ML11209B538

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Confirmatory Survey Results for Portions of the Material and Equipment from Units 1 and 2 at the Hbpp. 2029-SR-01-0
ML11209B538
Person / Time
Site: Humboldt Bay
Issue date: 04/20/2011
From: Adams W
Oak Ridge Institute for Science & Education
To: John Hickman
NRC/FSME/DWMEP
References
DCN: 2029-SR-01-0, RFTA-11-003
Download: ML11209B538 (45)
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CONFIRMATORY SURVEY RESULTS FOR PORTIONS OF THE MATERIALS AND EQUIPMENT FROM UNITS 1 AND 2 AT THE HUMBOLDT BAY POWER PLANT EUREKA, CALIFORNIA W. C. Adams Prepared for the U.S. Nuclear Regulatory Commission Oak Ridge Institute for Science and Education Approved for public release; further dissemination unlimited.

The Oak Ridge Institute for Science and Education (ORISE) is a U.S. Department of Energy institute focusing on scientific initiatives to research health risks from occupational hazards, assess environmental cleanup, respond to radiation medical emergencies, support national security and emergency preparedness, and educate the next generation of scientists. ORISE is managed by Oak Ridge Associated Universities.

NOTICES The opinions expressed herein do not necessarily reflect the opinions of the sponsoring institutions of Oak Ridge Associated Universities.

This report was prepared as an account of work sponsored by the United States Government.

Neither the United States Government nor the U.S. Department of Energy, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe on privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement or recommendation, or favor by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof.

CONFIRMATORY SURVEY RESULTS FOR PORTIONS OF THE MATERIALS AND EQUIPMENT FROM UNITS 1 AND 2 AT THE HUMBOLDT BAY POWER PLANT EUREKA, CALIFORNIA Prepared by W. C. Adams Independent Environmental Assessment and Verification Program Oak Ridge Institute for Science and Education Oak Ridge, Tennessee 37831-0017 Prepared for the U.S. Nuclear Regulatory Commission FINAL REPORT APRIL 2011 This report is based on work performed by the Oak Ridge Institute for Science and Education under contract number DE-AC05-06OR23100 with the Department of Energy.

Prepared by the Oak Ridge Institute for Science and Education, under interagency agreement (NRC FIN No. F1008) between the U.S. Nuclear Regulatory Commission and the U.S. Department of Energy.

TABLE OF CONTENTS LIST OF FIGURES .......................................................................................................................................... v LIST OF TABLES ............................................................................................................................................ v ABBREVIATIONS AND ACRONYMS .................................................................................................... vi

1.0 INTRODUCTION

AND SITE HISTORY ............................................................................ 1 2.0 SITE DESCRIPTION ................................................................................................................. 2 3.0 RADIONUCLIDES OF CONCERN ...................................................................................... 2 4.0 CONFIRMATORY SURVEY OBJECTIVE .......................................................................... 4 5.0 DOCUMENT REVIEW ............................................................................................................. 4 6.0 MARSAME CLASSIFICATION ............................................................................................... 4 7.0 RADIOLOGICAL SURVEY PROCEDURES ...................................................................... 6 7.1 REFERENCE SYSTEM ..................................................................................................................... 7

7.2 BACKGROUND

MEASUREMENTS ................................................................................................. 7 7.3 SURFACE SCANS ............................................................................................................................. 7 7.4 SURFACE ACTIVITY MEASUREMENTS ......................................................................................... 8 7.5 MARSAME DATA COMPARISON ................................................................................................ 8 8.0 DATA INTERPRETATION ..................................................................................................... 8 9.0 FINDINGS AND RESULTS ..................................................................................................... 8 9.1 DOCUMENT REVIEW ..................................................................................................................... 8 9.2 SURFACE SCANS ............................................................................................................................. 9 9.3 BETA DIRECT MEASUREMENTS ................................................................................................... 9 9.4 MARSAME DATA COMPARISON ..............................................................................................10 10.0 COMPARISON OF RESULTS WITH GUIDELINES .....................................................11 11.0

SUMMARY

..................................................................................................................................11

12.0 REFERENCES

...........................................................................................................................13 APPENDIX A: FIGURES APPENDIX B: TABLES APPENDIX C: MAJOR INSTRUMENTATION APPENDIX D: SURVEY PROCEDURES Humboldt Bay Power Plant, Eureka, CA iv 2029-SR-01-0

LIST OF FIGURES Figure A-1: Map Indicating Location of the Humboldt Bay Power Plant in Eureka, California ..... A-1 Figure A-2: Plot Plan of the Humboldt Bay Power Plant Indicating Units 1, 2 and 3 ...................... A-2 LIST OF TABLES Table 1: Decay Corrected Radionuclide Inventory....................................................................................... 3 Table 2: MARSAME Survey Packages .......................................................................................................... 6 Table 3: Maximum Scan Value Ranges Per Survey Unit Humboldt Bay Power Plant, Eureka, California.............................................................................................................................................. 9 Table 4: Net Beta Activity Value Ranges Per Survey Unit Humboldt Bay Power Plant, Eureka, California............................................................................................................................................10 Humboldt Bay Power Plant, Eureka, CA v 2029-SR-01-0

ABBREVIATIONS AND ACRONYMS AEC Atomic Energy Commission AL action level BSI Bartlett Services, Inc.

CFR Code of Federal Regulations cpm counts per minute Cs-137 cesium-137 dpm/100 cm2 disintegrations per minute per one hundred square centimeters DS disposition survey ESI Enercon Services, Inc.

HBPP Humboldt Bay Power Plant HBRP Humboldt Bay Repowering Project IA initial assessment IEAV Independent Environmental Assessment and Verification ISFSI Independent Spent Fuel Storage Installation M&E materials and equipment MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MARSAME Multi-Agency Radiation Survey and Assessment of Materials and Equipment MDC minimum detectable concentration MDCR minimum detectable count rate NI non-impacted NRC U.S. Nuclear Regulatory Commission ORAU Oak Ridge Associated Universities ORISE Oak Ridge Institute for Science and Education PG&E Pacific Gas & Electric Company PNL Pacific Northwest Laboratory RCA radiological control area RCRA Resource Conservation and Recovery Act ROC radionuclides of concern SAFSTOR cold shutdown and safety storage SU survey unit USEI U.S. Ecology Idaho Humboldt Bay Power Plant, Eureka, CA vi 2029-SR-01-0

CONFIRMATORY SURVEY RESULTS FOR PORTIONS OF THE MATERIAL AND EQUIPMENT FROM UNITS 1 AND 2 AT THE HUMBOLDT BAY POWER PLANT EUREKA, CALIFORNIA

1.0 INTRODUCTION

AND SITE HISTORY The Pacific Gas & Electric Company (PG&E) operated the Humboldt Bay Power Plant (HBPP)

Unit 3 nuclear reactor near Eureka, California under Atomic Energy Commission (AEC) provisional license number DPR-7. HBPP Unit 3 achieved initial criticality in February 1963 and began commercial operations in August 1963. Unit 3 was a natural circulation boiling water reactor with a direct-cycle design. This design eliminated the need for heat transfer loops and large containment structures. Also, the pressure suppression containment design permitted below-ground construction.

Stainless steel fuel claddings were used from startup until cladding failures resulted in plant system contaminationzircaloy-clad fuel was used exclusively starting in 1965 eliminating cladding-related contamination. A number of spills and gaseous releases were reported during operations resulting in a range of mitigative activities (see ESI 2008 for details).

