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Humboldt Bay Power Plant - Final Report - Confirmatory Survey of the Fuel Oil Tank Area
	ML16250A432
Person / Time
Site:	Humboldt Bay
Issue date:	04/09/2012
From:	Adams W C; Oak Ridge Institute for Science & Education
To:	John Hickman; NRC/NMSS/DWM
References
	5167-SR-01-0
	Download: ML16250A432 (62)
	v • d • e

April 9, 2012 Mr. John Hickman Mail Stop: T-E18 Division of Waste Management .S. uclear Regulatory Commission 11545 Rockville Pike Rockville, N ID 20852

0 E OAK RIDGE INSTITUTE FOR SCIENCE AND EDUCATION Managed by ORAU for the U.S. Depertment of Energy

SUBJECT:

FINAL REPORT-CONFIRMATORY SURVEY OF THE FUEL OIL TANK AREA, HUMBOLDT BAY POWER PLANT , EUREKA, CALIFORNIA DCN: 5167-SR-01

-0

Dear Mr. Hickman:

The Oak Ridge Institute for Science and Education (ORISE) performed confirmatory radiological survey activities on the former Fuel Oil Tank Area and other portions of the Humboldt Bay Power Plant as requested b y the .S. Nuclear Regulator y Commission (NRC) site representative.

These survey activities were conducted during the period of Febmary 14 a nd 15, 2012. Enclosed is the final report that summarizes ORISE's survey procedures and provides the results of the ORISE radiological survey activities.

T he surveys included gamma walkover scans, gamma direct measurements, and soil sa mpling. My contact information is listed below , or yo u ma y contact E rika Baile y at 865.576.6659 or T im Vitkus at 865.576.5073, s h ould yo u require any additional information.

Wade C. Adams Project Manager/Health Ph ys ici st Independent Environmental Assessment a nd Verification WCA:fr Enclosure c: electronic:

G. Schlapper, NRC Region IV T. Carter, N R C HQ S. Roberts, ORISE/I EA V E. Baile y, ORISE/IEA V R. Evans, NRC Region IV File 516 7 T. Vitkus, ORISE/IEA V A. Hood, ORISE/IEA V Telephone:

865.576.0065 Fax: 865.241.3497 E-mail: Wad e.Adams@o rau.org P.O. Box 117 I Oak Ridge. TN 37831 I www.on s e.orau.gov CONFIRMATORY SURVEY OF THE FUEL OIL TANK AREA HUMBOLDTBAYPOWERPLANT EUREKA, CALIFORNIA W. C. Adams Prepared for the U.S. Nuclear Regulatory Commission Approved for public release; further dissemination unlimited.

The Oak Ridge Institute for Science and Education (ORISE) is a U.S. Department of Energy facility focusing on scientific initiatives to research health risks from occupational hazards, assess environmental cleanup, respond to radiation medical emergencies, support national security and emergenc y 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 b y 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 an y specific commercial product, process, or service b y 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 OF THE FUEL OIL TANKAREA H U MBOLDT BA Y POWER PLANT E U REKA , CALIFORNIA Prepared by W. C. A d ams OR I S E Independent E nvironmental Assessme nt and Verification Program Oak Ridge Institute for Science and Education Oak Rid ge, Tennessee 37831-0017 Prepared for the U.S. Nuclear Regulat ory Commiss ion FINAL REPORT APRIL 2012 This report is based on work performed b y the Oak Ridge In s titute for Science and E ducation u nd er contract number DE-AC0 5-060R23100 with the Department of Energy. Prepared b y the Oak Rid ge In s titute for Science and E duc atio n , under intera ge nc y agreement (NRC FIN o. F1008) between the U.S. uclear Regulat ory Commission and the U.S. Department of Energy.

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.S.oepwtmentofEnergv CONFIRMATORY SURVEY OF THE FUEL OIL TANKAREA HUMBOLDT BAY POWER PLANT Prepared by: Reviewed by: EUREKA, CALIFORNIA W. C. Adams, Health Physicist/Project Manager Independent Environmenta l Assessment and Verification Pr gram ey Operations Director Independent E nmental Assessment and Verification Program Reviewed by ft,;' rUY f. W. P. Ive y, LaborntoGroup Manager Independent Environmental Assessment and Verification Program Reviewed b y i1 Bto\T;iualitYAs;urnncespecialist Approved for release by: Independent Environmental Assessment and Verification Program {), E. N. Bailey, Survey Projects Independent Environmental and Verification Program HBPP Fuel Oil Tank Area, Eureka, CA Date 'f /q (n_ Date 1/{bB-Date: .l/ J 9/J Z. 516 7-SR-01-0 THIS PAGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank Area, Eureka, CA. 516 7-SR-01-0 C>R , SE OAK fW>Oa H8Tl'TU1'E llOA 9CaNCa: AHO U>UCATlON C O NTENTS F IG U RES .....................................................................

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........... vi AC R ONYMS ...........................................................................................................

........................................ vii 1. I NT R O D UC TI O A D S IT E HIST O R Y ............................................................................................ 1 2. SIT E D E S C RIPTI ON ..........................................................................................

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2 2.1 FUEL OIL TA KAREA (FO T A) .................................................................................................

.. 2 2.2 U IT 1 AND U I T 2 CONCRETE P ADS ........................................................................................ 2 2.3 ORTHEAST L AYDO AREA ................

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....................................... 3 2.4 NE\V ASPf-L\LT R OADWAY ......................................................................

...................................... 3 3. O BJ ECT I VES ..............

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........................ 3 4. D OCUME NT RE V I EW ............................................................................................................................. 3 5. D ATA QUAL I TY O BJ ECT I VE S ..........................................................................

................................... 4 6. CO FIRMA T O R Y RA DI OLOG I CAL SU R VEY PR OCE D URES .................

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5 6.1 SURVEY u IT CLASSIFICATIO

................................................................................................... 5 6.2 REFERE NCE SYSTEl\f ..................................................................................................................... 6 6.3 SURFACE S CANS ............................................................................................................................. 6 6.4 GAMl\f.A D IRECT MEASUREl\fENTS

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6 6.5 SO I L SAl\IPLING

.............................................................................................................................. 6 6.5.1 S ys t e m ati c Sam pl e Lo c atio n s .....................

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6 6.5.2 Jud gme nt a ll y-S el e cted Sampl e Lo c a ti o n s ..............

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................. 7 6.6 I NTERLABORATORY COM P ARISON ANALYSES ..................

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.................... 7 7. A DDI T I O N A L RADI O L O GI CAL S U R VEY PR OCE D U RE S ........................................................ 8 8. RADI O N UC LID E S OF CONCE RN ......................................................................................................

8 9.SAMPLEA ALYS IS A DD A T A I TE RP RE T A TI O ............................................................... 1 0 1 0. F I N DI GS AN D RESULTS ....................................................................................

............................. 1 0 1 0.1 D OCUl\ffi TREV I EW .................... , ......................................................

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......................... 10 1 0.2 S U RF ACE S CANS .............................................

.............................................................................. 10 1 0.3 GAMl\f.A D IRECT MEASUREl\ffiNTS

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................................... 11 1 0.4 RA DIO UCLIDE Co CE TRAT I O N S IN Co F I RMATORY SOIL SAMPLES ............................ 11 HB PP F u el O il Ta nk Area, E u re k a, CA 111 51 67-S R-0 1-0 1 0.5 .RADIO N U C LIDE CO NCEN T R ATIO N S I N I N T E RL A BORATORY COMP A RISO N AN ALYS E S S O IL SAMPL E S ..................................

............................................................................................. 1 2 11. COMPA RI SON OF RE SUL TS W ITH REL EA SE C RIT E RI A. ..................................................... 12 1 2. A DDITI ONA L RADI O L OG I CA L S U R VEY AC T IV IT IES ......................................................... 13 1 2.1 U N IT 1 AN D U N IT 2 -GAMMA WALKO VE R S C A N S ...................................................

.............. 13 12.2 NO R THE A ST L A YDOWN AREA -GAMMA WALKOVER S C A N S ............................................... 1 3 12.3 N E W ASPHALT R OADWA Y -GAMMA WALKOV E R S C\NS ...................................................... 13 1 3. SUMMA R Y ................................................................................................................................................ 1 3 1 0. RE FE RE NCE S ...........................................................................................................................

