CA ACCEPTABLE SURFACE CONTAMINATION LEVELS Nuclides*

Average Maximum *

Removable *>

w 6

2 2

2 (dpm/100cm )

(dpm/100cm )

(dpm/100cm >

U-nat,235U,2sau, & associated decay.

5,000 15,000 1,000 products Transuranics,22 era,22sRa,8 Th, 22eTh, 100 300 20 rs'Pa. 227Ac.12si, tasi Th-nat, as2Th, "Sr, 222Ra, 22'Ra, 232U, imel, 1,000 3,000 200 usi, tati 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, 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 1 square meter. For objects of less 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.

8 8

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 instrument cf known efficiency. When removable contamination on objects of less 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 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-1 Guidelines For Decontamination of Facilities and Equipment Prior to Release for Unrestricted Use or Termination of l

Licenses For byproduct, Source, or Special Nuclear Material, also known as "Decon-1" incorporated into GA's State of CA I

Radioactive Materials License.

l E

29 l-I I

TABLE 3: LIST OF INSTRUMENTS o

RATEMETER DETECTOR

~ RANGE (CPM)

CALIBRATION EFFICIENCY BACKGROUND DESCRIPTION DUE DATE (cpm) 8 Active Probe Area = 434cm. The detector and ratemeter are Ludlum Model 43-37 gas Four Linear Ranges 7-9-97 a = 20.15%

Varies according Model 2221 proportional (434 crn )

0 - 500,000 & One Th-230 to surface being combined and mounted on a ron around cart. The instrument features a S/N 97287 A!pha detector Log 50 - 500,000 scanned.

static-flow system, quick connects, a portable gas bottle and a means to S/N 086238 See Table 4 adjust the height of the detector from the floor for optimum performance..

2 Lud!um Ludium Model 43-37 Four Linear Ranges 7-9-97 0 = 21.0%

Varies according Active Probe Area = 434cm. The detector and ratemeter are combined Model 2221 gas proportional (434 0 - 500,000 & One Sr-90 to surface being and mounted on a roll around cart The instrument features a static-flow S/N 73701 cm ) Beta detector Log 50 - 500,000 scanned.

system, quick connects, a portable gas bottle and a means to adjust the r

S/N 083265 See Table 4 height of the detector from the floor for optimum performance.

Luctum Ludium ModeT43-68 Fourlinear ranges 9-1-97 0 = 34.98%

Varies according 100 cm' gas flow proportional counter.

Model 2221 100 cm' proportonal 0 - 500,000 & one Sr-90 to surface being S/N 8.8423 counter S/N 119444 tog 50 - 500,000 scanned.

See Table 4 Ludlum Ludium Model 43-65 Four Ranges 8-28-97 21.22 %

0 Active Probe Area = 50 cm2 Model 12 Alpha Scintillator 0 - 500,000 Th-230 S/N 91051 ZnS(Ag) S/N 94053 Ludlum Ludlum Model 44-9 Four Ranges 6-11-97 27.38 %

0-120 Active Probe Area = 15 cm2 Model 14A beta / gamma prote 0 - 500,000 S/N 83842 S/N 290314 Ludlum Ludium Model 44-9 Four Ranges 9-27-97 22.24 %

0-120 Active Probe Area = 15 cmr Model 3 betalgamma probe 0 - 500,000 S/N 60851 S/N 60851 Ludlum Model RCA 6199 coupled to Five Ranges 1 inch x 1 inch Nal (TI) scintittator is mounted intema!!y 19 MKnR Meter a Nat (TI) Scintillator 0 - 5 mR/hr S/N 87120 9-24-97 N/A 10-18 pR/hr S/N 101758 7-28-97 15-20 pR/hr Canberra Gas Flow N/A Count smears 26-30 %

a < 0.5 Low Levet al D gas proportional counting system Low Level Proportional for removable p<2.0 al p Counter Detector alp surface Model 24G4 contamination 30

.A

.4---

• a, A-.

4.-La

&-a,-Au-&

. - - =.

h

• -#--+

Jls--a b

4.

