Measurement and Survey Protocols Defining and Identifying Radioactive Materials

2 Overview Materials disposition overview Expected materials and isotopes Field surveys –Protocols and procedures –Minimum Detectable Activity (MDA) determination Gamma spectroscopy Portal monitor surveys Initial field surveys –PEP-II Ring and BaBar

3 Materials from Inside Accelerator Housing

4 Expected Materials and Isotopes Materials: –Concrete blocks –Electronic copper cables of various diameters and lengths –Iron and steel plates –Electronic components and crates including PMTs –Rubber and plastic hoses –Aluminum piping, cable plant, and components –Special items including the Be DHC Isotopes: –In Copper: Co-60, Fe-55, Mn-54 –In Plastic: Na-22, Si-32, H-3 –In Lead: Bi-207, Tl-204, Hg-194, Pt-193, Ta-179 –In Stainless Steel: Co-60, Fe-55, Mn-54, Co-57, V-49, Ni-63, Nb-91, Ar-39, Ti-44

5 Path Forward for Suspension Relief: 1. Evaluation Process knowledge –Identify areas and activities that can potentially activate materials FLUKA calculations –BaBar detector model –Other geometries model Confirmatory measurements –Measurement and survey protocols that follow MARSSIM guidance Gross beta-gamma field surveys Gamma spectroscopy surveys Portal monitor surveys

6 Measurements Gross beta-gamma field survey on all surfaces using an appropriate survey instrument –Detailed procedures for surveying and defining radioactive material –Technical Basis Document Optimized survey instrument performance Point-source geometry measurement efficiency as reference MCNP calculations of measurement efficiency for an unknown volumetric source distribution based on the point-source geometry –Source distribution for BaBar components can be estimated by FLUKA MDA calculated for most conservative case of source distributions Gamma spectroscopy survey using portable or fixed HPGe system on critical items Portal Monitor survey of outgoing shipments

7 Field Surveys – Gross beta-gamma SLAC uses the Ludlum Model 18 with ”x1” NaI detector –Sensitive from <100 keV to several MeV Protocols per Procedure –All surfaces of every item surveyed CERN protocols are similar: –All surfaces of every item surveyed in low background area – slow scanning on contact CERN used comparable detector: CERN used a NaI (1.3”x1.3”) that could detect down to 3.5 µrem/hr Ludlum Model 18 with 44-2 NaI detector used at SLAC

8 Field Surveys – Gross beta-gamma Surface contamination surveys performed using a GM pancake detector (Eberline HP360, Ludlum 44-9, TBM P15) Protocols per Procedure –All surfaces of every item surveyed –Swipes taken on Fe/steel for LSC measurement for Fe-55 Pantex used comparable detectors: Pantex used a Ludlum Model 12 with a GM frisker for surface contamination. Pantex estimated their MDAs for contamination to be about 8 dpm for alpha, 13 dpm for beta, and 60 dpm for tritium TBM P15 used at SLAC

9 Field Surveys: Minimum Detectable Activity (MDA) MCNP then used to model volumetric activation Activation profile for BaBar/PEP components estimated by FLUKA Conversion factor used to determine MDA in field setting 2m  2cmt x 10 NaI detector (1” x 1”  ) with Pb wrap Fe MCNP geometry used for volumetric model Expected count rate per unit specific activity, cpm/(pCi/g) =0  2902 =0  = =0  = uniform214  =∞ =  =∞ =  =∞ =

10 Path Forward for Suspension Relief: 2. Release Criteria Screening levels for clearance –DOE Order Guidance for surface contamination (based on 25 mrem/yr) Case-by-case approval for volumetrically contaminated materials ALARA principle be observed –ANSI N Guidance for volumetrically activated materials (based on 1 mrem/yr) 30 pCi/g for most beta-gamma isotopes at SLAC such as Co- 60, Na-22, etc. Only items without radioactivity, i.e., below MDA, would be released for recycling

11 Gamma Spectroscopy Surveys Surface and/or sampling measurements with portable or fixed HPGe systems on critical items –Very sensitive instruments –Long count time required Critical items pre-selected Measurement results compared with FLUKA results to confirm FLUKA results and establish efficiencies and MDAs of measurement methods SLAC Radioanalysis Laboratory’s fixed HPGe system

12 Portal Monitor Surveys Every truck that leaves with a non-regulated load would be surveyed by a portal monitor Portal Monitor system at CERN

13 Preliminary Field Surveys: PEP Activation Gross survey map Yellow shading represents some items in the area read above background on the Ludlum Model-18

14 Preliminary Field Surveys: BaBar Activation Past surveys suggest little activation will be found inside of detector Preliminary survey of Muon Shield indicated no detectable activity