Uranium recovery

Uranium recovery is the extraction or concentration of uranium from any ore processed primarily for its source material content. Similarly, thorium was also extracted or processed in the past. The uranium recovery processes result in wastes that typically contain relatively low concentrations of radio­active materials having long half-lives. The wastes, in both solid and liquid forms, are classified as 11e(2) byproduct material in accordance with AEA definitions (see Table 18.3).

Three types of uranium recovery facilities have operated, are currently operating, or are planned to operate in the future within the United States: conventional mills, heap leach facilities, and in-situ recovery facilities. Con­ventional mills and heap leach facilities extract uranium from ore processed above ground and, consequently, generate large volumes of solid 11e(2) byproduct material. This material is disposed of in licensed near-surface impoundment(s) on the site of the processing facility or in an offsite waste disposal facility licensed to accept 11e(2) byproduct material. In-situ recov­ery facilities differ from the others in that they leach uranium from ore bodies in the subsurface. Consequently, the predominant waste stream for in-situ recovery facilities consists of liquid wastes generated during their operation (typically less than 200 megaliters per year). The liquid wastes are disposed of by deep disposal well injection, by evapotranspiration to the atmosphere through land application of partially treated liquid waste, or by evaporation to the atmosphere from man-made lined ponds. The volume of solid waste generated at an in-situ recovery facility (including salts from the evaporation process) is relatively small (typically less than 1000 m3 per year) and is ultimately disposed of offsite at a waste disposal facility licensed to accept 11e.(2) byproduct material.

Prior to the mid-1980s, the sole type of uranium recovery facility in the United States was the conventional mill. Many of those previously operat­ing facilities were reclaimed or are in the process of remediating (decommissioning) waste resulting from extracting uranium. Because of near-surface impoundments, those properties (and heap leach facilities) will be subject to long-term care after closure through government ownership. In-situ recovery facilities do not include onsite disposal impoundments and, thus, do not require long-term care after closure.

Whiteshell Laboratories (WL) has provided research facilities for the Cana­dian nuclear sector since the early 1960s. In 1997, AECL decided to discon­tinue research programs and operations at the facility, and in 1999 began to prepare plans for the safe and effective decommissioning of the WL site.

The major structures located on the WL site include the organic-cooled WR-1 research reactor (in storage with surveillance since 1995), the shielded facilities, research laboratories, and liquid and solid RAW management areas and facilities, including the concrete canister storage facility for the dry storage of research reactor fuel. In preparation for decommissioning, a comprehensive environmental assessment was successfully completed (AECL, 2001), and the CNSC issued a decommissioning licence for the WL site which came into effect on 1 January 2003. The CNSC has approved a

detailed decommissioning plan for the site, which provides information, as required, under the Class I Nuclear Facilities Regulations.

Initially, the decommissioning activities have been focused on decontami­nating and modifying nuclear facilities, laboratories and the associated service systems and removing redundant buildings to reduce risk and oper­ating costs. As buildings are prepared for final decommissioning, enabling facilities are being constructed to handle and store contaminated wastes that will arise from decommissioning (Koroll et al., 2009). Other work is ongoing in support of commitments made during the environmental assessment, including ongoing confirmation of the hydrogeological conditions of the waste management area on the site, fitness-for-service studies and an updated groundwater monitoring plan. Some areas within the waste management area were identified for early remediation within the overall site plan, including the fuel-bearing (in-ground) standpipes (Stepanik et al., 2011). The current plan has the major nuclear facilities being finally decommissioned/ dismantled in the 2020-2035 timeframe, consistent with the planned avail­ability of final long-term waste management facilities. These plans undergo reassessment as new cost and schedule information becomes available. It is anticipated that the site will be under institutional control for an extended period following decommissioning of the site infrastructure.

The Necsa waste management plan methodology as described in this docu­ment provides the basis for the development of the NRWMP. The NRWMP in turn will provide the general approach for the management of RAW on the Necsa site. It forms the basis of the complete Necsa RAW management process. Generators of RAW and the RAW management department together with the SHEQ department will align themselves in order to give expression to the contents of this plan. The actions to be followed after the evaluation of the methodology described in this document by the National Committee on Radioactive Waste Management and the subsequent approval by the Minister (DME) includes the following:

• Development of the NRWMP It was decided to develop the NRWMP in two steps. The first step will address the Necsa historical RAW while the second step will address the Necsa current and future RAW streams. The two steps will be submitted to the national committee separately.

