7.2.Nhà máy chuyển đổi plutoni và thiết bị được thiết kế đặc biệt hoặc chế tạo đặc biệt cho nhà máy đó

INTRODUCTORY NOTE
Plutonium conversion plants and systems perform one or more transformations from one plutonium chemical species to another, including: conversion of plutonium nitrate (PuN) to plutonium dioxide (PuO₂), conversion of PuO₂ to plutonium tetrafluoride (PuF₄), and conversion of PuF₄ to plutonium metal. Plutonium conversion plants are usually associated with reprocessing facilities, but may also be associated with plutonium fuel fabrication facilities. Many of the key equipment items for plutonium conversion plants are common to several segments of the chemical process industry. For example, the types of equipment employed in these processes may include: furnaces, rotary kilns, fluidised bed reactors, flame tower reactors, liquid centrifuges, distillation columns and liquid-liquid extraction columns. Hot cells, glove boxes and remote manipulators may also be required. However, few of the items are available ‘offthe-shelf’; most would be prepared according to the requirements and specifications of the customer. Particular care in designing for the special radiological, toxicity and criticality hazards associated with plutonium is essential. In some instances, special design and construction considerations are required to address the corrosive properties of some of the chemicals handled (e.g., HF). Finally, it should be noted that, for all plutonium conversion processes, items of equipment which individually are not especially designed or prepared for plutonium conversion can be assembled into systems which are especially designed or prepared for use in plutonium conversion.
7.2.1. Especially designed or prepared systems for the conversion of plutonium nitrate to oxide
EXPLANATORY NOTE
The main functions involved in this process are: process feed storage and adjustment, precipitation and solid/liquor separation, calcination, product handling, ventilation, waste management, and process control. The process systems are particularly adapted so as to avoid criticality and radiation effects and to minimise toxicity hazards. In most reprocessing facilities, this process involves the conversion of PuN to PuO₂. Other processes can involve the precipitation of plutonium oxalate or plutonium peroxide.
7.2.2. Especially designed or prepared systems for plutonium metal production
EXPLANATORY NOTE
This process usually involves the fluorination of PuO₂, normally with highly corrosive HF, to produce plutonium fluoride which is subsequently reduced using high purity calcium metal to produce metallic plutonium and a calcium fluoride slag. The main functions involved in this process are fluorination (e.g., involving equipment fabricated or lined with a precious metal), metal reduction (e.g., employing ceramic crucibles), slag recovery, product handling, ventilation, waste management and process control. The process systems are particularly adapted so as to avoid criticality and radiation effects and to minimise toxicity hazards. Other processes include the fluorination of plutonium oxalate or plutonium peroxide followed by a reduction to metal.
ANNEX C
CRITERIA FOR LEVELS OF PHYSICAL PROTECTION
1. The purpose of physical protection of nuclear materials is to prevent unauthorised use and handling of these materials. Paragraph 3(a) of the Guidelines document calls for effective physical protection levels consistent with the relevant IAEA recommendations, in particular those set out in INFCIRC/225.
2. Paragraph 3(b) of the Guidelines document states that implementation of measures of physical protection in the recipient country is the responsibility of the Government of that country. However, the levels of physical protection on which these measures have to be based should be the subject of an agreement between supplier and recipient. In this context these requirements should apply to all States.
3. The IAEA document entitled “The Physical Protection of Nuclear Material” (INFCIRC/225) and similar documents which from time to time are prepared by international groups of experts and updated as appropriate to account for changes in the state of the art and state of knowledge with regard to physical protection of nuclear material are a useful basis for guiding recipient States in designing a system of physical protection measures and procedures.
4. The categorisation of nuclear material presented in the attached table or as it may be updated from time to time by mutual agreement of suppliers shall serve as the agreed basis for designating specific levels of physical protection in relation to the type of materials, and equipment and facilities containing these materials, pursuant to paragraph 3(a) and 3(b) of the Guidelines document.