In July 1973, Unit 3 was shut down for annual refueling and seismic modifications. However, by December 1980 it was concluded that completing the required upgrades and restarting Unit 3 would be cost prohibitive. PG&E decided in June 1983 to decommission Unit 3, received a possession-only license amendment, and placed the unit into cold shutdown and safety storage (SAFSTOR). Unit 3 is currently undergoing decommissioning. As part of the Humboldt Bay Repowering Project (HBRP), PG&E has built ten new fossil fuel units (16.3 MWe [megawatt electric] each) on the site in the vicinity of Unit 3.

Decommissioning activities have also begun on the adjacent fossil fuel Units 1 and 2. Currently, PG&E is planning to demolish Units 1 and 2 and seeks to dispose of the materials and equipment (M&E) that is generated during demolition of the Units 1 and 2 structures. The subject waste material consists of concrete, steel, insulation, roofing material, gravel, other metal, wood and soil debris generated during dismantlement activities. PG&E used a Multi-Agency Radiation Survey and Assessment of Materials and Equipment (MARSAME)-based method for determining M&E disposal paths (NRC 2009). The method consisted of beta radiation surface scans and limited direct beta activity measurements of M&E from Unit 1 and 2 structures. The preferred disposal method is for recycling if the surfaces of the M&E meet the disposition release criteria (PG&E 2010a). In the Humboldt Bay Power Plant, Eureka, CA 2029-SR-01-0

event that the M&E does not meet the release criteria for recycling, PG&E has requested approval from the U.S. Nuclear Regulatory Commission (NRC) for alternate disposal of approximately 200,000 cubic feet (ft3) of hazardous waste containing low-activity radioactive debris, at the U.S. Ecology Idaho (USEI) Resource Conservation and Recovery Act (RCRA) facility in Grand View, Idaho (PG&E 2010b).

At the request of NRC's Headquarters and Region IV Offices, the Independent Environmental Assessment and Verification (IEAV) program of the Oak Ridge Institute for Science and Education (ORISE) performed confirmatory surveys of the M&E from Units 1 and 2 of the HBPP that will be released for recycling or disposed of as low-activity radioactive waste. Specifically, ORISE was tasked with verifying compliance with the licensees 10 Code of Federal Regulations (CFR) Part 20.2002 exemption request that was approved by the NRC on November 2, 2010 (PG&E 2010b and NRC 2010). The survey activities were to be concurrent with the licensees surveys and sampling. The NRC also tasked ORISE with reviewing the licensees MARSAME data packages (BSI 2010).

2.0 SITE DESCRIPTION The HBPP site, owned by PG&E, consists of 143 acres on the southern edge of Humboldt Bay four miles southwest of the town of Eureka, in Humboldt County, in the State of California (Figure A-1).

PG&E maintains ten new operating electric generating units at the HBPP site (in the New Generation Footprint Area) that run on fossil fuels, two non-operating fossil fuel units (Units 1 and 2) and one non-operational nuclear unit (Unit 3). The controlled land that includes Unit 3 encompasses approximately 13 acres. Units 1 and 2 are interconnected with and west of Unit 3 (ESI 2008). The balance of the property includes mostly open areas and protected wetlands (Figure A-2).

An Independent Spent Fuel Storage Installation (ISFSI) has been constructed on-site for dry cask storage of the spent nuclear fuel and greater than Class C wastes. The spent nuclear fuel has been transferred to the ISFSI.

3.0 RADIONUCLIDES OF CONCERN The radionuclides of concern (ROCs) for the HBRP are consistent with other nuclear reactors that have had fuel cladding failures. Since the reactor has not been in operation for the last 30 plus years, Humboldt Bay Power Plant, Eureka, CA 2 2029-SR-01-0

the radionuclides with half lives of 4.3 years or less have decayed to less than 99% of their original activities, as seven or more half-lives have elapsed during the 30-year shutdown period. Table 1 lists the primary ROCs for the site, noting the 1981 quantities are from Pacific Northwest Laboratory (PNL)-4628, Residual Radionuclide Distribution and Inventory at the Humboldt Bay Nuclear Plant (PNL 1983), and the projected 2008 levels that were based on radiological decay alone. The overall inventory focuses on the systems and surfaces in Unit 3 and associated buildings and does not focus on quantities in the reactor vessel and environs surrounding the power plant. Site-wide ROCs are therefore condensed in Table 1.

TABLE 1:

DECAY CORRECTED RADIONUCLIDE INVENTORY HUMBOLDT BAY POWER PLANT EUREKA, CALIFORNIA Half-Life 1981 Inventory 2008 Inventory Soils Nuclide Commentd (years) (millicuries)a (millicuries)b ROCc H-3 12.3 unknown unknown N Not a surface soils ROC Fe-55 2.7 149,000 146 N Reactor systems ROC only Co-60 5.27 18,000 517 Y Surface soil ROC Cs-137 30.2 2,200 1,180 Y Surface soil ROC Ni-63 100 1,400 1,160 Y Surface soil ROC Mn-54 0.855 337 1.1 E-07 N Decayed to de minimus levels Sr-90 28.5 17.9 9.3 Y Surface soil ROC e

Am-241 432 12.1 11.6 N Not a surface soils ROC Pu-238 87.7 7.0 5.7 N Not a surface soils ROC Pu-239/240 24,110 6.1 6.1 N Not a surface soils ROC Cm-244 18.1 4.9 1.7 N Reactor systems ROC only a1981 inventory based on data from Table 2-1 of ESI 2007.

b2008 inventory calculated by ORISE with time of decay being 27 years.

cROC = radionuclide of concern.

dMedium/systems-specific comment based on input from Tables 2-1 and 2-2 of ESI 2007.

eThe inventory of Am-241 does not account for the decay of Pu-241 to Am-241.

The M&E for Units 1 and 2 are outside the radiological control area (RCA) and most of the M&E are located outdoors where deposition of radioactive gaseous effluent from Unit 3 was a potential source of contamination. Characterization surveys were not performed on Units 1 and 2 M&E; however, volumetric samples during characterization surveys of Unit 3 M&E indicated that radioactivity above background levels was present on surfaces and consisted primarily of cesium-137 (Cs-137). Based on the MARSAME survey contractors, Bartlett Services Inc. (BSI),

initial assessment (IA) for each of the MARSAME data packages [survey units (SUs)] regarding the Humboldt Bay Power Plant, Eureka, CA 3 2029-SR-01-0

potential source of contamination, length of time since shutdown, and process knowledge, Cs-137 was selected as the primary ROC for M&E for Units 1 and 2 (BSI 2010).

4.0 CONFIRMATORY SURVEY OBJECTIVE The objective of the confirmatory survey was to generate independent radiological data for use by the NRC in evaluating the adequacy and accuracy of the licensees radiological surface activity results from the MARSAME data packages for M&E from Units 1 and 2. Data collected by ORISE and the licensee were reviewed to assess whether MARSAME-based waste lot classifications were appropriate (NRC 2009), and whether the reported surface activity results met the disposition release criteria presented in the MARSAME data packages. ORISE initially reviewed the licensees MARSAME data packages. ORISE also verified the licensees compliance with the 10 CFR 20.2002 exemption request (PG&E 2010b and NRC 2010).