.............. 15 A PP EN DI X A: F I GURES A PP EN D IX B: TA BL ES A PP E NDI X C: MA J O R I NS TR UMEN T A TI O N A PP EN DI X D: SU R VEY AN D ANALY TI CAL PR OCE D URES HB PP F u el Oil Ta n k Area, Eu r e k a, CA l V 5 1 6 7-S R-0 1-0 C>R , SE OAK NDOa ...-nTVTW EOUCAllON

FI G U R ES Fig. A-1. Site Location Map -Humboldt Ba y Power Plant, Eureka, California

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A-1 Fig. A-2. Humboldt Ba y Power Plant -Site Overview of Surveyed Areas .........................................

A-2 Fig. A-3. HBPP Fuel Oil Tank Area -Gamma Walkover Scans ...................................................

....... A-3 Fig. A-4. HBPP FOTA -PG&E Systematic Soil Sample Locations

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A-4 Fig. A-5. HBPP FOTA -Confirmatory Soil Sample Locations

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.......... A-5 Fig. A-6. HBPP Unit 1 and Unit 2 Concrete Pads -Gamma Walkover Scans ................................... A-6 Fig. A-7. HBPP Northeast Lay down Area -Gamma Walkover Scans ................................................

A-7 Fig. A-8. HBPP New Asphalt Roadway -Gamma Walkover Scans ..........

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........................ A-8 Fig. A-9. HBPP Fuel Oil Tank Area -Gamma Scan Count Rate Distribution

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............ A-9 Fig. A-10. Fuel Oil Tank A rea -Pictures of the Natural Strata La ye r that Exhibited Elevated Gamma Radiation Levels ..........................

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..... A-10 Fig. A-11. HBPP Units 1 & 2 Concrete Pads -Gamma Scan Count Rate Distribution

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A-11 Fig. A-12. HBPP Northeast La y down Area Asphalt Pad-Gamma Scan Count Rate Distribution

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A-12 Fig. A-13. HBPP New Asphalt Roadway-Gamma Scan Count Rate Distribution

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..... A-13 HBPP Fuel Oil Tank .Area, Eureka, CA v 516 7-SR-01-0

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TABLES Table 1. Derived Concentration Guideline Levels for Surface Soil Radionuclides-of-Concern Humboldt Ba y Power Pl a nt E ureka , California

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9 Table 2. Radionuclide Concentrations in FOTA Soil Samples Summary Re s ults .................................

11 Table B-1. Radionuclide Co ncentration s in ORISE Soil Samples ..........................................................

B-1

Table B-2. Fuel Oil Tank Area Comparison Data ............

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B-2 Table B-3. Radionuclide Concentrations in Interlaboratory Comparison Soil Sample s .....................

B-4 HBPP Fuel Oil Tank Area, Eureka, CA vi 516 7-SR-01-0 L C>R , SE OAK AIOGa ...-nnlTW 9CIENCE AHO EDUCATION

MenepdbyORAUforhtU.S.

Depw1montofl!ntM"VY CPR cpm CSPW DCGL DQO ES I FOTA PSS GPS GWS HBPP HBRP IEAV MARSSIM MDC MeV MWe NORM NRC OOL ORAU ORI S E pCi/g PG&E RC A RER ROC SAFSTOR SOR SPCS S U A CRO NYMS Code of Federal Regulations counts per minute Characterization Survey Planning Worksheet deri ve d concentration guideline le ve l data quality objectives Enercon Service s , Incorporated Fuel Oil Tank Area final status survey global positioning system gamma walkover s cans Humboldt Ba y Power Plant Humboldt Ba y Repo w ering Project Independent Environmental Ass essment a nd Verification Multi-Agency Radiation Surve y and Site In ves ti g ation Manual minimum detectable concentration million electron volts megawatt electric naturall y occurring radioactive material U.S. Nuclear Regulatory Commission Open Outside (o f RC A) Land A rea Oak Ridge Asso ciated U ni ve r s itie s Oak Ridge Institute for Science and Education picocunes per gram Pacific Gas & Electric Company radiological control area Replicate Error Ratio radionuclide of concern cold shutdown and safe storage Sum-of-Ratios State Plane Coordinate System survey unit HBPP Fuel Oil Tank Area, E ureka , CA vu 5167-SR-01-0 THIS PAGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank Area, Eureka, CA viii 516 7-SR-01-0 C>R , SE OAK R100a INSTITU'T9 8CENC8 AHO EDUCAT'tON

CONFIRMATORY SURVEY OF THE FUEL OIL TANK AREA H U MBOLDT BA Y POWER PLAN T EUREKA, CALIFORNIA

1. 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 U.S. Atomic Energy Commission provisional license number Demonstration Power R eactor license 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 contamination-zircaloy-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 Ju l y 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 p l aced the unit into cold shutdown and safety storage (SAFSTOR). Unit 3 is currently undergoing decommissioning.

Decommissioning activities have also been completed on the adjacent fossil fuel Units 1 and 2, with all materials being removed to ground level. 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. Currently, PG&E has demolished the Fuel Oil Tank and has performed final status surveys (FSS) on the former Fuel Oil Tank Area (FOTA) soils. Hence, the U.S. Nuclear Regulatory Commission's (NRC's) Headquarters and Region IV Offices have requested that the Independent Environmental Assessment and Verification (IEA V) Program of the Oak Ridge Institute for Science and Education (ORISE) perform confirmatory surveys of the former FOTA excavation.

Due to the small footprint of the site, the licensee has found it necessary to conduct surveys of the decontaminated survey areas and then backfill and/ or pave those areas to allow for further decommissioning work. Therefore, the RC requested that ORISE perform confirmatory surveys coincident with the HBPP Fuel Oil Tank Area , Eureka, CA 516 7-SR-01-0

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licensee's surveys and so il sa mpling prior to b ackfilling. During the ORISE survey activities, the NRC also requested additional radiological s urve y activities consisting of gamma walkover scans (GW S) of the newl y paved road along the north and east side of the site, the Unit 1 and Unit 2 concrete pads and the Northeast Laydown Area. 2. SITE DESCRIPTION The HBPP site, owned b y PG&E, consists of 143 acres on the southern edge of Humboldt Ba y four mile s sou thwest of the town of Eureka, in Humboldt County, in the State of California (Fig. A-1). PG&E maintains ten new operating electric generating units at the HBPP site (i n 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). Units 1 and 2, which were recentl y decommissioned to ground level, were interconnected with and west of Unit 3 (ES I 2008). The remaining property includes mostl y open areas and protected wetlands.

2.1 F UEL O IL TANK AREA (FOTA) The FOTA, pictured in Figs. A-2 and A-3, co vers approximately 6,500 square meters (m 2) and is located in the northwest section of the HBPP to the west of Units 1 and 2, north of the Intake Canal and south of the Independent Spent Fuel Storage Installation.

Within the FOTA is a bermed soil area that contains some asp h a l t roadway on portions of the berm and concrete pads, which are positioned between a n access ramp and metal stairs. With the exception of the areas that were remediated from under the tank and immediatel y adjacent to the tank due to h y drocarbon contamination, the soil remains at the level that existed when the fuel oil tank was present. FSS activities were performed on a section of the FOTA so that a portion of the FOTA could be used for a soil pile. ORISE did not perform any confirmatory activities of that portion of the FOTA. The FOTA is identified as an Open Outside (of the Radiological Control Area) Land Area (OOL) by PG&E. The survey unit (SU) designation is OOL10. 2.2 UNIT 1 AN D U NI T 2 CONCRE TE PAD S The Unit 1 and Unit 2 concrete pads are located east of the FOTA and west of the nit 3 (the Reactor Building). These were where the fossil fuel units once stood (Fig. A-2). Portions of these pad areas were in use for radiological waste container storage and as material la y down areas and these portions were therefore ina cc essible. HBPP Fuel Oil Tank .Area, Eureka, CA 2 5167-SR-01-0 C>R , SE ON< M>CMf ..anT\ITW POA ICIENCa AHO EDUCATION

