18.1.3 Federal agencies

US Nuclear Regulatory Commission

The NRC is an independent regulatory agency created from the former AEC by Congress under the Energy Reorganization Act of 1974 to ensure protection of the public health and safety and the environment, and to promote the common defense and security in the civilian use of byproduct, source, and special nuclear materials. The NRC is authorized to regulate private sector and certain government nuclear facilities, regulating the pos­session and use of nuclear materials as well as the siting, construction, and operation of nuclear facilities. It performs its mission by issuing regulations, licensing commercial nuclear reactor construction and operation, licensing the possession of and use of nuclear materials and wastes, safeguarding nuclear materials and facilities from theft and radiological sabotage, inspect­ing nuclear facilities, and enforcing regulations. The NRC regulates com­mercial nuclear fuel cycle materials and facilities as well as commercial sealed sources, including disused sealed sources.

The NRC regulates:

• commercial nuclear power, nonpower research, test, and training reactors

• fuel cycle facilities and medical, academic, and industrial uses of nuclear materials

• licensing of nuclear waste management facilities (including storage and disposal of SNF and HLW) as well as independent SNF management facilities

• certain DOE activities and facilities over which Congress has provided NRC licensing and related regulatory authority.

The NRC also regulates manufacture, production, transfer or delivery, receiving, acquisition, ownership, possession, and use of commercial radio­active materials, including associated RAW. The key elements of the NRC regulatory program are described in detail at http://www. nrc. gov. In addi­tion, the Department of Transportation has certain regulatory authority over the transport of SNF and HLW. Specifically, the NRC regulates man­agement and disposal of LLW and HLW, as well as decontaminating and decommissioning of facilities and sites. The NRC is also responsible for establishing the technical basis for regulations, and provides the informa­tion and technical basis for developing acceptance criteria for licensing reviews.

An important aspect of the NRC regulatory program is inspection and enforcement. The NRC has four regional offices that inspect licensed facili­ties in their regions, including nuclear waste facilities. Specific information on NRC Regional Offices can be accessed at http://www. nrc. gov/about-nrc/ organization. html. The NRC Office of Federal and State Materials and Environmental Management Programs communicates with state, local, and tribal governments, and oversees the Agreement State Program.

18.8.1 US experience

For over five decades, the United States generated a large quantity and variety of nuclear wastes. Significant progress has been made in the treat­ment and disposal of these wastes and the cleanup and closure of nuclear sites. Much has been accomplished, but work remains to be done before the cleanup mission is complete.

The DOE has over 20 years of experience in site cleanup. DOE EM manages the DOE cleanup program, which has:

• stabilized millions of liters/gallons of radioactive tank waste

• completed 11 waste tank closures, including two in 2012 at the SRS in South Carolina

• operated the DWPF at the SRS since 1996 making 5,850 metric tons of borosilicate glass, which stabilized 1.5 x 106 Tera-Becquerels of radioactivity

• operated and completed waste processing at the West Valley Demon­stration Project (WVDP) in New York from 1996 to 2002 making -500 metric tons of borosilicate glass which stabilized 9 x 105 Tera-Becquerels of radioactivity

• begun construction of three major tank waste processing facilities.

The tank waste processing facilities include the WTP in Washington (2003), SWPF in South Carolina (2005), and the Sodium Bearing Waste Treatment Facility in Idaho (2003). The IWTU at the Idaho facility is expected to begin operations in 2013. See Section 18.7.6 for more detail about these three construction projects.

In addition, the world’s first geological repository — WIPP — began opera­tions in 1999, and had received over 11,000 shipments as of February 2013. The first CH TRU waste shipment arrived at WIPP from Los Alamos in 1999, and the first RH waste shipment arrived at WIPP from Idaho in 2007.

The DOE has also treated 240 km2 of contaminated groundwater and stabilized more than 180 contaminated groundwater plumes. It has exten­sive experience in deactivation and decommissioning (D&D), including D&D of about 1,500 facilities. For example, it is in the process of decom­missioning and demolishing the K-25 facility in Tennessee, a building nearly one mile long used to enrich uranium from 1945 to 1964. It contained nearly 5 million ft2 of floor space. Demolition of the west wing, which comprises just under half of the entire facility, began in 2008 and finished in 2010.