5. The agreed levels of physical protection to be ensured by the competent national authorities in the use, storage and transportation of the materials listed in the attached table shall as a minimum include protection characteristics as follows:
CATEGORY III
Use and Storage within an area to which access in controlled.
Transportation under special precautions including prior arrangements among sender, recipient and carrier, and prior agreement between entities subject to the jurisdiction and regulation of supplier and recipient States, respectively, in case of international transport, specifying time, place and procedures for transferring transport responsibility.
CATEGORY II
Use and Storage within a protected area to which access is controlled, i.e., an area under constant surveillance by guards or electronic devices, surrounded by a physical barrier with a limited number of points of entry under appropriate control, or any area with an equivalent level of physical protection.
Transportation under special precautions including prior arrangements among sender, recipient, and carrier, and prior agreement between entities subject to the jurisdiction and regulation of supplier and recipient States, respectively, in case of international transport, specifying time, place and procedures for transferring transport responsibility.
CATEGORY I
Materials in this category shall be protected with highly reliable systems against unauthorised use as follows:
Use and storage within a highly protected area (i.e., a protected area as defined for Category II above), to which, in addition, access is restricted to persons whose trustworthiness has been determined, and which is under surveillance by guards who are in close communication with appropriate response forces. Specific measures taken in this context should have as their objective the detection and prevention of any assault, unauthorised access or unauthorised removal of material.
Transportation under special precautions as identified above for transportation of Category II and III materials and, in addition, under constant surveillance by escorts and under conditions which assure close communication with appropriate response forces.
6. Suppliers should request identification by recipients of those agencies or authorities having responsibility for ensuring that levels of protection are adequately met and having responsibility for internally co-ordinating response/recovery operations in the event of unauthorised use or handling of protected materials. Suppliers and recipients should also designate points of contact within their national authorities to co-operate on matters of out-of-country transportation and other matters of mutual concern.
TABLE: CATEGORISATION OF NUCLEAR MATERIAL
| Material | Form | | Category | |
| | | I | II | III |
| 1. Plutonium*[a] | Unirradiated*[b] | 2 kg or | Less than 2 kg but more than 500 g | 500 g or |
| | | | | |
| | | more | | less*[c] |
| 2. Uranium-235 | Unirradiated*[b] | 5 kg or more | Less than 5 kg but more than 1 kg | 1 kg or less*[c] |
| | | | | |
| | - uranium enriched to 20% 235U or more | | | |
| | - uranium enriched to 10% 235U but less than 20% | - | 10 kg or more | Less than 10 kg*[c] |
| | - uranium enriched above natural, but less than 10% | - | - | 10 kg or more |
| | | | | |
| | 235U*[d] | | | |
| 3. Uranium-233 | Unirradiated*[b] | 2 kg or more | Less than 2 kg but more than 500 g | 500 g or less*[c] |
| 4. Irradiated fuel | | | Depleted or natural uranium, thorium or low-enriched fuel (less than 10% fissile content)*[e][f] | |
a. As identified in the Trigger List.
b. Material not irradiated in a reactor or material irradiated in a reactor but with a radiation level equal to or less than 1 gray/hour at one metre unshielded.
c. Less than a radiologically significant quantity should be exempted.
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d. Natural uranium, depleted uranium, and thorium and quantities of uranium enriched to less than 10% not falling in Category III should be protected in accordance with prudent management practice.
e. Although this level of protection is recommended, it would be open to States, upon evaluation of the specific circumstances, to assign a different category of physical protection.
f. Other fuel which by virtue of its original fissile material content is classified as Category I or II before irradiation may be reduced one category levels while the radiation level from the fuel exceed 1 gray/hour at one metre unshielded.