5.0 DOCUMENT REVIEW ORISE personnel reviewed the HBPP preliminary MARSAME radiological survey data packages prior to these confirmatory survey activities, as well as those data packages that were revised and re-submitted after ORISE demobilized from the site (BSI 2010). The objective of the reviews was to evaluate the technical processes and radiological survey techniques that were used to determine the disposition of M&E from Units 1 and 2. Comments addressing the technical issues within the data packages were submitted via electronic mail to the NRC and HBPP on January 17, 2011 (ORISE 2011a).

6.0 MARSAME CLASSIFICATION The MARSAME disposition survey (DS) design classification process is similar to the classification in the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) and is used to determine the level of survey effort for the disposition of the M&E (NRC 2000). However, in regards to MARSAME, the classification is based on estimated radionuclide concentrations or radioactivity relative to the action levels (ALs). The level of survey effort is linked to the potential to exceed a specified AL and a graded approach is used in the survey design. Impacted M&E with the highest potential to exceed ALs (i.e., Class 1) receive the greatest effort for the DS, while M&E with a lower potential to exceed the ALs (Classes 2 or 3) require less survey effort.

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Therefore, some knowledge of the radionuclide concentrations is required before M&E can be classified. This information is generated from available historical data or process knowledge or generated by the performance of preliminary surveys. In the absence of information on the radionuclide concentrations, the default assumption is that all M&E is considered Class 1. PG&E is using the following MARSAME classifications:

Non-impacted (NI): M&E that has no reasonable potential for radioactive concentration(s), or residual radioactivity, from site operations.

Impacted M&E: M&E that may contain radioactive concentration(s), or residual radioactivity, from licensed operations. Impacted M&E include Class 1, 2, and 3 M&E.

Class 1: M&E that have, or had, the following: (1) highest potential for, or known, radionuclide concentration(s) about the AL(s); (2) highest potential for small areas of elevated radionuclide concentrations(s) or radioactivity; and (3) insufficient evidence to support classification as Class 2 or 3 M&E.

Class 2: M&E that have, or had, the following: (1) low potential for radionuclide concentration(s) or radioactivity above the AL(s); and (2) little or no potential for small areas of elevated radionuclide concentration(s) or radioactivity.

Class 3: M&E that have, or had, the following: (1) little or no potential for containing radionuclide concentration(s) or residual radioactivity above background; and, (2) insufficient evidence to support classification as non-impacted.

With one exception, the 19 MARSAME Survey Packages [SUs in Table 2] provided to ORISE were designated as either Class 3 or NI. The one exception was for miscellaneous material which may contain Class 1, Class 2, or Class 3 M&E. BSI, the MARSAME survey contractor, provided the following MARSAME Survey Packages (BSI 2010).

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TABLE 2:

MARSAME SURVEY PACKAGES HUMBOLDT BAY POWER PLANT EUREKA, CALIFORNIA Package # Class Description Additional Description Units 1 and 2 Generators HBPP-GN-001 3 Units 1 and 2 Generators Units 1 and 2 Exciters HBPP-TB-001 3 Units 1 and 2 Turbines Turbines HBPP-CS-001 3 Condensate System Condensate System Distilled Water Tanks HBPP-DWT-001 3 Distilled Water Tanks Fire Water Tank Light Oil Tank HBPP-EL-001 3 Electrical Components Various Electrical Components Storage Tank (1)

HBPP-FOT-001 3 Fuel Oil System Service Tanks (2)

Feedwater Heaters (10)

HBPP-FW-001 3 Feedwater System Feedwater Pumps (4)

Circulating Water Pumps (4)

HBPP-IS-001 3 Intake Structures Screen Wash Pumps (4)

Smaller Pumps (6)

HBPP-LO-001 3 Lube Oil Systems Lube Oil Tanks HBPP-NG-001 3 Natural Gas Systems Multiple Gas Lines HBPP-SA-001 3 Station Air Receiver Tanks (4)

HBPP-SS-001 3 Structural Steel Various-Sized Steel HBPP-PT-001 3 Propane Tank NA HBPP-BL-001 3 Boilers NA Main Steam System HBPP-MS-001 3 Main/Auxiliary Steam Auxiliary Steam System HBPP-TF-001 3 Units 1 and 2 Transformers Transformers (2)

HBPP-VN-001 3 Ventilation System Stacks (2)

MEPP Buildings HBPP-MEPP-001 NI Mobile Electric Power Plants Control Buildings HBPP-MM-001 1, 2, 3 Miscellaneous Materials Various Classifications 7.0 RADIOLOGICAL SURVEY PROCEDURES ORISE personnel visited the HBPP property from November 15 through 19, 2010 to perform visual inspections and independent measurements and sampling. The confirmatory radiological survey activities were conducted in accordance with a project-specific plan, the ORISE Survey Humboldt Bay Power Plant, Eureka, CA 6 2029-SR-01-0

Procedures Manual and the Oak Ridge Associated Universities (ORAU) Quality Program Manual (ORISE 2010 and 2008 and ORAU 2009).

ORISE judgmentally selected nine of the partially completed M&E SUs for confirmatory radiological surveys (Table B-1). In addition, the NRC site representative requested that ORISE perform radiological surveys on the concrete reactor shield plug from Unit 3 (Table B-2).

7.1 REFERENCE SYSTEM Measurements and sampling locations were referenced to the existing HBPP M&E figures, maps, and/or pictures and documented on the figures and/or ORISE confirmatory survey activity data sheets.

7.2 BACKGROUND

MEASUREMENTS ORISE performed five shielded ambient background measurements at each SU location. A shielded background measurement was performed in an effort to simulate the ambient gamma background that would be present during beta surface scans on the M&E surfaces. ORISE also performed unshielded and shielded material-specific background measurements on unaffected metal and concrete surfaces in order to determine an appropriate material-specific beta background for metals and concrete surfaces.

7.3 SURFACE SCANS ORISE performed medium density (up to 50% scan coverage) beta radiation surface scans on the selected M&E MARSAME SUs focusing on locations where contamination may have concentrated during operations as well as other judgmentally selected locations based on site observations. With two exceptions, ORISE also performed scans on ten 1 m2 areas within each SU and recorded the highest observed count rate in counts per minute (cpm) within the 1 m2 areas. The location within each 1 m2 area exhibiting the maximum count rate was selected for a quantitative direct measurement. ORISE performed scans on nine 1 m2 areas in SU HBPP-NG-001 and eleven 1 m2 areas in SU HBPP-MS-001. Beta radiation scans were performed using hand-held gas proportional detectors coupled to ratemeter-scalers with audible indicators. Locations of direct beta radiation that were possibly distinguishable from background were marked for further investigation. At the request of the NRC, ORISE performed alpha and beta scans on two sections of the concrete reactor shield Humboldt Bay Power Plant, Eureka, CA 7 2029-SR-01-0

plug which had been cut into eight sections. A total of five 1 m2 areas were scanned on each of the sections.

7.4 SURFACE ACTIVITY MEASUREMENTS A one-minute static beta count measurement was performed at the location that exhibited the highest beta scan count rates within each of the 1 m2 scan areas within each SU. These surface activity measurement locations are indicated on the figures embedded in the data tables for each specific SU (Table B-1) and the reactor shield plug (Table B-2).

7.5 MARSAME DATA COMPARISON ORISE performed side-by-side direct measurements with PG&E survey personnel within SU HBPP-SA-001. A total of ten surface activity measurements were performed by ORISE and BSI personnel on the Surface Air and Instrument Air tanks within Unit 1 M&E (Table B-3).