• Facility-specific radioactive waste management programmes. Develop­ing of facility-specific radioactive waste management programmes by each radioactive waste generator. These programmes should take into account the system requirements such as the principles of waste preven­tion and waste minimization and should allow for the pre-treatment of the waste in order to conform to the Necsa waste management depart­ment’s waste acceptance requirements.

• Full implementation of the Necsa radioactive waste management system.

The NRWMP finally aims to provide an overview of the RAW management processes at Necsa in an open, transparent way. It will ensure that all RAW generated during past, present and future operations will be dealt with in a responsible manner that will not present an undue burden on future generations and the environment.

In the 1980s, radioactive waste disposal work was initiated in China. The former Ministry of Nuclear Industry (MNI) subsidiary Science and Technol­ogy Committee set up a panel to examine RAW treatment and disposal. The siting of solid LILW disposal facilities began in the 1980s and was implemented under the auspices of the former MNI. The initial siting work was conducted in South China, East China, Northwest China, and Southeast China based on the distribution of nuclear facilities at that time. Determina­tion of the South China disposal site began in 1991, with 27 candidate areas being selected. Of these, 20 were investigated on site and three candidate sites were identified. In 1998, initial reconnaissance was carried out within the area of Zhejiang province, East China, with 17 areas surveyed and five candidate sites identified. In Northwest China, two candidate sites were identified on the basis of six surveyed areas. After further comparison, a disposal site in the northwest was determined. In southwest China, exami­nation of disposal sites was carried out from 1989 to 1991. The site survey was carried out in ten candidate areas selected from an initial 38 areas, of which three candidate sites were finally recommended.

China’s Environmental Policy on Disposal of LILWs was issued in 1992 (hereinafter referred to as Paper 45) [15], which clarify the environmental policy on LILW. Paper 45 states that national disposal facilities for LILWs shall be constructed in the regions where major waste generation occurs in order to dispose of LILWs generated in the region and neighbouring regions. Paper 45 played an active role in promoting the siting and construction of LILW disposal sites. In 1998, construction of the Northwest disposal facility was completed, with planned capacity of 200,000 m3. The first phase of construction was planned to generate 60,000 m3 of disposal capacity, and so far 20,000 m3 has been constructed. The Northwest disposal facility is currently in trial operation. By the end of 2006, this site received 471 m3 of LILW with total activity of 3.05 x 1012Bq. In August 2000, Guangdong Beilong, China’s second solid LILW disposal facility was constructed in the Guangdong Province with planned long-term capacity of 240,000 and planned near-term capacity of 80,000 m3 . The total capacity that has been constructed in the first phase was about 8,800 m3 and, by the end of 2006, the received waste amounted to 1403.2 m3. Environmental monitoring indi­cates that operation of these two LILW disposal sites has no negative impact on the surrounding environmental radiological levels and no radia­tion accident has occurred to date.

Under the Law of the People ’s Republic of China on Prevention and Control of Radioactive Pollution of 2003 [9], the relevant government agen­cies are developing the national programme of finding solid radioactive waste disposal sites. The principle is to make an overall plan and implement the project in a step-wise, convenient and economical way to ensure safety. Based on the future development of NPPs and the distribution of waste generation varying with time and region, the overall development pro­gramme for LILW disposal will be established including allocation of regions, siting planning, capacity of disposal site and construction plan. Based on the programme, a phased implementation approach shall be developed to keep the number and capacity of disposal sites countrywide adequate to meet the demand for RAW disposal in the various regions. Construction of disposal facilities on the sites that have been chosen should be implemented in phases based on the quantity of LILWs generated and on a basis of gradual disposal capacity extension so as to achieve the effec­tive disposal capacity. When considering the safety of LILW disposal, trans­portation is one of the most important factors. Full account must be taken of the safety, economics, and convenience of RAW transport. To this end, a reasonable arrangement should be made for the coverage of each regional disposal site.