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Explanation and Comparison Table of Changes - Guidelines for Nuclear Transfers and Annexes A, B and C of the
Guidelines for Nuclear Transfers (NSG Part 1 Guidelines)
| Old (Revision 14) | | New (Revision 15) | Reason for Amendment |
| 2. | Annex B, Section 2 | Annex B, Section 2 | This amendment to add an Export Note to |
| | | | |
| 2.1. | Non-nuclear materials for reactors | 2. Non-nuclear material for reactors | Section 2 clarifies that exports of Deuterium and Heavy Water are only controlled if they are for nuclear reactor use. |
| | | | |
| | Deuterium and heavy water | EXPORTS | |
| | | | |
| | Deuterium, heavy water (deuterium oxide) and any other deuterium compound in which the ratio of deuterium to hydrogen atoms exceeds 1:5000 for use in a nuclear reactor as defined in paragraph 1.1. above in quantities exceeding 200 kg of | For the purposes of export control, the Government will determine whether or not the exports of non-nuclear materials meeting the specifications identified in paragraphs 2.1. and 2.2. are for nuclear reactor use. Nonnuclear materials having the specifications in paragraphs 2.1. and 2.2. not for use in a nuclear reactor as defined in Annex B, Section 1.1. are not covered by this section. | |
| | | | |
| | | 2.1. Deuterium and heavy water | |
| | | | |
| | | Deuterium, heavy water (deuterium oxide) and any other deuterium compound in which the ratio of deuterium to hydrogen atoms exceeds 1:5000 for use in a nuclear reactor as defined in paragraph 1.1. above in quantities exceeding 200 kg of | |
| 2.2. | deuterium atoms for any one recipient country within a period of one calendar year (1 Jan – 31 Dec). | 2.2. | deuterium atoms for any one recipient country within a period of one calendar year (1 Jan – 31 Dec). | |
| | | | | |
| | Nuclear grade graphite | | Nuclear grade graphite | |
| | | | | |
| | Graphite having a purity level better than 5 ppm (parts per million) boron equivalent and with a density greater | | Graphite having a purity level better than 5 ppm (parts per million) boron equivalent and with a density greater | |
| | | | | |
| | 3 than 1.50 g/cm for use in a nuclear reactor as defined in paragraph 1.1. above, in quantities exceeding 1 kg. | | 3 than 1.50 g/cm for use in a nuclear reactor as defined in paragraph 1.1. above, in quantities exceeding 1 kg. | |
| | | | | |
| | EXPLANATORY NOTE | | EXPLANATORY NOTE | |
| | | | | |
| | For the purpose of export control, the Government will determine whether or not the exports of graphite meeting the above specifications are for nuclear reactor use. Graphite having a purity level better than 5 ppm (parts per million) boron equivalent and with a density greater than 1.50 g/cm³ not for use in a nuclear reactor as defined in paragraph 1.1. above is not covered by this paragraph | | ~~For the purpose of export control, the~~ ~~Government will determine whether or~~ ~~not the exports of graphite meeting the~~ ~~above specifications are for nuclear~~ ~~reactor use. Graphite having a purity~~ ~~level better than 5 ppm (parts per~~ ~~million) boron equivalent and with a~~ ~~density greater than 1.50 g/cm3 not for~~ ~~use in a nuclear reactor as defined in~~ ~~paragraph 1.1. above is not covered by~~ ~~this paragraph.~~ | |
| | | | | |
| | Boron Equivalent (BE) may be determined experimentally or is calculated as the sum of BE_(z) for impurities (excluding BE_(carbon) since | | Boron Equivalent (BE) may be determined experimentally or is calculated as the sum of BE_(z) for impurities (excluding BE_(carbon) since | |
| carbon is not considered an impurity) including boron, where: | carbon is not considered an impurity) including boron, where: | |
| | | |
| BE_(z) ppm = CF x concentration of element Z (in ppm); | BE_(z) ppm = CF x concentration of element Z (in ppm); | |
| | | |
| CF is the conversion factor: (σ_(z) x A_(B)) divided by (σ_(B) x A_(z)); σ_(B) and σ_(z) are the thermal neutron capture cross sections (in barns) for naturally occurring boron and | CF is the conversion factor: (σ_(z) x A_(B)) divided by (σ_(B) x A_(z)); σ_(B) and σ_(z) are the thermal neutron capture cross sections (in barns) for naturally occurring boron and | |
| | | |
| element Z respectively; and | element Z respectively; and | |
| | | |
