Annex 7 - Decommissioning Activities

7.1     AECL Whiteshell Laboratories

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 the Canadian federal government concurred with the decision in 1998. In 1999, AECL began to prepare plans for the safe and effective decommissioning of WL.

The Whiteshell Laboratories facility is a nuclear research and test establishment located in Manitoba on the east bank of the Winnipeg River about 100 kilometres northeast of Winnipeg, about 10 kilometres west of Pinawa and nine kilometres upstream from Lac du Bonnet. The major structures located on the site include a WR-1 reactor, the shielded facilities, research laboratories, and liquid and solid radioactive waste management areas, including the concrete canister storage facility for the dry storage of research reactor fuel.

WL is currently licensed under a Nuclear Research and Test Establishment Decommissioning License. This licence authorizes AECL to operate and undertake decommissioning activities at the facility until December 31, 2008. An application for the renewal of the licence beyond 2008 is being assembled, and will include a description of the work expected to be performed during the period of the renewed licensee.

The Canadian regulatory body has approved a Detailed Decommissioning Plan, which provides information, as required, under the Class I Nuclear Facilities Regulations. The initial six-year decommissioning licence covered only Phase 1 of a planned three-phase decommissioning program for the site. Activities planned in this initial phase include those directed toward the shutdown and decontamination of nuclear and radioisotope laboratory buildings and facilities, with the purpose of placing them in a safe and secure interim end state. The Van de Graaff Accelerator and the Neutron Generator have been completely decommissioned.

Major activities planned for the next licensing period include preparing for and undertaking demolition of the principal radioisotope laboratory building, advancing the plans for the standpipe remediation, and re-establishing the functions of the existing site liquid-waste treatment, active laundry and decontamination facilities into updated facilities, followed by the decommissioning of their existing buildings. Also included is the design and construction of associated enabling facilities, including a waste clearance facility, a waste handling facility, remediation and expansion of waste storage facilities, site infrastructure service systems reconfiguration, and the demolition of redundant non-nuclear service buildings. Activities planned for subsequent licensing periods include the final decommissioning of the WR-1 reactor, waste management area (WMA) storage structures, the shielded facilities and the enabling facilities.

The decommissioning of Whiteshell Laboratories will be completed in the period leading up to approximately 2024, with the exception of the reactor and the WMA, which is expected to remain under institutional control for another 200 years.

Figure 7.1 - Aerial View of Whiteshell Laboratories

7.1.1     Underground Research Laboratory (URL)

The Underground Research Laboratory (URL), located approximately 15 kilometres northeast of AECL's Whiteshell Laboratories in Manitoba, is an underground, experimental facility used for research into controlled blasting techniques, rock mechanics and hydrological studies associated with potential deep underground disposal of spent nuclear fuel and the behaviour of various materials under the conditions of storage in deep-rock formations. No spent fuel or high-level radioactive materials were ever placed in the URL.

Two underground radioisotope laboratories (using low levels of tracer isotopes) were licensed by the CNSC under its NSRDR. These laboratories were closed and decontaminated several years ago. The CNSC personnel confirmed this during an inspection conducted prior to the revocation of the CNSC's operating licence in 2003. The URL, therefore, is no longer a CNSC licensed site, and requires no further radiological decommissioning. The present URL Decommissioning Project is much more closely related to a mine shutdown than a nuclear decommissioning project, and is following the requirements of the Province of Manitoba's Mines Act and Regulations. Natural Resources Canada is currently conducting an environmental assessment of the URL Closure Project under the Canadian Environmental Assessment Act.

7.2     AECL Gentilly-1 Waste Management Facility

The Gentilly-1 Waste Management Facility consists of a permanently shut down, partially decommissioned prototype reactor and associated structures and ancillaries. This facility is presently in the long-term storage-with-surveillance phase of a deferred decommissioning program. Located on the south bank of the St. Lawrence River about 15 kilometres east of Trois-Rivières in the Province of Québec, the Gentilly Complex accommodates both the Gentilly-1 Waste Management Facility and the Gentilly-2 Nuclear Generating Station, a CANDU 600 Megawatt unit.