_=J-#

n

=

TABLE 4: B*_ckgrcund Mmur:msnts 100 cm beta detector (5 Minute Counts) 2 Background Material Average of 5 measurements MDA (dpm/100 cm )

2 (5 minutes each) total counts i 2 SD Drywall 1184 14 94 Plasterboard 1299 32 99 Wood 1597i46 109 Concrete Block wall 2030194 123 Linoleum over Concrete 1969i 24 117 Concrete 2435i152 135 Metal 1313ie 99 Grating ")

1212107 198 100 cm2 beta detector (2 N5knute Counts)

Background Material Average of 5 measurements MDA (dpm/100 cm )

2 (2 minutes each) total counts i 2 SD Drywall 541128 161 Plasterboard 516i42 157 Wood 621148 172 Concrete Block wall 820i76 197 Linoleum over Concrete 804e30 195 Concrete 912 i 18 207 Metal 600 167 170 Grating ")

473 1 50 198 Floor Monitor Background Scan Results Alpha Scan Range Beta / gamma Scan Range Surface (counts per minute)

(counts per minute)

Drywall 0-15 841-1187 Plasterboard 0-17 951-1173 Wood 0-15 862-1081 Concrete block wall 0-20 1321-1560 Linoleum over concrete 0 -17 947-1393 "I Average of 10 measurements.

31

Table 5: Results of Radiation Scans and Fixed Measurements Fixed Measurements (100 cm' beta dettctor)

F rmo to Figure Range of Total

Background

Type of' Surface g

Muimum Alpha Beta

1. of ead T'

e Max mum ctiv ty Activity MDA cpm cpra Measurements (minutes)

(counts / time indicated) indicated)

I Lab 441 Floor, tile (100%)

0-18 645-923 Floor, concrete (100%)

5 0-20 753-1114 5

5 1587-1649 2435 1152

<135 135 Walls (100% 2m up) 0-20 463-836 Walls (10% above 2m) 0-20 463-836 On top of drain (drain is 5

1 5

1169 1313

• 4

<99 99 above ground), metal Service Core behind lab, 5

0-16 637-758 1

5 1169 1212i97

<198 198 Metal grating Mezzanine above Lab 439/441 Floor, wood (100%)

8 0-17 503-723 30 5

865-996 1597 i 46

<109 109 Metal plate 8

6 5

729-781 131314

<99 99 Walls (100% 2m up) 0-24 452-1042 Walls (10% above 2m) 0-24 452-1042 Service Core, metal grating 0-16 503-723 Labs 5111513 Floor, tile (100%)

0-21 735-973 Floor, Concrete (100%)

11 0-28 883-1264 10 5

1919-7036 2435 i152

<135 135 Walls (100% 2m up) 0-25 515-1257 Walls (10% above 2m) 0-25 515-1257 32

Tcbla 5: R: cults of Rrdi: tion Sc n cnd Fix:d Menur:m3nts Fixed Measurements (100 cm' beta detector) p Figure Range of Total

Background

Type of' Surface Count Beta Activity or Maximum g

Alpha Beta

1. Of Readings Time Maximum Activity Activity MDA cEm cpm Measurements (counts / time (minutes)

(counts! time (dpml100cm')

indicated) indicated)

Inside Large Duct, metal 1

5 1028 131314

<99 99 Lights 8

5 903-993 1313 i4

<99 99 l-beams 4

5 960-1008 1313 i4

<99 99 Service core, concrete 11 0-25 1262-1487 1

5 2075 2435i152

<135 135 Lab 517 Floor, concrete (100% scan) 14 0-18 953-1135 5

5 1534-1693 2435 i152

<135 135 Walls (100% 2m up) 0-24 638-1451 Walls (10% above 2m) 0-24 638-1451 N wall, drywall 14 0-20 638-853 1

5 1275 1184 i14

<94 94 S wall, concrete t, lock 14 0-22 1123-1451 1

5 2257 2030 i 94 130 123 E wall, drywall 14 0-17 511-874 1

5 1454 1184 i14 154 94 W wall, concrete block 14 0-24 1115-1432 1

5 2161 2030 t94

<123 123 Service Core, concrete 14 0-26 1140-1500 Lab 645 Floor, tile (100%)

0-19 777-945

" te 0-23 973-1189 6

5 1936-2002 2435i152

<135 135 Re e seoe Walls (100% 2m up) 0-24 635-1158 Waits (10% above 2m) 0-24 635-1158 Service Core, metal grating 0-18 623-781 33

TABLE 6: EXPOSURE RATE MEASUREMENTS Grolup 9 Measurements l

Location /

Number of Range of Exposure Rates Type of Surface Measurements at 1 Meter (pR/hr)

Lab 441 8

10-11 Mezzanine Above Labs 439/441 Entire Floor Surface 5-6 Labs 511/513 16 13-14 Lab 517 8

13-16 Lab 645 8

13-15 La' 645 Scan 16-18 a

Lab 645 4

28-30 Pit in SE corner-2' x 3' x 10' deep (From top to bottom of pit)

Background Measurements Location /

Number of Range of Exposure Rates Type of Surface Measurements at 1 Meter (pR/hr)

Breezeway r sidewalk outside 5

11 - 14 building t'

..; 534 Outsi+

ding 13 (near 1

20-21 conc '

ors and concrete bloc.4 alls) l Outside Building 13 (near 5

14-19 stairwells)

Electrical Pit Outside Building 2 4

27-30 (See Figure 3B for Location) l 4

A 34

....o.