Another example of a completed D&D activity is the P Reactor in South Carolina (which was entombed in place using concrete grout to fill the rooms below ground level), disassembly basin, and reactor vessel. Cleanup of the Experimental Breeder Reactor-II in Idaho, which operated for about 30 years from the mid-1960s to the mid-1990s, is currently in progress. The systems and structures above the reactor building will be demolished and most of the remaining systems and structures will be grouted in place.

Other D&D projects include the K-Basins project and N Reactor closure in Washington. The K-Basins stored spent fuel; they were demolished in 2009, and remediation of the nearby soil was completed in 2010. N-Reactor operated from 1963 to 1987; its support facilities have been demolished, and it is being placed into safe interim storage.

The DOE has experience in LLW disposal. At the Hanford site, the Environmental Restoration Disposal Facility began operation in 1996 to dispose of contaminated soils, D&D waste, asbestos, and hazardous waste from onsite cleanup. Waste is disposed in cells approximately 150 x 150 m in area and about 20 m deep. Another LLW disposal facility at the Oak Ridge Reservation in Tennessee, the Environmental Management Waste Management Facility, has been operating since 2002.

The DOE has closed two former nuclear sites: the Rocky Flats Plant in 2005 and the Fernald Site in 2006. The Rocky Flats Plant was established in 1951 as part of the US nuclear weapons complex to manufacture nuclear weapons components. The site covers about 6,500 acres near the Rocky Mountains northwest of Denver. Most of the land served as a security buffer around an approximately 400-acre industrial area near the center of the site. When production of weapons components ended at Rocky Flats in 1994, its mission changed to cleanup and closure.

Because of operational problems and practices during the plant’s history, facilities contained substantial amounts of hazardous materials and con­tamination. Liquids remained in process piping and in tanks in unknown quantities and chemical configuration, which resulted in a significant envi­ronmental cleanup and closure challenge for the DOE.

In October 2005, the DOE and its contractor completed an accelerated ten-year, $6.7 billion cleanup of chemical and radiological contamination left from nearly 50 years of production. The cleanup required the decom­missioning, decontamination, demolition, and removal of more than 800 structures, including six processing and fabrication building complexes; removal of more than 500,000 m3 of LLW; and remediation of more than 360 potentially contaminated environmental sites. The majority of the prop­erty at the site was transferred to the US Department of Interior for man­agement by the US Fish and Wildlife Service as the Rocky Flats National Wildlife Refuge in July 2007 (DOE, 2011a).

The Fernald site, formally known as Feed Materials Production Center, was a uranium processing facility that produced high-purity uranium metal products as the first step in the US nuclear weapons production cycle. The site ’s production mission began in 1951 and continued until 1989, when production operations ceased and Fernald’ s mission changed to environ­mental remediation. The comprehensive environmental remediation and ecological restoration of the site was completed in 2006, at a total cost of $4.4 billion.

The 1,050-acre site, now known as the Fernald Preserve, is open to the public as a nature preserve. The ecological restoration has made the Fernald Preserve attractive to a large number of nesting and migrating birds, including locally rare species. Restoration activities at the site have created one of the largest man-made wetlands, including open water, forests, 360 acres of grassland, and seven miles of trails that provide access to varied habitats (DOE, 2011b).

Significant challenges remain in the DOE cleanup program. The DOE must safely store, retrieve, and treat approximately 340 million L (about 90 million gallons) of liquid radioactive waste stored in 230 underground tanks, remediate approximately 6.5 trillion L of contaminated groundwater, reme­diate approximately 40 million m3 of contaminated soil, and D&D over 2,500 facilities.

In addition, the DOE has decommissioned and cleaned up uranium mines and mill tailings. For conventional US uranium mills, waste is primarily the onsite disposal of tailings (residual ore after the uranium was leached). UMTRCA classified the tailings as either residual radioactive material or 11e.(2) byproduct material depending on the status of the facility at the time UMTRCA was passed in 1978. Since passage of UMTRCA, activities at Title I sites have focused largely on decommission­ing and cleanup of residual radioactive material by US governmental entities.

