ML003727271

Request to Release Certain Portions of General Atomics Facilities to Unrestricted Use and Delete Them from License (Building 2 Laboratories - Group 12) and Radioactive Materials License No.0145-37: Request to Release Certain Portions to Unr

ML003727271
Person / Time
Site:	07000734
Issue date:	06/16/2000
From:	Asmussen K General Atomics
To:	Adams M, Wesley D NRC/NMSS/FCSS, State of CA, Dept of Health Services
References
-RFPFR, 696/CAL-3248
Download: ML003727271 (77)

Text

+ GENERAL ATOMICS June 16, 2000 696/CAL-3248 VIA EXPRESS MAIL SERVICE Ms. Mary Adams Licensing Section 1/Licensing Branch Division of Fuel Cycle Safety and Safeguards, NMSS U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Docket No.70-734; SNM-696: Request to Release Certain Portions of General Atomics' Facilities to Unrestricted Use and Delete them from License (Building 2 laboratories - Group 12) and ATTN: Mr. David Wesley (in Duplicate)

State of California Department of Health Services Radiologic Health Branch Mail Stop 178 601 North 7th Street Sacramento, CA 95814-0208

Subject:

Radioactive Materials License No. 0145-37: Request to Release Certain Portions of General Atomics' Facilities to Unrestricted Use and Delete them from License (Building 2 laboratories - Group 12)

Dear Ms. Adams and Mr. Wesley:

As you are aware, General Atomics (GA) is in the process of decontaminating, and obtaining the release to unrestricted use, certain of its facilities (i.e., facilities for which GA has no plans for conducting future activities involving the use of radioactive materials). For example, to date, eleven (11) groups of laboratories in GA's Building 2 (also known as the Science Laboratories Building or "L" Building) have been decontaminated, surveyed and released to unrestricted use and deleted from GA's license.

Most recently, GA completed the decontamination and final surveys of four (4) more laboratories in Building 2. The four laboratories (labs 401, 403, 405, and 407) have a total area of -1,365 ft2 or -127 M2. During initial surveys, Cs-137, thorium, and enriched uranium contamination was detected in the floors and on the lower walls of these laboratories. The results of GA's extensive and comprehensive final radiation and contamination surveys, sampling and analyses (performed after decontamination) demonstrate conclusively that the "Group 12" laboratories meet the NRC-and State-approved criteria for release to unrestricted use. These results are summarized in the enclosed report titled, "Decontamination of Selected General Atomics' Science Laboratories for Release to Unrestricted Use - Group 12" dated June 2000.

3550 GENERAL ATOMICS COURT, SAN DIEGO, CA 92121-1194 PO BOX 85608, SAN DIEGO, CA 92186-5608 (619) 455-3000 C)e-

U.S. NRC & State of California June 16, 2000 696/CAL-3248 Page 2 Accordingly, GA hereby requests that its "Group 12" laboratories and associated offices be released to unrestricted use and deleted from its NRC and State material licenses. Because of the history of use of enriched uranium in these labs, it is GA's understanding that the NRC has agreed to take the lead in coordinating their release.

Please note that GA has an immediate need to occupy the subject laboratories and associated offices. It is therefore of the utmost importance to GA to obtain the release of these laboratories to unrestricted use as soon as possible.

If you should have any questions regarding this information, please contact Mr. Paul R.

Maschka at (858) 455-2959, Laura Q. Gonzales at (858) 455-2758, or me at (858) 455-2823.

Your assistance in responding to our request is very much appreciated.

Very truly yours, Keith E. Asmussen, Ph.D., Director Licensing, Safety and Nuclear Compliance

Enclosure:

Report titled "Decontamination of Selected General Atomics' Science Laboratories for Release to Unrestricted Use - Group 12" dated June 2000.

cc:

Mr. Wayne L. Britz, Fuel Cycle Inspector, NRC Region IV Ms. Kathleen Henner, State, Brea, CA Dr. Ron Rogus, State, Sacramento, CA

Building 2 Group 12

+ GENERAL ATOMICS FINAL RADIOLOGICAL SURVEYS OF SELECTED BUILDING 2 LABORATORIES FOR RELEASE TO UNRESTRICTED USE "GROUP 12" Prepared by: Paul R. Maschka, Richard Stowell, Cornelius Stanley, Steve Finchum, Joseph Sullivan, Barbara Hunter, Laura Gonzales, and Michael Dupray June 2000 C ENERAL A70MICS

A7,EOMI Building 2 Group 12 TABLE OF CONTENTS Page LIST OF TA BLES..............................................................

iii LIST O F FIGURE S.............................................................

iii INTRODUCTION 1

SITE DESCRIPTION 1

PREVIOUS ACTIVITIES (HISTORY OF USE) AND CLASSIFICATION..................

2 CRITERIA FOR RELEASE TO UNRESTRICTED USE.................................

2 INSTRUM ENTATION............................................................

4 BACKGROUND MEASUREMENTS................................................

4 SURVEY PLAN S................................................................

5 RESULTS OF THE INITIAL SURVEYS.............................................

5 Scanning.................................................................

5 Scan of T ile...............................................................

5 Initial Survey..............................................................

5 DECONTAM INATION...........................................................

6 FINAL SURVEY S................................................................

6 Objectives and Responsibilities................................................

6 Final Survey Plans..........................................................

6 G ridding..................................................................

7 D ocum entation............................................................

7 Comparisons with Site Decommissioning Plan...................................

7 RESULTS OF THE FINAL SURVEYS...............................................

8 Final Survey Scans.........................................................

8 Fixed M easurem ents........................................................

8 Removable Contamination Surveys..............................

I.............

9 Exposure Rate M easurements.................................................

9 INTERNAL CONFIRMATORY SURVEY...........................................

10 CON CLU SION.................................................................

10 T A B L E S......................................................................

11 FIG U R E S......................................................................

22 APPENDIX A: Final Survey Plan.................................................

A-1 APPENDIX B: Results of GA's Internal Confirmatory Surveys B-1 ii

CMATUMIC Building 2 Group 12 LIST OF TABLES Page Table 1:

USNRC's Acceptable Surface Contamination Levels 12 Table 2:

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

13 Table 3:

List of Instrum ents..................................................

14 Table 4.

Background Measurements and MDA'S.................................

16 Table 5:

Results of Final Surveys in Building 2 Group 12...........................

18 Table 6:

Soil Sam ple Results.................................................

20 Table 7:

Background Soil Sample Results........................................

21 LIST OF FIGURES (Unpaged)

Figure 1:

General Atomics Main Site and Sorrento Valley Site Figure 2:

Building 2 Laboratory Figure 3:

Building 2 Group 12 Laboratories Figure 4:

Lab 401 - Alpha Scans of Lower Wall and Floor Figure 5:

Lab 401 - Beta Scans of Lower Wall and Floor Figure 6:

Lab 401 - Locations and Results of Fixed Alpha Measurements Figure 7:

Lab 401 - Locations and Results of Fixed Beta Measurements Figure 8:

Lab 401 - Locations of Removable Contamination Survey Figure 9:

Lab 401 - Locations and Results of Exposure Rate Measurements Figure 10: Lab 403 - Alpha Floor Scans and Locations of Soil Samples Taken Figure 11: Lab 403 - Beta Floor and Walls Scans Figure 12: Lab 403 - Locations and Results of Fixed Alpha Measurements Figure 13: Lab 403 - Locations and Results of Fixed Beta Measurements Figure 14: Lab 403 - Locations of Removable Contamination Survey Figure 15: Lab 403 - Locations and Results of Exposure Rate Measurements Figure 16: Lab 405 - Alpha Floor Scans Figure 17: Lab 405 - Beta Floor and Walls Scans Figure 18: Lab 405 - Locations and Results of Fixed Alpha Measurements Figure 19:

Lab 405 - Locations and Results of Fixed Beta Measurements Figure 20: Lab 405 - Locations of Removable Contamination Survey Figure 21: Lab 405 - Locations and Results of Exposure Rate Measurements Figure 22: Lab 407 - Alpha Floor Scans and Soil Sample Locations Figure 23: Lab 407 - Beta Floor and Walls Scans Figure 24: Lab 407 - Locations and Results of Fixed Alpha Measurements Figure 25: Lab 407 - Locations and Results of Fixed Beta Measurements Figure 26: Lab 407 - Locations of Removable Contamination Survey Figure 27:

Lab 407 - Locations and Results of Exposure Rate Measurements Figure 28: Labs 401, 403, 405, and 407 - Vent Ducts IIi

A+OMWS Building 2 Group 12 INTRODUCTION General Atomics (GA) is continuing its efforts directed at decontaminating, as appropriate, and obtaining the release to unrestricted use of selected laboratories and associated offices in GA's Building 2. The building was built in 1958 for purposes of conducting research and development activities. To date, eleven (11) groups of labs in this building have been decontaminated and released to unrestricted use.

GA has recently surveyed additional laboratories in Building 2 designated as "Group 12". This report summarizes the surveys completed for the "Group 12" laboratories which consist of four (4) labs having a total area of 1,365 ft2 or -127 M2. The four labs are labs 401, 403, 405, and 407. Cs-137, thorium, and enriched uranium were detected in all the labs, on the floor and on several walls.

The partition walls between labs 401 and 403 and between 403 and 405 were removed. The contaminated sections of the walls were removed and disposed of as radioactive waste. The sections that met the approved release criteria were disposed of as clean waste. The remaining walls and the floors were decontaminated as required. Post-decontamination surveys demonstrated that the areas had been cleaned to the approved release criteria. A Final Survey was completed in the labs after decontamination.

GA has no plans for conducting any future activities involving radioactive materials in these laboratories. (The offices across the hall from these laboratories have never been used for work involving radioactive materials). This report documents the results of extensive and comprehensive measurements completed in Building 2 "Group 12" 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 DESCRIPTION GA's Main Site and Sorrento Valley Site are shown in Figure 1. A layout of Building 2 (on GA's Main Site) and the "Group 12" laboratories are shown in Figures 2 and 3, respectively. The total area to be released to unrestricted use is 1,365 ft2 as follows:

Totals 1

-1,365 1

-127 I

"Group 12" Labs Lab ft2 m2 401

-249

-23 403

-409

-38 405

-367

-34 407

-340

-32

G ENERAL.

A70OWiS Buildina 2 GrouD 12 PREVIOUS ACTIVITIES (HISTORY OF USE) AND CLASSIFICATION GA's Work Authorization logs were researched in order to review the previous activities conducted in each lab and to identify the radionuclides of concern. All four labs had a fairly extensive history of use of radioactive materials. The following is a brief summary of the activities performed in each lab and the classification of each lab based on its history.

LABS History Summara of Group 12 Labs 401,403, and Projects Performed: Radio-chemistry Laboratories from 1974 through 1989.

405 Uranium, thorium, and depleted uranium were authorized to be used in these labs.

Chemical and Spectro-Graphic analyses were performed on various types of nuclear fuels.

The labs were also used in the manufacture of fuel for thermionics for the DOE in the 1980's. The fuel used -20% enriched uranium.

407 Projects Performed: From 1974 through 1982, Uranium, thorium, natural and depleted uranium as well as mixed fission and mixed activation were authorized to be used in these labs. Chemical and Spectro-Graphic analyses were performed on various types of nuclear fuels. Dissolution and radio-chemistry was performed on samples. Performed chemical and instrument analysis The lab was also used in the manufacture of thermionics fuel for the DOE in the 1980's. The fuel used -20%

enriched uranium.

Based on this, the labs were initially classified as:

401 = Suspect Affected Area 403 = Non-Suspect Affected Area 405 = Non-Suspect Affected Area 407 = Non-Suspect Affected Area Initial surveys revealed radioactive contamination to some degree in each lab. Therefore, the classification of each lab was changed to Suspect Affected Areas.