The Gentilly-1 NGS consists of a CANDU-BLW-250 reactor and was put into service in May 1972. It attained full power for two short periods in 1972, and operated intermittently for a total of 183 effective full-power days until 1978, when it was determined that certain modifications and considerable repairs would be required. The station was put into a lay-up state in 1980, and the decision not to rehabilitate the station was made in 1982.

The main components of Gentilly-1 NGS were the reactor core, heat transport system, turbines and shielding. The reactor was heavy-water moderated, cooled by light water and fuelled with natural uranium, in the form of Zircaloy-clad UO₂ pellets. The reactor vessel was a vertical cylinder that contained a heavy-water moderator and was traversed by 308 pressure tubes and surrounding calandria tubes. The heat produced by the reactor fuel (mostly by boiling) was removed by the light water coolant and then pumped through inlet, outlet headers and feeder pipes in a closed circuit. The steam generated by the reactor core was separated from the liquid coolant in the steam drum before being delivered to the turbine generator.

The decision to permanently shutdown the reactor was made in 1984. A two-year decommissioning program began in April of that year to bring the Gentilly-1 NGS to an interim safe and sustainable shutdown state that is equivalent to storage with surveillance. The moderator was drained and shipped to other operating sites. Non-radioactive hazardous materials such as combustible and flammable materials, laboratory supplies and oils were identified and removed. The transfer of used fuel from wet storage in the reactor pool to dry storage in the canister storage area constructed for that purpose was completed in 1986. Major and minor decontamination activities (disassembly, decontamination and consolidation) were completed as required. All major radioactive or radioactively contaminated components not shipped to other licensed facilities were consolidated on site in either the reactor building or turbine building. Areas that possess significant residual contamination or radioactive materials have been reduced to a few locations. Radiological surveys were performed at the completion of each decommissioning activity.

7.3     AECL Douglas Point Waste Management Facility

The Douglas Point Waste Management Facility (DPWMF) is located at the site of the former Douglas Point Nuclear Generating Station (DPNGS) situated on the BNPD site. The DPNGS, which consists of a 200 MW CANDU reactor, was put into service in 1968. It was owned by AECL and operated by Ontario Hydro until 1984. During this operational period, the station generated 17 x 10⁹ kWh of electricity and attained a capacity of 87.3 percent.

The main components of DPNGS were the reactor, heat transport system, turbines and power generating equipment. The reactor was heavy water moderated, cooled by pressurized heavy water and fuelled with natural uranium. The reactor core contained 306 horizontal fuel containing pressure tubes and was surrounded by the heavy water moderator. The heat transport system pumps circulated the pressurized heavy water through the reactor coolant tubes to eight boilers, where the heat is transferred to the boiler steam and water system. The reactor primarily used heavy concrete, steel and water as shielding to protect the surrounding area from radiation during operation. Steam generated in the boilers was transferred to the turbine for power generation.

The DPNGS was permanently shutdown on May 5, 1984 and placed in an interim, safe and sustainable shutdown state. This interim state was referred to as the storage-with-surveillance state. The DPNGS then became the Douglas Point Waste Management Facility.

Following the shutdown of the reactor, the primary heat transport and moderator medium (heavy water) was drained and shipped to other operating sites. The booster rods were removed and shipped to the Chalk River Laboratories in February 1985. Non-radioactive hazardous materials such as combustible and flammable materials, laboratory supplies and oils were identified and removed. The transfer of used fuel from wet storage in the reactor pool to a dedicated dry storage facility was completed in 1987. Major and minor decontamination activities (disassembly, decontamination and consolidation) were completed as required. All major radioactive or radioactively contaminated components that were not shipped to other facilities licensed to receive them were consolidated on site. Areas that possessed significant residual contamination or radioactive materials have been reduced to a few locations, and radiological surveys were performed at the completion of each decommissioning activity.

The DPWMF is presently in the storage-with-surveillance phase of a deferred decommissioning program. For decommissioning purposes, the DPWMF is divided into three planning envelopes. Envelope A consists primarily of nominally uncontaminated buildings and structures, which may be decommissioned at any time, with health, safety and environmental concerns taken into account. Envelope B consists primarily of contaminated buildings, which will be decommissioned after allowing for a period of radioactive decay and after long-term waste management facilities become available. Envelope C includes the used fuel canister area.