8.0 DATA INTERPRETATION Data were returned to ORISE for interpretation. Beta and alpha surface activity measurement results were reported in units of disintegrations per minute per 100 square centimeters (dpm/100 cm2). The data generated were compared against MARSAME data package results and the HBPP M&E action levels. Additional information regarding instrumentation and procedures may be found in Appendices C and D.

9.0 FINDINGS AND RESULTS The results for each radiological survey procedure component are discussed below.

9.1 DOCUMENT REVIEW HBPP preliminary MARSAME data package survey data were used to determine the statistical variables for calculating scan and static minimum detectable concentrations (MDC). However, per ORISE procedure, ORISE uses an index of sensitivity (d') of 2.32, which represents a true positive detection rate of 95% and a false positive detection rate of 25%. ORISE reviewed the preliminary and several final versions of the MARSAME data packages that were provided for review. Minor comments were submitted either through electronic mail or during the closeout meeting at the end of the survey activities (ORISE 2011a). A remaining open action item is that to date, ORISE has not Humboldt Bay Power Plant, Eureka, CA 8 2029-SR-01-0

received requested information regarding the HBPP instrument calibration procedures and direct measurement calculation procedures for confirmatory reviews.

9.2 SURFACE SCANS ORISE, through the beta radiation surface scans, identified the location within each 1 m2 area which exhibited the maximum beta radiation level. The maximum beta scan count rate within each 1 m2 area is provided in the specific SU data table (Table B-1). The maximum beta scan count rate within each 1 m2 area in each SU was compared with the Scan Action Level (Table B-1) value determined from the calculation of the scan minimum detectable count rate (Scan MDCR) plus the average ambient background for each SU. Results above the calculated Scan Action Level value indicated locations that potentially were above ambient background levels.

A summary of the Max Scan values are presented in Table 3.

TABLE 3:

MAXIMUM SCAN VALUE RANGES PER SURVEY UNIT HUMBOLDT BAY POWER PLANT EUREKA, CALIFORNIA Max Scan Range (cpm) within 1 m2 Scan Action Level Survey Unit Low High (cpm)

HBPP-TB-001 160 380 415 HBPP-GN-001 220 320 415 HBPP-FW-001 210 360 415 HBPP-TF-001 140 430 422 HBPP-NG-001 190 420 486 HBPP-MS-001 210 450 486 HBPP-SA-001 100 300 362 HBPP-BL-001 260 540 416 HBPP-IS-001 250 500 349 9.3 BETA DIRECT MEASUREMENTS The summary data for the net beta activity direct measurements for the nine SUs are presented in Table 4; the individual net beta surface activity measurements for each direct measurement location are provided in Table B-1. At the request of the NRC site representative, ORISE also performed beta (and alpha) direct measurements on two of the reactor shield plug sections (Table B-2).

Humboldt Bay Power Plant, Eureka, CA 9 2029-SR-01-0

TABLE 4:

NET BETA ACTIVITY VALUE RANGES PER SURVEY UNIT HUMBOLDT BAY POWER PLANT EUREKA, CALIFORNIA Minimum Detectable Net Beta Activity Range (dpm/100 cm2)

Survey Unit Concentration Low High (dpm/100 cm2)

Confirmatory Survey Unit MARSAME Data Packages HBPP-TB-001 97 390 260 HBPP-GN-001 110 390 260 HBPP-FW-001 24 860 260 HBPP-TF-001 17 650 260 HBPP-NG-001 3 580 280 HBPP-MS-001 52 820 280 HBPP-SA-001 -130 130 230 HBPP-BL-001 -66 270 260 HBPP-IS-001 0 720 230 Reactor Shield Plug Beta Measurements HBPP-BP-09-081 240 15,000 160 HBPP-BP-09-079 160 17,000 160 Reactor Shield Plug Alpha Measurements HBPP-BP-09-081 0 60 64 HBPP-BP-09-079 -9 9 64 9.4 MARSAME DATA COMPARISON ORISE received the requested comparison measurement data from the licensees contractor for MARSAME data package HBPP-SA-001 (ORISE 2011b and BSI 2011). A comparison of the surface activity data identified a probable issue in the method that the HBPP uses to determine the appropriate background levels used in calculating net surface activity levels. The surface activity comparison data are presented in Table B-3. BSI collects an ambient background value by positioning their detector one meter from the surface of the SU M&E that was surveyed. However, as indicated in Table B-3, all of the surface activity cpm were less than their ambient background count value, which resulted in all the data being reported as negative values. Provided an appropriate background correction factor is used and the measurement population represents background conditions, then the data should have exhibited both a positive and negative distribution, with a mean approximating zero. The above factor, combined with field observations, determined that HBPP subtracts a background that does not account for the surveyed material shielding the ambient Humboldt Bay Power Plant, Eureka, CA 10 2029-SR-01-0

background level. Therefore, the background being subtracted is considered to be too high and results in a systematic measurement error bias.

ORISE took a different approach in determining background levels. Since the majority of the measurements on M&E were on metal surfaces, ORISE performed paired unshielded and shielded direct measurements on metal surfaces at five locations in an area unaffected by Unit 3 effluent releases. The shielded (gamma only) measurement was subtracted from the unshielded (beta and gamma) to yield a beta only measurement for each paired measurement location. The average beta only cpm background value was determined to be 13 cpm for metal surfaces. Likewise, ORISE performed paired unshielded and shielded surface activity measurements on M&E surfaces. Again, the shielded measurement was subtracted from the unshielded measurement to yield a beta only surface activity measurement in cpm. The metal beta background cpm value was then subtracted from the beta only surface activity value providing the beta only surface activity level in cpm.

Dividing this value by the total efficiency and geometry yields the beta only surface activity value in units comparable to the HBPP action levels for M&E.

10.0 COMPARISON OF RESULTS WITH GUIDELINES The detection requirements for release of M&E within the RCA from the HBPP are identified for the primary ROC, Cs-137, as 1,000 dpm/100 cm2 for removable contamination and 5,000 dpm/100 cm2 for total (fixed) contamination. ALs, determined for scans and static measurements, were calculated for each SU based on ambient backgrounds determined for each SU.

All scans and static measurements for the nine confirmatory SUs met the M&E release criteria. As expected, static measurements for beta activity on the reactor shield plug exceeded the recycling release criteria.

11.0

SUMMARY

During the period of November 15 through 19, 2010, ORISE performed radiological confirmatory survey activities on a portion of the MARSAME M&E available for release at the Humboldt Bay Power Plant in Eureka, California. The confirmatory survey results are in agreement with the licensees preliminary MARSAME data package survey results as far as demonstrating compliance with the approved release criteria for recycling. The reactor shield plug, which was not approved for recycling, did exhibit elevated beta radiation levels exceeding the recycling levels and is appropriately dispositioned for burial at USEI.

Humboldt Bay Power Plant, Eureka, CA 11 2029-SR-01-0

Although the ORISE and BSI surface activity data indicated that the M&E surfaces met the AL release criteria, there were fundamental differences in the determination of appropriate background levels used in the calculation of net total surface activity levels. It is ORISEs opinion that HBPPs contractor should provide technical justification for the use of ambient background measurements in the determination of total net surface activity levels at HBPP.

Humboldt Bay Power Plant, Eureka, CA 12 2029-SR-01-0

12.0 REFERENCES

Bartlett Services, Inc. (BSI). Humboldt Bay Power Plant, MARSAME Survey Packages (multiple data packages). Plymouth, Massachusetts; October 2010.