CRITERIA FOR RELEASE TO UNRESTRICTED USE Facilities and Equipment U.S. NRC's and State of California's criteria for releasing facilities and equipment to unrestricted use are shown in Tables 1 and 2, respectively. Based on the previous history of use in these labs, the primary contaminants of concern are Cs-137, uranium (high enriched uranium, low enriched uranium, and depleted uranium) and thorium. The applicable NRC guidelines for residual surface activity levels for uranium and thorium are:

2

GLENERL

+ATOMICS Building 2 Group 12 Uranium and Gamma/Beta Emitters (i.e.. Cs-137) 5,000 dpm a/ I00cm2, averaged over a 1 m2 area 15,000 dpm a/100cm2, maximum in a 100 cm2 area if the average over I m2 is met.

1,000 dpm l/l100cm 2, removable activity Thorium 1,000 dpm/1OOcm 2, averaged over a 1 m2 area 3,000 dpm/1OOcm 2, maximum in a 100 cm 2 area if the average over 1 m2 is met 200 dpm/1 00cm 2, removable activity As interpreted by the NRC, the average 1,000 dpm/1 00cm 2 and the maximum 3,000 dpm/1 00cm 2 should apply to both alpha and beta measurements, independently, for surface contamination involving natural thorium. ("Interpretation of Thorium Surface Decontamination Limits," U.S.

Nuclear Regulatory Commission, February 9, 1992). Thorium emits alpha radiation and beta radiation in a 1:0.67 ratio; therefore, if beta radiation measurements are used to demonstrate compliance with the release criteria, the corresponding average and maximum beta activity guidelines are 670 dpm/100cm2 and 2000 dpm/100cm2, respectively.

Exposure Rate Guideline The guideline value for exposure rates measured at 1 m above the surface, is 10 htR/hr above background levels.

Soil (bulk material) release Criteria The soil release criteria, which also apply to concrete rubble, asphalt rubble and gravel, are provided below. The release criteria (which are concentrations above background levels) for radionuclides used in Building 39 are as follows:

Thorium (Th-228 and Th-232) 10 pCi/g Enriched Uranium (U-234 and U-235) 30 pCi/g Depleted Uranium 35 pCi/g If more than one radionuclide is detected, the sum of the fractions of the concentrations, calculated as follows, must be less than or equal to one (1):

=1 Li Where:

Ci

=

The average soil concentration of radionuclide i Li=

The maximum soil limit for i (pCi/g).

3

4 MCSE Building 2 Group 12 INSTRUMENTATION Table 3 lists the instruments used during the radiological surveys. The table includes: (1) a description of the instrument, the model and serial numbers, (2) a description of the detector (If applicable) and its serial number, (3) instrument ranges, (4) calibration due dates and efficiencies and (5) typical background count rates. All instruments used were calibrated semiannually and after repair except for exposure rate meters which were calibrated quarterly.

BACKGROUND MEASUREMENTS Instrument Background Measurements Building 13 on GA's main site was used for conducting background measurements on most instruments used for the final survey because: (1) there is no history involving use or storage of radioactive materials in Building 13, (2) the various surfaces found in Building 2, Group 12 labs could also be found in Building 13, and (3) the age of the building approximates the age of Building

2.

Background measurements are provided in Table 3 and Table 4. The mean and standard deviation for each surface surveyed with the 100 cm 2 beta detector, 50 cm 2 alpha detector and/or 15 cm 2 geiger counter were calculated using equations 8-11 and 8-12 from NUREG/CR-5 849 as shown below:

Equation (8-11):

n Equation (8-12):

n-1 Background measurements and minimum detectable activities (MDA's) for each type of surface and for various counting times are also provided in Table 4. Minimum detectable activities (MDA's) for each type of surface, were calculated using equation (5-2) from NUREG/CR-5849 as shown below:

Equation (5-2):

MD 2.71 +4.65 R (dpmOOcm 2) txEx A 100 Where:

B.=background rate (cpm) t count time (min)

E efficiency A = area of the detector (cm 2) 4

+GENERAL ArT2MICS Building 2 Group 12 Background Soil Concentrations Typical background concentrations in soil near the GA site have been measured by gamma spectroscopy (at the 95% confidence level) and are provided in Table 7 along with a description of the locations where these samples were taken.

Exposure Rate Background Typical exposure rate background is about 15 fiR/hr measured at 1 m from the surface. This value can 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 gave an average of about 15 jtR/hr measured at I m from the surface.

SURVEY PLANS Survey plans which documented the types of surveys to be performed and the locations were developed based upon the physical characteristics of the labs, the radioactive material used, the potential for contamination, and the results of the characterization surveys. The physical characteristics of the labs include the consideration of vents, ducts, floor drains, whether surfaces are painted or unpainted, overhead structures, floor coverings, etc. Types of surveys performed include scanning, exposure rate measurements and survey measurements (wipes and fixed measurements). In areas where elevated readings were detected, additional surveys were taken.

The first surveys performed were surveys of the tile or floor covering. Contaminated tile was found in Labs 401 and 407 which was removed and disposed of as low level waste before the non contaminated tile was removed. The floor coverings in labs 403 and 405 were not contaminated, i.e.,

they were at or near background levels. All floor coverings, mastic, and glue were removed before the final surveys were conducted.

RESULTS OF THE INITIAL SURVEYS Scanning Scan of Tile In each area where tile was present, the tile was scanned for alpha and beta/gamma radiations over 100% of the surface using floor monitors having a 434 cm2 gas-flow proportional detector. Some contaminated tile was detected. The contaminated tile was removed and disposed of as radioactive waste, the clean tile was removed for the final survey.

Initial Survey 100% of the floors, walls up 2m, and 10% of the walls above 2m were scanned for beta/gamma radiations using floor monitors with 434 cm 2 gas-flow proportional detectors whenever possible. The 5

A70MIFCS Building 2 Group 12 floor was also scanned 100% with an alpha 434 cm 2 detector. In areas where the large area detectors could not be used, e.g., overhead structures, scanning was conducted using 15 cm2 GM pancake detectors and/or 50 cm' alpha detectors. Initial scans in the labs showed elevated radiation levels on portions of the floors and on some walls below 2m, no radioactive contaminations was detected above 2m.

DECONTAMINATION Contamination was found on portions of the concrete floors and some of the walls in each lab during scanning using floor monitors with 434 cm 2 alpha and beta gas flow proportional detectors. The maximum contamination level on the floor measured 207,000 dpm/l 00 cm 2 beta in lab 407. The maximum contamination level found on the walls measured 47,000 dpm/100 cm 2 beta in lab 401.

Samples of contaminated concrete and drywall from labs 401, 405, and 407 were collected and analyzed by gamma ray spectroscopy. The contaminants were identified as Cs-137, thorium, and enriched uranium with Cs-137 being the predominant radionuclide. The contaminated floors and walls were initially decontaminated using a needle gun and a scabbler. The contaminated wallboard was removed and disposed of as radioactive waste. No contamination was detected on the walls above 2m or on any of the overhead fixtures.

The floor drain in lab 407 was found to be contaminated. The concrete floor was cut and removed and the drain line, which was immediately under the concrete, was removed and packaged as radioactive waste. Two soil samples were collected from the bottom of the trench. The soil sample results were below the approved release criteria as shown in Table 6.

FINAL SURVEYS Objectives and Responsibilities The objectives of the final survey plans were: (1) to demonstrate that the average surface contamination levels for each survey unit were below the approved release criteria, (2) to show that the maximum residual activity did not exceed three times the approval release criteria for average surface contamination value in an area up to 100 cm', (3) to demonstrate that the soil sample results were well below GA's approved release criteria for unrestricted use, (4) to show that the exposure rate measurements taken in these labs measured at 1 meter above the surface are less than 10 MR/hr above background.

Final Survey Plans A Final Survey Plan which specified the types of surveys to be performed and the locations where surveys were to be performed was developed based upon the physical characteristics of the area, the radioactive materials used, and the potential for contamination. The plan followed the requirements stated in GA's approved Site Decommissioning Plan. The surveys completed include x, P3, and y 6

+CENE"RL ATOMICS Building 2 Group 12 scanning, collection and analyses (by gross alpha/beta counting) of smears, the taking of fixed ca and P3 measurements on the concrete surfaces, exposure rate measurements (,uR/hr), and the sampling and isotopic analyses (by gamma spectroscopy) of soil exposed during drain line removal. A copy of the Final Survey Plan and Amendment # 1 to the Final Survey Plan is provided in Appendix A.

Gridding The floors in the labs were gridded into Im x Im grids in order to: (1) facilitate systematic selection of radiological measurement and soil sampling locations, (2) provide a means for referencing a measurement back to a specific location and (3) establish a uniform and distinct identification system.

The horizontal (X) axis of the grid was delineated by numerical characters and the vertical (Y) axis by alphabetical characters. This established unique grids of easily identifiable entities.

Documentation Surveys were taken in accordance with an approved survey plan by qualified Health Physics Technicians having a minimum of three years health physics experience. Soil samples and wipes (100 cm2) were counted in GA's Health Physics Laboratory which maintains an effective QA program.

Every survey taken was documented on a daily basis to a worksheet/drawing showing the approximate locations surveyed/sampled. The figures provided in this report include the measurement locations (and, in some cases, the results of these measurements (including units), the technician's name, date(s) of the surveys, instrument(s) used (including the model and serial number of both the ratemeter and detector), calibration due date, % efficiency, background readings (if applicable) and any other pertinent information.

Comparisons with Site Decommissioning Plan Comparisons of the site Decommissioning Plan requirements with the Final Surveys performed in relation to the percentage of surface area scanned, number of fixed and removable measurements performed, exposure rate measurements (p.R/hr) and soil samples taken are provided as follows:

7

A70C Building 2 Group 12 Comparisons of Site Decommissioning Plan (Site D-Plan) Requirements with the Final Surveys Performed inithe Sorrento Valley North Area Suspect Affected Scanning

1. of Measurements

1. of Exposure Rate Soil Samples Area a,p/ X on concrete (fixed & wipes)

Measurements

(/gR/hr) @lIm above the surface Site D-Plan 100% coverage 30 minimum 1 per 4m' or Suspect affected 1 per 4m. or 1 every -2m areas.

I every -2m or I every -3m One every 5m Final Surveys 100% a on concrete 20 a and 20 P3 on I every -2m 2 per trench (< 5m)

Performed 100% [3y on concrete surface concrete

-1 every 2m If no gamma emitters are present.

RESULTS OF THE FINAL SURVEY Final Survey Scans For the final survey, 100% of the floor was scanned with floor monitors for alpha and beta/gamma radiations. 100% of the walls up 2m were scanned for beta radiation. In areas where the floor monitors indicated elevated readings, the area was scanned with 100 cm 2 beta detectors or hand held GM detectors and 50 cm2 alpha detectors. Results of the scans are in Table 5 and the locations are shown in the respective figures as noted on Table 5.

Fixed Measurements Fixed measurements were performed for beta/gamma radiation using a gas-flow proportional counter having a 100 cm' detector. The counting time for the beta fixed measurements was one(l) minute.

Alpha fixed measurements were obtained using the 50 cm' alpha detector. The counting time for each alpha fixed measurements was -30 seconds.

For all fixed measurements, an appropriate background was determined for each type of surface and subtracted from the survey readings. The readings were converted to dpm/l100 cm2 using the efficiency of the detecto and the detector size. GA's intent was to demonstrate (with fixed measurements) that levels were < 670 dpm/100 cm2, which is the strictest release criteria for the contaminants found (thorium beta limit). A total of 198 fixed measurements were taken. In Lab 403, an area -lm 2 had several measurements greater than 670 dpm/100 cm 2 with a maximum reading of 1104 P dpm/100 cm 2. Thirty eight (38) beta measurements were then taken in and around this area; the average of all the measurements was 439 P3 dpm/100 cm2. In Lab 407, two areas were found that measured > 670 dpm/100 cm 2. One area measured 959 beta dpm/100 cm2. Five measurements were taken around this location and averaged with the elevated reading. The average was 521 dpm/1 00 2

cm.

