NPD Closure Project: Calculating the Total Waste Inventory NS DF/ NPD Breakfast Briefing 2019 December 04 | Andy McVeigh | NPD Health Physicist UNRESTRICTED / ILLIMITÉ -1-
Agenda • General Approach • Establishing bounding source term • Waste verification activities • Waste database • Hazardous Substances Inventory • Radiological Inventory NPD Characterization Summary • UNRESTRICTED / ILLIMITÉ -2-
General Approach UNRESTRICTED / ILLIMITÉ -3-
General Approach Relevant S tandards or Guidance CSA 292.0-19 General principles for the management of radioactive • waste and irradiated fuel (e.g., waste classification and characterization) • CSA 292.5 Guidance for the exemption or clearance from regulatory control of materials that contain, or potentially contain, nuclear substances • US NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM). US NUREG-1575, Supp 1, Multi-Agency Radiation Survey and • Assessment of Materials and Equipment Manual (MARSAME). • IAEA Safety Report Series (95) – Methodologies for Assessing the Induced Activation Source Term for use in Decommissioning Applications UNRESTRICTED / ILLIMITÉ -4-
General Approach NPD Characterization Plan Obj ectives 1. Ensure source term used in the safety case is the bounding waste inventory. 2. Characterize the Structure, System and Components (which are essentially the waste inventory of the final disposal facility). UNRESTRICTED / ILLIMITÉ -5-
General Approach Establishing Bounding S ource Term Radionuclides embedded within • metals and other materials, present due to the interaction of neutrons from the reactor operation within the structure and components. Contamination on surfaces, • mainly resulting from the handling of fuel elements which had suffered failure of their protective cladding, enabling the release of some radionuclides. UNRESTRICTED / ILLIMITÉ -6-
General Approach Establishing Bounding S ource Term – Reactor Vault Materials Activated reactor components account for ~ 99% of the radiological • inventory: • Concrete (containing characteristic activation products such as Cl‐36 and Ca‐41, become soluble on contact with groundwater due to the porous nature of the material); • Stainless steel (containing characteristic activation products such as Co‐60, Ni‐59 and Ni‐ 63, released slowly as corrosion occurs); • Carbon steel (with a similar activation products from stainless steel but greatly reduced in some key isotopes such as Ni‐59 and Ni‐63, also released slowly by corrosion); • Aluminium (with specific activation products, likely to corrode rapidly depending on water chemistry); • Zircaloy (with specific activation products such as Zr‐93, released very slowly by corrosion); • Approximately 1% of the inventory is fission products and actinides present as surface contamination in nuclear systems which are modeled to be released instantaneously on contact with water. UNRESTRICTED / ILLIMITÉ -7-
General Approach Waste Verification Activities Characterization of the reactor (i.e. sample collection and analysis) was performed for verification to the calculated estimates associated with the activated reactor core components. Internal sampling of the primary heat transport and moderator systems, as well as the other minor subsidiary systems, confirmed the radiological profile and verify the source term related to surface contamination. Systematic survey and volumetric sampling of the facility structure confirmed the hazardous substances inventory as well as verify the residual radiological contamination is negligible in comparison to the developed source term. UNRESTRICTED / ILLIMITÉ -8-
General Approach Waste Database Post-Closure Safety Case Inputs: radionuclide inventory, non-radionuclide inventory, material types, mass/ density of waste, location within model compartments. Waste Database Inputs: radionuclide inventory, hazardous substance inventory, material type, mass of waste, disposal location within facility. UNRESTRICTED / ILLIMITÉ -9-
General Approach Waste Database • Compliant with all CNL Waste Management Program requirements. Waste database will be a format that is retrievable and entries • are verified. The individual radionuclide inventories, as well as total • inventory, are summed for the entire facility. Total inventories are then compared against the bounding • source term. • Wastes that exceed the bounding case limits would be removed for alternate disposition via other approved routes. UNRESTRICTED / ILLIMITÉ -10-
