New projects – Recommended for fiscal year 2011–2014

Identification of Canadian novel technologies

Purpose: To meet future needs, the Canadian Nuclear Safety Commission (CNSC) must identify and understand up-and-coming innovative technologies that could be employed in the nuclear and safeguards fields.

Scope: This project would survey Canadian academia, industry and possibly government departments to identify potential novel technologies that could be adopted within the nuclear fuel cycle. Unfortunately, only a select few are presently known. This work will establish a database containing institutions, which have or are developing such technologies, country wide. The first phase of this project will be to establish a plan to best seek out this information and populate a database. The next two phases will be to execute the developed plan, with one portion occurring in one part of Canada and the following portion in another part of the country.

Quality management – Inspection evaluation

Purpose: The Quality Management online course is mandatory for all new and longer-term International Atomic Energy Agency (IAEA) staff. The training will provide a sound introduction to the Quality Management System (QMS) and will answer commonly asked questions on how it affects staff and their work. This will in turn allow IAEA employees to better perform their duties when validating and verifying State declarations. The direct benefit to Canada is it will potentially reduce the amount of time inspectors take to draw a conclusion on Canada's nuclear fuel cycle. The knowledge management portion of this course is currently being employed by supervisors to support their efforts in retaining knowledge from staff who are leaving.

Scope: Continue work by providing support with video capturing of current and former IAEA staff, as well as provide consultation assistance with the training package.

OECD Component Operational Experience, Degradation and Ageing Programme (CODAP)

Purpose: To continue CNSC staff participation in an Organisation for Economic Cooperation and Development (OECD)/Nuclear Energy Agency (NEA) international project entitled "OECD Component Operational Experience, Degradation and Ageing Programme (CODAP)". The CODAP project will establish a knowledge base, similar to the one developed in the Stress-Corrosion Cracking and Cable Ageing Project (SCAP) database. It will collect general information on component and degradation mechanisms such as applicable regulations, codes and standards; bibliography and references; research and development programs and proactive actions; information on key parameters, models, thresholds and kinetics; fitness-for-service criteria; and information on mitigation, monitoring, surveillance, diagnostics, repair, and replacement. The CODAP will support participating countries in developing and assessing aging management programs and will support several kinds of applications, including those for statistical analysis.

Scope: The CODAP database will be based on the existing OECD Piping Failure Data Exchange Project database. The latter was developed with financial support of the 11 countries, including Canada, and the SCAP Stress Corrosion Cracking database, which was defined based on the experience of the Piping Failure Data Exchange Project and research and development information provided by the member countries (including Canada) and funded through a Japanese voluntary contribution to the NEA.

Standards resource support for Canadian Standards Association

Purpose: To contribute funding for the Nuclear Safety Standards Program of the Canadian Standards Association (CSA).

Scope: The CSA will manage a program and activities related to facilitating the development and maintenance of standards for nuclear facilities, including CANDU nuclear power plants and related facilities. Specifically, the CSA will work towards the publication of standards through the CSA-accredited standards development process. Activities may include standards development management, arrangement and sponsoring of committee meetings, preparation of minutes, preparation and review of draft material, obtaining committee approval of the document through the letter ballot process, and publishing the final document, committee maintenance, program related travel, and administrative support.

Updated analysis of the Ontario uranium miners' cohort

Purpose: To obtain scientifically sound estimates for the risk of lung cancer as a result of radon decay product exposure. This study will refine our understanding of the occupational health risks of uranium mining, and will be important for refining uranium mining standards/regulations by the CNSC and other regulatory agencies.

Scope: Conduct a detailed statistical analysis of the updated Ontario uranium miners' cohort to address the study objectives, as outlined in the study protocol. Conduct a detailed peer review of the draft and final report (three external peer reviewers). Prepare an article for publication in a peer-reviewed scientific journal of high quality.

Incorporating aging effects into probabilistic safety assessment applications – Phase 3

Purpose: To determine an appropriate regulatory approach and to acquire an expertise in addressing aging effects in probabilistic risk assessment, which will provide the CNSC with a credible tool for risk-informed decision-making in the area of aging management.