8

+G&NERAL ATOMICS Buildina 2 Grouo 12 Note: It was decided to check these areas in more detail during the internal GA Confirmatory Survey (see Appendix B). Additional measurements still showed levels > 670 dpm/100 cm 2 in the same locations in labs 403 and 407. Concrete samples were collected and analyzed by gamma spectroscopy. The contaminant was identified as Cs-137 which has a 5,000 dpm/100 cm 2 average limit; therefore, the levels were below the release criteria for Cs-137. However, after removal of the concrete sample, it was noted that fixed radiation levels increased. Most likely this was due to previous decontamination efforts and subsequent repair of the concrete done in the 1980's. In order to (1) avoid the need to investigate further and (2) to check the soil underneath the concrete, it was decided to remove the concrete entirely from the 3 locations where elevated levels remained and dispose of the concrete as radioactive waste. In lab 403, concrete was removed from an area -1 m2 and in lab 407, concrete was removed from 2 locations; one -1 m2 area and another -0.5 m2 area. Exposure rate measurements on the surface of the soil were taken. In addition, soil samples were collected and analyzed by gamma spectroscopy. These results are provided with the Confirmatory Survey Report in Appendix B.

The fixed beta measurement locations taken in lab 403 (after concrete removal) are shown in Figure 13 and results provided in Figure 13 and Table 5. The maximum fixed measurement in lab 403 is 624 dpm/100 cm2.

The fixed beta measurement locations taken in lab 407 (after concrete removal) are shown in Figure 25 and results provided in Figure 25 and Table 5. The maximum fixed measurement in lab 403 is 544 dpm/100 cm2.

Alpha measurements taken in these areas were all <MDA (323 cx dpm/100 cm 2).

The results of the fixed measurements in the other laboratories are summarized in Table 5 and the locations are shown in the respective figures as noted on Table 5.

Removable Contamination Surveys Removable contamination measurements (smears) were performed on all surfaces including the floors, walls, ducts, lights and support beams. Smear surveys consisted of using a Whatman Filter Paper (4.7 cm diameter) and wiping an area of -100 cm2. The smears were counted in GA's Health Physics Laboratory using a Canberra 2404 low level alpha/beta gas flow proportional counter.

A total of 69 smears were taken. The approximate locations where smears were collected are shown in the Figures. The results of all removable contamination surveys are provided in Table 5.

Removable contamination levels were all below the release criteria alpha results were all <10 dpm/1 00 cm2 and beta results were all _<

10 dpm/1 00 cm 2).

Exposure Rate Measurements Direct radiation exposure rate measurements using a microR meter were taken in every room at 9

G ENERAL AVMANCE BuildinQ 2 Group 12

-every 2m. A total of 42 measurements were taken. The radiation levels ranged from 15 to 19 ýtR/hr, which are at or near normal background radiation levels.

INTERNAL CONFIRMATORY SURVEY After completing its' final surveys, GA conducted an internal confirmatory survey of the "Group 12" labs. The results of this survey are discussed in the Final Survey section of this report as well as in Appendix B.

CONCLUSION The results of the final and confirmatory surveys provided in this report, demonstrate that the labs, designated as "Group 12", meet the NRC-and State-approved guidelines for release to unrestricted use.

10

Building 2 Group 12 TABLES 11 G

ENERAL A7ODMICS

ATIOMMI Building 2 Group 12 Table SNRC'S ACCEPTABLE. SURFACE CONTAMINATION LEVELS Nuclides

} Averageb-c" Maximum b "'f RernovablOeý'~.

________________________________ J(dpnutO Q.cm2)

J(dpW/lO00cim) j(p/Oc 2

U-nat, 235U, 238u, & associated decay products 5,000 a 15,000 a 1,000 I Transuranics, 226Ra, 228Ra, 230Th, 228Th, 231Pa, 100 300 20 2 2 7 Ac, 1251, 1291 Th-nat, 232Th, 90Sr, 223Ra, 224Ra, 2 32 U, 1261, 1331, 1311 1,000 3,000 200 Beta/gamma emitters (nuclides with decay modes other than alpha emission or spontaneous fission) 5,000 15,000 1,000 except 'Sr and other noted above.

II 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.

e The amount of removable radioactive material per 100 cm 2 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 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 I 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.

12

Buildinq 2 Group 12 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-l" incorporated into GA's State of CA Radioactive Materials License.

13 GL-EJEAL

+ATOMWCS Table 2: STATE OF CA ACCEPTABLE SURFACE CONTAMINATIOtJ LFVFL!

I Average b,',

Maximumbld~f Remrovablebx'f (dpm/ IO.Ocm 2)

(dpn/100@cm 2' (pLEI 10 crn)

U-nat, 2 35U, 2 38U, & associated decay products 5,000 15,000 1,000 Transuranics, 226Ra, 22 5Ra, 23°Th, 22 8Th, 231Pa, 100 300 20 227 Ac, 1251, 1291 Th-nat, 232Th, 90Sr, 2 2 3Ra, 2 24Ra, 2 3 2 u, 1261, 1331, 1311 1,000 3,000 200 Beta/gamma emitters (nuclides with decay modes other than alpha emission or spontaneous 5,000 15,000 1,000 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 2 e

The amount of removable radioactive material per 100 cm 2 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 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 1 cm, respectively, measured through not more than 7 milligrams per square centimeter of total absorber.

>X+>X-

+GENERAL ATOMICS Buildino 2 Grouo 12

TABLE 3: List of Instruments_______

Instrument Detector Range Calibration Efficiency Blackground Description (cpm)

Due Date (cpm)

Ludlum Ludlum Model 43-37 Four Linear Varies according Active Probe Area = 434cm2. The detector and Model 2221 gas proportional Ranges 9-13-00 21.25%

to surface being RATE METER are combined and mounted on a S/N 97287 (434 cm 2) 0-500,000 & one scanned roll around cart. The instrument features a static Alpha detector Log See Table 4 flow system, quick connects, a portable gas bottle S/N 148926 50-500,000 and a means to adjust the height of the detector from the floor for optimum performance.

Ludlum Ludlum Model 43-37 Four Linear Varies according Active Probe Area = 434cm2. The detector and Model 2221 gas proportional Ranges 10-17-00 22.79%

to surface being RATE METER are combined and mounted on a S/Ni54202 (434 cm2) 0-500,000 & one scanned roll around cart. The instrument features a static Beta detector Log See Table 4 flow system, quick connects, a portable gas bottle S/N 149017 50-500,000 and a means to adjust the height of the detector from the floor for optimum performance.

Ludlum Ludlum Model 43-37 Four Linear Varies according Active Probe Area = 434cm2. The detector and Model 2221 1 gas proportional Ranges 10-30-00 21.45%

to surface being RATE METER are combined and mounted on a S/N 84459 (434 cm 2) 0-500,000 & one scanned roll around cart. The instrument features a static Beta detector Log See Table 4 flow system, quick connects, a portable gas bottle S/N 086213 50-500,000 and a means to adjust the height of the detector from the floor for optimum performance.

14 BuiTdin 2

r 12

CEN-CRAL

+ATOMICS Building 2 Group 12 TABLE 3: List of Instruments______

Instrument Detector Range Calibration Efficiency

Background

Description (cpm)

Due Date (cprn)

Ludlum Ludlum Model 43-68 Four Linear Varies according 100 cm' gas flow proportional counter.

Model 222 1 100 cm' proportional Ranges 7-10-00 26.27%

to surface being S/N 148436 Beta detector 0-500,000 & one 12-7-00 27.40%

scanned S/N 120477 Log See Table 4 50-500,000 Ludlumi RCA 6199 Five Ranges N/A 1 inch x 1 inch Nal (TI) scintillator is mounted Model 19 coupled to a 0-5 mR/hr 7-13-00 10-18 gR/hr internally. Used for initial survey on ground floor N/Micro-R Meter NaI (TI) Scintillator and for measuring external dose rates on the S/N 123930 surface and at one meter.

Ludhim -

Ludlum Model 43-64 Four ranges Active Probe Area = 50 cm2 Model i2 Alpha Scintillator 0-500,000 7-11-00 21.58%

1-20 S/N 138801 ZnS(Ag)

S/N 145696 Canberra Gas Flow Proportional Canberra Model 2404 Low Level c/r3 gas Low Level Detector N/A As needed 30%

Varies proportional counting system used to count wip[es a/P Counter for removable contamination. Results are usually Model 2404 reported as dpm/100 cm2.

Canberra High Purity N/A As needed Varies with Varies with Gamma Spectroscopy MCA system using a high Gamma.

Germanium Detector Sample Sample purity Germanium detector. Used to identify U Spectroscopy 235 (and other gamma emitters).

S y s t e m :

I I

_III_1_-11 15

Building 2 Group 12 Wood 289 +/- 12 311 Metal 209 + 70 266 Stucco/Plaster 304 + 36 319 Effcitency =25.04%

Concrete 554 +/- 56 443 Concrete Block 437 +/- 36 399 Average of 10 Measurements 2 minutes each (cp2m - 20)

Efficiency = 27.06 Metal 575 +/- 28 213 Ludlun Model 2221 Rate Meter S/N 97287 with Model 43-37 Probe S/N 086238 Alpha Floor Monitor~ Background Scan Results: 434 cni2detector (Efficiency =21.36%)

Background Surface Material Alpha Scan Rangec spm)

Concrete 0-20 Cement Block 0-20 Ludlum Model 2221 Rate Meter S/N 84459 with Model 43-37 Probe SIN 086213 Beta Floor Monitor Back-ground Scan Results: 434 em' Detector (Efficiency 21.14%)

Background Surface Material Beat/Gamma Scan Range (epm)

Concrete 1858-2036 Metal 816 - 1047 Efficiency = 2 1.27%

Wood 915 - 1244 Efficiency =21.42%

Glass 787-917 16 CEIVERAL

+A70MICE

+

Building 2 Group 12 Stucco/Plaster 1083 - 1250 Ludlum Model 2221 Rate Meter S/N 154202 with: Model 43-37 Probe SIN 149017 Beta Floor Monitor Background Scan Results: 434 em' Detector (Efficiency 22.84%)

17

G~

ENERAL.

6-ATO7MICS Buildina 2 Groun 12 Table 5: Results of Final Surve~ys in Buiilding 2 Group 12 Labs

1. of Fixed j

~ Maximum 93 of fFixed a~

Max imni m a Scan Results Scan Results Maximum Results Exposure Figure Location Measurements Result Measurements Result 434 cm' 0 434 em" am

1. of (Jpmfl100 cmý)

Rate Range (100 cm2 daetetor)

(dpru/ 00 cm)

(0 mdeetr)

(p/00e 2

(epul range)

(clpm range)

Smas(~RR/r)

Suspect Affected Areas Lab 401 11

< MDA 14

<MDA 1600-2300 0-40 13

<10

<10 4, 5, 6 Floor

(<443)

(<323) 17-19 7,8,9 Lab 401 1000-1800 0-80" 3

<10

<10 Walls 28 Lab 401 1

499 1

<MDA 1-

<10

<10 Vents

(<323)

• An alpha scan of the west wall was done due to previous alpha contamination and subsequent decontamination.

Lab 403 22 624 22

<MDA 1500-2800*

0-60 14

<10

<10 10, 11 Floor

(<323) 16-18 12, 13 Lab 403 1000-1600 2

<10

<10 14, 15 Walls 28 Lab 403 2

246 2

<MDA 2

<10

<10 Vents

(<323)

"*Five fixed Beta measurements were taken in this area, -500 cm'. The maximum result was 624 dpm/100 cm2 and the average of the five was <443 dpm/lOO cm', (MDA). Three fixed Alpha measurements a were taken in this area. All three were <323 dpm/100 cm' (MDA).