BSI. Electronic Mail; RE: Measurement Data Comparison from William Barley, (BSI) to Wade Adams (ORISE). Oak Ridge, Tennessee; February 17, 2011.

Enercon Services, Inc. (ESI). Site Characterization Plan - Humboldt Bay Power Plant.

HBPP-PP-003, Rev. 0; July 16, 2007.

ESI. Historical Site Assessment, prepared for the Humboldt Bay Power Plant Pacific Gas &

Electric Company, Eureka, California, Draft; September 2008.

NRC. Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM), NUREG-1575; Revision 1. Washington, DC; August 2000.

NRC. Multi-Agency Radiation Survey and Assessment of Materials and Equipment Manual (MARSAME), NUREG-1575; Supp. 1. Washington, DC; January 2009.

NRC. Humboldt Bay Power Plant Unit 3 - Request for 10 CFR 20.2002 Alternate Disposal Approval and 10 CFR 30.11 Exemption for Plant Waste Disposal at US Ecology Idaho (TAC No. J00369). Washington, DC; November 2, 2010.

Oak Ridge Associated Universities (ORAU). ORAU/ORISE Health & Safety Manual.

Oak Ridge, Tennessee; April 2, 2008.

ORAU. Quality Program Manual for the Independent Environmental Assessment and Verification Program. Oak Ridge, Tennessee; June 30, 2009.

Oak Ridge Institute for Science and Education (ORISE). Survey Procedures Manual for the Independent Environmental Assessment and Verification Program. Oak Ridge, Tennessee; May 1, 2008.

ORISE. Project-Specific Plan for the Confirmatory Survey of Materials and Equipment from Units 1, 2 and 3 at the Humboldt Bay Power Plant, Eureka, California. Docket No. 50-00133; RFTA No.11-003. DCN: 2029-PL-01-0.. Oak Ridge, Tennessee; November 12, 2010.

ORISE. Electronic Mail; RE: Humboldt Bay MARSAME Data Packages from Wade Adams (ORISE) to William Barley, et. al.(BSI). Oak Ridge, Tennessee; January 17, 2011a.

ORISE. Electronic Mail; RE: Measurement Data Comparison from Wade Adams (ORISE) to William Barley, et. al.(BSI). Oak Ridge, Tennessee; February 16, 2011b.

Pacific Gas & Electric Company (PG&E). MARSAME Disposition of Materials and Equipment; RCP-6Q, Revision 0. Eureka, California; March 15, 2010a.

Humboldt Bay Power Plant, Eureka, CA 13 2029-SR-01-0

PG&E. Revision to Request for 10 CFR 20.2002 Alternate Disposal Approval and 10 CFR 30.11 Exemption of Humboldt Bay Power Plant Waste for Disposal at US Ecology Idaho.

Eureka, California; August 12, 2010b.

Pacific Northwest Laboratory (PNL). Residual Radionuclide Distribution and Inventory at the Humboldt Bay Nuclear Plant, (PNL-4628); May 1983.

Humboldt Bay Power Plant, Eureka, CA 14 2029-SR-01-0

APPENDIX A FIGURES Humboldt Bay Power Plant, Eureka, CA 2029-SR-01-0

Figure A-1: Map Indicating Location of the Humboldt Bay Power Plant in Eureka, California Humboldt Bay Power Plant, Eureka, CA A-1 2029-SR-01-0

Humboldt Bay Power Plant, Eureka, CA A-2 2029-SR-01-0 Figure A-2: Plot Plan of the Humboldt Bay Power Plant Indicating Units 1, 2 and 3

APPENDIX B TABLES Humboldt Bay Power Plant, Eureka, CA 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-TB-001 Recycling Action Level (dpm/100 cm2) Burial Action Level DESCRIPTION Turbines Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Units 1 and 2 Turbines Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity Turbine 2 (1 m2) (cpm) (cpm) (cpm) (dpm/100 cm2)

Turbine 2 Turbine 2 3 1 160 211 157 140 4 2 190 283 178 320 2

3 250 231 151 230 1

5 4 380 331 204 390 5 240 226 153 210 Turbine 1 6 250 215 129 250 7 210 175 114 170 8 330 265 192 210 9 310 241 182 160 Turbine 1 10 280 218 177 97 77 10 Ambient BKG Measurements Instrument Efficiency Other Data 6 8 Location: Shielded Static Efficiency Mat.-Spec.Beta BKG 9 Count cpm i = 0.46 13 7

1 228 s = 0.5 Scan MDCR Dashed box indicates 2 196 t = 0.23 181 cpm measurement on opposite side of structure 3 233 Scan Efficiency Scan Action Level 4 233 i = 0.3 415 cpm Indicates scanned 1m2

  1. area and surface activity 5 279 s = 0.5 Scan MDC measurement location Average 234 t = 0.15 1708 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-1 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-GN-001 Recycling Action Level (dpm/100 cm2) Burial Action Level DESCRIPTION Generators and Exciters Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Units 1 and 2 Generators Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity 2

(1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2)

Unit 2 Generator and Exciter 1 220 198 134 180 8 7 9 2 260 253 183 200 10 6 3 230 278 162 360 Exciter 2 4 270 238 192 110 Generator 2 5 240 218 171 120 Unit 1 Generator and Exciter 6 320 230 184 110 Dashed box indicates

  1. measurement on 7 320 260 185 210 opposite side of structure 8 250 269 143 390 9 250 238 165 210 10 230 217 155 170 3

Ambient BKG Measurements Instrument Efficiency Other Data 5 4 Location: Shielded Static Efficiency Mat.-Spec.Beta BKG 1 2 Count cpm i = 0.46 13 1 228 s = 0.5 Scan MDCR Generator 1 Exciter 1 2 196 t = 0.23 181 cpm 3 233 Scan Efficiency Scan Action Level Indicates scanned 1m2 4 233 i = 0.3 415 cpm

  1. area and surface activity measurement location 5 279 s = 0.5 Scan MDC Average 234 t = 0.15 1708 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-2 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-FW-001 2 Recycling Action Level (dpm/100 cm ) Burial Action Level DESCRIPTION Feedwater System, Unit 2 Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Feedwater System Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity 2

(1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2)

Upper Level, Unit 2 1 240 249 135 350 4 3 5 2 300 285 139 460 3 240 165 145 24 2 4 360 426 173 830 1 5 350 437 174 860 Lower Level, Unit 2 6 240 275 176 300 Dashed box indicates

  1. measurement on 7 210 245 174 200 opposite side of Upper Level, Unit 2 structure 8 260 264 197 190 9 230 255 138 360 Lower Level, Unit 2 10 210 170 142 52 9

Ambient BKG Measurements Instrument Efficiency Other Data 10 Location: Shielded Static Efficiency Mat.-Spec.Beta BKG 8

Count cpm i = 0.46 13 1 228 s = 0.5 Scan MDCR 6 2 196 t = 0.23 181 cpm 3 233 Scan Efficiency Scan Action Level 7

Indicates scanned 1m2 4 233 i = 0.3 415 cpm

  1. area and surface activity measurement location 5 279 s = 0.5 Scan MDC Average 234 t = 0.15 1708 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-3 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-TF-001 2 Recycling Action Level (dpm/100 cm ) Burial Action Level DESCRIPTION Transformers and Control Breakers Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Units 1 and 2 Transformers Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity 2