A three-phase approach has been established for reactor decommissioning. Phase 1 brings the facility to a safe, sustainable shutdown state. Phase 2 is a period of storage - with-surveillance. Final decommissioning occurs in Phase 3. The DPWMF has completed Phase 1 and is currently in Phase 2.

7.4     AECL Nuclear Power Demonstration Waste Management Facility

The NPDWMF consists of a permanently shut down, partially decommissioned demonstration CANDU reactor and associated structures and ancillaries. The facility, which is presently in the interim storage-with-surveillance phase of a deferred decommissioning program, is located adjacent on the west bank of the Ottawa River in the Province of Ontario, some 25 kilometres upstream from the AECL CRL and 15 kilometres from the Town of Deep River. The NPD NGS, consisting of a 20 MW CANDU PWR, was placed in service in October 1962 and was operated by Ontario Hydro (now OPG) until May 1987. In 1988, operating and compliance responsibilities were transferred from Ontario Hydro to AECL, and the facility became the NPDWMF.

The facility produced electrical power for the Ontario Hydro grid, trained people for the commercial nuclear generating stations of Ontario Hydro, and performed experiments in process systems concepts to be incorporated in the design of the commercial nuclear generating stations. During this operations period, the station generated 3 x 10⁹ kWh of electricity at a net electrical capacity factor of 65 percent.

The main components of the NPD NGS were the reactor, heat transport system, turbine and electrical power generator equipment. The reactor was heavy water moderated, cooled by pressurized heavy water and fuelled with natural uranium. The reactor core contained 132 horizontal fuel containing pressure tubes, and was surrounded by a heavy-water moderator. The heat transport system pumps circulated the hot pressurized heavy water through the reactor coolant tubes to a heat exchanger/boiler unit, where the heat was transferred to the boiler steam and water system. The reactor, boiler and auxiliary systems were installed below ground, and were surrounded by concrete shielding to protect the surrounding accessible areas from radiation during operation. Steam generated in the boilers was transferred to the turbine/generator for electrical power generation.

The NPD NGS was permanently shut down on May 24, 1987 and placed into an interim, safe and sustainable shutdown phase. This interim storage period is referred to as the storage-with-surveillance phase. Following the shutdown of the reactor, the heavy water from the primary heat transport and moderator systems was drained and shipped off site. The reactor was defuelled and the fuel bundles were transferred to CRL. Demineralizer system equipment was removed from the various nuclear process systems and transferred to CRL. Major and minor decontamination activities were completed as required. The facility was functionally divided into nuclear and non-nuclear areas, with any equipment or structures either radioactive or radioactively contaminated confined to the nuclear area. All cross connections between the two areas were blocked off, sealed or permanently locked.

7.5     AECL Chalk River Laboratories decommissioning activities

 

7.5.1     Pool Test Reactor

The Pool Test Reactor (Ptr) was a type of reactor whose fuel elements were suspended in a pool of water that serves as the reflector, moderator and coolant. It was a low-power research reactor (less than 100 W) designed and built to conduct reactivity studies on irradiated fuel samples and to determine the cross-section of fission products. Ptr usage then shifted to testing and calibration of self-powered flux detectors on a commercial basis.

The Ptr began operating in 1957 and was permanently shut down in 1990. The fuel was removed and placed in a tile hole at the CRL. Since then, the Ptr has been monitored and kept under surveillance, and is currently in a safe shutdown state. The decommissioning objective is to return the area to the site landlord for use as general active laboratory space at CRL.

The Ptr consists of a pool that is approximately 4.5 metres square by six metres deep, and contains about 125,000 litres of water. Specific decommissioning activities undertaken with regard to the Ptr include:

• removing the Ptr equipment: aluminum-graphite reflectors, fission chamber, core plate and support, oscillator mechanism, core tube support brackets, control rod drive system and control rod support,
• draining and drying the pool,
• removing the de-ionized water supply and purification system from the pool,
• removing all electrical components associated with the facility, including metres, switches and panels. Wiring will be removed to clear termination points,
• removing all signs and fixtures associated with the facility from walls, floor and ceiling, and
• segregating and transferring all waste generated by the decommissioning project to Waste Management Operations for storage and disposal as appropriate.