Lab 405 14

<MDA 15

<MDA 1600-2000 0-80 13

<10

<10 16, 17 Floor

(<443)

(<323) 15-19 20, 21 Lab 405 900-1600

<10

<10 Walls 3

1

<10 18 Buildina 2 Grou* 12

J+. GENERAL 19 Table 5: Results of Final Surveys in Building 2 Group. 12 Labs

1. of Fixed f ~ Maximum P3 9 of fixed a~

Maximum a Scan Results Seari Results Maximum Results Exposure Fig-ure Location Measurements Result Measurements Result 434 cnm I 434 cm' a

1. of

(-dpmIIOO culZ)

Rate Range (100 cm 2 detector)

(dpm/1 00 cm2)

(50 Qm'detector)

(dpnillOO cni2)

(epm range)

(Cpmn range)

Smears (gR/hr)

Lab 407 19 544 13

<MDA 1300-2300 0-38 12

<10 10 22,23 Floor

(<323) 17-19 2,5 Lab 407 900-2000 4

<10

<10 26, 27 Wal Lab 407 900-2000 4

<10

<10 Walls 28 Lab 407 2

<MDA 2

<MDA 1

1 Vents

(<213)

____10____

(<323 S...............

. 2:'.I..::::::::::::::::V!,

23 (lo

<323) 1 1-1

Buildina 2 Groun 12

+CENERAL ATOMICS TABLE 6: GAMMA SPECTROSCOPY RE~SULTS 01F SOIL SAMPLES FROM LABS 403 AND:407 Radion~uclide Concentration (pCi/gm) - Results +/- 2or - B~ackground not Subtracted. 30 minu~te counts Sample Sample 137Cs 60Co 228Th 228Ra Total 238U 235u Evaluation and ID Location 662 Kev Ave.of Ave. of (232Th)

Thorium 92.77 keV 186(144)

Comments peak 1173/1332 238/583 kev Ave.

228Th-+232Th peak keV peak Key peaks peaks 338/911 keV peaks B2 407A Soil A from under ND ND 0.69 +/- 0.08 1.23 +/- 0.28 1.92 0.90 +/- 0.45 0.17 +/- 0.06 Below Release drainline Criteria B2 407B Soil B from under ND ND 0.66 +/- 0.12 1.27v0.40 1.92 1.06 +/- 0.60 0.14 +/- 0.08 Below Release drainline I

I I

I I

I Criteria 20 Buildina 2 Grou 12

k EENERL ATOMICS Buildina 2 Groiin 12 a-Table 7: Background Soil Sample Res~ults Samrple Cs-137 Th-228 Ra-228 h$2ý-3

-1 ID'

(.Uh-232)

Radionuclide Concentrations (pCilg)

AJ ND 1.28 +/- 0.07 1.47 +/- 0.14 2.75 1.98

-0.31 0.15 +/- 0.03 G2 0.12+/-0.03 0.92 +/-0.07 1.01 +/-0.12 1.93 1.864-0.29 0.12 +/-0.02 AC ND 1.29 +/- 0.07 1.34 +/- 0.14 2.63 2.27+/- 0.27 0.20 +/- 0.03 BKG-1 ND 1.40 +/- 0.16 1.44 +/- 0.28 2.84 2.06 +/- 0.48 0.19 +/- 0.06 BKG-2 ND 1.54 +/- 0.15 1.57 +/- 0.27 3.11 2.30 +/- 0.45 0.17 +/-L 0.05 BKG-3 ND 1.40 +/- 0.14 1.62+/- 0.26 3.02 ND 0.19 +/- 0.05 BKG-4 ND 0.67 +/- 0.09 0.84 +/- 0.17 1.51 1.15 +/- 0.37 0.09 +/- 0.04 BKG-5 ND 1.51 +/- 0.16 1.79 +/- 0.31 3.30 2.77 +/- 0.67 0.12 +/- 0.06 BKG-6 ND 0.68 +/- 0.09 0.76 +/- 0.16 1.44 ND 0.08 +/- 0.03 BKG-7 ND 1.17 +/- 0.12 1.28 +/- 0.22 2.45 1.83 +/- 0.43 0.11 +/- 0.04 Mean-2 cy 1.19 +/- 0.64 1.31 +/- 0.68 2.5 +/-1.32 2.03 +/- 0.93 0.14 +/-0.09 Samples gamma scanned for I hour.

ND=

< 0.1 pCi/g for Cs-137, < 1.0 pCi/g for U-238 Samples collected in June and August 1993, typically about 1-2 miles from the Building 37 site at the following locations:

Collected on a hillside west of Building 39 & northwest of building 37, -3' from GA's fence.

Collected about 1200 feet west of Bldg 1 (near T.P. RD.), and -7/8 of a mile southwest of Building 37.

Collected about I mile southeast of the main site & about 2 miles southeast of Building 37.

G-1 Collected about 1 mile from Building 37 at the Scripps Hospital Entrance, east of Genesee Ave.

G-2 Collected about 1.2 miles from Building 37 at Sorrento Court Rd. by North entrance to Post Office.

G-3 Collected about 1.5 miles from Building 37 at Sorrento Vista Parkway near Lusk Blvd. South.

G-4 Collected about I mile west from Building 37, west off Genesee corner of North Torrey Pines Road and Torrey Pines Scenic Drive G-5 Collected about 2 miles west of GA off of La Jolla Shores Drive.

G-6 Collected about 2 miles northwest of Building 37 on North Torrey Pines Road G-7 Collected about 2 miles near V.A. Hospital on La Jolla Village Drive (southwest) 21 2

AJ G2 AC BK BK BK BK BK(

BIC(

BK(

1

A AT@MIC~

Rijildin, 00 (Grro, 1')

FIGURE S 22 416. GENERAL ATOMMS

Figure 1: Main Site and Sorrento Valley Site Names Building Numbers Bui lding 1 But Iding 2 But Iding 7 Building 9 Building 10 Building 13 Building 14 Building 15 Building 19 Building 21 Building 22 Building 23 Building 25 Building 27 Building 27-7 Building 29 Bu il ding 29-2 Building 30 Building 31 Building 31-1 Building 31-2 Building 31-3 Building 33 Building 33-1 Building 33-5 Building 34 Building 34-1 Building 34-2 Building 34-3 Building 35 Building 35-1 Building 36 Building 37 Building 39 Building 39-1 Building 41 Building 42 Building 45 Building 63 Building 64 Building 65 Building 66 Building 66 FENCING PROPERTY LINE 0

250 500 750 1000 SCALE IN FEET N

Administration Science Laboratories A. B, C Cafeteria Experimental Building Maintenance Building Technical Office Building Technical Office East Technical Office East Swimming Pool Building TRIGA Building TRIGA Fuel Lab Building Hot Cell Waste Yard Building Experimental Area Experimental Area Experimental Area Emergency Vehicle Storage Building LINAC Complex TRIGA Storage Building Neutron Radiography Building ECF Critical Building Storage Building Fusion Building Fusion Lab Building Fusion Building Annex 5 Fusion Doublet III Building Fusion Doublet III Capacitor Building Fusion Doublet III Lab Building Fusion Doublet III Storage Building Test Tower Building Facilities (Shipping & Receiving) Building Blower Assembly Building Sorrento Valley Building Sorrento Valley Building Storage Building Raw Stock Facility NDT Facility Helium Circulator Test Facility 3550 Dunhill St.

11030 Roselle St

/

11040 Roselle St.

3520 Dunhill St.

3510 Dunhill St.

w 4

• E S

SITE OPEN SPACE LOTS (X

C,)

t oX 0

UCSD LOTS

'9 w

Figure 2: Building 2 Laboratory E

N Section A Group 12 Section C

FIGURE 3: BUILDING 2 GROUP 12 LABORATORIES I

Z

N S

Figure 4: Lab 401 - Alpha Scans of Lower Walls and Floor 1

2 3

4 5

6 7

A B

C D

~~.

E Concrete F/lor F

0-780 G

.INSTRUMENT 0-40 MODEL Ludlum 2221 "97287 PROBE 148926 PROBE MOIDEL 43-37 CAL DUE 09/13100 EFF 21.25%

BKGD (Cem:.

Bblck) 0-20 cpm BKGD (Concrete) 0-20 cpm Surveys Conducted By: R. Stowell and M.Dupray Date: 05/12-17/00 1 meter Notes:

1.

Results are in cpm.

2.

Survey results are also provided in Table 5.

3.

-100% of the Floor and West Wall (below 2m) was scanned for Alpha.

Scan results in cross hatched area.

4.

East partition wall removed.

N W*+

. E s

Figure 5: Lab 401 - Beta Scans of Lower Walls and Floor 1

2 3

4 5

6 7

INSTRUMENT MODEL Ludlum 2221 3

SN 154202

.PRO.BI 149017 PROBE MODEL 43-37 CAL DUE.

10/17/00 EFF 22.79%

BK<GD (Cemt. B

)

1567-1719 cpm INSTRRUMENT MOD'EL Ludlum 2221 0 0.BK0 (Plast.er)

BKGD (Meta*),

1083-1250 cpm 816-1047 cpm A

B C

D E

F G

H J

K 1 meter Notes:

1.

Results are in cpm.

2.

Survey results are also provided in Table 5.

3.

-100% of the Floor and Walls (below 2m) were scanned for Beta.

Scan results in cross hatched area.

4.

East partition wall removed.

Surveys Conducted By: R. Stowell Dates: 05/112-17/00 SN 84459

.PROBE :

086213 PROBE MODEL 43-37 CAL DUE 10/30/00 EFF 21.45%

SBKGD (Concriete) [

1858-2036 cpm

Figure 6: Lab 401 - Locations and Results of Fixed Alpha Measurements 1

2 3

4 5

6 7

INSTRUMENt MODEtL L dIUml2 a IN PROBE SIN)

PFROBE MODEL CAL DUE EFF

ýBkGD (C rte)

MbA 138801 145696 43-64 07/11100 21.58%

1-20 cpm 323 dpmVl100..

Survey Conducted by: R. Stowell Date: 05/1 6/00 1 meter Notes:

1.

Survey results are also provided in Table 5.

2.

The values are dpm/lO0CM 2 and indicate the approximate locations of measurements taken. Counting time for fixed Alpha readings was 30 seconds.

3.

East partition wall removed.

N S

I E

C E

E F

G H

J K

N W*+-b E S

Figure 7: Lab 401 - Locations and Results of Fixed Beta Measurements 1

2 3

4 5

6 7

e443

ý443

)<443 Concrete Floor

<443

<443

<443 INSTRUMENT

<443

<443 MODEL Ludlum 2221 0 SN 148436 PROBE 120477 4 PROBE MODEL 43-6B "cAL.E.

07110100

..EFF26.27%

SBKGD (Concrete) 554 cpm 443

<43 "MDA 443 dprn/100cmn Survey Conducted By: R-Stowell Date: 05/16/00 1 meter Notes:

1.

Survey results are also provided in Table 5.

2.

The values are dpm/1 00cm 2 and indicate the approximate locations of measurements taken. One minute fixed Beta readings were taken.

3.

East partition wall removed-

Figure 8: Lab 401 - Locations of Removable Contamination Survey 1

2 3

4 5

6 7

Survey Conducted by: R. Stowell Date: 05/18/00 1 meter Survey results are provided in Table 5.

The Numbers circled are the approximate locations of wipes taken.

East partition wall removed.

N W*E S

Notes:

1.

2.

3.

Figure 9: Lab 401 - Locations and Results of Exposure Rate Measurements 1

2 3

4 5

6 7

A B

C D

E F

G H

J K

1 meter Notes:

1.

