ML052140134

Final Status Survey Report for Saxton Nuclear Experimental Corp Saxton Steam Generating Station Structural Surfaces - Seal Chamber Roofs SS17 (1&2) and SS18 (1&2).

ML052140134
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Site:	Saxton File:GPU Nuclear icon.png
Issue date:	07/31/2005
From:	GPU Nuclear
To:	Office of Nuclear Reactor Regulation
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Download: ML052140134 (18)

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Final Status Survey Report For Saxton Nuclear Experimental Corporation Saxton Steam Generating Station Structural Surfaces - Seal Chamber Roofs SS17(1&2) and SS18(1&2)

UZ-10, *.. I Prepared by GPU Nuclear, Inc.

July 2005

Table Of Contents Executive Summary

1.0 Purpose and Scope

2.0 Survey Area Description 3.0 Operating History 3.1 Plant Operations 3.2 Survey Area Remediation Status 4.0 Site Release Criteria 5.0 Final Status Survey Design / DQO Process 6.0 Final Status Survey Results 6.1 Summary for Survey Unit SS17-1 6.2 Summary for Survey Unit SS17-2 6.3 Summary for Survey Unit SS18-1 6.4 Summary for Survey Unit SS18-2 6.5 7.0 Data Assessment 7.1 Assessment Criteria 7.2 Summary of Overall Results 7.3 Survey Variations 7.4 Quality Control Measurements 8.0 Final Survey Conclusions 9.0 References 10.0 Appendices i

Executive Summarv This report presents the results and conclusions of the final status survey (FSS) of the Class 1, 2, and 3 structural surfaces of the Saxton Nuclear Experimental Corporation (SNEC) facility designated as SS17-1, SS17-2, SS18-1, and SS18-

2. The survey unit designated SS17 is not included. This FSS includes surveys of residual structural surfaces (e.g. concrete and steel) in the roof areas of the three discharge tunnel seal chambers of the Saxton Steam Generating Station of the SNEC site and was conducted in the summer of 2004.

The FSS was performed in accordance with the SNEC License Termination Plan (LTP). The seal chamber roof survey area was divided into four survey units.

Each unit consisted of relatively flat residual structural surfaces but did contain some uneven concrete and steel. Data was collected from each survey unit in accordance with the specific survey design data collection requirements. The following is a summary of the measurements performed:

1) Gas Flow Proportional Counter (GFPC) scans of concrete and steel surfaces

2) Nal scans of concrete and steel surfaces

3) Fifty one GFPC static measurements

4) Twenty five smear samples The collected FSS survey data demonstrate that the 148 square meters of the SSGS Seal Chamber Roof survey area meets the radiological release criteria for unrestricted use specified in IOCFR20.1402. Therefore GPU Nuclear, Inc.

concludes that the area meets the NRC requirements and may be released for unrestricted use.

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1.0 Purpose and Scope

This report presents the results and conclusions of the final status survey of the residual structural surfaces of the SSGS Seal Chamber Roof areas (four survey units designated SS17-1, SS17-2, S18-1, and SS18-2) west of the SNEC facility.

The area designated SS17 (with no extension) is a different survey area and is not included herein and will be reported separately. This report provides the information required by 10CFR50.82(a)(11) and the SNEC license termination plan (LTP) to demonstrate that this area meets the radiological criteria for unrestricted use specified in 10CFR20.1402.

This report describes the radiological data collected in one Class 1, two Class 2, and one Class 3 survey units of residual structural surface of the SSGS Seal Chamber roof area. This report only addresses the FSS performed on this specific area. The format of this report follows the guidance contained in reference 9.2.

2.0 Survey Area Description The SSGS Seal Chamber Roof areas are Class 1, 2, and 3 impacted structural surface located below grade to the west of the SNEC facility. The survey unit encompasses about 148 square meters of concrete and steel. Because the area exceeds the size guidance in the SNEC LTP for Class 1 survey units (up to 100 square meters recommended), because the classification varies spatially through the area, and because there are distinct regions of the chamber roof area, the survey area has been divided into four survey units. The four survey units are discussed below. The individual survey unit designations are derived from table 5-2 of the SNEC LTP (reference 9.3).