UMTRCA Title I required the DOE to complete surface remediation and groundwater cleanup at the listed inactive uranium milling sites at which uranium was processed solely for sale to the US government. Resid­ual radioactive material, including any wind-blown dust, may have been consolidated into a single cell or perhaps relocated to a cell constructed on another site. These cells are now under long-term surveillance by the DOE (or possibly by the state or tribal governments in which the cell is located) and licensed by the NRC. Annual site inspections are performed as part of the long-term surveillance program at 22 Title I disposal sites.

VLLW is waste with very low radionuclide concentrations. VLLW consists mainly of bulk quantities of waste due to the operation and decommission­ing of nuclear facilities. VLLW has radionuclide concentration levels slightly above the levels specified for clearance of material with a limited radiological hazard potential that justifies limited radiation protection pro­visions. Pre-treatment of bulk quantities of VLLW as LLW would be cost intensive and not justifiable. VLLW could contain non-radioactive materials that render the waste hazardous. VLLW also needs to be classed and managed in terms of all its non-radiological hazards.

Subject to specific authorization, VLLW may be disposed of in engi­neered landfill facilities or surface impoundments, general waste landfill facilities and hazardous chemical waste disposal facilities. Authorized re-use of material (e. g., recycling of concrete as aggregate or use for road construc­tion) may also be considered as a management option. Specific criteria are derived for a specific facility or management option. VLLW could have radionuclide concentration levels of up to factor 100 above the clearance/ exemption criteria for engineered landfill facilities. Longer lived radionu­clides could be more limiting, depending on the site factors and design, due to the longer duration for which safety has to be demonstrated. Longer term institutional control arrangements may also be necessary for the VLLW disposal facilities. Mixing and consolidation of different VLLW or potential VLLW waste streams could be justified in order to lower radio­nuclide concentration levels or to obtain a more stable waste form, taking into consideration the physical and chemical compatibility of waste streams. Existing bulk waste collection systems (e. g., evaporation ponds) could also be considered for conversion and authorization as VLLW engineered dis­posal facilities.

Most SRAW consists of dry active waste (DAW) and secondary process waste. The DAW is generated during maintenance and repair of contami­nated systems and includes items such as used parts, paper, clothes, gloves and shoes. Secondary waste is generated from the liquid RAW treatment system and includes concentrated wastes from evaporators, spent resin from demineralizers, and spent filters from liquid purification systems.

Laundry waste ►

Other
liquid
waste
>

Filtration Evaporation desalinization concentration

The DAW is compressed by a conventional compactor (capacity: 2,000 tons) into 200 L drums. Solidification by Portland cement, which had been commonly applied in the past, is no longer used. Instead, the concen­trated waste is now dried and stabilized by paraffin wax in drums, and spent resin is kept in a high-integrity or equivalent container after drying in the spent resin drying facility. Spent filters are stored in shielded high integrity containers (HIC).

23.2.1 Sources, types and classification of radioactive waste

In Japan, RAW is categorized as shown in Table 23.14 . In May 2007, the Nuclear Safety Commission of Japan (NSC) issued a document which pro­vides for upper bounds of concentration of radioactive elements in waste packages from power reactors and in TRU waste packages. The upper bounds of concentration of radioactive elements are so decided, that the

Classification Origin of Disposal method High-level radioactive waste Reprocessing plant Deep geological disposal (>300 m) Low-level radioactive waste Waste power reactor Relatively higher level Nuclear power plant Sub-surface disposal (50-100 m) Lower level Near-surface disposal with artificial barrier Very low level Near-surface disposal without artificial barrier TRU Reprocessing plant, MOX fuel fabrication plant Deep geological, sub-surface and near-surface disposal Uranium waste Enrichment plant, fuel fabrication plant and conversion and refining plant Not yet decided Rl and research waste Research facility Rl utilizing facility Deep geological, sub-surface and near-surface disposal

public exposure due to waste packages is well within the reference value, and that the upper bounds conform to the latest knowledge in the interna­tional community. Based on these concepts, disposal of RAW is categorized into Category 1 Waste disposal (geological disposal) and Category 2 Waste disposal (sub-surface disposal, near-surface disposal with artificial barrier and near-surface disposal without artificial barrier).

Concerning the waste that does not need to be dealt with as RAW, the NSC has studied the clearance level of radionuclide concentrations and its calculation method, by reference to the ICRP document (Pub. 46, 1985) and IAEA-TECDOC-855, respectively.