DeportrnentOllE.norw 2.3 NO RTHEAST LAYDOWN AREA The Northeast La y down Area is located northeast of U nit 3 and the curve of the New A sphalt Roadwa y and west of the Discharge Canal (Fig. A-2). The area has been repaved with asphalt and at the time of the GWS, a portion of the area was inaccessible due to radiological waste containers and other radiological waste storage bins. 2.4 N EW A SPHALT RO ADWAY The New Asphalt Roadway stretches from an east/west direction at the northern portion of the site and curves to a north/ south direction along the eastern portion of the site just east of Unit 3 and west of the Discharge Canal (Fig. A-2). 3. OBJECTI V ES The objective of the confirmatory side-by-side surve y was to generate independent radiological data for use b y the NRC in evaluating the adequacy and accurac y of the licensee's radiological soil sampling results from the FOTA. Data collected by ORISE and the licensee were reviewed to assess whether classifications based on the Multi-Agenr y Radiation Surory and Site Investigation Manual (MARSSIM) (NRC 2000) were appropriate; whether radionuclides of concern (ROCs) were detected above historically low levels in the HBRP footprint (i.e., averaged 0.38 picocuries per gram [pCi/ g] for cesium-137

[Cs-137] and non-detected for all other ROCs); and, whether data quality were sufficient for comparison to generic NRC screening values and FOTA-specific derived concentration guideline levels (DCGLs). During the ORISE confirmatory survey activities for the FOT A, the NRC site representative also tasked ORISE with performing GWS of three additional areas as stated in Section 1. 4. DOC U MENT REVIEW ORISE has reviewed PG&E's Characterization Surory Planning Worksheet (CSPW) (PG&E 2012). Since the FOTA was classified as Class 3 SU as described in Section 5, it was PG&E's intention to use the data as FSS data in the event that the characterization survey findings met the classification criteria for a Class 3 SU. The characterization plan worksheet was specifically reviewed for historical information and to identify the ROCs and the applicable DCGLs for the FOTA. ORISE also reviewed preliminary FSS data for the soil pile area within the FOTA. The purpose of these reviews was to ensure that regulatory requirements were being met by PG&E and to develop the HBPP Fuel Oil Tank Area , Eureka, CA 3 516 7-SR-01-0 OR , SE OAK NDQI: ...-nT'\l1W 110A ll>UCATION

confirmatory survey plan. ORISE also ensured that the current FSS activities within the area were a dequate and appropriate, taking into account any supporting documentation and MARSSIM guidance (NRC 2000). 5. DATA Q U ALI TY OBJECTIVES The ORISE independent confirmatory survey planning relies on the Data Quality Objectives (DQO) process to design and implement the confirmatory activities planned for the HBPP site. The DQO process includes the following seven steps:

Step 1: State the problem

Step 2: Identify the decisions

Step 3: Identify inputs to the decision s

Step 4: Define the study boundaries

Step 5: Develop a decision rule

Step 6: Specify the decision errors

Step 7: Optimize the survey design The confirmatory DQO steps for the HBPP s ite were as follows:

Step 1, problem: The confirmatory survey must assess the reliability and adequacy of the HBPP FSS results.

Step 2, decisions:

Are HBPP procedures sufficiently robust to identify residual material with concentrations that exceed the DCGL s for the ROCs, and are the residual concentrations of the primary ROC, Cs-137, sufficiently low (a t background levels)?

Step 3, decisions inputs: The decision inputs included:

1) gamma walkover scan results, and 2) soil sample results and comparison of ORISE and PG&E soil sample concentrations.

Step 4, study boundaries:

The former FOTA is the study boundary.

Step 5, decision rules: There were two decision rules. The first was ba se d on the comparison of the confirmatory soil sample results to the HBPP FSS results and to the site cleanup goals. The second rule was based on surface scan and judgmental sample results to HBPP Fuel Oil Tank Area, Eureka, CA 4 5167-SR-01-0

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determine whether any residual " hot s pots" were present and if the FOTA had been cla ssifie d appropriately as Class 3.

Step 6, decision errors: The gamma wa lk over scans an d si de-by-side split soil sample results should be in goo d agreement and soil sa mple re s ult s for the MARSSIM Class 3 Survey nit should be at or near background le ve ls and all ROCs below the CSPW survey design release criteria.

Step 7, survey design optimization:

The s urve y design was optimized to collect the appropriate data ba se d on the procedures detailed below. 6. CONFIRMATORY RADIOLOGICAL SURVEY PROCEDURES To expedite the survey process, ORISE coordinated and worked with the NRC site representative as the licensee planned their s urve y activities.

This assured that O RIS E would complete s ide-b y-side confirmatory surveys at such a time as the lic ensee determined the probability of satisfying the FSS DQOs was high. ORISE personnel visited the HBPP site from February 14 to 15, 2012 to perform visual inspections and independent measurements and sampling.

The radiological survey activities were conducted in accordance with a project-s pecific plan submitted to and approve d b y the RC, the ORISE Suro ry Pro cedures Manual and the Oak Ridge Associated Universities (ORAU) Q11aliry Program Manual (ORISE 20 1 2, 2008 and ORAU 2011). 6.1 S U R VEY UNIT C LASSIF ICATION PG&E classifies SUs in accordance with MARSSIM guidance RC 2000) with three classification s for impacted areas, b ased on contamination potential-as either Class 1, 2, or 3. The FOTA ha s been classified by PG&E as a Class 3 SU and the historical documentation supports this classification.

Class 3 area are designated as any impacted areas th at are not expected to contain residual contamination, or are expected to contain levels of residual contamination at a small fraction of the DCGL. Although the FOTA is a Class 3 SU, ORISE confirmatory survey activities coverage within the FOTA SU were conservative an d on the sa me order of rigor as the PG&E CSPW (PG&E 2012). The PG&E CSPW called for 100% gamma scan coverage of the FOTA. Also, a portion of the HBPP Fuel Oil Tank Area, E ureka , CA 5 516 7-SR-01-0

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FOTA had already been s urve ye d and so il sam ples had been collected b y the licen see. This was done so that a dirt pile could be pl ace d in thi s porti o n of the FOTA SU. 6.2 RE FE RENC E S YSTEM Global p os iti o ning system (G PS) c oor dinate s were used for referencing measurement an d sam plin g locations. The s pecific reference system used by the licen see was the California State Pl ane Coordinate S ys tem (SPCS FIPS 0401 U S Surve y feet; orth American Datum 83). 6.3 S U RF A C E S CANS High-density gamma radiation surface scans were conducted over the soil, concrete, and asphalt surfaces within the FOTA, the area of intere s t for this survey report (Fig. A-3). Surface s cans were performed u si ng sodium iodide thallium-activated (Nal[Tl])

s cintillation detector s coupled to ratemeter-scalers with audible indicators.

Detectors were also coupled to g lobal p osi ti oning systems (G PSs) that enabled real-time ga mma count rate and p os ition data capture. Field per so nnel relied on the audio output to identify and mark any locations of elevated direct gamma radiation for further investigations that mi g ht s u gges t the presence of residual contamination.

6.4 G AMMA DIR ECT M EASUREMENTS A one-minute static gamma count rate mea s urement was performed at each of the twelve remaining characterization soil samp le locati o ns determined per PG&E for the FOTA (F ig. A-4). A fter each soil sample was collected , a po s t-sample one-minute static gamma count rate was performed.

Pre-and post-sample gamma direct measurements were also performed at judgmentall y-s elected locations exhibiting elevated ga mma radiation level as determined b y surface scans (Fig. A-5). 6.5 SOI L S AM P LING 6.5.1 S ys t e m a tic S a mpl e L o c a tion s Twel ve duplicate systematic s urface sa mple s, 0 to 15 cm each, were collected from the FOTA at locations predetermined in the PG&E CSPW (Fig. A-4). Although ORISE collected one of the duplicate samples in conjunction with PG&E personnel, the final number of so il samples retained for confirmatory analysis d epe nded upon the ORISE gamma direct mea s urement results and/ or the PG&E preliminary gamma s pectroscop y analyses of the ORISE samples. Ba se d on the ORISE review of the aforementioned data, four of the twelve sys tematic soil sample duplicates were HBPP Fuel Oil Tank Area, Eu rek a, CA. 6 5167-SR-01-0 C>R , SE OAK A100a ...nTUTE FOR 8C1ENCa NllO EDUCAllON

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.... U.&-of"'-vY retaine d for radio l ogical analyses (PG&E samples OOL10-1, 2, 7, and 11 which corresponded to ORISE samples S001, 2, 7, and 11, respectively).

Refer to Figs. A-4 and A-5, and Table B-1. 6.5.2 Judgment a ll y-Selected S a mpl e Loc a ti o ns Judgmental surface so il samples were collected at six locations of suspected elevated gamma radiation detected during the ORISE GWS of the FOTA surfaces (Fig. A-5). Since these were judgmental samples, ORISE requested each of these samples for independent analyses.