| A_(B) and A_(z) are the atomic masses of naturally occurring boron and element Z respectively. | A_(B) and A_(z) are the atomic masses of naturally occurring boron and element Z respectively. | |
| Annex B, Section 6 | Annex B, Section 6 | This amendment to Section 6 (Heavy Water production plants) adds three new processes used for the production of heavy water or for heavy water upgraders systems. The previous text identified (and explained) the Water-Hydrogen Sulphide Exchange Process (or Girdler-Sulphide |
| | | |
| 6. Plants for the production or concentration of heavy water, deuterium and deuterium compounds and equipment especially designed or prepared therefor | 6. Plants for the production or concentration of heavy water, deuterium and deuterium compounds and equipment especially designed or prepared therefor | (GS) process) and the Ammonia- |
| | | |
| INTRODUCTORY NOTE | INTRODUCTORY NOTE | Hydrogen Exchange Process. |
| | | |
| Heavy water can be produced by a variety of processes. However, the two processes that have proven to be commercially viable are the waterhydrogen sulphide exchange process | Heavy water can be produced by a variety of processes. ~~However, the two~~ Five processes are demonstrated here. Older processes that have proven to be commercially viable are the waterhydrogen sulphide exchange process, the Girdler-Sulphide (GS) process~~)~~, | The amended section also includes Combined Electrolysis and Catalytic |
| | | |
| (GS process) and the ammoniahydrogen exchange process. | | Exchange (CECE), Combined Industrial |
| | | |
| | | Reforming and Catalytic Exchange (CIRCE) and Bithermal Hydrogen-Water exchange (BHW). In addition, entry (6.6) on infrared absorption analyzers has been |
| The GS process is based upon the exchange of hydrogen and deuterium between water and hydrogen sulphide within a series of towers which are operated with the top section cold and the bottom section hot. Water flows down the towers while the hydrogen sulphide gas circulates from the bottom to the top of the towers. A series of perforated trays are used to promote mixing between the gas and the water. Deuterium migrates to the water at low temperatures and to the hydrogen sulphide at high temperatures. Gas or water, enriched in deuterium, is removed from the first stage towers at the junction of the hot and cold sections | and the ammonia-hydrogen exchange process. Three newer processes first demonstrated in the early 2000s, are based on catalysed hydrogen-water exchange and have been shown to have the potential for production or upgrading of heavy water on an industrial scale with favourable economics. These processes are: Combined Electrolysis and Catalytic | deleted since the infrared absorption analyzers used in heavy water production plants are not especially designed or prepared for heavy water production. |
| | | |
| | Exchange (CECE), Combined | A new entry (6.10) has been added for columns or towers packed with hydrogen isotope exchange catalyst to account for the addition of the 3 new processes. |
| | | |
| | Industrial Reforming and Catalytic Exchange (CIRCE) and Bithermal Hydrogen-Water exchange (BHW). | Finally, some small updates to process data were made within Section 6. |
| | | |
| | The GS process is based upon the exchange of hydrogen and deuterium between water and hydrogen sulphide within a series of towers which are operated with the top section cold and the bottom section hot. Water flows down the towers while the hydrogen sulphide gas circulates from the bottom to the top of the towers. A series of perforated trays are used to promote mixing between the gas and the water. Deuterium migrates to the water at low temperatures and to the hydrogen sulphide at high temperatures. Gas or water, enriched in deuterium, is removed from the first stage towers at the junction of the hot and cold sections | |
| and the process is repeated in subsequent stage towers. The product of the last stage, water enriched up to 30% by weight in deuterium, is sent to a distillation unit to produce reactor grade heavy water; i.e., 99.75% by weight deuterium oxide (D₂O). | and the process is repeated in subsequent stage towers. The product of the last stage, water enriched up to 30% by weight in deuterium, is sent to a distillation unit to produce reactor grade heavy water; i.e., 99.75% by weight deuterium oxide (D₂O). | |
| | | |