Radioactive materials released from the Fukushima NPP have contami­nated leaves of plants exposed to the air and also is very likely to be in the stems of plants adsorbing nutrients from the contaminated soil. As a result, radioactive materials may enter the food chain for human consumption. Between mid-March 2011 and February 8, 2012, three categories of foods were sampled to check for radiation contamination: plant-based foods (e. g., vegetables, tree fruits, bamboo shoots, tea leaves, rice and other cereals), animal-based foods (e. g., cow’s milk and meat), and foods from natural and semi-natural environments (e. g., forest products and aquatic species). These tests included 104,318 food samples from different sites in Japan (not including Fukushima), and about 1% of these samples showed signs of contamination exceeding the standard limits for sale or consumption in Japan. In the Fukushima area, 18,350 samples were examined, and 3.5% of them were determined to exceed the standard limits [11].

Investigation of residual effects from peaceful explosions is a laborious and expensive task, requiring the creation of special missions with the appropri­ate hardware and monitoring equipment including vehicles, staffed by highly qualified scientific and technical personnel. For example, to study the thermal fields, among other things, requires manned aircraft. It is consider­ably more convenient to study the geophysical implications and methods of their control at test ranges where a developed technological infrastruc­ture and trained personnel with the necessary qualifications exist to ensure that the results of these studies for relevant peaceful uses of nuclear explo­sions are adequate. Therefore, a significant part of the material in this section is based on the results of experiments conducted at the Semipalat — insk nuclear proving ground.

The majority of the surveyed explosions took place at the Degelen moun­tain range, located near the Kalba-Chingiz deep fault. This complex, mostly granite, volcanic and volcanic-sedimentary rocks, forms a large structure with a diameter of about 30 km. Intrusive rocks are interspersed in the form of individual granite-like bodies of relatively small size. A smaller part of the surveyed explosions were in the area of the test site Balapan located close to the eastern border of the landfill. Geologically, much of it is placed in the Zaisan folded region. A latitudinal piece of the Kalba-Chingiz deep fault, which separates this area from Chingiz-Tarbagatai, runs almost along the southern border of the latter. The depth of the water table is 200-400 m. The entire area is characterized by a homogeneous filler surface, folded eluvial sands of 4-6 m, or dense clays (Busygin and Andreev 2004).

Climatic conditions at Semipalatinsk are sharply continental with an average temperature of about +1°C. Summer is hot and dry with tempera­tures up to +40°C. Autumn and spring are cloudy and cold with average temperatures not higher than +7°C. The exception is May, when it is warm and clear. Winter is cold with little snow and with temperatures as low as -40°C. These geological and climatic characteristics of the area determine the conditions of conservation of thermal lesions in the rocks, the formation of thermal anomalies on the ground surface, and the possibility of their detection.

The first results of the thermal regime created by the underground explo­sions (UGE) on the ground surface were obtained in the late 1980s and were published in a series of papers by Busygin et al. (1999) and Busygin and Andreev (2004). First ring-shaped forms were discovered covering the cleavage zone of the UGE as they were luminous in the infrared spectrum. The physics of these phenomena remains unclear. The formulation and solution of rigorous mathematical tasks was required to describe the proc­esses of heat transfer and gas flow. However, a comprehensive package of initial data and a set of direct measurements of temperature and air flow in the cavity and the Earth ’s surface, made in a wide range of temporary, geometric, and meteorological conditions, was also required.

Review of materials on the sprung hole of a UGE shows that for many years they have a high internal temperature, slowly decreasing over time (Israel, 1974’ Taylar, 1973). Results for the domestic UGE show that the average air temperature in the boiler cavities of the explosion conducted more than 10 years before, is 30-50°C, i. e., the boiler cavities of UGEs are long-term sources of heat.

It follows from Section 27.2 that the boiler cavity after the UGE is not absolutely airtight. The presence of anthropogenic influences, fracture zones, column collapses and other tectonic features makes the contents of the boiler cavity available for air transport and, consequently, for the removal of heat and gases present in the cavity to come to the surface. To control the intensity and configuration of thermal anomalies on the ground surface, the method of heat shot is employed from onboard aircraft, using the ‘Volcano’ thermal imaging equipment which is modified with a unit controlling the film transport rate, which requires a flight height range of 200-3,500 m above the surface. The method of optical-and-mechanical scan­ning was used in the direction perpendicular to the direction of travel of the thermal imager in the aircraft. The flights carried out tasks over the examined area, and the height of the flight was supposed to provide the required coverage.