Scope: To develop generic time-dependent reliability models for selected degradation mechanisms, operational stressors and aging management activities.

Preparation of United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) documents of internal emitters (tritium and uranium) and uncertainty (past and modern uranium miners)

Purpose: To support the United Nations Scientific Committee on the Effects of Atomic Radiation, by providing objective scientific information on the sources and effects of ionizing radiation. This information will be based upon Canadian experiences and expertise on doses arising from exposures to tritium and uranium, and uncertainties in Canadian uranium miners' radon progeny exposure estimates.

This body of work will refine the international understanding of sources and health effects of tritium and uranium. It will also refine international understanding of the improvements and uncertainties in the estimates of radon progeny exposures and adverse health effects based on past, present and future uranium miners.

Scope: Help CNSC staff prepare draft document sections on the sources and health effects of tritium and uranium based on Canadian literature, experience and expertise.

Help CNSC staff prepare a case study based on an epidemiological feasibility study of modern uranium miners on the uncertainties in past, present and future uranium mining exposures and health effects.

Tritium transport in terrestrial environments

Purpose: To clarify the regulatory implications of dose to the public from tritium in current models of tritium's behaviour in the environment and human food chain (such as the Canadian Standards Association N288.1 standard currently used by licensees).

Scope: The work will involve collaborative research with selected organizations with special tritium expertise and equipment, to pool intellectual and laboratory resources. Field studies will be conducted at sites with ongoing releases of tritium as both tritium gas (HT) and tritiated water (HTO) in Canada and abroad.

The scope of the work will be developed through discussions between the CNSC and the Institut de Radioprotection et de Sûreté Nucléaire in France (IRSN). IRSN has just initiated a four-year study on the environmental behaviour of tritium at the nuclear fuel recycling plant at La Hague with the Laboratoire de Radioécologie de Cherbourg-Octeville. Initial discussions have been held with IRSN on the scope of collaboration, and agreement has been reached on five general topics:

• methods for measuring the chemical forms of tritium in air
• evolution of tritium's chemical forms in air (HT, HTO, etc.)
• reservoirs of tritium in both dry and wet media
• rate of transfer of tritium from air to human food chains
• kinetics of the formation of organically bound tritium

Participation in OECD CSNI activity proposal sheet

Purpose: To participate in the Organisation for Economic Cooperation and Development (OECD) CSNI Activity Proposal Sheet (CAPS) round robin, with a goal to develop a systematic study that investigates the comparative advantages and disadvantages of various post-tensioning techniques in reactor containments (bonded versus unbonded tendons).

Scope: The first round robin devoted to the numerical simulation of structural behavior, structural capacity and expected failure modes of containments post-tensioned by: (1) bonded tendons; and (2) unbonded tendons, by means of all available structural simulation and techniques, methodologies and software. The results of numerical simulation round robin will benchmarked against all available experimental data on ultimate behavior of bonded versus unbonded tendons. The prominent test programs in this sense are ISP48 (already completed) and benchmarks on concrete containment (to be executed during this year).

The second and third round robin studies are currently considered options in the OECD CAPS project.

The second round robin will be devoted to the study of amounts of work in executing the post-tensioning and maintaining activities for whole expected lifetime of the containment by: (1) bonded tendons; and (2) unbonded tendons. The third round robin is planned to be devoted to the study of amounts of work in corrosion protection and in ensuring the durability of the tendon material for whole expected life time of the containment by (1) bonded tendons; and (2) by un-bonded tendons.

Development of simplified analytical tools for impact and impulsive loading analysis of reinforced and pre-stressed and composite steel-plate-concrete slabs

Purpose: To develop an alternative analytical approach that will support our regulatory position in terms of reducing uncertainties and improving the level of confidence in analytical results.