(1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2) 1 430 294 164 400 1 2 Elec box 180 203 152 130 5

3 270 263 154 330 3

4 210 152 123 55 4

5 260 288 173 350 6 6 fin 200 245 181 180 2

7 fin 280 245 204 97 8 top 290 305 103 650 9 240 137 119 17 10 140 149 102 120 Indicates scanned 1m2

  1. area and surface activity measurement location Ambient BKG Measurements Instrument Efficiency Other Data Location: Shielded Static Efficiency Mat.-Spec.Beta BKG 8 Count cpm i = 0.46 13 7

10 1 236 s = 0.5 Scan MDCR 9 2 240 t = 0.23 183 cpm 3 222 Scan Efficiency Scan Action Level 4 265 i = 0.3 422 cpm 5 233 s = 0.5 Scan MDC Average 239 t = 0.15 1728 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-4 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-NG-001 2 Recycling Action Level (dpm/100 cm ) Burial Action Level DESCRIPTION Natural Gas Systems Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Units 1 and 2 Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity 6 2 (1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2) 5 1 370 328 228 300 2 NA Location 2 was actually on Main/Auxillary System for #11 4

3 240 179 152 48 4 350 343 265 220 5 370 300 286 3 6 420 497 317 580 7 340 275 221 140 3 8 280 299 242 150 9 190 253 237 10 1

10 400 312 249 170 Indicates scanned 1m2

  1. area and surface activity measurement location Ambient BKG Measurements Instrument Efficiency Other Data Location: Shielded Static Efficiency Mat.-Spec.Beta BKG Count cpm i = 0.46 13 7 1 314 s = 0.5 Scan MDCR 10 2 309 t = 0.23 200 cpm 8 9 3 238 Scan Efficiency Scan Action Level 4 240 i = 0.3 486 cpm 5 329 s = 0.5 Scan MDC Average 286 t = 0.15 1889 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-5 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-MS-001 2 Recycling Action Level (dpm/100 cm ) Burial Action Level DESCRIPTION Main/Auxiliary Steam Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Units 1 and 2 Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity 2

(1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2) 1 210 155 127 52 11 2 420 523 321 650 1

3 400 395 268 390 Indicates scanned 1m2 4 430 420 301 370

  1. area and surface activity 7 measurement location 5 230 337 231 320 6 350 459 270 610 7 360 386 243 450 4

8 380 472 220 820 9 350 463 234 750 8

10 410 282 220 170 3 5 11 450 443 259 590 9

Ambient BKG Measurements Instrument Efficiency Other Data Location: Shielded Static Efficiency Mat.-Spec.Beta BKG 10 Count cpm i = 0.46 13 1 314 s = 0.5 Scan MDCR 2 309 t = 0.23 200 cpm 2

6 3 238 Scan Efficiency Scan Action Level 4 240 i = 0.3 486 cpm 5 329 s = 0.5 Scan MDC Average 286 t = 0.15 1889 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-6 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-SA-001 2 Recycling Action Level (dpm/100 cm ) Burial Action Level DESCRIPTION Station Air and Instrument Air Tanks Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Unit 1 Station Air Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity 2

2 (1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2) 9 Station Air 1 1 230 170 130 93 2 300 216 185 62 3 200 162 138 38 4 280 140 165 -130 7 5 250 173 151 31 Instrument Air 8 6 280 207 180 48 5

7 300 154 144 -10 10 8 100 169 148 28 3 9 300 183 175 -17 4

10 250 208 158 130 Ambient BKG Measurements Instrument Efficiency Other Data Location: Shielded Static Efficiency Mat.-Spec.Beta BKG Count cpm i = 0.46 13 1 198 s = 0.5 Scan MDCR 2 205 t = 0.23 166 cpm 3 212 Scan Efficiency Scan Action Level Indicates scanned 1m2 # Dashed box indicates 6

  1. area and surface activity measurement on 4 i = 0.3 362 cpm 182 measurement location opposite side of structure 5 185 s = 0.5 Scan MDC Station Air Tank Instrument Air Tank Average 196 t = 0.15 1566 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-7 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-BL-001 2 Recycling Action Level (dpm/100 cm ) Burial Action Level DESCRIPTION Boilers Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Unit 2 Lower and Upper Levels Removable 1,000 15 16,600 Lower Level Scan Location Max Scan Unshielded Shielded Net Beta Activity 2

(1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2) 2 Lower Level 1

1 270 217 214 -35 2 300 223 198 41 5

4 3 340 230 183 120 3

4 310 243 202 97 5 260 264 235 55 Upper Level Dashed box indicates 6 540 446 452 -66 measurement on opposite side of 7 480 246 228 17 structure 8 330 281 218 170 Upper Level 9 410 302 212 270

  1. Indicates scanned 1m 2

area and surface activity measurement location 10 430 281 194 260 Ambient BKG Measurements Instrument Efficiency Other Data 7 6 Location: Shielded Static Efficiency Mat.-Spec.Beta BKG 9 Count cpm i = 0.46 13 1 215 s = 0.5 Scan MDCR 8 2 220 t = 0.23 181 cpm 3 326 Scan Efficiency Scan Action Level 10 4 224 i = 0.3 416 cpm 5 187 s = 0.5 Scan MDC Average 234 t = 0.15 1710 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-8 2029-SR-01-0

TABLE B-1:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-IS-001 2 Recycling Action Level (dpm/100 cm ) Burial Action Level DESCRIPTION Intake Structures and Piping Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Intake Structures Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity 2

(1 m ) (cpm) (cpm) (cpm) (dpm/100 cm2) 1 360 291 156 420 2 250 174 150 38 4 3 260 187 127 160 2

4 330 408 186 720 5 490 388 216 550 6 500 370 239 410 7 330 238 165 210 8 330 245 174 200 1 3 9 420 301 191 330 6 10 340 194 181 0 5

Indicates scanned 1m2

  1. area and surface activity Ambient BKG Measurements Instrument Efficiency Other Data measurement location Location: Shielded Static Efficiency Mat.-Spec.Beta BKG Count cpm i = 0.46 13 1 180 s = 0.5 Scan MDCR 2 186 t = 0.23 162 cpm 7

3 182 Scan Efficiency Scan Action Level 9

10 8 4 198 i = 0.3 349 cpm 5 190 s = 0.5 Scan MDC Average 187 t = 0.15 1529 dpm/100 cm2 Humboldt Bay Power Plant, Eureka, CA B-9 2029-SR-01-0

TABLE B-2:

ORISE CONFIRMATORY SURVEYS OF HBPP MARSAME SURVEY UNITS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-BP-09 Recycling Action Level (dpm/100 cm2) Burial Action Level DESCRIPTION Reactor Shield Plug Cut Into 8 Sections Cs-137 Total 5,000 (pCi/g) (dpm/100 cm2)

SURVEY UNIT Reactor Shield Plug Removable 1,000 15 16,600 Scan Location Max Scan Unshielded Shielded Net Beta Activity Alpha Net Alpha (1 m2) (cpm) (cpm) (cpm) (dpm/100 cm2) (cpm) (dpm/100 cm2) 2 BP-09-081 1 top 920 945 528 1700 8 60 4

3 1 2 top 3600 3879 440 15000 8 60 3 side 380 341 243 240 1 0 4 side 360 313 145 560 5 34 5 back top 550 545 194 1400 6 43 BP-09-079 Reactor Plug BP-09-081 6 side 510 446 179 1000 1 0 7 top 2500 2931 317 12000 2 9 8 top 570 461 316 450 2 9 5