| The ammonia-hydrogen exchange process can extract deuterium from synthesis gas through contact with liquid ammonia (NH₃) in the presence of a catalyst. The synthesis gas is fed into exchange towers and to an ammonia converter. Inside the towers the gas flows from the bottom to the top while the liquid NH₃ flows from the top to the bottom. The deuterium is stripped from the hydrogen in the synthesis gas and concentrated in the NH₃. The NH₃ then flows into an ammonia cracker at the bottom of the tower while the gas flows into an ammonia converter at the top. Further enrichment takes place in subsequent stages and reactor grade heavy water is produced through final distillation. The synthesis gas feed can be provided by an ammonia plant that, in turn, can be constructed in association with a heavy water ammonia-hydrogen exchange plant. The ammonia-hydrogen | The ammonia-hydrogen exchange process can extract deuterium from synthesis gas through contact with liquid ammonia (NH₃) in the presence of a catalyst. The synthesis gas is fed into exchange towers and to an ammonia converter. Inside the towers the gas flows from the bottom to the top while the liquid NH₃ flows from the top to the bottom. The deuterium is stripped from the hydrogen in the synthesis gas and concentrated in the NH₃. The NH₃ then flows into an ammonia cracker at the bottom of the tower while the gas flows into an ammonia converter at the top. Further enrichment takes place in subsequent stages and reactor grade heavy water is produced through final distillation. The synthesis gas feed can be provided by an ammonia plant that, in turn, can be constructed in association with a heavy water ammonia-hydrogen exchange plant. The ammonia-hydrogen | |
| exchange process can also use ordinary water as a feed source of deuterium. | exchange process can also use ordinary water as a feed source of deuterium. | |
| | | |
| Many of the key equipment items for heavy water production plants using GS or the ammonia-hydrogen exchange processes are common to several segments of the chemical and petroleum industries. This is particularly so for small plants using the GS process. However, few of the items are available ‘off-the-shelf’. The GS and ammoniahydrogen processes require the handling of large quantities of flammable, corrosive and toxic fluids at elevated pressures. Accordingly, in establishing the design and operating standards for plants and equipment using these processes, careful attention to the materials selection and specifications is required to ensure long service life with high safety and reliability factors. The choice of scale is primarily a function of economics and need. Thus, most of the equipment items would be prepared according to the requirements of the customer. | Many of the key equipment items for heavy water production plants using GS or the ammonia-hydrogen exchange processes are common to several segments of the chemical and petroleum industries. This is particularly so for small plants using the GS process. However, few of the items are available ‘off-the-shelf’. The GS and ammoniahydrogen processes require the handling of large quantities of flammable, corrosive and toxic fluids at elevated pressures. Accordingly, in establishing the design and operating standards for plants and equipment using these processes, careful attention to the materials selection and specifications is required to ensure long service life with high safety and reliability factors. The choice of scale is primarily a function of economics and need. Thus, most of the equipment items would be prepared according to the requirements of the customer. | |
| | | |
| Finally, it should be noted that, in both the GS and the ammonia-hydrogen exchange processes, items of equipment which individually are not especially | Finally, it should be noted that, in both the GS and the ammonia-hydrogen exchange processes, items of equipment which individually are not especially | |
| designed or prepared for heavy water production can be assembled into systems which are especially designed or prepared for producing heavy water. The catalyst production system used in the ammonia-hydrogen exchange process and water distillation systems used for the final concentration of heavy water to reactor-grade in either process are examples of such systems. | designed or prepared for heavy water production can be assembled into systems which are especially designed or prepared for producing heavy water. The catalyst production system used in the ammonia-hydrogen exchange process and water distillation systems used for the final concentration of heavy water to reactor-grade in either process are examples of such systems. | |