Scope: Develop simplified software to perform non-linear analysis of impact and impulsive loading on reinforced, pre-stressed and composite steel-plate-concrete (SC) slabs. The non-liner ties should include material (constitutive laws, material erosion) and geometrical non-linearities (big displacements, contact problems). The program will be performed over three years in three main phases related to: (1) reinforced concrete; (2) pre-stressed concrete, with or without a liner; and (3) SC concrete slabs.

Applicability of NUREG/CR-6850 to Canadian nuclear power plants

Purpose: To determine the applicability of the US Nuclear Regulatory Commission report NUREG/CR-6850 (Fire Probabilistic Risk Assessment Methodology for Nuclear Power Facilities) to Canadian nuclear power plant design and the Canadian regulatory regime.

Scope: Review the different components of NUREG/CR-6850 to evaluate its applicability to Canadian nuclear power plants. Determine limitations or potential areas of concern (such as portions of the methodology or data based on operational experience from non-CANDU nuclear power plant designs that may reduce conservatism or defence in depth) when applying it, and potential modifications or adjustments to more adequately reflect Canadian experience and the Canadian regulatory regime.

Human reliability assessment operating procedure validity for probabilistic safety assessment study

Purpose: To determine an appropriate regulatory approach and to acquire expertise in addressing operator actions in complex occurrence of events addressed by probabilistic safety assessment (PSA) studies. The CNSC currently lacks this specific expertise.

Scope:

Phase 1: Perform a case study where critical operating procedures were employed to mitigate a specific sequence of PSA Level 1 interfere and validate operator actions required by these procedures.

Phase 2: Perform a case study where critical operating procedures were employed to mitigate a specific sequence of PSA Level 2 interfere and validate operator actions required by these procedures.

Phase 3: Perform a case study where critical operating procedures were employed to mitigate a specific sequence of PSA Level 1 and 2 interfere and validate operator actions required by the procedures. Phase 3 is dedicated to multi-unit power plants that share systems among units located at the same facility.

Canadian participation in the ICDE (International Common-Cause Data Exchange)

Purpose: Access and make use of the Organisation for Economic Cooperation and Development (OECD) / Nuclear Energy Agency's (NEA) International Common Cause Failure Database to assess the correctness and completeness of the licensees' modeling of the common cause failure (CCF) events in the unavailability and the Probabilistic Safety Assessment models. These assessments generate qualitative insights into the root causes of CCF events in order to prioritize and improve inspections as well as checking the adequacy of licensees' corrective actions to prevent occurrence of these CCFs.

Scope: The work includes providing the collected data to the ICDE clearing house (data collection is to be performed by a separate support contracts), which will assess the quality of the data and check for compliance with the coding guidelines. The work scope also includes the participation to the biannual meetings of the ICDE steering committee, which aims at identifying the follow-up actions for managing the database as well as its circulation with the licensees. The steering committee also generates technical documentation regarding the data collection on specific components of the campaigns. It is to mention that access to the data bank is confidential and restricted to the project participants who have delivered data to the clearinghouse.

Data collection for Canadian participation in the International Common-Cause Data Exchange Project

Purpose: Collect common-cause failure (CCF) data from Canadian utilities in order to fulfill Canada's obligation to the International Common-Cause Data Exchange (ICDE) project. Providing data on specific components will grant Canada access to the international database. Access to the ICDE database will allow the CNSC to assess the correctness and completeness of licensees' modeling of CCF events in the unavailability model and the probabilistic safety assessment model. These assessments generate qualitative insights into the root causes of CCF events, in order to prioritize and improve inspections as well as check the adequacy of licensees' corrective actions to prevent CCFs.

Scope: Gather data on failures of specific components (centrifugal pumps, motor-operated valves, safety relief valves, check valves, batteries, switching devices/breakers, level detectors and heat exchangers), analyze it for detection of CCFs and prepare records according to the ICDE-specific coding guidelines. Components and the sites from which the data will be gathered, as well as the observation end date, will be specified after the ICDE Steering Committee meeting in April 2011.