Survey unit SS17-1 is a Class 3 residual concrete and steel surface of the SSGS Seal Chamber Roof area. It consists of the walls above the roof of discharge tunnel seal chamber number 3 - an underground room at the upstream end of the discharge tunnel from the SSGS to the river outfall. The survey unit is approximately 35 square meters.

Survey unit SS17-2 is a Class 2 residual concrete and steel surface of the SSGS Seal Chamber Roof area. It consists of the walls above the roof of discharge tunnel seal chamber numbers 1 and 2 - underground rooms at the upstream end of the discharge tunnel from the SSGS to the river outfall. The survey unit is approximately 50 square meters.

Survey unit SS1 8-1 is a Class 2 residual concrete and steel surface of the SSGS Seal Chamber area. It consists of the horizontal top or roof surface of discharge tunnel seal chamber number 3 - an underground room at the upstream end of 2 of 16

the discharge tunnel from the SSGS to the river outfall. The survey unit is approximately 20 square meters.

Survey unit SS18-2 is a Class 1 residual concrete and steel surface of the SSGS Seal Chamber area. It consists of the horizontal top or roof surface of discharge tunnel seal chambers numbers 1 and 2 - underground rooms at the upstream end of the discharge tunnel from the SSGS to the river outfall. The survey unit is approximately 43 square meters.

3.0 Operating History 3.1 Plant Operation The Saxton Nuclear Experimental Corporation (SNEC) facility included a pressurized water reactor (PWR), which was licensed to operate at 23.5 megawatts thermal (23.5 MWTh). The reactor, containment vessel and support buildings have all been removed. The facility is owned by the Saxton Nuclear Experimental Corporation and is licensed by GPU Nuclear, Inc. The SNEC facility is maintained under a Title 10 Part 50 license and associated Technical Specifications. In 1972, the license was amended to possess but not operate the SNEC reactor.

The facility was built from 1960 to 1962 and operated from 1962 to 1972 primarily as a research and training reactor. Steam from the SNEC reactor was directed to the adjacent Saxton Steam Generating Station (SSGS) to generate electricity.

Other shared systems also introduced SNEC activity into the SSGS and the main SNEC discharge entered the SSGS discharge tunnel. After shutdown in 1972, the SNEC facility was placed in a condition equivalent to the current SAFSTOR status. Since then, it has been maintained in a monitored condition. The fuel was removed in 1972 and shipped to a (now DOE) facility at Savannah River, SC, who is now the owner of the fuel. As a result of this, neither SNEC nor GPU Nuclear, Inc. has any further responsibility for the spent fuel from the SNEC facility. The building and structures that supported reactor operation were partially decontaminated by 1974. The SSGS was dismantled circa 1974.

In the late 1980s and through the 1990s, additional decontamination and disassembly of the containment vessel and support buildings and final equipment and large component removal was completed. Final decontamination and dismantlement of the reactor support structures and buildings was completed in 1992. Large component structures, pressurizer, steam generator, and reactor vessel were removed in late 1998. Containment vessel removal (to below grade) and backfill was completed in late 2003. Currently, decontamination, disassembly and demolition of the SNEC facility buildings and equipment has been completed and the facility is in the process of Final Status Survey for unrestricted release and license termination.

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3.2 Survey Area Remediation Status There was no known remediation in the seal chamber roof areas. Loose material and debris was removed from the areas to facilitate survey.