Survey results are provided in Table 5.

2.

The values are.tR/hr and indicate the approximate locations of Exposure Rate Measurements taken -1m above Floor surface - 1 every 2 meters.

3.

East partition wall removed.

N V

s Survey conducted By: R. Stowell Date: 05/18/00

.:--FINSTRUMENT:

MODEL Ludlum 19 y SN::

123930

PROBE NIA PROBE MODEL N/A CAL DUE--

07113/00 EFF N/A B3KGD

• 19-18 VR/hr

Figure 10: Lab 403 - Alpha Floor Scans and Soil Samples Locations 1

2 3

4 5

6 7

8 9

N S

A B

C D

E F

G H

J K

1 meter Survey results are provided in Table 5. Results are in cpm.

-100% of the Floor was scanned for Alpha. Scan results shown in cross hatched area.

East and west partition wa~lls removed.

Concrete removed and Soil samples collected.

Soil sample (403-1 & 403-2) results are provided in Appendix B Table 2 B.

Survey Conducted By: M. Dupray 05/12,100 INSTRUMENTr MOD)EL::

L:u.dl[.iium 2221 c.

"SN 97287 PROBE 148926 PROBE MODEL 43-37 CAL DUE D9113/00 EF:

21.25%

EKcD CcDete) 01-20 rpm Notes:

1.

2.

3.

4.

Figure 11: Lab 403 - Beta Floor and Walls Scans 1

2 3

4 5

6 7

8 9

N WE S

INSTRUMENT MODEL Ludlum 2221 A SN 154202 PROBE 149017 PROBE MODEL 43-37 CALDUE 10/17/00 EFF 22.79%

"BKGDf(Iemt.: BI) 1567-1719 cpm

.MODEL:

Ludlum 2221 P SN 84459 P ýROBE 086213 PROBE MODEL 43-37 CAL-DUE 10/30/00

EFF 21.45%

BKGD.(Concrete) 1858-2036 cpm dBKGr-D:Plastter) 1063-1250 cpm 6KGD(IMeta')

E16-1047 cpm Surveys Conducted by: R. Stowell 05/12-17/00 1 meter Notes:

1.

Survey results are provided in Table 5. Results are in cpm.

2.

-100% of the Floor and Walls (below 2m) were scanned for Beta. Scan results shown in cross hatched area

3.

Five additional fixed Beta measurements were taken in this area, -500 cm 2. The maximum result was 624 dpm/1OOcm 2 and the average of the five was <443 dpm/1OOcm 2 (MDA).

4.

East and west partition walls removed.

Figure 12: Lab 403 - Locations and Results of Fixed Alpha Measurements 1

2 3

4 5

6 7

8 9

A B

C D

E F

INSTRUMENT MODEL Ludlum 12,

:i~~i:* ;:S*.*

i.; i:ii 138601 POBE 145696 PRO*BE MOEL 43-64 CAL DUE EFF MBKGD (CcrAee)

S::"::MDA Survey Conducted By: R. Stowell Date: 05/16/00 1 meter Notes:

1.

Survey results are provided in Table 5.

2.

The values are dpm/1OOcm 2 and indicate the approximate locations of measurements taken. Counting time for fixed Alpha readings was 30 seconds.

3.

Three additional fixed Alpha measurements were taken in this area (-500cm 2) all <323 (MDA)

4.

East and west partition walls removed.

N S

H J

K 7-11-00 21.58%

1-20 cpm 323 dpm/100 cmz

Figure 13: Lab 403 - Locations and Results of Fixed Beta Measurements 1

2 3

4 5

6 7

1 8 N

S 9

A B

C D

E F

G H

J K

1 meter Notes:

1.

Survey results are provided in Table 5.

2.

The values are dpm/1 00cm 2 and indicate the approximate locations of measurements taken.

One minute fixed Beta readings were taken.

3.

Five additional fixed Beta measurements were taken in this area, -500 cm2. The maximum result was 624 dpm/100cm2 and the average of the five was <443 dpm/100cm2 (MDA).

4.

East and west partition walls removed.

INSTRUMtiNT MODEL Ludlum'2221 Ip

[

• SN 148436 PROBE 120477 PROBE M DEL 43-68 CAL D

-UE 07/10100 EFF :

26m27%

BKGD (Cntt) 54cm MDA 443 dpmfOU1om, Survey Conducted By: R. Stowell 05/16100

Figure 14: Lab 403 - Locations of Removable Contamination Survey 1

2 3

4 5

6 7

8 9

A B

C D

E F

G H

J K

Notes:

1.

2.

3.

1 meter Survey results are provided in Table 5.

The Numbers circled are the approximate locations of wipes taken.

East and west partition walls removed.

N W+*

s Survey Conducted By: R. Stowell Date: 05/18/0

Figure 15: Lab 403 - Locations and Results of Exposure Rate Measurements

• 1 2

3 4

5 6

7 8

9 INSTRUMENT MODELE Ludlum 197 SN; 123930 P R:,

ROBE N/A rPROBE MODEL N/A CALIE 07113100 EFF N/A

• :!:BKGO 10-18

• .P-.hr Survey Conducted By: R. Stowell Date: 06/09/00 1 meter Note:

1.

Survey results are provided in Table 5.

2 The values are [tR/hr and indicate the approximate locations of Exposure Rate Measurements taken -1 m above floor surface.

3.

East and west partition walls removed.

N S

Figure 16: Lab 405 - Alpha Floor Scans 1

2 3

4 5

6 7

8 A

B C

D E

F G

H J

K N

S

.NSTRUIE!T MODEL Lu-----

Im 2221 1

SN:

97287 PROBE 148926 PROBE

-MODEL:

43-37 CAL DU-E 09/13/00 EFF 21.25%

ýBKGD 0Cnree

-20 cpm Survey Conducted By: M. Dupray 1 meter Date:05/1 2/00 Notes:

1.

Survey results are provided in Table 5. Results are in cpm.

2.

-100% of the floor was scanned for Alpha. Scan results shown in cross hatched area.

3.

West partition wall removed-

Figure 17: Lab 405 - Beta Floor and Walls Scans 1

2 3

4 5

6 7

8 A

CQoncrete Bok

-130 -.1600 B............. -.

cociete Rloof:

E 1200-1600 S........