These were ORISE samp l es S016 to S021 (Refer to Fig. A-5 and Table B-1). 6.6 INTERLABORA T OR Y CO M PARISON AN ALY SE S Since some areas within the FOTA were covered with clean fill prior to ORISE gaining access, thus precluding direct confirmatory surveys for the soil pile area, ORISE requested that the three samp l es previously collected b y PG&E (PG&E samples OOL10-4, 9, and 15, which were ORISE samples S004, 9, and 15, respectively) be provided to ORISE for interlaboratory comparison analysis.

HBPP Fuel Oil Tank A rea, Eureka, CA 7 516 7-S R-0 1-0

7. ADDITIONAL RADIOLOGICAL S U R V E Y PROCED U RES At the request of the NRC site representative, ORISE also performed limited, low-density radiological GWS of three other areas: the Unit 1 and Unit 2 remaining concrete pads (Fig. A-6), the Northeast Laydown Area (Fig. A-7), and the newl y paved asphalt haul road (Fig. A-8). The additional surveys were to provide radiological scan data to ensure that radiological contamination was not being spread by continuing decommissioning activities of the Unit 3 reactor on previousl y released site surfaces as per the Cross Contamination Pre vention and Monitoring Plan (CC PMP) (PG&E 2008). 8. RADION U CLIDE S OF CONCERN The major ROC identified in the FOTA was Cs-137. A complete listing of ROCs and associated generic NRC Screening Values and FOTA-specific DCGLs are provided in Table 1. The soil DCG Ls are reported in units of picocuries per gram (pCi/ g). HBPP Fuel Oil Tank Area, Eureka, CA 8 5167-SR-01-0 C>R , SE OAK NOa8 IMST1T\ITE FOR 8CaNCtl AHO EDUCA TION ----------------------------

Table 1. Derived Concentration Guideline Levels for Surface Soil Radionuclides of Concern Humboldt Bay Power Plant Eureka, California Nuclide NRC Screening Value DCGLs (pCi/ g)* FOT A-Specific DCGLs (pCi/ g)b Easy to Detect -Gamma Spectroscopyc Co-60 3.8 1.9 Nb-94 5.8 2.9 I-129 0.5 0.25 C s-137 11 5.5 Eu-152 8.7 4.35 Eu-154 8 4 Np-23 7 d 11 5 -Hard to Detect -Wet Chemistryc H-3 1 1 0 55 C-14 12 6 Ni-59 5,500 2,750 Ni-63 2, 1 00 1,0 5 0 Sr-90 1.7 0.85 Tc-99 1 9 9.5 Pu-238 2.5 1.2 5 Pu-239 2.3 1.1 5 Pu-240 1,240 Pu-241 72 36 A m-241 2.1 1.05 Cm-243 3.2 1.6 Cm-244 2,200 Cm-245 276 Cm-246 1 , 1 90 *Derived concentration guideline levels from UREG-1 757, Volume 1, Revision 1 Table B-2 (NRC 2003) bDCGLs a p plied under the Characterization Survry Pia1111ing Worksh e et for the HBPP FOTA correspond to the l esser of either an annual dose of 15 mrem/y (the 25 mrem/y DCGL adjusted to an assumed California Department of Toxic Substance Contro l risk-based release of 15 mrem/y) or 50% of the NRC Screening Va l ues (PG&E 2012) c Easy-to-detect radionuclide concentrations determined via gamma spectroscopy dNRC Screening Va l ue not provided <Hard-to-detect radionuclide concentrations may be determined with wet chemistry analytical procedures based on the gamma spectroscopy results and with guidance from the NRC site representative HBPP Fuel Oil Tank Area, Eureka, CA 9 5167-SR-0 1-0 C>R , SE OAK A100a ..-nTUTE FOfll llCll£NC&

NID IEDUCATtON

9. SAMPLE ANALYSIS AND DATA INTERPRETATION Samples and data were returne d to the ORISE laboratory in Oak Ridge, Tennessee for anal y si s and interpretation. Sa mpl e analyses were performed i n accordance with the ORISE Laboratory Procedures Manual (ORISE 2011 ). Soil samples were anal yz ed b y gamma spectroscop y with the primary ROC being Cs-137; however, s pectra were al s o reviewed for other gamma-emitting radionuc lid es (i.e., fission and activation products) associated with the HBPP. After reviewing the ga mm a spectros c opy results, wet chemistry analyses for additiona l radionucli d es such as Ni-63, Sr-90, and transuranics were deemed not necessary. Soil samp l e results were reported in units of pCi/ g. Gamma count rate measurement re s ults were reported in units of counts per minute (cpm). The data generate d were compared with the PG&E anal y tical re s ults (specifically for Cs-137) and then with the CSPW surve y design release criteria established for t h e primary site-specific ROC for the FOT A. All sample results were compared \.vith the FOTA-specific applicab l e DCGL and MARSSIM guidance to determine if the FOTA Class 3 designation was appropriate. Additional information regarding instrumentation and procedures ma y be found in A ppendices C an d D. 10. FINDINGS AND RESULTS The results for each radiological s u rve y procedure component are discussed in the following sections.

10.1 DOCUMENT REVIEW The O RI SE reviews of PG&E's CSPW and preliminary radiological data indicated that the procedures and methods implemented were appropriate for the FOT A (PG&E 2012). 10.2 SURFACE SCANS Gamma radiatio n surface scans identified six areas of elevated gamma radiation, primaril y along the excavation trenches used to drain standing water from the site, along other surfa c e water runoff areas, a nd at the asphalt entrance at the northeast corner of the b erm. The gamma scan paths and the normali z ed count rate in cpm are provided in Fig. A-3. The gamma scans ranged from less than 3,800 to 11,390 cpm. Figure A-9 is the frequency histogram of the normali z ed walkover gamma count rate data population for the FOTA; the histogram indicates a normal distribution typical of the background concentrations associated wit h those areas. O RI SE did observe slightly e l evate d HBPP Fuel Oil Tank Area , E ureka, C A 1 0 516 7-SR-0 1-0 C>R., SE OAK NDOm ll'OA 8QIENCa: AHO EDUCATION

gamma radiation levels over the ground surface where the standing water excavation trench dirt was piled. Further investigation indicated a natural soil strata la y er deposit. The dark lines in the trench pictures (Fig. A-10) indicate the locations where the elevated gamma radiations were in the southern portion of the FOTA near where the former fuel tank used to be located. The ORISE GWS data indicates that the low gamma radiation levels associated with the Class 3 SU is typical of background leve l s that ranged from 3 , 200 to 5,400 cpm o v er the various surfaces (soil, asphalt and concrete) within the FOTA. 10.3 GAMMA DIRECT MEAS U REMEN TS Gamma direct measurements were performed at each soil sample location.

The results indicated that gamma radiation levels were at or near background levels (3,500 cpm). ORISE selected soil samples from locations that exhibited the highest gamma radiation levels even though those locations were slightly above background levels. 10.4 RADIO NU CLID E CONCEN T RA T ION S IN CON F I RMAT OR Y SOI L S AM P LES The summary data for the FOTA s y stematic and judgmental soil samples are presented in Table 2. The data for the radionuclide concentrations in individual samples are provided in Table B-1. All soil results for Cs-137 were less than the respective FOTA CSPW designed release criteria for each individual soil samp l e. Total uranium concentrations, as a naturall y occurring radioactive material (NORM), are provided to account for the elevated gamma radiation levels determined by the GWS in the FOTA. Table 2. Radionuclide Concentrations in FOT A Soil Samples Summary Results Soil Sample Summary Cs-137 S ys tematic 0.03 to 0.37 Mean Concentration 0.26 Judgmental

-0.01 to 0.51 Mean Concentration 0.14 *Total U = U-238

2 + U-235 b Zero v alues due to rounding HBPP Fuel Oil Tank Area, Eureka, CA Radionuclide Concentrations (pCi/ g) Co-60 U-235 U-238 Total U* -0.02 to 0.01 0.04 to 0.16 0.15 to 0.69 0.34 to 1.48 0.001 0.0 7 0.45 0.9 7 -0.01 to 0.01 -0.02 to 0.08 0.28 to 1.84 0.60 to 3.75 0.00 0.04 0.8 2 1.69 11 516 7-SR-01-0 C>R , SE OAK ..:>Oii ....-nnnw H>flll 8CCHCa AHO EOUCATIOH

MenogedbyORAUforhtU

.&OepenmentofEnorgy ORISE also performed a comparison of the ORISE and PG&E soil samples results (Ta ble B-2). PG&E's Cs-137 results, for those samp le l o cation s where both ORISE and PG&E provide analytical data, are in good agreement and indicate that the FOTA Cs-137 concentrations are at background levels. 10.5 RADIO NU CLID E CO N C ENTRAT IO NS IN IN TERLAB O RAT OR Y CO MPARIS O N ANALYSES SOI L S AM P LES The results of the interlaboratory comparison soil samples indicate that the ORISE and PG&E radiological so il sample results are in good agreement.