4.0 Site Release Criteria The site release criteria applied to the structural surface areas of the SSGS seal chamber roof area correspond to the radiological dose criteria for unrestricted use per 10CFR20.1402. The dose criteria is met uif the residual radioactivity that is distinguishable from background radiation results in a Total Effective Dose Equivalent (TEDE) to an average member of the critical group that does not exceed 25 mrem/yr, including that from groundwater sources of drinking water, and that the residual radioactivity has been reduced to levels that are as low as reasonably achievable (ALARA)".

Levels of residual radioactivity that correspond to the allowable dose to meet the site or survey unit release criteria for structural surfaces were derived by analyses using a building re-use scenario. The dose modeling for this scenario is explained in the SNEC LTP (reference 9.3). The derived concentration guideline levels (DCGL) shown in Table 5-1 of the SNEC LTP form the basis for satisfying the site release criteria.

Residual radioactivity sample results for the surfaces were used to calculate a surrogate Cs137 DCGL. The adjusted surrogate DCGL was developed using the methodology described in the SNEC LTP section 5.2.3.2.3 based on nuclide specific DCGLs from Table 5-1 of the LTP.

An adjustment was made to the surrogate Cs137 DCGL to address the de-listed radionuclides as described in the LTP section 6.2.2.3. SNEC has instituted an administrative limit of 75% of the DCGL for all measurement results. The de-listed radionuclides are conservatively accounted for in this 25% reduction since the de-listed radionuclides were only 4.7% of the dose contribution. These adjustment factors are discussed in section 6 of the SNEC LTP.

5.0 Final Status Survey Design and DQO The SNEC calculations providing the design of the survey for these survey units are provided in Appendices A and B. Scan coverage of the Class 1 survey unit covered approximately 100% of the available surfaces. Scan coverage of the Class 2 and Class 3 survey units was about 50% of the surface. Scans were conducted using Gas Flow Proportional Counters (GFPC) and 2 inch by 2 inch Nal detectors. Fixed point measurements were performed with the 43-68 GFPC detector.

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The survey design uses a surrogate Csl 37/gross beta effective DCGL developed from radionuclide mix analyses from samples collected before the Final Status Survey in the vicinity of the survey unit. The mix was based on radionuclide mix data (including the hard-to-detects listed in Table 5-1 of the LTP) from the CV tunnel and SSGS mezzanine (attachment 3 of appendix B).

Cs137, Co6O, and Sr9O were positively detected in one or more of these samples and are accounted for in the adjusted surrogate DCGL. The following table (Table 5.0-1) presents the Data Quality Objectives (DQO) and other relevant information from the survey design package.

Table 5.0 DQO/Design DQOfDesign Parameter* SS17-1, SS18-1 SS17-2, SS18-2 SNEC Design Caic. # E900-03-032 E900-04-012 MARSSIM Classification 3, 2 2, 1 2

Survey Unit Area (M ) 35, 20 50, 43 Statistical Test WRS WRS Type 1 decision error (a) 0.05 0.05 Type 2 decision error (P) 0.10 0.10 LBGR (cpm) 1200 1640 Estimated a (cpm) 34.5 147 Relative Shift (A/cr) 2.9 2.9 Number of static points 14,12 10,15 DCGLw (Cs137 27250 27250 dpm /100cm 2 )__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

75% Admin Limit* (Cs137 20438 20438 dpm/ 00cm 2 )

75%Admin Limit -scan 900 (net GFPC) 1100 (gross GFPC)

(cPm) 200 (gross Nal) 300 (gross Nal)

Scan MDC (dpm/lOOcm2) 738 837 Scan MDC (pCi/g) 2.7 5.3 SNEC Survey Request # SR154 SR144 L2350 w/ 43-68, L2350 w/ 43-68, Scan Survey Instrument L2350 w/ 44-10 L2350 w/ 44-10 6.0 Final Status Survey Results The following sections provide the survey summary results for each survey unit as required by the respective design. Summary data was taken from references 9.8 and 9.9 which is filed in the SNEC history files.