| | | |
| | Of the three main heavy water production processes employing hydrogen-water exchange, two (CECE and CIRCE) are only practical when integrated into large hydrogen production processes where hydrogen is being made for other commercial uses. The third process Bithermal Hydrogen-Water exchange (BHW) could potentially be used in a standalone plant. All these processes require large quantities of specialised wet-proofed platinised catalysts installed in long columns to provide good contact with the water flowing down. The CECE process requires such wet-proofed platinised catalyst exchange columns to be provided with hydrogen from a water electrolyser that receives its water feed from the exchange columns. In this way, the | |
| | heavier isotope (deuterium) will build up a concentration in the electrolyser that receives its water feed from the exchange columns. The electrolyser system may potentially build up its deuterium concentration to almost pure heavy water. In practice the process will be staged and the large first stage typically raises the deuterium concentration by a factor between 5 and 20. The CIRCE process is similar, but uses a steam- | |
| | | |
| | hydrocarbon reformer as the source of hydrogen, providing the reformer with its source of water for steam. In all these plants, the CECE process is typically used as the final stage to produce reactor-grade heavy water. It should be noted that the largest hydrogen production plants in the world produce enough hydrogen to extract about 20-60 Mg per year of heavy water using a CECE or CIRCE process. A BHW process is conceptually the same as the GS, but using hydrogen instead of hydrogen sulphide with a catalyst to promote the deuterium transfer. In an arrangement analogous to the GS process, the BHW process exploits the effect of temperature on the equilibrium ratio of deuterium | |
| The items of equipment which are especially designed or prepared for the production of heavy water utilising | between water and hydrogen. The equilibrium falls with rising temperature. As water flows down through upper cold and lower hot towers, deuterium is enriched between them while hydrogen is circulated up through the hot and cold towers in turn. Water taken from between cold and hot towers is sent on to higher stages for further deuterium enrichment. A BHW process could be built for any scale of production. | |
| | | |
| | The key component in these processes is clearly the specialised wet-proofed platinised catalyst that has proven to be relatively difficult to manufacture on a large scale at reasonable cost. Operating conditions are benign, with non-toxic fluids and catalysts, pressure between atmospheric and about 4 MPa and temperatures in the range 293 K (20°C) to 473 K (200°C). None of the equipment is significantly different from that used in various part of the chemical process industry other than the wet-proofed platinised catalyst. | |
| | | |
| | The items of equipment which are especially designed or prepared for the production of heavy water utilising | |
| 6.2. | either the water-hydrogen sulphide exchange process or the ammoniahydrogen exchange process include the following: | 6.2. | ~~either~~ any of the ~~water-hydrogen~~ ~~sulphide exchange process or the~~ ~~ammonia-hydrogen exchange process~~ technologies described above include the following: | |
| | | | | |
| 6.3. | Blowers and compressors | 6.3. | Blowers and compressors | |
| | | | | |
| | Single stage, low head (i.e., 0.2 MPa) centrifugal blowers or compressors for hydrogen-sulphide gas circulation (i.e., gas containing more than 70% by weight hydrogen sulphide, H₂S) especially designed or prepared for heavy water production utilising the water-hydrogen sulphide exchange process. These blowers or compressors have a throughput capacity greater than or equal to 56 m³/s while operating at pressures greater than or equal to 1.8 MPa suction and have seals designed for wet H₂S service. | | Single stage, low head (i.e., 0.2 MPa) centrifugal blowers or compressors for hydrogen-sulphide gas circulation (i.e., gas containing more than 70% by weight hydrogen sulphide, H₂S) especially designed or prepared for heavy water production utilising the water-hydrogen sulphide exchange process. These blowers or compressors have a throughput capacity greater than or equal to ~~56~~ 5 m³/s while operating at pressures greater than or equal to 1.8 MPa suction and have seals designed for wet H₂S service. | |