Iodine-131 is a fission product having a half-life of 8 days, and is important in view of its radiological risk to children by accumulation in the thyroid, which was a major issue at Chernobyl. The estimated total amount of iodine-131 released into the atmosphere lies in the range from 120 to 500 PBq, which means that there is still considerable uncertainty associated with the calculated estimate. This amount corresponds to about one fifth or one tenth of the release from Chernobyl. The latest estimate by TEPCO is about 500 PBq, while those by JAEA, NISA, and the Japan Nuclear Safety Commission (NSC) are in the range from 120 to 150 PBq. According to the study on the analysis of gaseous sample by JAEA, the release rate of iodine — 131 was initially 1015 Bq/h, and continued to be of the order of 1014Bq/h in the period from March 15 to 24. It is probable that the majority of the iodine release occurred in these ten days. Analysis of iodine deposition has been performed at 2,200 locations, and with this a map created of the radioactive contamination. This map showed that iodine-131 spread northwest of the plant, just like cesium-137 as was indicated on an earlier map. Iodine-131 was also found south of the plant at relatively high levels, even higher than those of cesium-137 in coastal areas south of the plant. According to the Ministry, clouds moving southwards apparently acquired large amounts of iodine-131 that were emitted at the time.

There were a total of 82 detonations on Pahute Mesa; 64 were located in the central or eastern part of the mesa and 18 were located in western Pahute Mesa. The detonations were in a variety of rock types ranging from confining units of zeolitized volcanic rocks to fractured lava flow and welded tuff aquifers. Pahute Mesa is a large plateau highland formed from the suc­cessive eruption of overlapping ash-flow sheets and local silicic lavas from at least six large collapse calderas (Figs 26.3 and 26.7). Three of the calderas are partly to completely covered by volcanic rocks from younger caldera cycles. The down gradient connectivity of the different rock types at the detonation depth strongly affects the local release and rate of groundwater transport of radionuclides from the underground tests. Transport of radio­nuclides is locally aided by multiple sets of north-northeast trending basin — range faults and may be aided or impeded by offsets of rock units along the basin-range faults or across volcanic structure (ring-fracture zones bounding zones of caldera collapse).

Groundwater flow beneath Pahute Mesa is controlled by underflow from the DVRFS and local recharge at the higher elevations of the eastern mesa areas. Flow is predominantly from higher topography on the northeast to lower topography on the southwest. Local diversions in directions of groundwater flow occur near basin-range faults (Blankennagel and Weir, 1976) and from juxtaposition of confining units and aquifer units across the basin-range faults and caldera structure (SNJV, 2009a). The resurgent dome of Timber Mountain south of Pahute Mesa (Fig. 26.7) diverts groundwater flow to the east or west from a combination of reduced permeability of volcanic rocks associated with intrusion of a granitic body beneath the resurgent dome and/or local recharge at higher elevations of Timber Moun­tain. Groundwater flow west of Timber Mountain follows the western ring — fracture zone of the Timber Mountain caldera and local basin-range faults,

26.6

Generalized geologic map of the Pahute Mesa corrective action units showing the domain area for numerical models of groundwater flow and radionuclide transport at sites of underground testing. Stiple = Quaternary playa deposits; white = Quaternary/Tertiary alluvium; light gray = Miocene volcanic rocks; cross-hatch = Quaternary/Pliocene basaltic rocks; diagonal line = Mesozoic granitic rocks; dark gray = Precambrian and Paleozoic sedimentary rocks. Dashed line is the PM-OV hydrostratigraphic framework model boundary. Solid line is the Nevada National Security Site boundary. Double-dashed line is the caldera structural margins. Dots show the location of 82 underground detonations in the Pahute Mesa corrective action units (as well as those in the Rainier Mesa CAU).

moving south and southwest to discharge areas of Oasis Valley (USDOE, 1997; Grauch et al., 1999). A smaller component of flow may be diverted around the eastern flanks of Timber Mountain, following the Fortymile Wash drainage beneath eastern Jackass Flats and reaching discharge areas of the Armagosa Valley (Fig. 26.2 ; SNJV, 2009a). A component of flow in western Pahute Mesa may be in carbonate rocks in the vicinity of the Black Mountain caldera west of and outside the Amargosa Desert rift zone. Here
groundwater flow remains west of the Purse fault, a probable hydrologic barrier, but merges with the recharge water from eastern Pahute Mesa near the juncture of the multiple coalesced calderas on the southwest edge of Pahute Mesa (Blankennagel and Weir, 1976; SNJV, 2009a).