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6.1 Survey Unit SS17-1 6.1.1 Scan survey Scan measurements were made in SS17-1 using the GFPC and the Nal detector. The GFPC had an MDCscan of 738 dpm/l1OOcm 2 (table 3 on page 2 of appendix A). The Nal had an MDCscan of 2.7 pClg (table 4 on page 3 of appendix A). The adjusted surrogate Csl 37 beta DCGLw for this survey unit was 27250 dpm/1OOcm 2 and the 75% administrative limit was 20438 dpml1OOcm 2 (attachment 3-5 of appendix B).

Of the 35 square meters of this survey unit portions were not scanned because it is a Class 3 survey unit. Of the 35 square meters, about 17.5 were scanned with both the GFPC and with the Nal. Therefore about 50 percent of the survey unit was scanned which is consistent with scan coverage requirements for Class 3 survey units.

All GFPC scan surveys indicated activity less than the action level of 900 net cpm. All Nal scan surveys indicated less than the action level of 200 gross cpm.

6.1.2 Fixed point measurements Fourteen random start triangular grid systematic fixed point measurement locations were defined for the survey unit. Based on a conservative relative shift of about 2.9 a minimum of 8 fixed points were required.

None of the design fixed point measurements in SS17-1 had results in excess of the of 75% administrative limit of 1300 net cpm (section 2.1.5 on page 3 of appendix A) for the GFPC measurements. The table below (Table 6.1-1) shows the gross beta results for each fixed point measurement, along with the mean, standard deviation and range of the fixed point measurement data.

The standard deviation of the GFPC measurements collected from the survey unit was greater than the variability assumed in the survey design. Since the LBGR used for the survey design was much greater than the typical 50% of the DCGL, a relative shift of about 3 would still result from the observed variability and adjustment of the LBGR. Therefore, the assessment of variability, relative shift , and number of fixed point measurements required is consistent between the survey design and the survey results. Based on this, no changes to the survey design or additional measurements are required.

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Table 6.1 Fixed point results for SSI7-1 Point GFPC Number Unshielded cpm A 344 B 259 o 312 D 361 E 310 F 277 G 285 H 270 l 208 J 232 K 351 L 310 M 262 N 228 Mean 286 Std Dev 47.3

. Min 208 Max 361 6.2 Survey Unit SS17-2 6.2.1 Scan survey Scan measurements were made in SS17-2 using the GFPC and the Nal detector. The GFPC had an MDCscan of 837 dpm/1 00cm 2 (attachment 8-12 of appendix B). The Nal had an MDCscan of 5.3 pCi/g (table 3 on page 2 of appendix B). The adjusted surrogate Cs137 beta DCGLw for this survey unit was 27250 dpm/1 00cm 2 and the 75% administrative limit was 20438 dpm/1 00cm2 (attachment 3-5 of appendix B).

Of the 50 square meters of this survey unit portions were not scanned because it is a Class 2 survey unit. Of the 50 square meters, about 25 were scanned with both the GFPC and with the Nal. Therefore about 50 percent of the survey unit was scanned which is consistent with scan coverage requirements for Class 2 survey units.

All GFPC scan surveys indicated activity less than the action level of 1100 gross cpm. All Nal scan surveys indicated less than the action level of 300 gross cpm.

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6.2.2 Fixed point measurements Ten random start triangular grid systematic fixed point measurement locations were defined for the survey unit. Based on a conservative relative shift of about 2.9 a minimum of 8 fixed points were required.

None of the design fixed point measurements in SS17-2 had results in excess of the of 75% administrative limit of 2077 net cpm (section 2.3.3 on page 3 of appendix B) for the GFPC measurements. The table below (Table 6.2-1) shows the gross beta results for each fixed point measurement, along with the mean, standard deviation and range of the fixed point measurement data.

The standard deviation of the GFPC measurements collected from the survey unit was less than the variability assumed in the survey design. Therefore, the assessment of variability, relative shift, and number of fixed point measurements required is consistent between the survey design and the survey results. Based on this, no changes to the survey design or additional measurements are required.