General Approach Training and Certification • NPD Historical Site Assessment and Characterization Plan were developed by Oakridge Association of Universities (ORAU). Contracted ORAU to also provide on-the-job training to CNL • characterization technicians on the specific instruments and data collection requirements of the radiological Characterization Plan. Radiological data assessed, interpreted and reported by CNL • staff. UNRESTRICTED / ILLIMITÉ -11-
General Approach QA/ QC Original ORIGEN calculations undertaken in 1988 but the pressure/ calandria • tubes were verified in 2012 using updated models (WIMS-AECL 3.1) and modern libraries (ENDF/ B-VII) as well as spot checks of ANISN calculations. • The Reactor components were re-calculated in 2018/ 19 using a later version of the ORIGEN-S code and Monte Carlo code MCNP5 to improve the reactor estimate. Survey instruments used in the field have annual calibrations as well as daily • response and background checks. Sample management includes unique identifiers, mitigation measures for • cross contamination, and precautions to maintain sample integrity as well as Chain of Custody requirements. • Laboratory performing the analysis is ISO 17025 qualified. • Total inventory estimates or calculations are verified by technical reviewers. UNRESTRICTED / ILLIMITÉ -12-
Hazardous Substances UNRESTRICTED / ILLIMITÉ -13-
NPD Source Term Hazardous S ubstances Inventory There is lead paint throughout facility as well as a significant quantity • of lead associated with shielding. Residual amounts of mercury are possible in the facility, associated • with thermometers and switches. PCBs are present in light ballasts and potentially paint and caulking. • The remaining transformers present on site have been found to be PCB free. • Asbestos is present in the form of pipe insulation, floor tiles and building cladding. All systems were drained of oil during the first phase of • decommissioning and previous remediation work was completed outside of the facility. UNRESTRICTED / ILLIMITÉ -14-
NPD Source Term Hazardous S ubstances Inventory – Lead Location‐Compartment at time of Location at start of Decommissioning closure Lead based paint above grade (3.1 m 3 ) – 351 kg Turbine Room – 351 kg Lead based paint below grade (3.5 m 3 ) – 397 kg Fuelling Room – 161,000 kg Exposed lead bricks in Rm 408 – 2 m 3 (22,680 kg) Reactor Vault – 25,000 kg Rm 405 – Fueling gates (2) Lead encased in steel and masonite – 2.5 m 3 Spent Fuel Storage Bay – 6,300 kg (66,000 kg) Rm 405 – Shielding walls and roof for Operator Rooms (lead encased in Boiler Room – 18,797 kg steel) – 35 m 3 (90,000 kg) Rm 405 – Shield plugs lead encased in steel and concrete (5,000 kg) Rm 201 ‐ Boiler Room Roof – lead encased in steel (5400 kg) Reactor Vault – Lead encased in steel (25,000 kg) Spent Fuel Storage Room – steel encased lead for booster rods (4500 kg) Rm 307 – Exposed lead shielding wall (0.25 m 3 ) (2,800 kg) Rm 201 – Lead encased in steel in Labyrinth between Boiler Room and Reactor Vault (13,000 kg) TOTAL: exposed lead – 26,228 kg encased lead – 208,900 kg UNRESTRICTED / ILLIMITÉ -15-
NPD Source Term Hazardous S ubstances Inventory –Asbestos, PCBs and Mercury ASBESTOS Location at start of Decommissioning Location‐Compartment at time of closure Sealand container outside facility (5) – 165 m 3 Basement of Control Wing – 175 m 3 Inside walls in above grade structure – 20 m 3 Turbine Room (Condenser Pit) – 20 m 3 Inside reactor vault – 5 m 3 Inside reactor vault – 5 m 3 Inside Boiler Room – 30 m 3 Inside Boiler Room‐ 30 m 3 Exterior Transite panels – 10 m 3 PCB LIGHT BALLASTS Location at start of Decommissioning Location‐Compartment at time of closure Boiler Room – 72 ballasts (1.699 kg) All PCB ballasts will be removed prior to grouting Condenser Pit – 54 ballasts (1.274 kg) MERCURY Location at start of Decommissioning Location‐Compartment at time of closure Boiler Room – residual contamination (<0.01 kg) Boiler Room – residual contamination (<0.01 kg) UNRESTRICTED / ILLIMITÉ -16-
Radiological Inventory UNRESTRICTED / ILLIMITÉ -17-
Radiological Inventory Reactor Components - Method Sample collection and analysis was • required for correlation to the calculated estimates. • Collect 3 representative samples of each type of activated material that comprises reactor core components (calandria and pressure tubes) and the biological shield (reactor vault). • Complete laboratory analysis, including radionuclide inventory concentrations and total radioactivity activation products and fission products. Establish the relative correlation of • characterization data to activation product inventory estimates. UNRESTRICTED / ILLIMITÉ -18-
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