The decommissioning is scheduled to begin following regulatory approval and is expected to last less than one year. The CNSC and NRCan approved the environmental assessment for this project in 2007. Lessons learned from the emptying of the NRX fuel rod bay will be incorporated into Ptr planning documents. The Detailed Decommissioning Plan and other planning documents will be written and submitted to the CNSC for approval prior to Ptr decommissioning. An application for decommissioning approval is expected during 2010.

7.5.2     Plutonium Recovery Laboratory

The Plutonium Recovery Laboratory was constructed in 1947, and was in operation from 1949 to 1957. During that period, it was designed to extract plutonium isotopes from enriched fuels used in research reactors. It is currently in storage-with-surveillance state. Following shutdown in 1957, the majority of the processing equipment was flushed, decontaminated and removed. The only process systems remaining are the fuel dissolver tanks, rod lifting mechanisms and basement sumps.

This facility has a footprint of about 514 square metres. Actual decommissioning activities are expected to be initiated in the next ten years, following regulatory approval to decommission. Decommissioning is to be carried out in three phases.

Phase I, which is expected to be carried out over a 2.5-year period, consists of the following activities:

• performing confirmatory radiological survey of all rooms in the building,
• completing isolation of process and service lines entering the building,
• removing all remaining process equipment and piping,
• completing decontamination of concrete rooms,
• removing the structure, including the steel frame, wood frame, cedar planks, asbestos shingles, roof and footing foundation,
• segregating solid wastes and transfer them to appropriate waste management facilities at CRL, and
• construct ingcovers for exposed areas of the shielded concrete enclosure, and a wall to separate associated buildings.

Phase II will last for a period of no less than ten years, and will maintain and monitor the remaining structure during the storage-with-surveillance period.

Phase III of decommissioning will be completed within an estimated two-year period, and will consist of the following activities:

• performing a confirmatory radiological survey to update the hazard status,
• demolishing the shielded concrete enclosure and its footings/foundations,
• removing any contaminated soils within the boundary of the original building footprint,
• segregating solid wastes and transfer them to the appropriate waste management facilities at CRL, and
• Restore the site and release it for future use within the CRL facility.

7.5.3     Plutonium Tower

The Plutonium Tower was used to develop means to extract plutonium from fuel rods irradiated in the NRX reactor, and was operated for a few years in the late 1940s. The building was permanently shutdown in 1954. All process equipment was removed from the building, and an initial clean-up was carried out. Further decontamination and dismantling was carried out in the 1980s.

The Plutonium Tower building is 19.2 metres high and has a footprint of about 28 square metres. All process equipment was removed from this building. Other decommissioning activities include:

• conducting a confirmatory radiological survey of the concrete tower interior, annexes and underground pipe chase to update the hazard status,
• isolating process and service lines entering the building from neighbouring interconnected buildings,
• demolishing the annexes, concrete tower, building structure and footings/foundations,
• segregating solid wastes and transferring them to appropriate waste management facilities at the CRL, and
• removing any contaminated soil and backfilling from the area, as required.

Decommissioning activities are expected to begin once regulatory approval has been granted. The removal of the Plutonium Tower is expected to take approximately one year. An environmental assessment, which is currently being performed pursuant to the Canadian Environmental Assessment Act, will be completed in 2009.

7.5.4     Waste Water Evaporator

The Waste Water Evaporator, which was constructed in 1952, was used to process and treat radioactive liquid wastes produced by the NRX fuel reprocessing work conducted between 1952 and 1958. Some evaporation activities were also carried out between 1958 and 1967 to concentrate about 450 cubic metres of stored process wastes remaining from earlier fuel processing. The facility was shut down in 1971.

The Waste Water Evaporator has a footprint of about 130 square metres. One of the seven tanks is suspected to hold about 100 litres of radioactive liquid waste, while two other tanks are suspected to contain a small quantity of dried contaminated sludge.

Decommissioning activities for this building include:

• isolating process and service lines entering the building from neighbouring interconnected buildings,
• removing, treating and storing any liquid wastes from the tank, process lines and equipment,
• decontaminating process equipment, processing cells and other components in the building to remove contamination,
• removing process equipment, processing cell, building structure and footing/foundations,
• segregating solid wastes and transferring them to appropriate waste management facilities at the CRL, and
• removing any contaminated soil surrounding the building to a distance of one metre from the building footprint, and backfilling the area as required.