Table 6.2 Fixed point results for SS17-2 Point GFPC Number Unshielded cpm 1 287 2 286 3 293 4 348 5 305 6 339 7 333 8 349 9 1 434 10 420 Mean 339 Std Dev 52.3 Min 2861 Max 434 Ten smears were collected at the locations of the fixed point measurements. All smear results were less then the MDCs of <166 dpm beta and <12.3 alpha.

6.3 Survey Unit SS18-1 6.3.1 Scan survey 8 of 16

Scan measurements were made in SS18-1 using the GFPC and the Nal detector. The GFPC had an MDCscan of 738 dpm/1OOcm 2 (table 3 on page 2 of appendix A). The Nal had an MDCscan of 2.7 pCi/g (table 4 on page 3 of appendix A). The adjusted surrogate Csl 37 beta DCGLw for this survey unit was 27250 dpm/1OOcm 2 and the 75% administrative limit was 20438 dpm/1OOcm 2 (attachment 3-5 of appendix B).

Of the 20 square meters of this survey unit portions were not scanned because it is a Class 2 survey unit. Of the 20 square meters, about 10 were scanned with both the GFPC and with the Nal. Therefore about 50 percent of the survey unit was scanned which is consistent with scan coverage requirements for Class 2 survey units.

All GFPC scan surveys indicated activity less than the action level of 900 net cpm. All Nal scan surveys indicated less than the action level of 200 gross cpm.

6.3.2 Fixed point measurements Twelve random start triangular grid systematic fixed point measurement locations were defined for the survey unit. Based on a conservative relative shift of about 2.9 a minimum of 8 fixed points were required.

None of the design fixed point measurements in SS18-1 had results in excess of the of 75% administrative limit of 1300 net cpm (section 2.1.5 on page 3 of appendix A) for the GFPC measurements. The table below (Table 6.3-1) shows the gross beta results for each fixed point measurement, along with the mean, standard deviation and range of the fixed point measurement data.

The standard deviation of the GFPC measurements collected from the survey unit was greater than the variability assumed in the survey design. Since the LBGR used for the survey design was much greater than the typical 50% of the DCGL, a relative shift of about 3 would still result from the observed variability and adjustment of the LBGR. Therefore, the assessment of variability, relative shift , and number of fixed point measurements required is consistent between the survey design and the survey results. Based on this, no changes to the survey design or additional measurements are required.

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Table 6.3 Fixed point results for SSI8-1 Point GFPC Number Unshielded cpm 1 340 2 424 3 405 4 466 5 498 6 525 7 292 8 373 9 519 10 444 11 517 12 498 Mean 442 Std Dev 76.7 Min 292 Max 525 6.4 Survey Unit SS18-2 6.4.1 Scan survey Scan measurements were made in SS18-2 using the GFPC and the Nal detector. The GFPC had an MDCscan of 837 dpm/100cm 2 (attachment 8-12 of appendix B). The Nal had an MDCscan of 5.3 pCi/g (table 3 on page 2 of appendix B). The adjusted surrogate Csl 37 beta DCGLw for this survey unit was 27250 dpm/100cm 2 and the 75% administrative limit was 20438 dpm/1OOcm 2 (attachment 3-5 of appendix B).

Of the 43 square meters of this survey unit off the area was scanned because it is a Class 1 survey unit. Of the 43 square meters, all 43 were scanned with the Nai detector. All but 1.7 square meters was scanned with the GFPC. Therefore 100 percent of the survey unit was scanned which is consistent with scan coverage requirements for Class 1 survey units.

All GFPC scan surveys indicated activity less than the action level of 1100 gross cpm. All Nal scan surveys indicated less than the action level of 300 gross cpm.

6.4.2 Fixed point measurements 10 of 16

Fiftees random start triangular grid systematic fixed point measurement locations were defined for the survey unit. Based on a conservative relative shift of about 2.9 a minimum of 8 fixed points were required.