The optical part of the recording apparatus was a cooled infrared radi­ometer with a sensitivity of 8-14 microns. The sensitive nature of the equip­ment required that it be placed in a hanging gondola on the outer side of the fuselage of the carrier, which eliminated the effects of the aircraft glass windows. Along with the heat-sensing aerial photography conducted in the visible spectrum which allowed detailed information about the surrounding landscape to be obtained, there was a need to decrypt the thermal images and a need to accurately reference the area of the thermal objects. In this way (Busygin and Andreev, 2004), more than 50 UGE were examined during the period from 1 to 26 after the date of the initial measurement.

Almost all of the surveys performed on the ground surface in the epicentral area were observed to be ring-shaped or curved thermal structures, cover­ing the cleavage zone of the explosion. The typical form of these structures is shown in Fig. 27.1.

To validate the existence of thermal anomalies, as long-term residual processes occurring in boiler UGE cavities, investigations were carried out in two directions. The first set of investigations was connected with the hypothesis of uneven solar heating of the soil due to the different solar exposure of mountain slopes and micro-relief. To this end, a loop of night and pre-dawn measurements in autumn and winter under cloudy conditions with zero duration of sunshine and little difference in day and night values of air temperature were performed. The results confirmed the presence of ring-shaped thermal anomalies. Indirectly, the role of solar warming from the thermal anomalies is refuted, as solar radiation during the cold season could ‘warm up’ only one side of the failure cone and warming was found in these ring-shaped patterns.

The second set of investigations was conducted to test the binding of thermal anomalies on the ground surface to a picture of the local actions of UGE. The problem was solved using ground-temperature well-logging methods in the area of the thermal anomaly tied to the locality on the thermal image. Measurements of ground surface temperature were made with copper wire resistance thermocouples (temperature sensors); the standard error did not exceed 0.2-0.4°C. For the measurements of each thermal anomaly, one or two measurement lines were created. Not less than 20 sensors were placed along a cable line at a distance of about 5 m from each other (Fig. 27.2). Measurement lines were located on the ground around the diameters of circles covering a cleavage zone. The sensors are protected from direct solar radiation by special shields. The true value of the measured temperature T was calculated for each sensor separately after adjusting for the actual impedance of the line. Each cycle of measurements was carried out for three days with interval readings after 2 hours. The duration of one data point on one line does not exceed 10 minutes.

Figure 27.3 shows the typical spatial distribution of temperature for the autumn-winter period for the profile of the location of temperature sensors

shown in Fig. 27.2 . Distances between sensors are marked as the abscissa on a proportional scale. It is evident that sensors located in a highlighted strip correspond to higher values of ground temperature compared with background values of temperature (about -9°C). The excess temperature reaches 8-10°C.

Figure 27.3 also shows that the gases exiting to the Earth’s surface have a temperature lower than the rock at the charge depth (6-8°C throughout the year). This has two causes. First, the cold-season air passing through an explosion cavity that is 20-40°C did not have sufficient time to warm up due to the high velocities of the air masses. Second, due to a lack of integrity arising from formation of a large number of deep cracks, there is deeper cooling of the rocks in the array, which significantly increases the contact area of the exhaust air from the cooled rock. To confirm the fact that the removal of heated air instead of air at the natural temperature of the boiler at the depth of the cavity was examined, a peaceful UGE was conducted in Kalmykia (Russia) in the warm season, i. e. at a background temperature of 21-23°C (Granberg et al. , 1997). Temperature thermal anomalies for it reached 28-34°C, which certainly indicates the presence of an artificial heat source from the UGE.

In parallel with the temperature well logging, estimates of the geometric dimensions of thermal anomalies were made. It was shown that a suffi­ciently broad energy spectrum at the depths of the UGE gives the maximum radius of the thermal anomalies which varies from 80 to 250 m, while the width of the thermal ring varies from 20 to 60 m. It was not possible to establish the full duration of thermal anomalies, as over a nearly ten-year period, their thermal anomalies remained virtually unchanged. For the UGE held in galleries, the largest fixed term for thermal anomalies at the time they could be observed was 25-26 years and for UGEs conducted in wells it was 16-18 years.