Contaminated site clean-up in Germany is primarily associated with the decommissioning and dismantling of former nuclear facilities. Germany has considerable experience in the decommissioning and dismantling of nuclear facilities. The preferred decommissioning strategy in Germany is the imme­diate dismantling of facilities as opposed to safe enclosure. The BMWi chose this option for the Greifswald nuclear power station, where five reac­tors had been operating. The former 100 MWe Niederaichbach NPP site was declared safe for unrestricted agricultural use in mid-1995. In addition to the Niederaichbach NPP, the Karlstein superheated reactor has also been fully decommissioned and returned to a ‘green-field’ state. Seventeen addi­tional NPPs are at various stages of decommissioning and dismantling. Additionally, 28 research reactors and 11 facilities associated with the nuclear fuel cycle have either completed decommissioning or are currently being decommissioned. As mentioned previously, as a result of the incident at the Fukushima nuclear station, the plans for the complete phase-out of German nuclear power production are being accelerated and considerable effort will be required with respect to the dismantling and decommissioning of the remaining German NPPs.

Decommissioning of nuclear facilities in Germany is based on the pol­luter-pays principle. With the exception of NPPs associated with the former GDR, the electric utilities are responsible for all current and former opera­tional NPPs. Responsibility for NPPs associated with the former GDR was transferred to the Federal Ministry of Economics and Technology (Bunde — sministeriums fur Wirtschaft und Technologie, BMWi) in accordance with the German Reunification Treaty. The Federal Ministry of Education and Research (Bundesministerium fur Bildung und Forschung, BMBF) is responsible for the management and decommissioning of nuclear research facilities.

Germany’s first commercial nuclear reactor, the 250 MWe Gundremmin — gen-A unit, operated from 1966 to 1977; decommissioning started in 1983. In 1990, using specifically developed underwater cutting technologies, dismantling of the highly contaminated portions of the facility began. Gundremmingen-A demonstrated that decommissioning could be undertaken safely and economically without long delays. Most of the metal from the facility was also successfully recycled (Hore-Lacy, 2009).

Decommissioning of the 17 currently operating and recently shut down reactors is expected to produce some 115,000 m3 of decommissioning wastes (WNA, 2011). Decommissioning wastes which fall under the control of the AtG with negligible heat-generating capacity will be disposed of at the Konrad repository once the facility becomes operational. Heat-generating waste will remain at interim storage sites pending the availability of a final repository.

Prior to German reunification in 1990, the former GDR in conjunction with the former Soviet Union developed the world’s third-largest uranium mining province operated by the joint German-Soviet company Wismut SAG. Operations continued from 1946 to 1990 for a total production of 220,000 tonnes of uranium. A significantly smaller uranium ore mining operation was also conducted in western Germany near Ellweiler. Germany no longer mines uranium currently and all uranium used in fuel production is imported. The sites have largely been restored to green-field status (Wismut GmbH, 2011; MUFV, 2011).

Prior to the break-up and privatisation of the electricity generation industry in the 1980s and 1990s, the operators of nuclear installations were primarily government-owned organisations. More recently, the UK government has given the go-ahead for a new generation of nuclear power stations to be built. Potential sites have been identified across England and Wales. However, the devolved Scottish government has no current plans for new nuclear power stations. A divergence in approaches to waste management between Scotland and the remainder of the UK has also been confirmed (Defra et al, 2008; Scottish Government, 2011). Northern Ireland currently has no nuclear power stations and no identified sites for potential new build, although there is no policy restricting the development of nuclear power in Northern Ireland.

RAW management in Scotland is considered in Chapter 17, but there is considerable overlap with England and Wales, and for much of the earlier history of nuclear developments, a UK-wide policy was applied.

As the older stations and other facilities have closed, a significant liability has accumulated, much of which has been retained in the public sector as privatisation of facilities reaching the end of their working lives was not practicable. The current status of reactors in England and Wales is sum­marised in Table 16.2.

A number of research and development reactors also produced some power for the grid, including two Winfrith reactors, two Dounreay fast reac­tors, and the prototype Windscale advanced gas-cooled reactor.

The Nuclear Decommissioning Authority (NDA) was established in 2005 to take on the role of addressing the nuclear legacy from these older sites in a planned and focused manner. The NDA is responsible for the largest current decommissioning and waste management liabilities in the UK, overseeing the continued operation, decommissioning and site clean­up at 19 sites across the UK. Following further restructuring of the UK civil nuclear industry in 2007, seven site licence companies (owned by sepa­rate parent body organisations) were established to work in partnership with the NDA to carry out decommissioning and commercial operations (Fig. 16.2 ).

Other significant producers of radioactive waste in the UK, as owner operators of nuclear licensed facilities, are currently EDF Energy, the Min­istry of Defence, GE Healthcare Ltd and Urenco UK Ltd. EDF Energy currently operates advanced gas-cooled reactor (AGR) power stations at seven sites across the UK in addition to one pressurised water reactor (PWR) at Sizewell B. The NDA has an additional responsibility to scrutinise EDF Energy’s site decommissioning plans (NDA, 2011).

