Sodium coolant

Reactor vessel height / diameter Primary coolant systems Primary coolant sodium mass Inlet / outlet reactor temperature Primary coolant flow rate Primary coolant flow velocity Secondary coolant systems Secondary coolant sodium mass Inlet / outlet IHX temperature Secondary coolant flow rate Secondary coolant flow velocity Water - steam systems Feed water flow rate Steam temperature (turbine inlet) Steam pressure (turbine inlet) Type of steam generator Refueling system... 

Chemical analysis of the plug consisting of 98% natural rubber highlighted the presence of a low content of impunties which, when diluted in the 3500 tonnes of reactor coolant sodium, led to a proportion lower than the limit permitted for nuclear quality sodium... 

That is why this report is devoted to the comparative assessment of general characteristics of a standard fast reactor coolant (sodium) and innovative ones, such as lead and lead-bismuth alloy. 

It should be pointed out that presently only liquid metal coolant-sodium is widely adopted for fast reactors. Mercury was used for a short period ("Clementine" reactor in the USA and BR-2 in the USSR having, respectively, thermal output powers of 30 and 100 kW). A number of lead cooled fast reactors are being studied presently. 

It is essential for steady and safe operation of a sodium cooled fast reactor to limit the coolant and cover gas impurities to prevent corrosion of reactor component materials and to reduce radiation dose by corrosion products (CPs). Therefore, impurity concentrations of both coolant sodium and cover gas argon were measured during the duty cycle operation and annual inspection period. The sodium impurity data include oxygen, hydrogen, nitrogen, chloride, tritium, metal elements and radioactive ° Ag, Na, Xs. The cover gas impurity data include O2, N2, CO, CO2, H2, CH4, He, H and radioactive xenon and krypton isotopes. 

FIG. 11. Hydrogen and oxygen content in JOYO primary coolant sodium. 

Ttwo DN monitoring systems are located adjacent to the primary cooling loops to detect the delayed neutrons emitted from precursors released into the coolant sodium. The CG precipitating system detects fission product of Rb i.e. beta decay of Kr released into the cover gas argon. 

Two types of FP traps have been installed in JOYO. One is a cesium trap installed in the primary coolant sodium purification system to capture cesium released from failed fuels. An open pore, foam-like glassy carbon that consists of thin struts of Reticulated Vitreous Carbon (RVC) is used as a material for collecting cesium. The capacity of this trap is designed to be 7.4E+12 Bq. The other trap is a Cover Gas Clean-up System (CGCS) to collect and store the noble fission gas released from failed fuels. Although it is planned that only one failed fuel pin will be in the core at any time, the CGCS is designed to handle the releases of up to twelve failed fuel pins. 

The sodium cooled fast reactor JOYO has been operated more than 20 years (about 5 years of effective full power years) since its initial criticality and the cumulative reactor output achieved over 1.9E+5 MWd. Since JOYO has not yet experienced any operation with breached fuels, FP radioactive contamination has not become an issue in the plant system. To reduce the radiation dose from long-lived Na, all primary coolant sodium in the main circulating loops is drained into a storage tank during annual plant inspections. Under these conditions, the spatial gamma-ray dose rate distribution is dominated by the radioactive CPs deposited on inner surfaces of the primary piping and components. This means that most personnel dose was due to these CPs. 

For decommissioning operations, the main specificity in LMFRs is the nature of the coolant that is, for all the reactors ever built, always a liquid metal and that has to be considered as a chemical waste at the final shutdown of the reactor. In its form, the liquid coolant (sodium or sodium-potassium alloy) cannot be considered as a stable nuclear waste due to its chemical properties strong reaction with water and potential ignition with air when liquid [6, 7], Thus in the decommissioning phases it will be necessary to consider the transformation of this coolant into a stable chemical product. 

N,N-Dimethyl-N-lauric acid-amidopropyl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyl-N-myristyl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyl-N-palmityl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyl-N-stearyl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyl-N-tallow-N-(3-sulfopropyl)-ammonium betaine N,N-Distearyl-N-methyl-N-(3-sulfopropyl)-ammonium betaine bactericide, apples Sodium o-phenylphenate bactericide, aq. metal coolants Sodium pyrithione bactericide, aq. metal cutting fluids Sodium pyrithione bactericide, aq. paints 2-Bromo-4 -hydroxyacetophenone bactericide, aqueous systems Tris (hydroxymethyl) nitromethane bactericide, awning/tarpaulin fabrics 10,10-Oxybisphenoxyarsine bactericide, bath gels Chlorhexidine digluconate bactericide, beer Sodium ethylparaben bactericide, biocides Cocamidopropyl hydroxysultaine N,N-Dimethyl-N-lauric acid-amidopropyl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyl-N-myristyl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyl-N-palmityl-N-(3-sulfopropyl)-ammonium betaine N,N-Dimethyl-N-stearyl-N-(3-sulfopropyl)-ammonium betaine... 

Alkyl dimethyl ethylbenzyl ammonium chloride biocide, antifoulant paints Methylenebis (thiocyanate) biocide, aq. inks Diazolidinyl urea biocide, aq. metal coolants Sodium pyrithione biocide, aq. metal cutting fluids Sodium pyrithione biocide, aq. paints Sodium pentachlorophenate biocide, aquatic Acrolein... 

TEA-phosphate Tolyltriazole corrosion inhibitor, antifreeze coolants Sodium benzoate... 

The possibility of reaction of the coolant (sodium) with water and air (fire). 

Plutonium enrichment (inner core / outer core) Coolant sodium mass 760 ton... 

In the SSC RF IPPE, boiling of the liquid metal coolant (sodium-potassium eutectic alloy) under the natural flow conditions has been studied. The objective of these studies is to investigate the possibility of the stable decay heat removal from the fast reactor core. 

Failedfuel detection Failed fuel is detected by sampling the cover gas and the sodium coolant. Sodium samples are taken from 4 locations in the hot pool. As this method cannot identify the failed fuel subassembly, 3 localization modules are provided and housed in the control plug. Samples of sodium from the top of the subassemblies are taken one by one by means of a selector valve and measured for delayed neutrons. The subassemblies are divided into three groups and each group has a localization module. 

Molten salt reactor NPP (reactor coolant — sodium-fluoride salt with dissolved uranium fuel Pom = 700/800°C jjrimary power cycle — indirect supercritical pressure carbon dioxide Brayton gas turbine cycle possible backup — indirect Rankine steam cycle). 50... 

Temperature of reactor coolant sodium, primary loop — °C 377/550 354/547 410/550... 

Temperature of intermediate coolant sodium, secondary loop — TiJToM- °C 328/518 309/505 355/527... 

MSR NPP thermal neutron spectrum (moderator—graphite) or fast neutron spectrum (no moderator) reactor coolant—sodium-fluoride salt with dissolved uranium fuel P w 0.1 MPa and Pom = 800°C primary power cycle—indirect supercritical pressure CO2 Brayton gas turbine cycle possible backup—indirect Rankine steam cycle 50... 

In the open-cycle externally cooled, two-fluid LMFR, the bismuth-uranium solution serves as the primary coolant as well as the fuel. In the reactor itself, there is no actual heat transfer. Instead, the solution acts as a transporter of heat to an external heat exchanger. In evaluating bismuth as a primary coolant, it is helpful to make a comparison between it and three other coolants sodium, a typical alkali metal coolant LiCl-KCl eutectic, a typical alkali halide salt mixture and water. (The salt eutectic used here would not be a suitable primary coolant for a thermal reactor. Its heat transfer properties, however, are typical of salt coolants.)... 

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