F 600-2000 Concreie Block Open F

HPR OI

~ 0 12/.i0Q :.*:PR0,,

1200-140 PROS CA K ~

~

PPlaster F1 V

~~~...

-:8..K

G D-t 1 meter BKGD BKGC BKGD Surve N

S

i:::I:.NSTRUMENT:

IODELLudlumn 2221 0 SNI 154202 ROBE:

149017 8EMDEL 43-37 AL DUE 10/17/00 EFF 22.79%

et Block 1567-1719 cpm I

INSTRUMENT IDEL Ludlum 2221p SN 84459 OBE :

086213 E MODEL 43-37 L DUE 1030/0o EFF 21.45%

Concrete) 1858-2036 cpm (Plaster) 1083-1 250 cpm as(Glass) 787-917 cpm I.{Wood) 915-1244 cpm y Conducted By: R. Stowell Date: 05/12-17/00 Notes:

1.

Survey results are provided in Table 5. Results are in cpm.

2.

-100% of the Floor and Walls (below 2m) were scanned for Beta.

Scan results shown in cross hatched area.

3.

West partition wall removed.

Figure 18: Lab 405 - Locations and Results of Fixed Alpha Measurements N

S 1

2 3

4 5

6 7

8 1 meter INSTRUMENT MODEL Ludum 12 *.

SN 138801 PROBE-145696 PROBE :MODEL 43-64 CAL DUE....

11/o0 EFF 2I1.58%

r'BKGD (Concrete) 1-20 cp,

.MDA 323 dpm/lO0cm 2

Survey Conducted By: R-Stowell Date: 05/16/00 Notes:

1.

Survey results are provided in Table 5.

2.

The values are dpm/100cm2 and indicate the approximate locations of measurements taken. Counting time for fixed Alpha readings was 30 seconmds.

3.

West partition wall removed.

Figure 19: Lab 405 - Locations and Results of Fixed Beta Measurements 1

2 3

4 5

6 7

8 A

B C

D E

F G

H J

K INSTRUMENT MODEL Ludlum 2221 3 "SN 148436

[ PROBE 120477 PROBE MOýDEL 43-68 CAL DUE 07/10100 EFF 26.27%

8KGO (Concrete) 554 cpm

• "MDA 443 dpm/1 D0cmý Survey Conducted By: R. Stowell Date: 05/16/00 1 meter Notes:

1.

Survey results are provided in Table 5.

2.

The values are dpm/100cm 2 and indicate the approximate locations of measurements taken. One minute fixed Beta readings were taken.

3.

West partition wall removed.

N W-+

E S

Figure 20: Lab 405 - Locations of Contamination Survey N

S Removable 1

2 3

4 5

6 7

8 Survey Conducted By: R. Stowell Date: 05/18/00 1 meter Survey results are provided in Table 5.

The Numbers circled are the approximate locations of wipes taken.

West partition wall removed.

Notes:

1.

2.

3.

Figure 21: Lab 405 - Locations and Results of Exposure Rate Measurements 1

2 3

4 5

6 7.8 A

B C

D E

F G

H J

K INSTRUMENT

7 MODEL Ludlum 1 9

SN

'123930 PROBE

-N/A PROBE MODEL N/A S.CAL DUE 07/130oo

'EFF NIA BKG

/

lO-81b18 Survey Conducted By: R. Stowell Date: 05/18/00 1 meter Note:

1.

Survey results are provided in Table 5.

2 The values are [tR/hr and indicate the approximate locations of Exposure Rate Measurements taken -1 m above floor surface.

3.

West partition wall removed.

N S

Figure 22: Lab 407 - Alpha Floor Scans and Soil Sample Locations 1

2 3

4 5

6 7

8 A

B C

D E

F G

H K

K INSTRUMENT MO-EL Ludlum 2221 a SN 97287

PROBE 148926

.PROBE MODL 43-37 CAL DUE 09/13100

.EF.

21.25%

BKD :(Concrete) 0-20 qpm Survey Conducted By: M. Dupray Date: 05/15100 1 meter Notes:

1.

Survey results are provided in Table 5. Results are in cpm.

2.

-100% of the floor was scanned for Alpha. Scan results in cross hatched area.

3.

Concrete removed and Soil samples collected.

Soil sample results are provided in Appendix B Table 2 B.

4.

Drainline removed and Soil samples collected.

Soil sample results are provided in Table 6.

W4o.

E S

N W*

E s

Figure 23: Lab 407 - Beta Floor and Walls Scans 1

2 3

4 5

6 7

8 A

B C

D E

F G

H J

K

"'INSTRUMENT M" O6-DEL.

Ludlum 2221 p SN 154202 S'PRO-BE 149017 PROBE MOD-EL 43-37 CAL DUE 10117/00 EFF 22.79%

81(00"(ClemI 8l ok) 1567-1719 cpm

" INSTRUMENT

.1 MODEL Ludlum 2221 p SN 84459 PROBE.

086213

-ROBE MODEL*

43-37 "CAL *DUE 10130/00 EFF 21-45%

8KGD (Concrete) 1858-2036 cpm BKSD (Plaster) 1083-1250 cpm SBKGC (Metat) 816-1047 cpm IGD (GIass) 787-917 cpm Survey Conducted By: R. Stowell Date: 5/15-18/00 1 meter Notes:

1.

Survey results are provided in Table 5. Results are in cpm.

2.

-100% of the Floor and Walls (below 2m) were scanned for Beta.

Scan results in cross hatched area.

Figure 24: Lab 407 - Locations and Results of Fixed Alpha Measurements 1

2 3

4 5

6 7

8 A

B C

D E

F G

H I

INSTRUMENT M :MO DEL Ludlum 12 SN 138801 PRO-E 145696 PROBE MODEL 43-64 CAL DUE 07/11/00 EFF 21.58%

BKGQ (Concrete) 1-20 cpm MOA 323 dpm/100crn Survey Conducted By: R. Stewell Date: 05/16/00 1 meter Notes:

1.

Survey results are provided in Table 5.

2.

The values are dpm/1OOcm 2 and indicate the approximate locations of measurements taken. Counting time for fixed Alpha readings was 30 seconds.

N W+

E S

N S

Figure 25: Lab 407 - Locations and Results of Fixed Beta Measurements 1

2 3

4 5

6 7

8 A

B C

D E

F G

H K

INST WMENT MOD-EL Ludlum 2221 p3 SN 148-436 PtRBE 120477 PROBE MODEL 43-68 CALW DUiE 07110/00 EF F 26.27%

BKGD (ConQete) 554 cpm M*DA 443 dpr/100cm 2

Survey Conducted By: R. Stowell Date: 05/16/00 1 meter Notes:

1.

Survey results are provided in Table 5.

2.

The values are dpm/100oCm 2 and indicate the approximate locations of measurements taken.

One minute (cpm) fixed Beta readings were taken.

Figure 26: Lab 407 - Locations of Removable Contamination Survey N

W$E S

1 2

3 4

5. 6 7

8 K

Survey Conducted By: R. Stowell Date: 5/18/00 1 meter Notes:

1.

Survey results are provided in Table 5.

2.

The Numbers circled are the approximate locations of wipes taken.

A B

C D

E F

G H

Figure 27: Lab 407 - Locations and Results of Exposure Rate Measurements 1

2 3

4 5

6 7

8 A

B C

D E

F G

-H I

'K INSTRMENT M

N ýMODEr=

L Ludlurn 1 9 SN 123930 PýR08E NIA PROBE MODEL NIA CAL DUE 07/13/00 EFF N/A BKGI" 10-18pRihr "Survey Conduicted By: R. Stowell Date: 05/18/00 1 meter Note:

1.

Survey results are provided in Table 5.

2.

The values are VR/hr and indicate the approximate locations of Exposure Rate Measurements taken ~-1 m above floor surface.

N W$E S

Figure 28: Labs 401, 403, 405 and 407 Vent Ducts 1

2 3

4 6

7 8

A B

C D

E 9

10 11 N

12 13 14 15 16 S

partition walls removed Notes:

1.

Survey results are provided in Table 5.

2.

Alpha and Beta values are in dpm/100 cm 2.

3.

The Numbers circled are the wipes.

INSTRUMENTS MODEL Ludlum 2221 0 Ludlum 12 a SN 148436 138801 PROBE 120477 145696 PROBE MODEL 43-68 43-64 CAL DUE 07/10/00 07111/00 EFF 27.40%

21.58%

BKGD (Metal) 575 cp2m 1-20 cpm MDA 213 323 dpm/lO0 cm*

4.

Wipes and fixed Alpha and Beta measurements were taken inside the vents.

Survey Conducted By: M. Dupray Dates: 6/14/00 1 meter

APPENDIX A FINAL SURVEY PLANS A-1

+ GENERAL ATOMICS INTERNAL CORRESPONDENCE, From:

Laura Gonzale In Reply Refer To:

LQG:2000:19 To:

Distribution Date:

March 8, 2000

Subject:

Issuance of the Final Survey Plan for the "Group 12" Laboratories in Building 2 Attached is a copy of the Final Survey Plan for the "Group 12" Laboratories in Building 2.

Please review the plan carefully. If you have any questions about implementing the plan, please talk to Paul Maschka or me. The "Group 12" labs is the most important project onsite other than the Hot Cell.

The responsibilities for performing these surveys are assigned as follows:

I.

Dick Stowell -- Responsible for coordinating all surveys to be performed.

2.

Dick Stowell - Responsible for collecting each survey performed at the end of each work day from each technician assigned to the project.

3.

Joe Sullivan -- Responsible for auditing the data the next morning to ensure that the following information has been documented. In cases where the information was not recorded properly, he will be responsible for getting the information recorded in a timely manner (within 2 days from the day the survey was performed).

Every survey conducted must be documented on a daily basis on a drawing showing the approximate locations surveyed. Include the results (including units), the technician"s name and signature, date, instrument(s) used (including model and serial number of both the rate meter and the detector), calibration due date, % efficiency, background readings, (if applicable), and any other applicable information.

4.

Dick Stowell -- Responsible for providing a detailed weekly report to Laura Gonzales and Paul Maschka. The report is due by Monday at noon every week. Please include what surveys have were completed the past week, the % completion for each survey and what is still needed.

5.

Barbara Hunter -- Responsible for preparing the tables for the final report by summarizing the data from the surveys performed.

6.

Stephen Finchum -- Responsible for doing the drawings needed for the surveyors and the drawing for the final report.

A-2

7.

Dick Stowell - Responsible for auditing the data collected to ensure that the Survey Plan is being properly implemented.

8.

Paul Maschka - Responsible for writing the Final Report.

K. Asmussen A. Lewis P. Maschka B. LaBonte R. Dairy (w/o attachment)

R. Noren (w/o attachment)

HP Surveyors:

B. Hunter R. Stowell M. Dupray A-3 Distribution:

J. Sullivan C. Stanley

Page 1 ofs FINAL SURVEY PLAN FOR "GROUP 12" LABS IN BUILDING 2 Prepared by:

O Date:

J-.,,

8: 2Wc)

Laura Q. Gonzales

Background

The Building 2 labs consist of a total of 142 laboratories. Of these, 132 labs have been released to unrestricted use in Groups 1-11. The Group 12 labs consist of Labs 218, 401, 403, 405, 407, 411, 413, 415, the mezzanine above labs 409, 411/413, and 415, and labs 619/621 and the mezzanine above labs 619/621. This Final Survey Plan covers the survey to be conducted in each of these laboratories.

Survey Objectives and Responsibility The purpose of performing a final survey is to demonstrate that the radiological conditions in each laboratory 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 show that the maximum residual activity ("hot spot" area) do not exceed three times the average value in an area up to 100 cm2 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 ftR/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.

History of Use with Radioactive Materials GA's Work Authorization logs were researched in order to review the previous activities conducted in each lab and to identify the radionuclides of concern. Three of the six labs (labs 216, 325 and 615) had no history of use involving radioactive materials. The following is a brief summary of the activities involving radioactive materials performed in each lab and the classification of each lab based on its history.

LABS G ROUP 112 S-'UM MARY..

219 No history of use of radioactive materials.

401, 403 and Projects Performed: Radiochemistry Laboratories from 1974 through 1989.

405 Uranium, thorium, and depleted uranium were authorized to be used in these labs.

Chemical and Spectro-Graphic analysis was performed on various types of nuclear fuels The labs were also used in the to manufacture thermionics fuel for the DOE in the 1980's. The fuel used -20% enriched uranium.

A-4

Page 2 of 5 LABS 13R UP'12SUM ARY 407 Projects Performed: Fuel saomples containing uranium and thorium were used-as well as fission and activation products. Dissolution and radiochemistry performed on samples. Performed chemical and instrument analysis.

From 1974 through 1982, Uranium, thorium, natural and depleted uranium as well as mixed fission and mixed activation were authorized to be used in these labs primarily for Chemical and Spectro-Graphic analysis was performed on various types of nuclear fuels. The lab Wýas also used in the to manufacture thermti ful fo the DOE in the 1980's. The fuel used

-20% enriched uranium.

409 Projects Performed: Radiochemistry lab beginning in

ý all ouantitleg of Sr-89 were handled in this lab. Src2 in graphite. Measured the degree of n reactor oxidation using the vacuum fusion apparatus. In 1974, an X-ray florescent X-ray unit within an enclosed system. From 1974 through 1982, Uranium, thorium, natural and depleted uranium as well as mixed fission and mixed activation were authorized to be used in these labs primarily for Chemical and Spectra-Graphic analysis was performed on various types of nuclear fuels. The lab was also used in the to manufacture thermionics fuel for the DOE in the 1980's. The fuel used -20% enriched uranium.