Interfacing seismological description of strong ground motion with engineering analysis of soil-structure interaction

Purpose: To develop a regulatory approach related to seismic soil-structure interaction.

Scope: The difficulties with current procedures for specifying the input into the soil-structure interaction calculations for nuclear power plants are that: (1) the soil is excited only by vertically incident waves; (2) the soil response is analyzed in linear or essentially linear manner; and (3) the modeling and the methods of analysis are essentially two-dimensional. Those assumptions lead to response results that only represent a subset of all possible outcomes, and are not conservative. This can be remedied by providing the time functions for all six components of motion at all contact points between the elastic layered half space and the soil-structure interaction model, which are used in finite element or finite difference calculations of soil-structure interactions.

Establishment of fire preparedness expectations for medical sector licensees

Purpose: This project will help establish the regulatory expectations for medical-sector licensees with respect to fire preparedness.

Scope: The contractor will:

• survey applicable existing standards (e.g., National Fire Protection Association NFPA 801), provincial and federal regulations/codes (e.g., Ontario Fire Code), that are applicable to hospitals
• identify practices currently in place in a representative group of institutions to address the issue of fire preparedness
• survey current regulatory expectations applied to licensees in other sectors regulated by the CNSC
• identify gaps and best practices

Assessment of mine waste management practices in Canada

Purpose: To systematically survey mine waste management practices in Canada to document what has worked and what hasn't, and to compare predicted and actual water quality for mines in Canada.

Scope: The work will include an identification of metal, precious-metal and uranium mines in Canada, along with an analysis of waste management practices employed at each site. Selected mines will also be chosen for a more detailed analysis of their ability to use science to predict environmental effects.

Estimation of the range of radiation dose for a radon progeny working level due to physical parameters

Purpose: To determine the most appropriate approach for assessing radon progeny dose (i.e., epidemiological or dosimetric approach) it is necessary to understand to what degree environmental factors within a mine affect the dose estimation when it is based on the working level.

Scope: To examine how variations in specified environmental factors affect the conversion of airborne concentrations in radon decay products in working levels to radiation dose. The specific environmental conditions are the particle size of the radon decay products; the ratio of attached and unattached fractions; the ratio of the concentrations of the immediate radon progeny (age of the air); humidity; and other factors, if applicable.

Multi-Stakeholder Tritium Working Group

Purpose: To increase stakeholder involvement in CNSC-based research studies, in order to gain expertise and support from multiple stakeholders.

Scope: Assist CNSC staff with epidemiology studies that examine health risks associated with lifetime exposure to tritium at low doses and consider additional studies in radiobiology and dosimetry, including review of the radiation weighting factor for low-linear-energy-transfer radiation types such as radiation from tritium.

Studies on the toxicity of tritium (³H)

Purpose: To provide the technical knowledge needed to assess potential changes to dosimetry and other standards related to tritium in order to enable the CNSC to determine its regulatory position.

Scope: The proposed project would use mice (CBA or C57Bl/6 strain). Further to sub-chronic and chronic irradiation by either tritiated water, tritiated OBT (an amino-acid mixture of alanine, glycine and proline) or external Co-60 gamma rays, the following health outcomes will be evaluated: lifespan; tumour type and frequency; chromosome aberrations (stable and unstable); blood chemistry; lipid metabolism; body and organ weights; urine chemistry; cytokine profile; gene expression; and DNA repair. The requested work includes short-term dosimetry studies, longer-term clinical studies and lifespan toxicity studies.

Long-term performance of bentonite seals for geological disposal repositories

Purpose: To enhance our ability to assess the long-term performance of bentonite material used to seal galleries and shafts of deep geological repositories, and to verify the full-scale constructability of these seals.

Scope: The sealing performance insitu experiments project will consist of the construction of seven boreholes at the Tournemire underground research laboratory, the placement of prefabricated bentonite or bentonite/sand mixture blocks in the borehole, the injection of water to saturate the blocks with continuous monitoring of the hydraulic and mechanical evolution of the bentonite during water injection, and the dismantling of the boreholes for potential analysis using micro-analytical methods. The whole project will last more than 10 years. This research proposal will cover the first five years, with a possibility of extension after that period.