9 side 350 352 272 160 2 9 10 top ledge 3000 4358 532 17000 0 -9

  1. Indicates scanned 1m2 area and surface activity measurement location Instrument Efficiency Material Background Static Efficiency Static Efficiency Material Concrete i = 0.44 i = 0.47 Shielded BKG = 45 s = 0.5 s = 0.25 Alpha BKG = 1 Reactor Plug BP-09-079 t = 0.22 t = 0.12 7

G= 1 G= 1 6 10 MDC = 155 MDC 64 9 8 Humboldt Bay Power Plant, Eureka, CA B-10 2029-SR-01-0

TABLE B-3:

ORISE AND BSI COMPARISON SURVEY DATA HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA Action Levels MARSAME Survey Package HBPP-SA-001 Recycling Action Level (dpm/100 cm2)

DESCRIPTION Station Air and Instrument Air Tanks Cs-137 Total 5,000 SURVEY UNIT Unit 1 Station Air Removable 1,000 ORISE Comfirmatory Surface Activity Measurements BSI Surface Activity Measurements Surface Activity Location Unshielded Shielded Net Beta Activity Unshielded Ambient BKG Net Beta Activity (1 m2) (cpm) (cpm) (dpm/100 cm2) (cpm) (cpm) (dpm/100 cm2)

Station Air 1 170 130 93 134 154 -66 2 216 185 62 124 154 -98 3 162 138 38 137 154 -56 4 140 165 -130 93 154 -200 5 173 151 31 131 154 -75 Instrument Air 6 207 180 48 128 157 -95 7 154 144 -10 128 157 -95 8 169 148 28 114 157 -140 9 183 175 -17 148 157 -30 10 208 158 130 126 157 -100 ORISE Instument Data Ambient BKG Measurements Instrument Efficiency Other Data Location: Shielded ORISE Static Efficiency Surface Material Count cpm i = 0.46 Metal 1 198 s = 0.5 2 205 t = 0.23 Mat.-Spec.Beta BKG 3 212 BSI Static Efficiency 13 4 182 i = NA 5 185 s = NA Detector Geometry Average 196 t = 0.2418 1.26 Humboldt Bay Power Plant, Eureka, CA B-11 2029-SR-01-0

APPENDIX C MAJOR INSTRUMENTATION Humboldt Bay Power Plant, Eureka, CA B-4 2029-SR-01-0

APPENDIX C MAJOR INSTRUMENTATION The display of a specific product is not to be construed as an endorsement of the product or its manufacturer by the author or his employer.

C.1 SCANNING AND MEASUREMENT INSTRUMENT/DETECTOR COMBINATIONS C.1.1 Beta Ludlum Ratemeter-Scaler Model 2221 coupled to Ludlum Gas Proportional Detector Model 43-68, Physical Area: 126 cm2 (Ludlum Measurements, Inc., Sweetwater, TX)

Calibration Due Date: 04/06/2011 Ludlum Ratemeter-Scaler Model 2221 coupled to Ludlum Plastic Scintillation Detector Model 44-142, Physical Area: 100 cm2 (Ludlum Measurements, Inc., Sweetwater, TX)

Calibration Due Date: 02/27/2011 C.1.2 Alpha Ludlum Ratemeter-Scaler Model 2221 (Ludlum Measurements, Inc., Sweetwater, TX) coupled to Ludlum Alpha Scintillation Detector Model 43-92, Physical Area: 100 cm2 (Ludlum Measurements, Inc., Sweetwater, TX)

Calibration Due Date: 04/20/2011 Humboldt Bay Power Plant, Eureka, CA C-1 2029-SR-01-0

APPENDIX D SURVEY PROCEDURES Humboldt Bay Power Plant, Eureka, CA 2029-SR-01-0

D.1 PROJECT HEALTH AND SAFETY The proposed survey and sampling procedures were evaluated to ensure that any hazards inherent to the procedures themselves were addressed in current Job Hazard Analyses (JHA). All survey and laboratory activities were conducted in accordance with Oak Ridge Associated Universities (ORAU) health and safety procedures (ORAU 2008) 1.

Pre-survey activities included the evaluation and identification of potential health and safety issues.

Survey work was performed per the Oak Ridge Institute for Science and Education (ORISE) generic health and safety plans and a site-specific Integrated Safety Management (ISM) pre-job hazard checklist. Humboldt Bay Power Plant (HBPP) personnel provided site-specific safety awareness training. ORISE personnel also performed a safety walk down of the site to check for unexpected hazards.

D.2 CALIBRATION AND QUALITY ASSURANCE Calibration of all field instrumentation was based on sources/standards, traceable to the National Institute of Standards and Technology (NIST).

Field survey activities were conducted in accordance with procedures from the following ORAU and ORISE documents:

  • Survey Procedures Manual (ORISE 2008) 2
  • Quality Program Manual (ORAU 2009)3 The procedures contained in these manuals were developed to meet the requirements of 10 Code of Federal Regulations (CFR) 830 Subpart A, Quality Assurance Requirements, Department of Energy Order 414.1C Quality Assurance, and the U.S. Nuclear Regulatory Commission Quality Assurance Manual for the Office of Nuclear Material Safety and Safeguards 4 and contain measures to assess processes during their performance.

1 ORAU. ORAU/ORISE Health & Safety Manual. Oak Ridge, Tennessee; April 2, 2008.

2 ORISE. Survey Procedures Manual for the Independent Environmental Assessment and Verification Program.

Oak Ridge, Tennessee; May 1, 2008.

3 ORAU. Quality Program Manual for the Independent Environmental Assessment and Verification Program.

Oak Ridge, Tennessee; June 30, 2009.

4 U.S. Nuclear Regulatory Commission (NRC). Minimum Detectable Concentrations With Typical Radiation Survey Instruments for Various Contaminants and Field Conditions, NUREG-1507; Washington, DC; June 1998.

Humboldt Bay Power Plant, Eureka, CA D-1 2029-SR-01-0

Quality control procedures include:

  • Daily instrument background and check-source measurements to confirm that equipment operation is within acceptable statistical fluctuations.
  • Training and certification of all individuals performing procedures.

D.3 SURVEY PROCEDURES These procedures provide guidance on the terms used by ORISE on the data spreadsheets (Appendix B) during the confirmatory survey activities to determine HBPPs compliance with approved Multi-Agency Radiation Survey and Assessment of Materials and Equipment (MARSAME) survey procedures and action levels.

D.3.1 AMBIENT BACKGROUND DETERMINATIONS For scanning measurements, ORISE performed five ambient background measurements within the vicinity of the Survey Unit (SU) that was being investigated. The average of the ambient background measurements was calculated and that value was used in the determination of the scan minimum detectable concentration (Scan MDC) measurements.

ORISE performed metal and concrete material-specific background measurements at five locations each within unaffected areas. At each location, an unshielded and shielded measurement was performed. The average shielded measurement was subtracted from the average unshielded measurement to determine the net material-specific beta background.

=

where:

Rm = reference material background beta count rate (ambient background subtracted out)

Ru = unshielded (gross) background count rate (gamma + beta)

Rs = shielded background count rate (gamma only)

The respective reference material-specific background was used for the surface activity calculations.