The comparison so il sample results are presented in Table B-3. 11. COMPARIS O N OF RES U LTS W ITH RELEASE CRI T ERIA The applicable site-specific soil DCGLs for the ROCs are provided in Table 1 and ha ve been approved b y the NRC (ESI 2007). The primary ROC for the FOTA, as designated b y the CSPW, was Cs-137. To demonstrate compliance with the Table 1 FOTA-specific criteria, each radionuclide concentration should be less than its respective DCGL-with consideration for small areas of elevated activity----as well as application of the unity rule (S um-of-Ratios

[SOR]). The uni ty rule requires that the sum of the concentration of each contaminant divided by the respective guideline be less than one. Con c 1 Co nc 2 C oncn SOR = DCGL 1 + D C GL 2 + ... + DCGl n ::::; 1 Cs-137 and Co-60 were the only identified ROCs in the ORISE-analyzed soil samples. ORISE also reported the uranium concentrations to determine the natural concentrations associated with the ORM soil strata determined in the FOTA. Radionuclide concentrations in soil samples were directly compared with the Cs-137 DCGLs prov i ded in Tab l e 1. ORISE did not apply the unity rule/SOR in the activity calculations for each of the soil samples since the primary ROC, Cs-137, was well below the release criteria and a review of the gamma spectroscopy data did not indicate any other easy-to-detect ROC other than Co-60. Each of the 13 soil samples analyzed by ORISE was below the individual Cs-137 FOTA-specific release criteria.

HBPP Fuel Oil Tank Area, Eureka, CA 12 516 7-SR-01-0 C>R , SE OAK AK>oa ....-mvTW FOA 8CCNCW AHO EOUCATlON

12. ADDITIONAL RADIOLOGICAL SURVEY ACTIVITIES 12.1 UNIT 1 AND UNIT 2 -GAMMA WALKOVER SCANS GWS over the Unit 1 and Unit 2 concrete pads indicated a gamma count rate range from less than 3,300 to approximately 13,000 cpm. The elevated gamma radiation levels were determined to be from shine when the surve y or was in the proximity of radiological waste containers and the radwater waste treatment facility.

Elevated gamma radiation levels were not found on the portion of the concrete pads that were scanned. The GWS results are presented in Fig. A-6 and the GWS frequency histogram is provided in Fig. A-11. 12.2 NORTHEAST LA Y DOWN AREA -GAMMA WALKOVER SCANS G\VS over the Northeast La y down Area asphalt pad indicated a gamma count rate range from less than 3,000 to approximatel y 21,000 cpm. The elevated gamma radiation levels were determined to be from shine when the surve y or was in the proximity of radiological waste containers and other wrapped radiological waste. The highest count rate was on a pie<:::e of equipment that had been determined to an X-bar equipment lift; this piece of equipment was determined to not be tagged wit h a radiological identification tag). Elevated gamma radiation levels were not found on the portion of the Northeast La y down A rea asphalt pad that was scanned. The GWS results and a picture of the X-bar are presented in Fig. A-7 and the GWS frequency histogram is provided in Fig. A-12. 12.3 NEW ASPHALT ROADWAY-GAMMA WALKOVER SCANS GWS over the new asphalt roadway indicated a gamma count rate range from less than 3,400 to approximatel y 11,000 cpm. The elevated gamma radiation levels were determined to be from shine w h en the surve y or was in the proximity of radiological waste containers and the radiological cleanup work associated with the reactor decommissioning.

E l evated gamma radiation levels were not found on the portion of the asphalt roadwa y that was scanned. The GWS results are presented in Fig. A-8 and the GWS frequency histogram is provided in Fig. A-13. 13.

SUMMARY

During the period of February 14 to 15, 2012, ORISE performed radiological confirmatory surve y activities for the former FOTA and additiona l radiological surve y s of portions of the HBPP site in Eureka, California.

The radiological survey results demonstrate that residual surface soil HBPP Fuel Oil Tank A rea, E ureka, CA 13 516 7-SR-01-0 C>R , SE OAK ..:>QA ...-nTVTa FOR 8C1ENCa: AHO IEDUCAnoN

contaminati o n was not present significantly above background le vels wit hin the FOTA. Therefore, it is ORISE's op ini on that the radiological condition s for the FOTA s u rveye d by ORISE (refer to Tables 2 and B-1) are c o mmensurate with the site release criteria for final sta tus surveys as specified in PG&E's CharacteriZfllion Sttrory Planning Worksheet (PG&E 2012). In addition, the confirmatory results indicated that the ORISE FOTA SU Cs-137 mean concentrati o n s results c o mpared favorably with the PG&E FOTA Cs-137 mean concentration results , as determined by ORISE from the PG&E characteri za tion data (refer to Table B-2). The interlaboratory comparison a nal ys es of the three soil samples analyzed b y PG&E's onsite laboratory and the ORISE laboratory indicated good agreement for the sample results and provided confidence in the PG&E analytical procedures and PSS soil sample data reporting (Table B-3). HBPP Fuel Oil Tank Area, Eureka, CA 14 5167-SR-01-0

C>RISE OAK N008 INS1'fTU'TE FOfll 8CENC9i AHO EDUCATION

10. REFERENCES Enercon Services, Inc. (ESI) 2007. Site CharacteriZfltion Plan -Humboldt Bery Power Plant. HBPP-PP-003, R ev. 0. Jul y 16. ES I 2008. Historical Site Assessment, prepared for the Humboldt Ba y P ower Plant Pacific Gas & E lectric Com p a n y, E ureka, Ca lifornia. D raft. September.

Pacific Gas & E lectric Co mpan y (PG&E) 2008. Cross Contamination Prevention and Monitoring Plan. Prepared for the Humb o ldt Ba y Power Plant, Pacific Gas & El ectric Co mpan y, Eureka, California.

HB A P C-220. October 14. PG&E 2012. Characterization Surory Pl anning Worksheet.

Prepared for the Humboldt Ba y P ower Plant , Pacific Gas & E lectric Company, E ureka, California.

Draft; Revisi o n 3. February 9. Oak Rid ge Asso ciated U ni ve r s ities (O RA U) 20 11. Quality Pro gram Manual for the Indep endent Environmental Assessment and Verification Pro gram. Oak Rid ge, Te nne ssee. D e c e mber 1. Oak Rid ge In s titute for Science and E ducati o n (ORISE) 2008. Surory Procedures Manual for the In dependent Environmental Assessment and Verification Pro gram. Oak Rid ge, Tennessee.

May 1. ORISE 2010. Radiation Prot ection Manual. Oak Rid ge, Tennessee.

June 3. ORISE 2011. Laboratory Procedures Manual for the Indep endent Environmental Assessment and Verificat ion Program. Oak Ridge, Tennessee.

December 1. ORISE 2012. Final Prqj ect-S p ecific Plan far th e Indep endent Confirmatory Survry of the Former Fue l Oil Tank Area at the Humboldt B ery Po we r Plant , Eureka, California.

DCN: 516 7-PL-0 1-0. Oak Rid ge, Tennessee. February 9. U.S. uclear Regul a t ory Co mmi ss ion (NRC) 2000. Multi-Agenry Radiation Surory and Site In vestigation Manual (MARSSIM), NUREG-15 75; Revision 1. Washington, DC. August. NRC 2003. Cons olidat ed NM SS D ec ommission ing Guidance:

D ecomm iss ioning Process for Materials Licensees.

NUREG-1 757; Volume 1 , Revision 1. Washington, D C. September.