Actual decommissioning activities will be initiated in the next ten years, following regulatory approval to decommission. Removal of the Waste Water Evaporator is expected to take one year. An environmental assessment, which is currently being performed pursuant to the Canadian Environmental Assessment Act, will be completed in 2011.

7.5.5 National Research Experimental (NRX) Reactor

The NRX reactor, Canada's first large-scale research reactor, commenced operation in 1947 and played a major role in developing the CANDU reactor. The reactor was used extensively for the testing of fuels and materials, and for nuclear physics research in support of the Canadian Nuclear Power program.

The reactor is a vertical assembly of permanent tubes kept in a calandria, which contain the reactor fuel assemblies. The reactor is heavy-water-moderated and light-water-cooled, and has a power rating of 42 MW. After approximately 250,000 hours of operating time, the NRX reactor was shut down on January 29, 1992.

The NRX reactor facility is divided into three planning envelopes: the NRX reactor, the fuel storage bays and the ancillary buildings. The decommissioning of the NRX reactor is planned in three phases.

• Phase 1 will bring the facility to a safe sustainable shutdown state, suitable for an ensuing period of storage with surveillance.
• Phase 2 is the storage-with-surveillance period.
• Phase 3 is the removal of the NRX reactor through a series of decommissioning work packages and achievement of the final end state.

The NRX decommissioning process began with the permanent shutdown of the NRX reactor facility. Shutdown operations for the NRX reactor and ancillary buildings have been completed. And the phase 1 activities to establish a safe sustainable storage-with-surveillance state for the fuel storage bays are currently in progress.

The NRX fuel bays are made up of A and B bays. The A bay's fuel was removed in the late 1990s after the facility was shutdown - after which cleaning of the A bay commenced. An environmental assessment was completed and approved by the CNSC in 2007. The CNSC then approved two advanced decommissioning work packages to remove water from the A and B bays, and remove approximately 30 metres of wooden building structure over the bays, creating a fire separation between the bays and NRX reactor. As a result, the A bay was cleaned and emptied in 2007. Future work will include the decontamination and removal of a 30-metre section of building, which will be completed in 2008.

The B bay consists of a network of water-filled and sand/water-filled bays that were connected to the A bay in the early 1950s. Work was undertaken in the late 1950s to isolate the B bays from the A bay by using a series of concrete dividing walls. Sections of the B bays were drained and filled with sand, while the remaining sections were re-filled with water. Emptying of the B bays will commence once final work is completed on the A bay. Lessons learned from decommissioning the A bay will be incorporated into the planning for the B bays. An application for decommissioning approval is expected during 2009.

7.6     Cluff Lake Project

The Cluff Lake Project, which is owned and operated by AREVA, began in 1981 and was completed at the end of 2002, when ore reserves were depleted. More than 62 million pounds of U₃O₈ was produced over the 22-year life of the project. Site facilities included the mill and tailings management area (TMA), four open-pit and two underground mines, the camp for workers and site infrastructure. Cluff Lake was the first of the northern Saskatchewan uranium mines to move into decommissioning. The decommissioning licence was received from the CNSC in July 2004, and followed five years of public consultation, environmental assessment and regulatory review, and marked the completion of the planning phase of work to return the site to a natural state. The objective is to return the site as closely as practical to its original state in a manner that both protects the environment and allows traditional uses such as fishing, trapping and hunting to be carried out safely.

Site staff and contractors carried out decommissioning work between 2004 and 2006, with re-vegetation of restored areas carrying into 2007. An extensive follow-up monitoring program to assess the performance of the decommissioned site is now underway. A small number of staff remains on site to carry out the monitoring program and provide minor maintenance at restored areas. Ultimately, when all stakeholders judge the performance of the decommissioned site satisfactory, it is expected that the site will be transferred to the Province of Saskatchewan through the institutional control framework established by the Reclaimed Industrial Sites Act (see Section H.10.3).

The following sections briefly describe the main decommissioning activities.