It is certainly interesting to study daily and seasonal measurements of the thermal effects of UGEs at individual sites. Diurnal temperature vari­ation, obtained by simultaneous measurements on a strip heater removed from the UGE and from the undamaged section of the Earth ’s surface, averaged over 48 experiments (October-November), is shown in Fig. 27.4 (here t0c = local time). It can be seen that the thermal effect at the UGE site was observed continuously for days in the field, according to the thermal image, due to removal of heat from the air cavity (line 1). Characteristically, the temperature fluctuations during a day in the field of thermal anomalies are about 1°C, while for the damaged portion of the UGE, site surface peak-temperature reaches 4°C.

Significant differences are observed in the form of plots of temperature versus time for undisturbed and disturbed UGE sites. For undisturbed sites, the temperature dependence is very ordinary, without thermal anomalies in the afternoon heating and only minimum temperature anomalies at 7-8 a. m. All this also suggests that the observed thermal anomalies are not the result of solar heating of the Earth ’s surface and that the surface albedo changes under the influence of the UGE.

Seasonal temperature variation, in contrast to the daily temperature vari­ation, was studied the least. In particular, during the warmer months there have been instances when the UGEs conducted in groups decreased by 2-3°C in the cleavage zone compared with the background temperature. To explain such phenomena, a phenomenological model for the formation and dynamics of thermal anomalies based on the principles of ‘heating effect’ was proposed. Its essence lies in the fact that the movement of air through the heated boiler cavity occurs by gas convection, and the direction of motion can be either from the portal tunnel up through tectonic faults in the epicentral area, or vice versa. From the equation for the depression

thrust air he = A(tB — tH), where A isa coefficient for atmospheric parameters and channel exhalation of air; tH is outside air temperature; and tB is aver­aged over the profile of raising the air temperature inside the rock, it is evident that the magnitude of depression is proportional to the temperature difference outside and passing along the tectonic disturbance of air, and the direction of motion is determined by the sign of this difference. If the tem­perature tB is calculated by using the empirical formula tB = 1.1(tp — 6)/H + 6 (Busygin et al, 1999), where tp is air temperature in the boiler cavity, and H is the reduced depth of the UGE, we can obtain approximate values of the external temperature of a UGE site, for which one should observe a positive depression (he > 0). For example, for an explosion with the yield 1 kt, warhead detonation depth H = 100 m, a positive depression is observed when the outside temperature does not exceed 16°C if the air temperature in the cavity is 100°C. If the temperature in the cavity decreases to 20°C, the boundary outside temperature decreases to 7-7.5°C.

The estimates given are quite approximate until a full-scale experiment can be carried out with monitored directions of transport and air flow to the outside air temperature. It should be noted that the direct measurement of air movements is possible only in the portal tunnel. In the area of the cleavage phenomena, as mentioned above, anemometric measurements are difficult due to the complexity of micro-relief areas and the inability to visu­ally determine the position of the majority of cracks, which serve as conduits to move the air.

Air mass velocity was measured using an anemometer at a distance of 40-50 m from the tunnel portal. The direction of air mass movement is determined by the deviation of the flame or the direction of motion of smoke from burning smoke grenades (at speeds below 0.2 m/s). The meas­urements were performed at two points located at the ‘top’ and ‘bottom’ gallery. In each session, measurements of velocity were carried out at least three times for a duration of 10 s. By measuring the mean values taken for air velocity at the point of measurement, the air flow can be calculated. Results are summarized in Table 27.1 which indicate the following:

The experimental results qualitatively confirm the adequacy of the pro­posed model to real processes. It should be noted that in wells, a high temperature persists for much longer than in galleries because the heat loss occurs only due to natural convection (i. e., there is no is ‘stove’ effect). According to field measurements at Semipalatinsk site, the temperatures in the wells have decreased to 42-45°C some 6 years after the explosion, while in the galleries the temperature has been observed for 1.5-2 years.

Along with air, radionuclide products are transported to the Earth’s surface. Direct measurements of the exposure dose on the profile of thermal anomalies have shown that in this case the radiation levels are 3-5 times higher than natural background levels (Fig. 27.6). Comparison of tempera­ture and gamma-radiation curves indicates a high degree of correlation of these two processes. The distribution of activity and concentration of radon behaves similarly. In the location of the thermal anomaly, the volume of radon activity is 80-100 Bq/m3. At the same time over the epicenter of the explosion, the natural background of ionizing radiation remains: 5-10 micro — R/h for gamma-rays and 30-40 Bq/m3 for radon.