Development of analytical tools for soil-structure analysis

Purpose: To develop a regulatory approach related to seismic soil-structure interaction.

Scope: In-depth investigation of seismic nuclear power plant soil-structure systems (NPPSSS), with emphasis on modeling and simulation of location and timing of energy dissipation and damage accumulation for NPPSSS of interest to the CNSC. In-depth investigation of the effects that realistic seismic motions (3-D, inclined, incoherent, body, and surface waves) have on various NPPSSS that are interest to the CNSC. In-depth investigation of the effects of uncertainty – seismic loading, material (mostly soil/rock, but also concrete) and modeling – on the fidelity of obtained simulation results, and the effects of those uncertainties on the CNSC's regulatory decision processes.

Testing and development of regulatory requirements for steel plate concrete structures

Purpose: To develop regulatory requirement for composite steel-plate-concrete (SC) structures.

Scope: The contractor should develop a testing program in collaboration with CNSC staff to define mechanical properties of simple SC elements (slabs) under combined in-plane and out-of-plane loadings. Two tests need to be carried out in this program. Based on all available test results, regulatory requirements will be established for the review of SC structures. This will be a three-year program; the first two years will be dedicated to the literature review, necessary analytical work, defining the testing program and the testing itself. The third year will be dedicated to the development of necessary guidance for CNSC staff to develop corresponding regulatory requirements.

Satellite Imagery Training Program

Purpose: To provide International Atomic Energy Agency country officers, facility officers and inspectors with knowledge of capabilities for remote sensing and image interpretation. This will increase their effectiveness during inspection activities. It is anticipated that safeguards inspectors will make more use of satellite imagery to monitor remote sites (e.g., mine sites in Canada) and large sites.

Scope: The Canadian Safeguards Support Program intends to continue to support this joint activity (in collaboration with Sweden and the UK). The training material must be updated and instructors provided.

Environmental sampling computer-based training

Purpose: To ensure that environmental samples collected by the International Atomic Energy Agency (IAEA) are properly handled by its inspectors.

Scope: A computer-based training module on environmental sampling was completed and delivered to the IAEA for trial use. Initial assessment by the IAEA training section and the IAEA Seibersdorf Laboratory was positive. However, subsequent discussions indicated that significant revisions are required.

Specialist training for imagery analysts

Purpose: To enhance expertise of International Atomic Energy Agency analysts, in particular their ability to analyze activities at a nuclear site.

Scope: Site visits are viewed as particularly important; these allow analysts to compare what is seen on foot to what can be observed from satellites. In addition, hold short seminars on the latest advances on optical and radar satellites.

Signatures of nuclear fuel cycle-related processes (satellite imagery/space-borne remote sensing data)

Purpose: To enhance capabilities in the monitoring of declared activities, as well as in detecting undeclared activities.

Scope: The Satellite Imagery Analysis Unit needs a comprehensive list of relevant indicators related to the nuclear fuel cycle. This list should include relevant indicators by using thermal, multi-spectral, hyper-spectral and radar imagery.

VIFM implementation support – Monitoring discharged fuel

Purpose: Reliable monitoring of the discharge of CANDU fuel and its transfer to dry storage, which is essential to maintaining safeguards.

Scope: The VIFM system (the Versa Module Europa's extended surface integrate fuel monitor) was designed to implement safeguards in CANDU reactors, specifically for the monitoring of the movement of irradiated fuel bundles from the core to the spent fuel bay. The systems are now also being deployed to monitor the loading of dry storage silos. Support is needed to keep systems up to date and to address problems that can appear during field use. Support must now be extended to the Next Generation Autonomous Data Acquisition Module (ADAM) a successor for the original ADAM hardware.