None of the design fixed point measurements in SS18-2 had results in excess of the of 75% administrative limit of 2077 net cpm (section 2.3.3 on page 3 of appendix B) for the GFPC measurements. The table below (Table 6.4-1) shows the gross beta results for each fixed point measurement, along with the mean, standard deviation and range of the fixed point measurement data.

The standard deviation of the GFPQ measurements collected from the survey unit was less than the variability assumed in the survey design. Therefore, the assessment of variability, relative shift, and number of fixed point measurements required is consistent between the survey design and the survey results. Based on this, no changes to the survey design or additional measurements are required.

Table 6.4 Fixed point results for SS18-2 Point GFPC Number Unshielded cpm 1 372 2 362 3 407 4 391 5 392 6 326 7 409 8 437 9 412 10 467 11 416 12 571 13 285 14 331 15 322 Mean 393 Std Dev 69.1 Min 285 Max 571 11 of 16

Fifteen smears were collected at the locations of the fixed point measurements.

All smear results were less then the MDCs of <166 dpm beta and <12.3 alpha.

7.0 Data Assessment 7.1 Assessment Criteria The final status survey data has been reviewed to verify authenticity, appropriate documentation, quality, and technical acceptability. The review criteria for data acceptability are:

1) The instruments used to collect the data were capable of detecting the radiation of the radionuclide of interest at or below the investigation levels.

2) The calibration of the instruments used to collect the data was current and radioactive sources used for calibration were traceable to recognized standards or calibration organizations.

3) Instrument response was checked before and, when required, after instrument use each day data was collected.

4) Survey team personnel were properly trained in the applicable survey techniques and training was documented.

5) The MDCs and the assumptions used to develop them were appropriate for the instruments and the survey methods used to collect the data.

6) The survey methods used to collect the data were appropriate for the media and types of radiation being measured.

7) Special instrument methods used to collect data were applied as warranted by survey conditions, and were documented in accordance with an approved site Survey Request procedure.

8) The custody of samples that were sent for off-site analysis were tracked from the point of collection until final results were provided.

9) The final status survey data consists of qualified measurement results representative of current facility status and were collected in accordance with the applicable survey design package.

If a discrepancy existed where one or more criteria were not met, the discrepancy was reviewed and corrective action taken (as appropriate) in accordance with site procedures.

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The statistical test does not need to be performed for this final status survey since the data clearly show that the survey unit meets the release criteria because all measurements in the survey units are less than or equal to the DCGLw.

7.2 Summary of Overall Results SS17-1 had no alarm points during scan surveys of approximately 50% of the surface. Scan MDCs were adequate. GFPC fixed point measurements were all less than the action level. Scan fraction and number of fixed point measurements meets LTP and MARSSIM requirements.

SS17-2 had no alarm points during scan surveys of approximately 50% of the surface. Scan MDCs were adequate. GFPC fixed point measurements were all less than the action level. Scan fraction and number of fixed point measurements meets LTP and MARSSIM requirements.

SS18-1 had no alarm points during scan surveys of approximately 50% of the surface. Scan MDCs were adequate. GFPC fixed point measurements were all less than the action level. Scan fraction and number of fixed point measurements meets LTP and MARSSIM requirements.

SS18-2 had no alarm points during scan surveys of approximately 100% of the surface. Scan MDCs were adequate. GFPC fixed point measurements were all less than the action level. Scan fraction and number of fixed point measurements meets LTP and MARSSIM requirements.

7.3 Survey Variations (Design, survey request, LTP) 7.3.1 Static points SS18-1 #11, SS18-2 #3, and SS18-2 #4 were moved slightly to accommodate interferences.

7.3.2 About 1.7 square meters of SS18-2 could not be surveyed using the GFPC due to interferences. The area was scanned using the Nal detector.