7.6.1     Mill area

Decommissioning the mill involved two phases, which were completed in 2004 and 2005. The mill demolition work was broadly similar to demolition of other comparable size industrial facilities, with special measures needed to protect workers from residual contamination and industrial hazards, and to prevent the spread of contaminants into the environment. Only two inactive warehouses remain. These warehouses are used for storage and equipment repair during the post-closure monitoring period. Waste materials were disposed in one of the open pits at the site, together with much larger volumes of waste rock. Following the mill demolition, till material was placed throughout the former mill area to serve as a growth medium for native wood species planted at the site and to ensure that radiological clearance levels were achieved throughout the area.

Figures 7.2 (a) and (b) - (a) A photograph of the mill areas during operation, and (b) a photograph of the area following decommissioning but prior to the re-vegetation becoming established.

7.6.2 Tailings Management Area

The TMA at Cluff Lake is a surface impoundment constructed using a series of engineered dams and dikes, and extending over about 70 hectares. It consisted of a solids containment area, water-decantation area and water-treatment facilities. Thickened tailings were pumped to the solids containment area, where consolidation and liquid decantation occurred. The decant water, together with wastewater from other sources, was piped to a two-stage water treatment facility for radium-226 precipitation. The TMA is surrounded by two diversion ditches, which divert run-off from the upstream drainage basin around the TMA to the downstream water body.

Decommissioning of the TMA was initiated by covering the tailings with till in stages to promote consolidation. When consolidation was complete, the TMA cover was contoured to provide positive drainage, using locally available till with a minimum cover thickness of one metre, and then re-vegetated. The surface contour and vegetated cover promote run-off of rainfall and snowmelt, as well as evapo-transpiration of moisture to the atmosphere, which minimizes net infiltration through the tailings. Extensive characterization of the tailings and the site's geology and hydrogeology has been performed to acquire reliable data on which to base the assessment of long-term performance. One of the objectives of the follow-up monitoring program is to verify the key assumptions used in the long-term performance assessment.

Figures 7.3 (a) and (b) - Photographs show the TMA during operation and after decommissioning but prior to the re-vegetation becoming established.

7.6.1.1     Mining area

Mining involved four open pits and two underground mines. One open pit (“D” pit) and its associated pile of waste rock were reclaimed in the mid 1980s. Water quality data from the flooded pit shows stable, acceptable surface water quality, and native species of vegetation have been re-established on the waste rock pile.

Two open pits have been used for the disposal of waste rock, with one of these two pits also used to accept industrial waste during operations and decommissioning. This waste included the mill demolition waste.

The major decommissioning activities consisted of:

• dismantling and disposing of all aboveground structures,
• sealing all access openings (ramps, ventilation shafts) to the two underground mines, and allowing them to flood naturally,
• relocating waste rock to complete the backfilling of one open pit (Claude pit), then re-contouring and establishing vegetation on these areas,
• removing a portion of - and then re-contouring - the waste rock within another open pit (DJN pit) and then allowing this pit and the contiguous DJX pit to flood to the natural level to eventually form a small lake that meets surface water quality criteria,
• reclaiming the remaining Claude waste rock pile by re-sloping for long-term stability, compacting the waste rock surface, covering with till and establishing a vegetation cover, and
• re-contouring and establishing native vegetation on all disturbed areas.

Extensive characterization of the waste rock, the geologic formations in the area and the site hydrogeology has been performed to acquire reliable data for the assessment of long-term performance. One of the objectives of the post-closure monitoring program is to verify the key assumptions used in the assessment of long-term performance.

(a) - DJ Operational (b) - DJ Decommissioned (c) - “D” Pit Approximately 20 Years After Decommissioning

Figures 7.4 (a), (b) and (c) - Photographs show one of the mining areas (DJ) during operations and after decommissioning but prior to re-vegetation becoming established.

7.7     Bruce Heavy Water Plant

The Bruce Heavy Water Plant (BHWP) was a Class 1B nuclear facility contained within the boundaries of the Bruce nuclear site located in Tiverton, Ontario. It began producing heavy water in 1973 and continued until the last production facilities were shutdown in 1998. Decommissioning of some of the older production systems began in 1993.

The demolition of the BHWP was completed in 2006. The only standing activity associated with the demolition is the remediation of oil-contaminated soil from the effluent lagoons. The contaminated soil was removed from the lagoons and put into bioremediation cells during the summer of 2006. These remediation cells should be removed from the site in November of 2008.

Figure 7.5 - Demolition of the Bruce Heavy Water Plant Site

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