• resolving hardware/software related issues to reliability and sustainability
• assistance with installation, operation, and maintenance of VIFM systems
• assistance in keeping up-to-date technical documentation, including technical manuals, user's manuals, service and maintenance procedures
• assistance in the field activities related to system installation and maintenance
• assistance in training for inspectors and technicians

Optically stimulated luminescence in forensics

Purpose: To enable the International Atomic Energy Agency to run a trial for a Canadian-developed portable optically stimulated luminescence device for use in the field. This device would assist in identifying inappropriate movement of radioactive material, possibly of Canadian origin.

Scope: The work consists of obtaining the prototype or a commercial version of this device.

Participation in probabilistic analysis as a regulatory tool for risk-informed decision guidance (PARtrIDGE) Project

Purpose: To further develop improve the PRO-LOCA code. PRO-LOCA, which was originally developed as part of an U.S. Nuclear Regulatory Commission program and subsequently as part of the Maximizing Enhancements in Risk-Informed Technology (MERIT) program, is a probabilistic fracture mechanics code specifically focused on piping. The current issues with PRO-LOCA are its lack of a quality assurance pedigree; the time required to estimate the distribution of the probabilities for very rare events (10-9 events); and a lack of user support, now that the MERIT program is over. As PRO-LOCA continues to evolve, its enhancements as part of PARtrIDGE will be made with the goal of possible future inclusion into extremely low probability of rupture (xLPR) and the Modular Code.

Scope: Enhanced quality assurance basis for the PRO-LOCA Code and the deterministic modules to be incorporated into xLPR and the Modular Code, along with improvement in software efficiency.

Expert advice on containment-filtered venting systems as means to mitigate containment pressure during severe accidents

Purpose: To support the CNSC's regulatory position on the adequacy and effectiveness of proposed design options for containment-filtered venting during severe accidents for existing CANDU nuclear power plants and for new builds.

Scope: Discuss the performances of various design solutions for preventing containment overpressure under severe accident conditions, and for providing guidance to assess the adequacy of containment-filtered venting systems.

Loading of steam generator tubes during main steam line break

Purpose: To address the issue of steam generator tube vulnerability in postulated design-basis and beyond design-basis accidents.

Scope: Develop and conduct experiments, using the CANDU designed steam generator experimental loop at McMaster University and analyze the results in order to determine the dynamic tube loading of model steam generator tubes during a simulated main steam pipe rupture and, thereby, a methodology to assist in evaluating the tube integrity safety margins during such an event.

Computational fluid dynamics modelling of CANDU end shields

Purpose: To assist CNSC staff in assessing potential safety issues related to the behaviour of CANDU end shields under various postulated conditions.

Scope: The work will include constructing a computational fluid dynamics (CFD) / conjugate heat transfer (CHT) model of a CANDU reactor end shield and performing simulations under conditions relevant to accident scenarios that are considered in safety analyses. The contractor is expected to select a major commercial CFD code as the analysis tool and to use a state-of-the-art grid generation software package compatible with this code in order to produce a model of one-half of an end shield of a reference CANDU design (e.g., CANDU-6) or a generic CANDU with dimensions and other details specified by the CNSC. In the second stage of the work, the contractor will use the grid generated in the first stage to obtain up to four solutions for conditions and scenarios where three-dimensional effects may be of potential interest. The scenarios, boundary conditions and heat source terms for these simulations will be specified by the CNSC.

International computational fluid dynamics (CFD) benchmark problem

Purpose: Participation in the Second International Benchmark Problem (IBP-2) exercise. This is to examine the performance of a potential successor to the current Canadian nuclear industry standard computational fluid dynamics (CFD) tool MODTURC_CLAS 2.9-IST against an experimental benchmark relevant to one of its possible applications and against other CFD software packages and modeling approaches.

Scope: The work will include constructing a family of CFD models of a Korea Atomic Energy Research Institute rod bundle used in the Measurements & Analysis of Turbulence in Subchannels - Horizontal test program, performing simulations under conditions specified by the IBP-2 organizers, selecting the best solution for submission, and post-processing its results to produce the required datasets in the prescribed formats.