D.3.2 SCANNING MEASUREMENTS A hand-held gas proportional detector was used to scan for elevated beta radiation. Identification of elevated radiation levels was based on increases in the audible signal from the recording and/or Humboldt Bay Power Plant, Eureka, CA D-2 2029-SR-01-0

indicating instrument. ORISE Survey Procedures (ORISE 2008) require a minimum scan speed of 0.5 to 1 meter per second (m/s) based on the site contaminant and the Derived Concentration Guideline Level (DCGL) for the primary contaminant of concern.

D.3.2.1 Scan MDCR For beta activity scans, ORISE determined Scan MDCs per NUREG-1507 guidance. Some of the factors for determining Scan MDCs are as follows: the intrinsic characteristics of the detector (efficiency, window area, etc.); the nature (energy of the beta emissions) and the relative distribution of the potential contamination (point versus distributed source and depth of contamination); the scan rate; background levels; and surveyor vigilance. Many of the factors used to determine Scan MDCs have already been estimated for typical field situations and contaminants. Therefore, Scan MDCs can be determined by using the calculational approach described in Chapter 6 of NUREG-1507 (NRC 1998).

To compare the actual surveyors performance to that of the ideal observer within acceptable performance parameters (in terms of true and false positive rates), decision errorsType I error ()

and Type II error ()must be determined. ORISE uses a 95% true positive rate (1-) and a 25%

false positive rate (), to determine the index of sensitivity (d') which is 2.32 (from NUREG-1507, Table 6.1).

The selection of the Scan MDC is based on the ability of the ideal observer (without typical human deficiencies) to make optimal use of the available survey information to make a correct determination of actual activity/concentration for the survey measurement. Therefore, the minimum detectable count rate (MDCR) for the ideal observer can be calculated as follows:

60

= ( )

Humboldt Bay Power Plant, Eureka, CA D-3 2029-SR-01-0

For a less than ideal observer, the MDCR is increased by dividing by the default efficiency of the human surveyor (p):

60

( )

=

where:

MDCR = minimum detectable (net) count rate in counts per minute d' = index of sensitivity (ORISE uses 2.32) bi = background counts in observation interval i = observation interval (in seconds), based on the scan speed, detector size, and the area extent of the contamination (size of hot spot).

p = surveyor efficiency (ORISE assumes a surveyor efficiency value at the lower end of the observed range (i.e., 0.5) when making Scan MDC determinations.

NOTE: The term MDCR (without subscript) refers to the performance of the ideal observer, and the MDCRsurveyor relates to the performance of the surveyor. In the data tables for this report (Appendix B), Scan MDCR relates to the MDCRsurveyor.

D.3.2.2 Scan Action Level The scan results were compared against the Scan Action Level calculation for each SU to determine if contamination above background levels was present on the M&E surfaces. The Scan Action Level was calculated as follows:

() = +

The maximum scan count rate (Max Scan) was compared with the Scan Action Level to determine if residual contamination, greater than background levels, was present on the scanned surfaces.

D.3.2.3 Scan MDC Scan minimum detectable concentrations (Scan MDCs) were then determined from the Scan MDCR by applying appropriate conversion factors to obtain results in terms of measurable surface activities.

These conversion factors account for the detector and surface characteristics, as well as surveyor Humboldt Bay Power Plant, Eureka, CA D-4 2029-SR-01-0

efficiency. The MDCR accounts for the background level, performance criteria [(d') index of sensitivity], and the observation interval (i) which is the actual time that the detector can respond to the contamination source (depending on the scan speed, detector size in direction of scan, and size of the hot spot).

The Scan MDC for a structure surface was determined as follows:

=

where, i = the instrument efficiency for scanning (ORISE has determined both static and scan instrument efficiencies for Cs-137 for gas proportional detectors. The static i = 0.46 and the scan i = 0.3 from Table 9.3 (Abelquist 2001) 5 s = the source efficiency (s = 0.25 for max 400 keV and s = 0.5 for max > 400 keV); for Cs-137, the s = 0.5 NOTE: ORISE determines the Scan MDC without the probe area correction factor in the above equation. This is contrary to the Static MDC equation, as well as for the calculation of net surface activity. The reason is that in order to calculate Scan MDC one must postulate a certain hot spot size. As long as this postulated hot spot measures 100 cm2 the Scan MDC will be determined in the appropriate units (dpm/100 cm2) (Abelquist 2001). HBPP determined their Scan MDC using a probe area correction factor.

The Scan MDCs for the hand-held gas proportional detector for each SU ranged from 1,529 to 1,889 dpm/100 cm2. Any audible increase in radiation levels were investigated by ORISE. It is standard procedure for the ORISE staff to pause and investigate any locations where surface scan radiation levels are distinguishable from background levels.

D.3.3 STATIC MEASUREMENTS Detection limits, referred to as MDCs, were based on 3 plus 4.65 times the standard deviation of the background count [3 + (4.65 (BKG)1/2)]. Because of variations in background levels, measurement 5 Abelquist, Eric W. (Abelquist). Decommissioning Health Physics: A Handbook for MARSSIM Users. Institute of Physics. 2001.

Humboldt Bay Power Plant, Eureka, CA D-5 2029-SR-01-0

efficiencies, and contributions from other radionuclides in measurement locations, the detection limits differ from measurement to measurement and instrument to instrument.

D.3.3.1 Static MDC For static measurements, ORISE performed five ambient background measurements within the vicinity of each SU that was being surveyed. The average of the ambient background measurements was calculated and that value was used in the determination of the Static Minimum Detectable Concentration (Static MDC or MDC) measurements. The MDCs shown in Table D-1 were calculated as follows:

3 + 4.65 (100 2 ) =

where:

MDC = minimum detectable concentration level in dpm/100 cm2.

BKG = background total counts in time interval, T (SU specific ambient background was used)

T = count time (min) used in field measurements Tot = total efficiency = i

  • s i = instrument efficiency s = source efficiency G = geometry = Physical Detector Area cm2/100 (Ludlum 43-68 physical area is 126 cm2)

TABLE D-1 MINIMUM DETECTABLE CONCENTRATIONS HUMBOLDT BAY POWER PLANT, EUREKA, CALIFORNIA MARSAME Survey Package MDC (dpm) Adjusted MDC (dpm/100 cm2)

HBPP-TB-001 322 256 HBPP-GN-001 322 256 HBPP-FW-001 322 256 HBPP-TF-001 326 259 HBPP-NG-001 355 282 HBPP-MS-001 355 282 HBPP-SA-001 296 235 HBPP-BL-001 323 256 HBPP-IS-001 290 230 Humboldt Bay Power Plant, Eureka, CA D-6 2029-SR-01-0

D.3.3.2 Surface Activity Measurements Surface activity measurements (unshielded and shielded pairs) were performed at ten locations within each SU. The determination of the net beta surface activity at each location was calculated as follows:

=

100 2 where:

U = unshielded (gross) surface activity count rate (gamma + beta)

S = shielded surface activity count rate (gamma only)

Rm = reference material background beta count rate (ambient reference material gamma background subtracted out)

Tot = total efficiency = i

  • s i = instrument efficiency s = source efficiency G = geometry = Physical Detector Area cm2/100 (Ludlum 43-68 physical area is 126 cm2)

The Net Beta Activity was compared against the Total and Removable Action Levels as provided by HBPP (refer to Appendix B data tables).

Humboldt Bay Power Plant, Eureka, CA D-7 2029-SR-01-0

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