411 and Projects Performed: From 1974 through 1982, Uranium, thorium, natural and 413 depleted uranium as well as mixed fission and mixed activation were authorized to be used in these labs for Chemical and Spectra-Graphic analysis was performed on various types of nuclear fuels. The lab were also used in the to manufacture thermionics fuel for the DOE in the 1980's. The fuel used -20% enriched uranium.

Reported a spill (date unknown) of Cs-134 (Half life: 2.0648 Y) and Sr-89 (Half life:

50.53 D) carelessly spilled. Precautions should be taken (survey wise) of other probability of Isotopic spills.

415 and 415 No history use of radioactive materials.

Mezzanine 619/621 and No history use of radioactive materials.

Mezzanine Survey Plan for Tile and Linoleum on floors of the Group 12 Labs A survey plan for the tile and linoleum cover over the concrete floors of the Group 12 labs was prepared and implemented. Radioactive contamination was found in five (5) of the labs; these labs are 218, 401, 407, 413, 415 and 619/621. The following action has been taken:

1.

The floor tile in lab 218 was removed and will be disposed of as radioactive waste.

2.

The radioactively contaminated portions of tile and/or linoleum from the other labs has been removed and will be disposed of as radioactive waste. The rest of the tile will be disposed of appropriately.

3.

Samples of the tile were collected in each of the 5 contaminated labs in order to try and A-5

Page 3 of 5 determine the radioactive contaminant(s) present in each lab for gamma spec analysis. In labs 407, 413 and 619/621, the contaminant was found to be Cs-137. In labs 218 and 415, the contaminant could not be identified. Both of these labs had no history of use involving radioactive material by GA. Lab 218 was recently used by a tenant who did use radioactive mals; GA believes the contaminant is C-14 (a low energy pure beta emitter). In lab 415, only a small area of the tile was found to have elevated beta/gamma levels but the levels were so low that even the gamma spec results did not identify the contamination. The survey did not identify the show any alpha contamination; therefore, the beta/gamma limits will be applied to this lab also.

Classification, Because of the history of use and the results of the tile/linoleum surveys, the following labs are classified as "Suspect Affected Areas": Labs 218, 401,403, 405, 407, 411, 413 and 619/621 for purposes of this Final Survey, i.e., all 10 labs except lab 415.

The following areas are classified as "Unaffected Areas": Lab 415 and the mezzanine above labs 409, 411/413, and 415, and the mezzanine above labs 619/621 Release Limits, The primary contaminants of concern for these labs are Cs-137 (beta/gamma emitter). The limit for C-14 is at least as high as the Cs-137 limit. Uranium also has the same limits as follows:

Uranium 5000 dpm a/100cm2, averaged over a 1 in2 area 15,000 dpm a/l100cm 2, maximum in a 100 cm2 area if the average over 1 m2 is met.

1000 dpm a/100cm2, removable activity Beta/Gamma Emitters 5000 dpm /100cm 2, averaged over a 1 m2 area 15,000 dpm/1 00cm 2, maximum in a 100 cm2 area if the average over I m2 is met.

1000 dpm /100cm 2, removable activity Alert Levels Notify Health Physics management if any of the following alert levels are exceeded.

Smears If any smear is >75% of the release level (750 dpm/100cm 2), increase the number of smears to define the area of contamination and mark the area.

Alpha Alert Levels If the following "alert levels" are exceeded, notify HP Management so an evaluation can be performed to determine if increased survey coverage is required or to evaluate if decontamination is required.

A-6

Page 4 of 5

> 100 cpm alpha using the large area (434 cm') probe

> 60 cpm using a hand-held alpha probe (50 cm2) -

(- 1500 dpm/100cm2)

Beta Alert Levels If the following "alert levels" are exceeded, notify HP Management so an evaluation can be performed to determine if increased survey coverage is required or to evaluate if decontamination is required.

• - 300 cpm beta above background using the large area (434 cm') probe

• - 200 cpm above background using the 100 cm2 probe

> -100 cpm above background using a portable GM detector.

Documentation Every survey conducted must be documented on a daily basis on a drawing showing the approximate locations surveyed. Include the results (including units), the technician"s name and signature, date, instrument(s) used (including model and serial number of both the rate meter and the detector), calibration due date, % efficiency, background readings, (if applicable), and any other applicable information.

A-7

Page 5 of 5 Radiological Final Surveys for the "Group 12" labs in Building 2 218 401 403 405 407 411 413 415 Mezzanine 619/621.

Mezzanine above 409, above

-300 ft2

-250 ft2

-408 ft2

-336 ft2

-312 ft2

-456 ft

-336 ft

-336 ft2 411/413,415

-672 ft2 619/621 Type of

-882 ft2

-464 ft2 Survey Suspect Suspect Suspect Suspect Suspect Suspect Suspect Unaffected Unaffected Suspect Unaffected Affected Affected Affected Affected Affected Affected Affected Area Area Affected Area Area Area Area Area Area Area Area Area Gridding Yes Yes Yes Yes Yes Yes Yes No No Yes No Floor a scan 10%

100%

100%

100%

100%

100%

100%

10%

10%

100%

10%

Floor 3 scan 100%

100%

100%

100%

100%

100%

100%

1.00%

100%

100%

100%

Walls Bottom 100%

100%

100%

100%

100%

100%

100%

100%

100%

100%

100%

2m P3 scan Walls above 10%

10%

10%

10%

10%

10%

10%

10%

10%

10%

10%

2m P3 scan No. of Fixed 16 16 16 16 16 16 16 16 22 20 16 Measurements I min.

l I min.P I min.P 1m in. P 1 min.

I mrin. P 1 min.

1m min. 3 I min.

1m min. P 1m min, No. Of Paint I per 1 per I per 1 per I per 1 per 1 per 1 per wall I per wall 1 per 1 per wall Samples wall wall wall wall wall wall wall wall Take a 1 minute fixed Beta measurement before and & after paint removal.

16 16 16 16 16 16 16 16 22 20 16 No. Smears 8 - floor 8 - floor 8-floor 8-floor 8-floor 8-floor 8-floor 8-floor 11-floor 10-floor 8-floor 8 - walls 8 - walls 8 - walls 8-walls 8-walls 8-walls 8-walls 8-walls 1 1-wall 10-wall 8-walls No. Of MicroR Every Every Every Every Every Every Every Every Every Every Every Readings 2m 2 m 2m 2m 2m 2m 2m 2m 2m 2m 2m Overhead 10 10 10 10 10 10 10 10 smears 10 smears 10 10 smears Fixtures smears smears smears smears &

smears &

smears smears

& scan 25%

& scan 25%

smears

& scan 50%

Smears &

& scan

& scan

& scan scan 25%

scan 50

& scan

& scan of fixtures of fixtures

& scan of fixtures Scans of flat 25% of 25% of 25% of of

% of 25% of 50% of 25% of surfaces fixtures fixtures fixtures fixtures fixtures fixtures fixtures fixtures Floor Drains T

ret adingx (alpha and beta) and smgarx on each floor drain found In addition, collect sludge sample when applicable

AMENDMENT #1 FINAL SURVEY PLAN FOR "GROUP 12" LABS IN BUILDING 2 Prepared by: f---//f

,4,1/* Ct Date:.

"-/'- CO Paul R. Maschka

Background

"Group 12" labs now consist of labs 401, 403, 405, and 407. The first survey found radioactive contamination in all of these labs on the floors, on the walls below 2 meters, and on the floor drain. No radioactive contamination was detected on the overhead fixtures or on the wall above 2 meters. A sample of material was removed from the floor drain in Lab 407. The sample was gamma scanned and Cs-137, Thorium, and enriched uranium were detected in the sample.

The contaminated drainline was removed and packaged as radioactive waste, a soil sample was taken. The floors and walls were decontaminated and post decontamination surveys verified that the deconned areas were below the approved release criteria.

Seven samples of the material removed during decontamination were collected and gamma scanned to determine the radioactive isotopes present.

Isotopes detected above release criteria Labs 401 - 403 = U-235.

Lab 405

= Thorium, U-238, and U-235.

Lab 407

= Cs-137, Thorium, U-238, and U-235.

Survey Objectives and Responsibility and History of Use See Final Survey Plan for "Group 12" Labs in Building 2 prepared by Laura Q.

Gonzales, dated March 8, 2000.

The thorium release criteria will apply to this final survey.

Classification All of these labs are classified as Suspect Affected Areas.

Release Limits The primary contaminants of concern for these labs are natural thorium, enriched C:IGEN-ATOMID&Dib-2IGrp 12Attach I Final Sug,;.wpd A-9

uranium, and Cs-137. The applicable NRC guidelines for residual Cs-13 7, uranium and thorium surface activity levels are:

Natural Thorium 1000 dpm t/100cm 2, averaged over a 1 m 2 area 3000 dpm 0/1OOcm 2, maximum in a 100 cm2 area if the average over 1 m 2 is met.

200 dpm

/1OOcm 2, removable activity As interpreted by the NRC, the average 1000 dprn/00cm2 and the maximum 3000 dpm/100cm 2 should apply to both alpha and beta measurements, independently, for surface contamination involving natural thorium. 1 Thorium emits alpha radiation to beta radiation in a 1:0.67 ratio; therefore, the corresponding average and maximum beta activity guidelines were adjusted to be 670 dpm/OOcm 2 and 2000 dpm/OOcm 2,

respectively.

Enriched Uranium 5000 dpm l/l100cm 2, total, averaged over a 1 m2 area 15,000 dpm a/1OOcm 2, maximum in a 100 cm 2 area if the average over I m2 is met.

1000 dpm a/1OOcm 2, removable activity Beta/Gamma Emitters 5000 dpm/100 cm2, averaged over J m2 area 15,000 dpm/100 cm2, maximum in a I00cmO area if the average over 1m 2 is met.

1000 dpnV/100 cm 2, removable activity.

Since the instruments cannot distinguish between uranium and thorium contamination, the most restrictive activity guideline for natural thorium (670 dpm/lOOcm 2 ) is used to compare all direct measurements for beta activity.

Alert Levels Notify Health Physics management if any of the following alert levels are exceeded.

Smears If any smear is >75% of the release level (150 dpm/100cm 2), increase the number of smears to define the area of contamination and mark the area.

Alpha Alert Levels If the following "alert levels" are exceeded, notify HP management so an evaluation can be performed to determine if increased survey coverage is required or to evaluate if further decontamination is required.

C:IGEN-ATOM1D&DIb-21Grp 12 Attach I Final Sumvy.wpd A-10

> 100 cpm alpha using the large area (434 cm 2) probe.

>60 cpm using a hand-held alpha probe (50 cm 2

- -1500 dpm/O0 cmI ).

Beta Alert Levels If the following "alert levels" are exceeded, notify HP management so an evaluation can be performed to determine if increased survey coverage is required or to evaluate if further decontamination is required.

>-300 cpm beta above background using the large area (434 cm 2) probe

>-200 cpm beta above background using the 100 cm 2 probe.

>- 100 cpm beta above background using a portable GM detector.

NOTE: Use the 100 cm2 beta probe to hand frisk any areas above the 434 cm 2 alert level.

C:IGEN-ATOMID&DIb-2[Grp 12 Atach I Final Sunme.y pd A-I1

Radiological Final surveys for the "Group 12" Labs in Building 2 401 403 405 407 Type of Survey Suspect Affected Area Suspect Affected Area Suspect Affected Area Suspect Affected Area Gridding Yes Yes Yes Yes Floor a scan 100%

50%

100%

100%

Floor P scan 100%

100%

100%

100%

Wall Bottom 2m 100%

100%

100%

100%

Pscan Number of Fixed 10-1 min. P3 (100 cm2 probe) 10-1 min. P (100 cm 2 probe) 10-1 min. P (100 cm 2probe) 10-1 min. P (100 cm2 probe)

Measurements 10 - 30 sec (X(50 cm2 probe) 10 - 30 sec a (50 cm2 probe) 10 - 30 see a (50 cm 2 probe) 10 - 30 see aX (50 cm 2 probe)

Number of 16 16 16 16 Smears Number of ý,R One Every 2m @ Im above One Every 2m @ lm above One Every 2m @ 1m above One Every 2m @ Im above readings the floor the floor the floor the floor C.IGEN.ATOMID&DIb-21Grp 12 Attach 1 Final Surpy.wpd

APPENDIX B GENERAL ATOMICS' INTERNAL CONFIRMATORY SURVEY B-1