The UK strategy has been developed to present an integrated approach to the management of RAW and the decommissioning process. All nuclear installations in the UK have been regulated through the Health and Safety Executive (HSE) Nuclear Installations Inspectorate using a site licensing system that applies conditions to operations carried out at the site. The Office for Nuclear Regulation (ONR) is the new regulator for the civil nuclear industry in the United Kingdom. Created on 1 April 2011, the ONR was formed from the merger of the Health and Safety Executive’s Nuclear Directorate (the Nuclear Installations Inspectorate, Office for Civil Nuclear Security, and the UK Safeguards Office) and the Department for Trans­port’s Radioactive Materials Transport Team. The change follows the rec­ommendations of a review conducted on behalf of the Government in 2008 (Nuclear Regulatory Review, 2008; HSE and ONR, 2011). The ONR was initially created as a non-statutory body and an agency of the HSE; however, the government has announced its intention to put the ONR on a statutory basis once the appropriate legislation has been passed. When fully opera­tional as a statutory corporation, ONR will be an autonomous organisation, legally separated from, but still supported by, the HSE.

The disposal of RAW has been legislated under the Radioactive Sub­stances Act 1960 (RSA60) and subsequently the Radioactive Substances Act 1993 (RSA93) before being incorporated into Schedule 23 of the Envi­ronmental Permitting (England and Wales) Regulations 2010 (EPR10) within England and Wales (RSA93 was retained in Scotland and Northern Ireland). EPR10 was amended in 2011 by the Environmental Permitting (England and Wales) (Amendment) Regulations (2011) to include revised exemption provisions and corresponding amendments were made to RSA93 in Scotland and Northern Ireland. The Environment Agency is the regula­tor with the responsibility for regulating the disposal of RAW in England and Wales. Responsibility for regulating RAW disposal in Scotland lies with the Scottish Environment Protection Agency, and with the Northern Ireland Environment Agency in Northern Ireland.

Information on the HAW in Scotland is given in one of the seven support­ing documents to the policy, Higher Activity Radioactive Waste in Scotland (Scottish Government, 2011d). This document is based on the NDA 2007 UK Radioactive Waste Inventory (UKRWI) and gives detailed breakdowns of the HAW by location, type of materials, radioactivity levels and volumes. It gives information on the current amounts of HAW in store and the final lifetime packaged volumes after decommissioning has been completed. The most up-to-date inventory for the UK is now the NDA 2010 UKRWI (NDA, 2011a) and an overview of NDA higher activity waste (NDA, 2012). The newer information for Scotland is not significantly different in overall terms from the 2007 UKRWI. There is no comparable analysis of the 2010 UKRWI data in the format of the Scottish government’s supporting docu­ment. For a specific review of a topic to be as accurate as possible, all three sources should be consulted. As these data are compiled from estimates that have different levels of robustness, there is naturally uncertainty in the figures but this does not affect description of the bigger picture and devel­oping strategies.

A summary of the HAW, by owner and location, currently stored in Scotland and the estimated final lifetime packaged volumes to around 2125 is given in Table 17.3 . A summary of the HAW, by type of waste, on the same basis is given in Table 17.4. The volume of HAW currently stored and the estimated final lifetime packaged volume are both about 8.5% of the total UK HAW inventory.

The radioactivity content of the HAW is currently around 700,000 TBq and is calculated to decay to 50,000 TBq by 2150. This radioactivity content is currently around 18% of the UK total radioactivity in intermediate level radioactive waste (ILW), dropping to around 9% by 2150. Around 40% of the radioactivity content in HAW in Scotland is in ILW at Dounreay both currently and in 2150. There is no high level radioactive waste (HLW) in Scotland.

The EPA establishes generally applicable environmental standards to protect the environment from hazardous materials and certain radioactive materials. It has authority to establish standards for remediating active and inactive uranium mill tailing sites, environmental standards for the uranium fuel cycle, and environmental radiation protection standards for manage­ment and disposal of SNF, HLW, and TRU waste. The EPA promulgates standards for and certifies compliance at the WIPP in New Mexico for disposal of defense-generated TRU waste. EPA standards, under the Clean Air Act (EPA, 1990), limit airborne emissions of radionuclides from DOE sites. The EPA’s radioactive waste regulatory functions are described in more detail below.