Table 7: Results of Removable Contamination Surveys i

Removable Activity Measurements Number of n ur.

Smears on each Laboratory Maximum Activity i

o Total Number (dpm/100 cm2)

Surface of smears Alpha Beta Lab 441 16 Floors 17 Walls 4

Light fixtures (2/ room) 4 44

<10

<10 6

tveams 1

Exhaust Vent Mezzanine Above Labs 439/441 30 Floor 6

Metal plate 6

Walls 8

Lights 10 l-Beams 7

82

<10

<10 16 Blinds 4

Ledge (under blinds) 1 Exhaust Vent 1

Inlet Vent M'

Labs 511/513 40 Floor 20 Walls (5/ wall) 3 Ducts 10 72

<10

<10 1

4 Lights 5

l-beams Lab 517 16 Floor 21 Walls 13 41

<10

<10 4

l-Beam Lab 645 16 Floor 37 Walls 2

Railing i

Old Light 15 61

<10

<20 2

Upper I-Beam 2

Piping i

1 Inside Drain Line in i

Service Core l

l

(

l 35

- _. =

l l

TABLE 8: Paint Sample Results l

Sample location Figure Sample ID Alpha (maximum)

Beta (maximum)

No.

dpm/100 cm2 dpm/100 cm' I

Lab 441 6

1. 9-16

<10 27 1

Mezzanine Above Labs 9

1. 17-20

<10 32 439/441 Labs 511/513 12

1. 5-8

<10

<10 i

Lab 517 No Paint Samples Collected (1 wall is new and the other 3 walls have no paint)

Lab 645 17

1. 14

<10 13 1

l l

l 36

Table 9: Fixed Measurements on Wall Surfaces Before and After Removal of Paint Sample Before Paint Sample Removal After Paint Sample Removal

Background

Typ,gg MDA Location.

Reading 5 minute 5 minute Sudace (dpm/100 cm')

(counts /5 minutes) reading (dpm/100 cm')

reading (dpm/100 cm')

Lab 517 Lab 517 No paint samples taken or wall measurements (1 wall is new and the other 3 have no paint on them)

Lab 645 Lab 645 #1 drywall 1184114 1127

<94 1197

<94 94 Lab 645 #2 plasterboard 1299i32 1286

<99 1332

<99 99 Lab 645 #3 concrete block 2030194 1739

<123 2120

<123 123 Lab 645 #4 plasterboard 1299132 1214

<99 1373

<99 99 6

38

.~

i s...

TABLE 10: Additional Surveys Geiger Removable Contamination Surveys Counter Exposure Laboratory Readings Rates Maximum Activity (cpm)

(pR/hr)

Surface No. of (dpm/100cm2)

Smears Alpha Beta Lab 441 100 -120 15-20 5 - Floor 2 - Wall 2 - Ceiling 14

<10

<10 4 - l-Beam 1 - Drain Mezz.

100 -120 15-20 5 - Floor 439/441 1 - Wall 7 - l-Beam 20

<10

<15 4 - Light Fixture i

2 - Vent 1 - Blinds Lab 511/513 100 -120 15 -26 3 - Door 7 - Floor 3 - Walls 20 64 23 5 - Pipes 1 - Hanger 1 - I-Beam Lab 517 100-120 15-28 1 - Door 5 - Floor 2 - Walls 9

<10

<10 1 - Pipe Lab 645 80-120 16 -20 4 - Floor 1 - Wall 5 - Light Fixtures 2 - Electric Boxes 19

<15 43 5 - l-Beams 2 - Pipes Lab 645 Pit 100-140 28 - 30 9 - Walls 9

<15

<15 (upper edge and

~2' below the edge of pit)

Additional Surveys in Lab 645 -- The floor was scanned using the floor monitor and the readings were found to range between 1140,1312 cpm (within background levels as shown in Table 3).

39