HBPP Fuel O il Tank .Area, Eureka, CA 1 5 516 7-SR-01-0 THIS PAGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank Area, Eureka, CA 516 7-SR-01-0 HBPP Fuel Oil Tank Area, Eureka, CA APPENDIX A FIGURES 5167-SR-01-0 THIS PAGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank Area, Eureka, CA 516 7-SR-01-0 D Site Loc a tion 0 50 1 00 Mil e s Nevada Arizona ll11r1 Humboldt B ay Pl a nt E urek a, C a hforru a ORISE Crea t ed b)': A. H oo d Date: 26, 201 1 Fig. A-1. Site Loc a tion M ap -Humboldt Ba y Power Plant, Eureka, C a liforni a HBPP Fuel Oil Tank Area, Eureka, CA A-1 5167-SR-01-0 Su rveye d Ar eas "" II F uel Oil Tanlc Area t H umbo ldt B ay --U ni t 1 an d 2 C onc r ete P a d s P ower Pl ant 51 67 --Northeast Lay d own Area Eureka, C alifor ni a --N ew As ph alt R oa d ORISE 0 50 100 C rc a r c d b y: A. H ood D a r e: 27 , 20 1 2 Miles "f\IEA Fig. A-2. Humboldt Ba y Power Pl a nt -S i te Overview of Surve y ed Areas HBPP F u el Oil Ta nk .A r ea, E ur eka, CA A-2 516 7-S R-0 1-0 Normalized Gamma Count Rate (CPM) .. 10001 -11390 .. 4601 -5000 6201 -10000 .. 4201 -4600 5801 -6200 .. 3601 -4200 .. 5401 -5800 .. < 3800 .. 5001 -5400 Survey Boundary 0 20 40 Feet II Humb o ldt Ba:;;:er Pl an t 5167 Gamma Walkover Scans ORISE Cn!it.ted b y: A. 1 lo o d Date: February 2.1, 2012 Fig. A-3. H BPP F uel O il Tank Area -Gamma Walkover Scans HBPP Fuel Oil Tank A r e a, E ureka , C A -3 516 7-SR-01-0

"' Survey B oun d ary t C oncrete R emnan t 0 25 Feet 50 Humboldt Bay Power Plant 5167 Site Sample Locations Cr e a ted b y: A. H ood D a t e: Febru a ry 8, 2012 l'\IEA Fig. A-4. HBPP FOTA -PG&E S y stematic Soil Sample Locations HBPP F uel Oil T a nk Are a, E ur e ka, CA A-4 516 7-SR-01-0

-Survey Boundary Inaccessible

O RISE J udgmental Sample Location

H B PP Systematic Sample Location 0 25 Feet A ORI SE Soil Samples at H BPP Systematic Location 50 II ORISE Humboldt Ba y Power Plant 5167 FOTA Soil Sample Locations Created b y: A. H ood D ate: Fitbrua.ry 23, 2012 'r:\JEAV\PUIJ8Cn

\S167 Humboktt\GIS\ F i g. A-5. HBPP FOTA -Confirm a t ory Soil S a mple L oca ti o n s H BPP F uel Oil Tank Area, Eureka, CA A-5 516 7-S R-01-0 Normalized Gamma Count Rate (CPM) 9301 -13332 .. 5301 -6300 8301 -9300 -4301 -5300 .. 7301 -8300 -3301 -4300 .. 6301 -7300 -< 3300 0 10 20 -=:::J Feet r II Humboldt Pl ant 5167 Gamma Walkover Scans ORISE Created by. A. Hood D ate: February 23, 2012 F ig. A-6. HBPP Unit 1 and Unit 2 C oncrete P ads -G amma Wa l kover Scans HBPP F uel Oil Tank Area, Eureka, CA A-6 5167-SR-01-0 10001 -15000 3601 -3700 .. 4501 -10000 .. 3301 -3600 .. 4201 -4500 .. 3001 -3300 .. 3901-4200 .. < 3000 0 10 20 Feet Ctt a ted b y: A. H ood D a le: Februar y 23, 2012 Fig. A-7. HBPP Northeast Laydown Area -Gamma Walkover Scans HBPP Fuel Oil Tank Area, Eureka, CA -7 516 7-SR-01-0 Gamma Count Rat e (CPM) .. 10001 -10633 -5601-6700 1 Humboldt B ay P ower Plant 5167 -4501-5600 New R oa d 8901 -10000 Gamm a Walkover Scans .. 7801-8900

-3401-4500 ORISE 0 25 50 .. 6701-7800

-<3400 Feet Created by: A. Hood Da1c: Febr u ary 23, 2012 'l"'IL.A\"*_Pft'lllflC'9\Slrll..-boldt(J.I" Fig. A-8. HBPP New Asphalt R oadway -Gamma Walkover Sc ans HBPP Fuel Oil Tank Area, E urek a , CA A-8 516 7-SR-01-0 Humboldt Bay Power Plant -Fuel Oil Tank Area Normalized Count Rate Histogram 900 800 700 600 Q. 500 0 c 400 r:T ... 300 200 100 3000 3500 4000 BKG = background Median BKG = 5051 CPM 4500 5000 5500 6000 6500 7000 Normal i zed Count s Per M i nute (CPM) Maximum Count Rate= 11 , 390 CPM \ 7500 8000 8500 More Fig. A-9. HBPP Fuel O il Tank Area -Gamma Scan Count Rate Distribution Fig. A-10. Fuel Oil Tank Area -Pictures of the Natural Strata La y er that Exhibited Elevated Gamma Radiation Levels HBPP Fue l Oil Tank Area, Eureka, C A-10 516 7-S R-0 1-0

0. u -0 c .. :I Cl" ... 1 200 1 000 800 600 400 200 Humboldt Bay Power Plant -Units 1 & 2 Concrete Pads Normalized Count Rate Histogram Median BKG = 6,436 CPM Maximum Count Rate = 13,33 2 C P M 0 3000 3800 4600 54 00 6200 7 0 00 7800 8600 9400 10200 11000 11800 12600 More Normalized Counts Per Minute (CPM) BJ.;:G = backgr ound Fig. A-11. HBP P U nits 1 & 2 Concrete P a d s -G a mm a Sc a n C ount R a te D is tr i bution

"' 200 180 160 140 120 0 100 c Qj :I 80 ... 60 40 20 Humboldt Bay Power Plant -Northeast Laydown Area Count Rate Histogram Median BKG = 3 , 674 CPM These outliers represent the elevated gamma activity around the rad waste conta i ners . 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5200 5400 5600 More Counts P er Minute (C P M) BJ.;:G = backgrow1d

/.r, F i g. A-12. HBPP Northe a st L ay down Ar ea Asph a lt P ad -G a mm a Sc a n Count R a te Distribution 6