In 1974, due to the oil crisis that followed the Yom Kippur War, France decided to develop a very large nuclear industry, including a number of NPPs and units to recycle spent fuel. The initiation of this significant pro­gramme had the effect of greatly increasing the volume of all categories of RAW: that of high-level and long-lived waste, coming from the recycling of the spent fuel, as well as that of short-lived low — and intermediate-level waste.

To address this situation, the government asked the CEA to create within its ranks an organization to take responsibility for managing all this waste. ANDRA was created inside the CEA in 1979.

16.1.2 Waste hierarchy and waste minimisation

A waste hierarchy is essentially a proactive management policy that priori­tises waste management options, with the overall aim of reducing the amount of waste that is ultimately disposed. The principle of the waste hierarchy has been the foundation of waste management policy for decades following its first appearance in EU policy in the mid-1970s and plays a central role in EU waste policy (Article 4 of the Waste Framework Directive). However, its introduction to RAW management did not take place until 2006-2008. The waste hierarchy (see Section 1.5.2) is summarised in Fig. 16.6.

Progression of the waste hierarchy towards the minimisation of the amount of wastes disposed does not necessarily go hand in hand with the most sustainable environmental option. Waste hierarchies are often imple­mented in a complementary way with BAT to ensure that sustainable approaches are integrated into the overall strategy. It is also implemented in combination with a life cycle approach, which affects every stage from design, construction, operation and decommissioning of disposal facilities.

Because of the considerable volume and weight reduction involved in combustion, low level wastes in the UK, particularly plastic, cellulose products and oil wastes, are often incinerated. Incinerators accepting LLW and high volume VLLW are licensed under EPR (2010) for disposal of

radioactive waste. Low volume VLLW is exempt under EPR (2010) as radioactive waste, but the operator of an incinerator will still require per­mission for non-radioactive waste incineration.

From the start of active operations at Dounreay, the site has managed its radioactive waste in its own waste management facilities.

LLW

Alone amongst UK nuclear sites, it has disposed of its LLW to near-surface disposal pits on site instead of sending the packaged LLW to the LLWR. A series of six disposal pits were constructed and operated from 1959 until 2005. These are situated at the north end of the site adjacent to the sea and contain around 33,000 m3 LLW. Pits 1-4 are unlined and accepted tumble tipped bagged LLW. Pits 5 and 6 have concrete bases and the LLW was disposed of in uncompacted or supercompacted 200 litre drums. All the pits contain large bulk items and are now capped off with rock and soil. Water ingress to the pits is collected in sumps and pumped to the LLLE treatment plant.

During the 1990s, it was clear that further extension of the existing LLW disposal facility was impracticable and would not meet current environmen­tal regulatory requirements. In 1999, a best practicable environmental option (BPEO) study (UKAEA, 2004a) was initiated to determine the most appropriate way in which to manage the continuing operational LLW and LLW that would be generated from decommissioning the whole site (approximately 150,000 m3 of packaged LLW). The BPEO study included significant stakeholder involvement (Broughton and Tait, 2008; Broughton, 2003). Preliminary performance assessment work and environmental impact studies (UKAEA, 2004b) were carried in parallel to inform the BPEO study. Eventually this led to the BPEO being identified as the construction of six new disposal vaults on the Dounreay estate south east and inland from the licensed site boundary. Their positioning was influenced by 10,000- year sea level rise assumptions. The BPEO proposal was endorsed by the Scottish Government Environment Minister in May 2005 (Scottish Execu­tive, 2005) and the planning application for this development was granted by the Highland Council in January 2009 (Highland Council, 2009). The project to construct the first two of the new vaults and associated facilities is currently in progress with the target of bringing them into operation in 2014. The vaults are of concrete construction with steel roofs and extend 15 m below ground level. Comprehensive water management features are included. The LLW will be disposed of in grouted half-height ISO contain­ers (HHISO) placed in one of the new vaults. Decommissioning waste of very low activity, but high volume (DLLW) such as concrete, rubble and steel will be disposed of in the other new vault in a designated bulk manner.