Appendix B: GA Internal Confirmatory Survey of the Group 12 Laboratories Confirmatory Survey Plan Objective To provide additional assurance that the Final Survey was effective in demonstrating that the radiological conditions of the "Group 12" labs (labs 401, 403, 405, and 407) meet the NRC and State approved criteria for release to unconditional use.

Beta Scans

1.

Scan -50% of all floors using a 434 cm 2 beta gas flow proportional counter.

2.

Spot check the wall along the floor and in and around areas that were decontaminated.

3.

Check all areas that measure above alert levels with a GM detector.

Alpha Scans

1.

Scan - 25% of all floors using a 434 cm 2 alpha gas flow proportional counter.

2.

Check all areas that measure above alert levels with a hand-held alpha counter.

Direct Measurements Use the 100 cm 2 beta counter and a hand-held alpha counter (50 cm2), take 4 measurements with each instrument on the floor in each lab. Beta reading 1 minute and alpha readings 30 seconds.

Removable Contamination Smears Collect 6 smears in each lab in random locations on the floors and walls.

Exposure Rate Measurements Scan -25% of the floor surface (-6" above the floor) in each lab.

Take 2 measurements in each lab at Im above the surface.

Alert Levels 434 cm2 beta detector

>300 cpm above background 434 cm 2 alpha detector

>100 cpm above background 100 cm2 beta detector

>200 cpm above background 50 cm 2 alpha detector

> 60 cpm above background 15 cm 2 GM detector

>100 cpm above background MicroR meter

> 25 iR/hr on the surface and 20 p.R/hr at Im from the surface.

Documentation Every survey conducted must be documented on a daily basis on a drawing showing the approximate locations surveyed. Include the results (including units), the technician's signature, date, instrument(s) used (including model and serial number of both the ratemeter and the detector), calibration due date, % efficiency, background readings (if applicable) and any other applicable information.

B-2

Survey Results Scanning - The results of the alpha and beta scans are provided in Table 1B and in Figures IB, 2B, 3B and 4B. The results were at or near background levels.

Fixed Measurements (and Soil Sample Results) - During the conduct of the Final Survey, several areas with remaining elevated readings were noted. During the Confirmatory Survey, these areas were further investigated using the floor monitor and the 100 cm2 beta probe. Additional measurements still showed levels > 670 dpm/100 cm2 in the same locations in labs 403 and 407.

The maximum measurement obtained with the 100 cm 2 beta probe was 1216 dpm/100 cm2.

Concrete samples were collected and analyzed by gamma spectroscopy. The contaminant was identified as Cs-137 which has a 5,000 dpm/100 cm 2 average limit; therefore, the levels were below the release criteria for Cs-137. However, after removal of the concrete sample, it was noted that fixed radiation levels increased. Most likely this was due to previous decontamination efforts and subsequent repair of the concrete done in the 1980's. In order to (1) avoid the need to investigate further and (2) to check the soil underneath the concrete, it was decided to remove the concrete entirely from the 3 locations where elevated levels remained and dispose of the concrete as radioactive waste. In lab 403, concrete was removed from an area -

m2 and in lab 407, concrete was removed from 2 locations; one -1 m2 area and another -0.5 m2 area. Exposure rate measurements on the surface of the soil were taken. In addition, soil samples were collected and analyzed by gamma spectroscopy. The approximate locations of the soil samples are shown in Figure 10 for lab 403 and Figure 22 for lab 407.

These results are provided with the Confirmatory Survey Report in Table 2B. Alpha fixed measurements were all at or near background levels (see Table 1 B).

Removable Contamination Levels - A total of 24 100 cm 2 smears were collected and counted for gross alpha/gross beta radioactivity. All results were < 10 dpm/100 cm2. (See Table IB).

Exposure Rate Measurements - Exposure rate measurements were taken at 1 m from the surface in each lab. Readings ranged from 17-19 MR/hr (see Table IB); well below the release criteria.

In addition, exposure rate measurements were taken in exposed soil areas on the surface and at 1 m from the surface. These results are provided in Table 3B and show levels well below the release criteria.

Conclusion The confirmatory survey indicated three small areas where elevated readings remained. GA decided to remove the concrete from these 3 locations and dispose of the concrete as radioactive waste. The results of surveys performed on the remaining concrete in each lab showed radiation levels well below the release criteria. Soil samples collected in labs 403 and 407 showed levels well below the approved soil release criteria.

The results of the final and confirmatory surveys provided in this report, demonstrate that the labs, designated as "Group 12", meet the NRC-and State-approved guidelines for release to unrestricted use.

B-3

Table IB: Results of Confirmatory Surveys in Building 2 Grou~p 12 Laboratorie's a Scan P3 Scan Fixed Measurements Removable Results Results Contamination Exposure Rate Figure Location 43 4 cm' 434 cm2 andTotalMeasurements and Surface (range in (range in cpmn)

AhaBt Tol Apa e

(1ý&Rhr)

Lbcpm) 1mrnfrom

.maximium Maximu~m surface dv/

0 m')dvm/100 cm2 I_____

1 concrete floor 0 -20 1600-2200 Lab 401 concrete block 15 MDA(323)

MDA (443) 6

<10

<10 18

______wal0

- 20 1608-2047 wall 2

concrete floor 0 - 20 1600-2000 Lab 403 concrete block 0- 20 1600-2000 13 MDA(323)

MDA (443) 6

<10

<10 17-18 wall 3

concrete floor 0 -20 1650-2000 concrete block 11 MDA (323)

MDA (443) 6

<10

<10 18 Lab 405 ccrebok 0 -20 1361-1881 wall concrete floor 0-20 1557-1804 4

concrete block 12 MDA (323)

MDA (443) 6

<10

<10 18-19 Lab 407 0 -20 1319-1342 B-4

TABLE 2B:_GAMMA SPECTROSCOPY RESULTS OF SOIL SAMPLES FROM LABS 403. AND 407 Radionuclide Concentration (pCi/gm) tResults 2

- Background not Subtracted - 30 minute counts Sample Sample 137Cs loco 228Th

ý281Ra Total 23U 35 Evaluation and ID Location 662 Key Ave.of

.Ave.

of (232Th>

Thoriu m 92.77 keV 186(144) keV

.Comments peak 117311332.

238/583 key Ave.

22STh4+22Th peak peak Key peaks.

peaks 3381911 B2 403-1 Soil from ND ND 1.25 +/- 0.16 2.35 +/- 0.54 3.60 3.06 +/- 1.11 0.25 +/- 0.11 Below Release lab 403 Criteria B2 403-2 Soil from ND ND 1.18 +/- 0.14 1.93 +/- 0.41 3.11 2.31 +/- 0.70 0.27 +/- 0.09 Below Release lab 403 Criteria B2 407-1 Soil from ND ND 1.15 +/- 0.13 2.09 +/- 0.44 3.24 2.01 +/- 0.72 0.14 +/- 0.08 Below Release lab 407 Criteria B2 407-2 Soil from ND ND 1.20 +/- 0.12 1.72 +/- 0.31 2.93 2.51 +/- 0.67 0.21 +/- 0.09 Below Release lab 407 Criteria B2 407-3 Soil from 0.15 +/- 0.10 ND 1.16 +/- 0.14 1.97 +/- 0.42 3.13 2.67 +/- 0.95 0.20 +/- 0.08 Below Release lab 407 Criteria B3 407-4 Soil from 0.09 +/- 0.09 ND 1.04 +/- 0.11 1.86 +/- 0.39 2.91 2.12 +/- 0.60 0.24 +/- 0.08 Below Release I lab 407 1

I__

I__I_

_I__

I Criteria j

B-5

Table 3B: Exposure Rate Measurements on Exposed Sail B-6 Location On Soil Surface (piR/hr)

At 1 m from the Surface (gR/hr)

Lab 403 20-21 17-18 Lab 407 (location 1) 22-26 18 Lab 407 (location 2) 21 18 Lab 407 Drain Line Trench 18-19 18

Figure 1B:

Lab 401 1

2 3

4 5

A B

C D

E F

G H

MEAR #

0cm 2 53 READING in dpm/100cm 2 cm2 oc READING in dpm/100cm 2

= iiR READING @

S...............

1 m e te r 1600 -1800= 434cm 2 f SCAN in cpm 0 -20

=434cm2 aSCAN in cpm 1 meter Building 2, Lab 401 - Confirmatory Survey M odel Serial #

Cal Due ECf%

a *"

Probe #

Probe Size Material

Background

Date cm, cpm Ludlam 2221 97287 09/13/00 21.25 C0 148926 434 concrete 0 - 20 Ludlum 12 91051 10/12/00 21.58 a*

094053 50 concrete 0 - 20 Ludlum 19 123930 07/13/00 N/A y

N/A N/A concrete 11 -15 1.RP/hr Lu dlum 2221 148436 07/10/00 26.27 4

120477 100 co nrrete 554 Li dlum 2221 86302 10/23/00 21.46 1

096215 1

434 concrete 1538 Ludlum 3 143349 11/23/00 20.26 145967 15 concrete 100 - 120 COMM EN TS:

The concrete floor was surveyed at contact using the Lud urn 19 ý, R meter. The read ings ranged from 17-20[1 R/hr.

All elevated readings were checked with handheld instruments. 100cm' beta MI DA= 443dpm/100crn'. 50cm' alpha M DA= 323d pm/100cm' S u rveyo r(s): B -H un tei/

J.Sui liv an/

Dat c:5/30/00 and 05/31 /00 Reviewed By: P. M aschka/

Date:

6 7

N S

LEGEND:

S--

St

-]

= 5c L6I

=50 J

K S urvev:

INSTRUM ENTS

Figure 2B:

Lab 403

! 2:3 4

5 6

7 C

G H

K 1 meter Survey:

Building 2, Lab 403 - Confirnmatory Survey IN STRUM ENTS M odel Serial #

Cal Due E ff%

a y

Probe l:

Probe Size M aterial B ackgrou nd Date cm 2 cpm Ludlum 2221 97287 09/13/00 21.25 a

148926 434 concrete 0 - 20 Ludlum 12 91051 10/12/00 21.58 a

094053 50 concrete 0 - 20 LLudlum 19 123930 07/13/00 N/A y

N/A N/A concrete I I -15 pR/hr Ludlum 2221 148436 07/10/00 26.27 13 120477 100 concrete 554 Ludlum 222L 86302 10/23/00 21.46 f3 086215 434 concrete 1538 Ludlum 3 143349 11/23/00 20.26 fI 145967 15 concrete 100 - t20 co0MI M EN TS:

The concrete floor was surveyed al contact using the Ludlum 19 p R meter. The readings ranged from 17-20 pR/hr.

Allelevated readings were checked with handheld instruments.

Surveyor(s):B. Hunter/

J.Sullivan/

Date:05/30/00 and 05/31/00 Reviewed By: P. Maschka/

Date:

8 9

N S

A B

LEGEND:

SOIL AREA

@1 meter RR/hr

@ contact gR/hr = p.R SOIL SMA f--7

= 100cm 2

READING 1

dpm/100cm2 A

= 50cm2 C READING in dpm/100cm 2

S=

pJ.R READING @

1 meter 1600 -2000

= 434cm2 f3 SCAN in cpm 0.20

=434cm2 SCAN in cpm in a

Figure 3B:

Lab 405 1

2 3

4 5

6 7

8

.....1.

L i~ii:

• i.....

1800o-o2200 y

0- 20:a N

S C

D E

F G

H Survey:

Building 2, Lab 405 Confirmatory Survey IN STRUM ENTS M odel Serial #

Cal Due Eff%

a py Probe #

Probe Size M aterial

Background

Date cm 2 cpm Ludlum 2221 97287 09/13/00 21.25 0c 148926 434 concrete 0 -20 Ludlum 12 91051 10/12/00 21.58 a*

094053 50 concrete 0 - 20 Ludlum 19 123930 07/13/00 N/A y

N/A N/A concrete I I -15,aR/hr Ludlum 2221 148436 07/10/00 26.27 3

120477 100 concrete 554 Ludlum 2221 86302 10/23/00 21.46 I3 086215 434 concrete 1538 Ludlum 3 143349 11/23/00 20.26 P

145967 15 concrete 100 - 120 COMM ENTS:

The concrete floor was surveyed at contact using the Ludlum 19 p R meter. The readings ranged from I7-20 aR/hr.

All elevated readings were checked with handheld instrun.rents.

The 50cm 2 alpha M DA = 323dpm/I 00cm 2.

The 100cm2 beta M DA =443dpm /100cm

2.

Surveyor(s):B. Hunter/

J.Sullivan/

Date.05/30/00 and 05/31/00 Reviewed By: P. Nlaschka/

Date:

A B

-: E ;

LEGEND:

=SMEAR #

100cm 2 Ayl READING in dpm/OOcm2 A*

= 50cm 2 a READING in dpmloocmz D#_

=RRREADING @

SImeter 1600 - 1800 = 434cm2 *yl SCAN in cpm 0-20 =434cm2 a SCAN in cpm J

K

Figure 4B:

Lab 407 1

2 3

4 5

6 7

N S

A C

E F

G H

Survey:

Building 2, Lab 407 - Confirmatory Survey IN STRUM ENTS Model Serial #

Cal Due Eff%

citpy Probe#

Probe Size Material

Background

Date Cr2 cpm Ludlurn 2221 97287 09/13/00 21.25 a

148926 434 concrete 0-20 Ludluin 12 91051 10/12/00 21.58 a

094053 50 concrete 0-20 Ludlum 19 123930 07/13/00 N/A y

N/A N/A concrete I1 -15 pR/hr Ludlum 2221 148436 07/10/00 26.27 P

120477 00 concrete 554 Ludlum 2221 86302 10/23/00 21.46 P

086215 434 concrete 1538 Ludlum 3 143349 11/23/00 20.26 t3 145967 15 concrete 100 - 120 COM M ENTS:

The concrete floor was surveyed at contact using the Ludlun 19 p R meter. The readings ranged from 17-20 pR/hr.

All elevated readings were checked with handheld instruments.

The 50crn2 alpha MDA = 323dprn/lO0ctn 2.

The 100cm 2 beta MDA = 443dpm/100 2 Surveyor(s):B. Hunter/

J.Sullivan/

Dale:05/30/00 and 05/31/00 Reviewed By: P. Nlaschka/

Date:

n/100cm 2

/100cm2 8

S....

LEGEND:

= SOIL AREA

@ m e te r ILR /h r

@contact JtR/hr = plR soil

= SMEAR #

~MDA W..

= 100cm2 1 READING in dpr

50cm2 C READING in dprr R

LR READING @ 1meter 1666 - 1791 =434cm 2 SCAN incpm 0-20

= 434cm 2 CC SCAN in cpm 1 meter K

............