-* c 8 If n > 250 200 ,; e; 150 0 c Cll 5-100 "" so 0 Humboldt Bay Power Plant -New Asphalt Roadway Count Rate Histogram M e d ian B KG = 6,672 CPM 5000 5500 6000 6500 7000 7500 8000 8500 9000 95 0 0 10000 More Counts Per M i nute (CPM) BK G = b a ck gr oun d Fig. A-13. H B PP Ne w A s ph a lt R oa d way -G a mm a Sc a n C ount R a te D i s t ri but i on THIS PAGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank .Area, E ureka , CA 516 7-SR-01-0 HBPP F uel Oil Ta nk Area, E ur eka, CA APPENDIX B TABLES 516 7-S R-0 1-0 THIS P AGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank Area, Eureka, CA 516 7-SR-01-0 I c;;; 0 ""I1 §. 2 ..., " ;:: ,,. " ? ::i !:; " F n > '? °' _. "' "' s 6 Table B-1. Radionuclide Concentrations in ORISE Soil Samples Confirmatory Survey Activities for the Fuel Oil Tank Arca Humboldt Bay Power Plant Eureka, California Cs-137 *** U-235 U-238 Humboldt B ay Systematically-Selected Soil Sample Location s SOO l 594907 1 2160777 003 +/- 0.02< -0.0 1 +/- 0.04 O.Q7 +/- 0.06 0.26 +/- S002 5948982 2160894 0.30 +/- 0.04 0.0 1 +/- 0.04 0.05 +/- 0.1 4 0.52 +/- S004 5948902 2160738 0.25 +/- 0.04 OO()d +/- 0.04 0.04 +/- 0.08 0.24 +/- S007 5949124 2 1 60907 0.37 +/- 0.04 0.00 +/- O.Q3 0.06 +/- 0.11 0.67 +/- S009 5948880 2 1 60868 0.20 +/- 0.02 O.Ql +/- O.Q3 0.1 6 +/- 0.1 1 0.59 +/- SO ll 5949 146 2160803 0.34 +/- 0.04 0.00 +/- 0.04 0.10 +/- 0.08 0.69 +/- S015 5948869 2160764 0.3 5 +/- 0.04 -0.02 +/- 0.04 0.04 +/- 0.11 0.15 +/- FOTAAvr:rage 0.26 0.00 0.07 0.45 FOT A Standard Deviati on 0.12 0.01 0.04 0.22 ORISE Jud gmental Soil S a mple Locati o ns S016 5948965 2 1 60774 0.02 +/- 0.0 1 0.00 +/- 0.03 0.08 +/- 0.06 0.72 +/- S017 5948969 2160768 0.00 +/- 0.03 0.00 +/- O.Q4 0.08 +/- 0.06 1.11 +/- 5018 5948967 2 16 0766 -0.0 1 +/- 0.03 O.Ql +/- 0.05 0.07 +/- 0.09 1.84 +/- 5019 5949108 2 16 0832 0.29 +/- O.Q3 -0.01 +/- 0.03 -0.0 2 +/- 0.13 0.58 +/- S020 5949061 2 16 0958 0.01 +/- 0.02 0.00 +/- 0.03 0.04 +/- 0.09 0.28 +/- S02 1 5949062 2160970 0.51 +/- 0.05 0.00 +/- 0.04 -0.01 +/- 0.12 0.4 1 +/- Judgmental Average 0.2 7 0.00 0.04 0.82 *Refer to Figs. A-4 and A-5 bTot al Uranium calculations for natural uranium were 2*U-238 + U-235 <Uncertainties repre s ent d1e 95°'o confidence Je,-el, ba se d on total propagated uncertaintie s d Zero ,-alues a.re due to row1ding Total Ub 0.28 0.59 +/- 0.56 0.32 1.09 +/- 0.66 0.33 0.52 +/- 0.66 0.33 1.4 0 +/- 0.67 0.2 1 1.34 +/- 0.43 0.32 1.4 8 +/- 0.64 0.36 0.34 +/- 0.73 0.97 0.4 7 0.30 1.52 +/- 0.60 0.34 2.30 +/- 0.68 0.42 3.75 +/- 0.84 0.24 1.14 +/- 0.50 0.23 0.60 +/- 0.47 0.27 0.8 1 +/- 0.55 1.69

> ;; ? " ? () > ORISE Sample ID* SOOl S002 S003 S004 SOOS S006 S007 SOOS S009 S010 SOll S012 S013 S014 S015 Table B-2. Fuel Oil Tank Arca Comparison Data Survey Activities for the Fuel Oil Tank Arca Humboldt Bay Power Plant Eureka, California PG&E Sample East (ft) Nonh (ft) Cs-137 Concentrations (pCi/g) I Db ORISE PG&E c Humboldt B ay S ys t e m a ticall y-Selected Soil Sampl e Loc a tions OOLl0-1 5949071 2160777 0.03 +/- 0.02< <0.120 OOLl0-2 5948982 2 1 60894 0.30 +/- 0.04 0.322 +/- OO Ll0-3 5948991 2160933 -+/- -0.353 +/- OOLl0-4 5948902 2 1 60738 0.25 +/- 0.04 0.1 93 +/- OOLl0-5 5949079 2 1 60855 -+/- -<0.099 OOLl0-6 5948946 2 1 60790 -+/- -<0.094 OO Ll 0-7 5949 1 2 4 2 1 6090 7 0.37 +/- 0.04 0.313 +/- OOLl0-8 5949013 2160829 -+/- -<0.106 OOLl0-9 5948880 2160868 0.20 +/- 0.02 0.195 +/- OOLl0-10 5948969 2 1 606 86 -+/- -<0.179 OOLl0-11 5949 1 46 2160 803 0.3 4 +/- 0.04 0.317 +/- OOLl0-1 2 5949002 2 1 60725 -+/- -0.350 +/- OO Ll 0-1 3 59489 1 3 2160842 -+/- -<0.088 OOLl0-14 5949087 2160957 -+/- -<0.129 OO Ll 0-1 5 5948869 2 1 60 7 64 0.35 +/- 0.0 4 0.345 +/- FOTAAverage 0.26 0.30 FOT A Standard Deviation 0.12 0.0 7 Relative Error Ratio (RER)d _J 0.080 0.25 0.096 -0.053 0.86 --0.082 0.62 -0.057 0.08 -0.088 0.24 0.076 ---0.083 0.05 0.30 0.32 n >

Table B-2. Fuel Oil Tank Arca Comparison Data Confirmatory Stlr\'C} ActiYitics for the Fuel Oil Tank Arca Humboldt Ba} Power Plant Eureka, California ORISE PG&E Cs-137 Concentrations (pCi/g) Relative Error Ratio S a mple ID* Sample East (ft) Nonh (ft) ORISE PG&E c (RER)* I Db ORI SE Judgm e nt a l S oi l S a mpl e Loc a tion s S016 OOLl0-20 5948965 2160774 0.02 +/- 0.0 1 <0.08 4 -S017 OOLl0-2 1 5948969 2160768 0.00 g +/- 0.03 <0.082 -S018 OOLl0-22 5948967 2 1 60766 -0.01 +/- 0.03 <0.1 08 -S0 19 OOLl0-23 5949 1 08 2160832 0.29 +/- 0.03 0.318 +/- 0.074 0.35 S020 OOLl0-24 5949061 2160958 O.Dl +/- 0.02 <0.077 -S02 1 OOLl0-25 5949062 2 1 60970 0.51 +/- 0.05 0.62 1 +/- 0.096 1.03 Judgmental Averag d' 0.4 0 0.4 7 0.69 *Refer to F i gs. A-4 and A-5 b PG&E Sample ID prm;ded b y PG&E <PG&E Cs-1 37 co ncentration s from PG&E-prm;ded gamma s pectroscopy report s *Re!atiYe Error Ratio (RER) was calcu l ated based on the formula in th e DO E's Q u a li ty Systems for Analy tica l Se rvic es a nd provides a wa y to d e ten ni.n e if a nal y tical results of duplicat es (in thi s case , s plit samp l es) a.re in agree ment. A RER < 3 means th e samp l es a.re in agree m e nt at the 99% confidence l e ,*el. *Un c ertainties r e pr esent the 95° o confidence 1e,-e1, ba se d on total propagated uncertainties

£Meas urem ent or anal ys is not p erformed *Zero ,*al ues a r e due to rounding "Calc ul ated u s in g co nc e ntr a tion s that were greater than t h e minimum detectabl e co n ce n tratio n (M DC); ORISE s ample s used were 50 1 9 and S021

,,,.

;--" J' ;:i =; " ? ORISE Sample ID* S004 S009 S015 --------Table B-3. Radionuclide Concentrations in lnterlaboratory Comparison Soil Samples Confirmatory Sur.'e) Activities for the Fuel Oil Tank Arca Humboldt Ba) P<mer Plant Eureka, California PG&E Sample IDb Cs-137 Concentrations (pCi/g) Relative Error Ratio (RER)< ORISE PG&E< OOLl0-4 0.25 +/- 0.04' 0.1 9 +/- 0.05 0.9 OOLl0-9 0.20 +/- 0.02 0.20 +/- 0.06 0.1 OOLl0-15 0.35 +/- 0.04 0.35 +/- 0.08 0.1 *Refer to Figs. 1\-4 and A-5 b PG&E s ample identification and samp l e Cs-137 concentrations provided b y PG&E 'Relati,-e Error Ratio (RER) wa s calculated based on the formula in the DOE's Quality S y stem s for A nal y tical Sen-ice s and prmide s a wa y to determin e if anal y tica l re s ults of duplicates (in thi s ca s e, s plit s ample s) ar e in agreement.