Investigation of consequences of concrete alkali aggregate reaction on existing nuclear structures

Purpose: To develop a regulatory approach to deal with the consequences of concrete alkali aggregate reaction in nuclear structures.

Scope: The contractor shall define, in collaboration with CNSC staff, the major degradation mechanisms and material pathologies found in Canadian NPP structures, with a special accent on alkali-aggregate reaction. Based on concrete simples from existing plants, a testing program shall define chemical composition and mechanical properties (ultimate strength under compression and tension, shear strength, constitutive laws) of structural elements with alkali-aggregate reaction. The relationship between chemical and mechanical properties shall be established for concrete elements. Moreover, tests of anchorages in the concrete with alkali-aggregate reaction should be carried out to define the potential modification of their capacity. Based on all available test results, the acceptance criteria for structures affected with alkali-aggregate reaction should be established. It will be a three-year program. The first two years will be dedicated to the literature review, analytical work, definition of required tests and testing. The third year will be dedicated to the development of the acceptance criteria and to necessary technical guidance for CNSC staff to develop a regulatory approach.

Integrity of U-bend tube bundles subjected to flow-induced vibrations

Purpose: To independently evaluate the integrity of Bruce B's Unit 8 steam generator tubes as the plant ages and degradation occurs. Special attention will be paid to the consequence of support loss in the straight portion of the tube in terms of wear rate and the stability of the tube bundle.

Scope: The objective of this research will be realized by utilizing a numerical simulation model for the geometry of the Bruce B Unit 8 steam generator. This will include formulations for a tube/support interaction model and an accurate fluid/structure coupling. The tubes should be modelled via finite beam elements. The forces acting on each tube due to cross flow must include both random components due to turbulence and nonlinear components due to fluid elastic forces.

Re-evaluation of default annual limits on intake for yellowcake and uranium ore

Purpose: To enable the CNSC to determine its regulatory position on an appropriate annual limits on intake (ALI) value.

Scope: Conduct a literature review for uranium ore dust, as well as calcined and non-calcined yellowcake. The work would include, inter alia, developing a method for the selection of ALIs for representative work locations and averaging rules to obtain ALI values that are representative of the radiological hazard in the workplace.This work will be peer reviewed. The review group would consist of one non-licensee specialist (for instance, from academia or a research institution), one representative from the Government of Saskatchewan and one licensee representative.

Characterization of alpha radiation hazards: Biosolubility of radionuclides within CANDU reactor aerosols and implications for internal dosimetry

Purpose: To fill gaps in knowledge concerning the biosolubility of actinide-contaminated particles and fuel particles that may be produced in CANDU reactors and that present a hazard during normal CANDU operation and/or during reactor refit/refurbishment operations.

Scope: Identify and collect alpha-contaminated samples from CANDU stations. More specifically, recover irradiated uranium dioxide (UO₂) CANDU fuel particles at different burn-ups. Samples will be characterized by inductively coupled plasma-mass spectrometry (ICP-MS) and alpha spectrometry to determine their radionuclide inventory. Measure the biosolubility of the irradiated fuel particles as a function of their burn-up by using in vitro and in vivo techniques. Unirradiated UO₂ fuel (ICRP inhalation class S) will be used as a reference standard material/comparator.

The composition of fuel particles prior to leaching technique used, the composition of fuel particles after leaching and the amount of leached radionuclides in the leachate, will be measured; changes in biosolubility as a function of fuel burn-up will be determined. The relative leaching rates of uranium, plutonium, higher actinides and major fission products from the irradiated fuel particles will be determined. In addition, determine the relative biosolubility of radionuclides within zirconium oxide films present on the interior surfaces of recovered pressure tubes, as well as magnetite recovered from the interior surfaces of feeder tubes. The solubility of these materials will be compared with the un-irradiated UO₂ standard material. The appropriate inhalation classification will be assigned, and recommendations for dosimetry and bioassay monitoring will be made in light of the foregoing.