7.4 QC comparisons 7.4.1 Scan surveys Numerous areas were rescanned as QC duplicates. The QC rescans did not identify any activity above alarm points and therefore are in agreement with the primary scans because they both support the same conclusion, that the survey 13 of 16

unit passes. GFPC QC scans were conducted on 12.6 m2 of the survey area, which represents about 13 percent of the 93.5 m2 originally scanned with the GFPC. Nal QC scans were conducted on 12 m2 of the survey area, which represents about 13 percent of the 95.5 m2 originally scanned with the Nal.

These exceed the minimum 5% required.

7.4.2 Fixed Point measurements Several fixed point measurements were duplicated for QC purposes. Table 7.4-1 below shows the GFPC comparison. The QC fixed point measurements did not identify any activity above alarm points and therefore are in agreement with the primary result because they both support the same conclusion, that the survey unit passes. GFPC QC fixed point measurements were performed on 7 locations, which represent 14 percent of the 51 primary measurements. This exceeds the minimum 5% required.

Table 7.4 Fixed point GFPC QC Point Initial QC Number result cpm result cpm SS17-1 M 262 287 SS17-2 1 287 349 SS17-2 5 305 349 SS18-1 2 424 450 SS18-2 5 392 360 SS18-2 6 326 400 SS18-2 14 331 399 7.4.3 Smears Two smear samples were duplicated for QC purposes. Table 7.4-2 below shows the smear sample comparison. The QC samples did not identify any removable activity in excess of the detection limits and therefore are in agreement with the primary result because they both support the same conclusion, that the survey unit passes. Two duplicates represents 8 percent of the 25 primary samples. This exceeds the minimum 5% required.

Table 7.4 Smear QC Point Initial alpha QC alpha Initial beta QC beta Number result dpm result dpm result dpm result dpm SS17-2 9 '12.3 <12.3 <166 <166 SS18-2 9 <12.3 <12.3 <166 <166 14 of 16

8.0 Final Survey Conclusions The Structural Surfaces of the SSGS Seal Chamber Roof area survey units SS17-1, SS17-2, SS18-1, and SS18-2 final status survey was performed in accordance with the SNEC LTP, site procedures, design calculations, and Survey Request requirements. FSS data was collected to meet and/or exceed the quantity specified or required for each survey unit design. The survey data for each survey unit meets the following conditions:

1) The average residual radioactivity on the surfaces is less than the derived surrogate DCGLw in all of the survey units.

2) All measurements were less than the DCGLw in all of the survey units.

These conditions satisfy the release criteria established in the SNEC LTP and the radiological criteria for unrestricted use given in IOCFR20.1402.

Therefore it is concluded that the SNEC Structural Surface Areas of the SSGS Seal Chamber Roof areas designated SS17-1, SS17-2, SS18-1, and SSI8-2 are suitable for unrestricted release.

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9.0 References 9.1 SNEC Facility Site area grid map Drawing number SNECRM-020 9.2 SNEC procedure E900-ADM-4500.60 "Final Status Survey Report" 9.3 SNEC License Termination Plan 9.4 NUREG 1575 'Multi-Agency Radiation Survey and Site Investigation Manual" (MARSSIM), revision 1 August 2000 9.5 COMPASS computer program, Version 1.0.0, Oak Ridge Institute for Science and Education 9.6 SNEC procedure E900-IMP-4500.59, uFinal Site Survey Planning and DQA" 9.7 SNEC procedure E900-IMP-4520.04, 'Survey Methodology to Support SNEC License Termination" 9.8 SNEC Survey Request (SR) # SR144 9.9 SNEC Survey Request (SR) # SR154 10.0 Appendices Appendix A - SNEC Calculation E900-03-032 - "Top of Seal Chamber 3 -

Survey Design" (10 pages plus numerous attachments)

Appendix B - SNEC Calculation E900-04-012 - "CV Tunnel & Top of Seal Chambers 1 & 2 Survey Design" (10 pages plus numerous attachments) 16 of 16