A RER < 3 means t h e s ample s are in agre e m e nt a t the 9 9°'o confidence l evel. d QRJSE uncertainties represent the 95° o confidence le,*el , ba s ed on total propagated uncertainties THIS PAGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank Area, E ureka, CA 5167-SR-01-0 APPENDIX C MAJOR INSTRUMENTATION HBPP Fuel Oil Tank Area, E urek a, CA 5167-SR-0 1-0 THIS PAGE LEFT BLANK INTENTIO ALLY HBPP Fuel Oil Tank Area, Eureka, CA 5167-SR-01-0 The displa y of a specific product is not to be construed a s an endorsement of the product or its manufacturer*b y the author or his emplo y er. C.1 SCANNIN G AND M EASUREMENT I NST R UMENT /D ETECT O R C OMBINAT IO NS C.1.1 G am m a Ludlum NaI Scintillation Detector Model 44-10, C ry stal:2 in x 2 in coupled to: Ludlum Ratemeter-scaler M o del 2221 (Ludlum Measurements , Inc., Sweetwater, TX) coupled to: Trimble GeoXH Recei v er and Data Logger (Trimble Navigation Limited, Sunnyvale, C A) C.1.2 L a b oratory An a l ytica l In s tru m en ta t io n High Purity E x tended Range Intrinsic Detector CA BERRA/Tennelec M o del No: ERVDS30-25195 (Canberra, Meriden, CT) U sed in conjunction with: Lead Shield Model G-11 (Nuclear Lead, Oak Rid g e , TN) and Multichannel Analyzer Canberra's A pe x Gamma Software Dell Workstation (Canberra , Meriden, CT) High Purity Extended Range Intrinsic Detector Model o. GMX-45200-5 (AMETEK/ORTEC, Oak Ridge, TN) used in conjunction with: Lead Shield Model SPG-16-K8 (Nuclear Data) Multichannel Anal yz er Canberra's A pex Gamma Software Dell W o rk s tation (Canberra, Meriden, CT) High-Puri ty Germanium Detector Model GMX-30-P4, 30% Eff. (AMETEK/ORTEC, Oak Ridge, TN) Used in conjunction with: Lead Shield Model G-16 (Gamma Products, Palos Hills, IL) and Multichannel Anal yz er Canberra's A pex Gamma Software Dell Workstation (Canberra, Meriden, CT) HBPP Fu e l Oil Tank Are a , E ureka, CA C-1 516 7-SR-01-0 THIS PAGE LEFT BLANK INTENTIONALLY HBPP Fuel Oil Tank Area, Eureka, CA 516 7-SR-01-0 APPENDIXD SURVEY AND ANALYTICAL PR O CEDURES HBPP Fue l Oil Tank Area, Eu reka , CA 516 7-SR-01-0 THIS PAGE LEFT BLA K INTENTIONALLY HBPP Fuel Oil Tank Area, E ureka, CA 5167-SR-01

-0 D.1 PROJ E C T HE A L T H AND SAFETY The propo s ed s urve y and s ampling procedures were evaluated to ensure that any ha z ards inherent to the procedures themselves were addressed in current Job Hazard Analyses GHA). All survey and laboratory activities were conducted in accordance with ORISE health and safety and radiation protection procedures (ORISE 2008 and 2010). Pre-survey activities included the evaluation and identification of potential health and safety issues. Survey work was performed per the ORISE generic health and safety plans and a site-specific Integrated Safety Management (ISM) pre-job hazard checklist.

PG&E personnel also provided site-specific safety awareness training.

An ORISE safety walkdown of the site indicated that the land clearing activities and restoration activities by PG&E personnel left uneven terrain in some areas typical for outdoor surve y activities, steep inclines on the berms, and standing water and thick mud in a portion of the FOTA. D.2 CALIBRATION AND Q U ALI TY ASS U RANCE Calibration of all field and laboratory instrumentation was based on sources/ standards, traceable to the ational Institute of Standards and Technology (NIST). Analytical and field survey activities were conducted in accordance with procedures from the following ORAU and ORISE documents:

Survey Procedures Manual (May 2008)

Laboratory Procedures Manual (December 2011)

Quality Program Manual (December 2011) The procedures contained in these manuals were developed to meet the requirements of 10 Code of Federal Regulations (CFR) 830 Subpart A,QualityAss11rance Requirem e nts, Department of Energy Order 414.1 C Quality Assurance, and the U.S. uclear Regulatory Commission Quality Assurance Manual for the Office of Nuclear Material Sefety and Sefeguards and contain measures to assess processes during their performance.

HBPP Fuel Oil Tank Area, Eureka , CA D-1 516 7-SR-01-0 Quality control procedures include:

Daily instrument background and check-source measurements to confirm that equipment Operation is within acceptable statistical fluctuations.

Participation in Mi.."Xed-Anal y te Performance Evaluation Program (MAPEP), !ST Radiochemistry Intercomparison Testing Program (NRIP), and Intercomparison Testing Program (ITP) Laboratory Quality Assurance Programs.

Training and certification of all individuals performing procedures.

Periodic internal and external audits. D.3 S U RVEY PROCED U RES D.3.1 S U R FA C E S CANS A Nal(Tl) scintillation detector was used to scan for elevated gamma radiation.

Identification of elevated radiation levels was based on increases in the audible signal from the recording and/ or indicating instrument.

Additionally, the detectors were coupled to GPS units with data loggers enabling real-time recording in one-second intervals of both geographic position and the gamma count rate. Positioning data files were downloaded from field data loggers for plotting using commerciall y available software (http://trl.trimble.com

/ docushare/ dsweb/ Get/Document-261826/GeoExpl2005_100A_GSG_E G.pdD. Position and gamma count rate data files were transferred to a computer system, positions were differentially corrected, and the results were plotted on geo-referenced aerial photographs.

Positional accuracy was within 0.5 meters at the 95m percentile.

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 DCGL for the primary contaminant of concern. A review of the gamma walkover scan data points relative to the scan area coverage indicate that the scan speed was less than 0.5 m/s. The scan minimum detectable concentrations for the Nal scintillation detectors was 6.6 pCi/g for Cs-137, the primary radionuclide of concern as provided in NUREG-1507 (Table 6.4). An y audible increa s e in radiation levels were investigated by HBPP Fuel Oil Tank Area, Eureka, CA D-2 516 7-SR-01-0 ORISE. It is standard procedure for the ORISE staff to pause and investigate any locations where gamma radiation is distinguishable from background levels. D.3.2 SOI L S AM P LIN G A pproximatel y 0.5 to 1 kg of soil was collected at each sample location.

Collected sa mple s were placed in a Marinelli jar, sea led, and labeled in accordance w ith ORISE s urve y procedure s. The systematic so il samples were collected as split soil samples with PG&E personnel from the systematically-selected soil sample locations as determined b y PG&E. The judgmental samples were collected as split sa mples with PG&E per sonne l from location s of elevated gamma radiation levels as determined by the ORISE gamma walkover scans. D.4 RADIOLOGICAL A NAL Y SIS D.4.1 G AMMA SP ECT RO SC O PY Samples of soil were dried, mixed, crushed, and/or homogenized as necessary, and a portion sealed in a 0.5-liter Marinelli beaker or other appropriate container.

The quantity placed in the beaker was chosen to reproduce the calibrated counting geometry.

Net material weights and vo lumes were determined and the samples counted using intrinsic germanium detectors coupled to a pulse height analyzer syste m. Background and Compton stripping, peak sea rch, peak identification, and concentration calculations were performed using the computer capabilities inherent in the analyzer system. All total absorption peaks (TA P) associated with the radionuclides of concern (ROCs) were reviewed for consistency of activity.

TAPs used for determining the activities of ROCs and the typical associated minimum detectable concentration (MDCs) for a one-hour count time were: ------Radionuclide TAP*' (MeV) MDC (pCi/g) -----------Co-60 1.173 0.06 Cs-137 0.661 0.05 U-235 0.143 0.24 U-238 b y Th-234 0.063 0.75 *Spectra were also reviewed for other identifiable easy-to-detect TAPs that would not be expected at this site. HBPP Fuel Oil Tank Area, Eureka, C D-3 516 7-SR-01-0 D.4.2 UNCERTAINTIES The uncertainties associated with the analytical data presented in the tables of this report represent the total propagated uncertainties for that data. These uncertainties were calculated based on both the gross sample count levels a nd the associated background count levels. D.4.3 DETECTION LIMITS Detection limits, referred to as minimum detectable concentrations, were based on 3 plus 4.65 times the standard deviation of the background count [3 + ( 4.65 (BKG) 1 1 2)]. Because of variations in background levels, measurement efficiencies, and contributions from other radionuclides in samp l es, the detection limits differ from sample to sample and instrument to instrument.

HBPP Fuel Oil Tank Area, Eureka, CA D-4 516 7-SR-01-0

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