| | | | | |
| | Ammonia-hydrogen exchange towers | | Ammonia-hydrogen exchange towers | |
| | | | | |
| | Ammonia-hydrogen exchange towers greater than or equal to 35 m in height with diameters of 1.5 m to 2.5 m capable of operating at pressures greater than 15 MPa especially designed or prepared for heavy water production utilising the ammonia-hydrogen exchange process. | | Ammonia-hydrogen exchange towers greater than or equal to 35 m in height with diameters of 1.5 m ~~to 2.5 m~~ or greater capable of operating at pressures greater than 15 MPa especially designed or prepared for heavy water production utilising the ammonia-hydrogen | |
| 6.6. | These towers also have at least one flanged, axial opening of the same diameter as the cylindrical part through which the tower internals can be inserted or withdrawn. | 6.6. | exchange process. These towers also have at least one flanged, axial opening of the same diameter as the cylindrical part through which the tower internals can be inserted or withdrawn. | |
| | | | | |
| 6.8. | Infrared absorption analysers | 6.8. | [No longer used – since 14 July 2023] ~~Infrared absorption analysers~~ | |
| | | | | |
| | Infrared absorption analysers capable of on-line hydrogen/deuterium ratio analysis where deuterium concentrations are equal to or greater than 90% by weight. | | ~~Infrared absorption analysers capable of~~ ~~on-line hydrogen/deuterium ratio~~ ~~analysis where deuterium~~ ~~concentrations are equal to or greater~~ ~~than 90% by weight.~~ | |
| | | | | |
| | Complete heavy water upgrade systems or columns therefor | | Complete heavy water finishing units, upgrade systems or columns therefor | |
| | | | | |
| | Complete heavy water upgrade systems, or columns therefor, especially designed or prepared for the upgrade of heavy water to reactor-grade deuterium concentration. | | Complete heavy water upgrade systems, or columns ~~therefor~~ with diameters of 0.1 m or greater, especially designed or prepared for the upgrade of heavy water to reactor-grade deuterium concentration. | |
| | | | | |
| | EXPLANATORY NOTE | | EXPLANATORY NOTE | |
| | | | | |
| | These systems, which usually employ water distillation to separate heavy water from light water, are especially designed or prepared to produce reactor grade heavy (i.e., typically 99.75% by | | ~~These~~ Heavy water upgrade systems typically support the operation of a heavy water moderated nuclear reactor or are part of a GS heavy water production plant (in which case | |
| weight D2O from heavy water feedstock of lesser concentration. | they are commonly termed ‘finishing units’). ~~, which usually employ water~~ ~~distillation to~~ Upgraders separate heavy water from light water~~,~~. ~~are especially~~ ~~designed or prepared to produce reactorgrade heavy water (i.e., typically~~ ~~99.75% by weight D~~₂~~O) from heavy~~ ~~water feedstock of lesser~~ Such systems usually employ water distillation, but may also be based on the CECE process. In heavy water moderated nuclear reactors, upgraders maintain the heavy water concentration in the reactor core. | |
| | | |
| | 6.10. Columns or towers packed with hydrogen isotope exchange catalyst | |
| | | |
| | Complete columns or towers especially designed or prepared for hydrogen isotope exchange having all of the following: | |
| | | |
| | 1. Packed with random or structured wet-proofed platinised catalysts; | |
| | | |
| | 2. Constructed of carbon steel or stainless steel; | |
| | 3. Capable of operating with pressure in the range of 0.1 to 4 MPa; and | |
| | | |
| | 4. Capable of operating at temperatures in the range of 293 K (20°C) to 473 K (200°C). | |
| | | |
| | EXPLANATORY NOTE | |
| | | |
| | In heavy water production processes, primary stage catalyst columns have typical diameters greater than 0.5 m and typical heights greater than 10 m. In heavy water upgraders, a typical minimum practical diameter is 0.1 m. | |
[1] The European Commission and the Chair of the Zangger Committee participate as observers.