Coolant Additive

In a fuel cell vehicle, the temperature of fuel cells rises due to the exothermic reaction of the fuel cells and thus, while the fuel cells are cooled by a coolant, a radiator installed in a cooling system radiates heat of the coolant to maintain the operating temperature of the fuel cells at an optimum value, e.g., 80°C (154). 

The coolant of fuel cells flows through a fuel cell stack and there is a danger of a short circuit of cells or a leakage of current if electrical conductivity of the coolant is high. Thus, ion exchanged water with an electrical conductivity of 1 mS or less, or a low-conductive antifreeze, is used as coolant. 

The coolant also poses the problem of the electrical conductivity of the coolant being high because of ionization of products of such organic acids or the like caused by heat degradation or elution of ions from component materials, such as rubber and metal, in the cooling system (154). 

low electrical conductivity of the coolant must be maintained by installing an ion exchange resin in the cooling system of fuel cells to remove ions. A mixed bed ion exchange resin in which both a cation exchange resin and an anion exchange resin are mixed can be used as ion exchange resin. 

A fuel cell system has been developed that includes the fuel cells, a circulation channel of a coolant to cool the fuel cells, and an ion exchange resin provided on the circulation chaimel to maintain electrical conductivity of the coolant. Further, the coolant contains an additive, and the ion exchange resin is prepared so that adsorption of the additive on the ion exchange resin is in a satiurated state (154). 

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Contamination of oil by water or coolant can cause major problems in a lubricating system. Many of the additives now used in formulating lubricants contain the same elements that are used in coolant additives. Therefore, the laboratory must have an accurate analysis of new oil for comparison. 

Select the engine coolant or antirust with care to ensure adequate corrosion protection. Use only those products conforming to recognized standards such as ASTM D 3306 for engine coolant. Additionally, if your vehicle engine contains major cast aluminum components, be certain the engine coolant meets the heat rejection corrosion limits in ASTM specification D 3306 as determined by ASTM Test Method for Corrosion of Cast Aluminum Alloys in Engine Coolants Under Heat-Transfer Conditions (D 4340). 

Withstand the chemical environment (hydrogen, air, water, coolant additives). 

This report discusses the positive and negative features of coolant addition as a means to arrest or mitigate a core degradation accident. It focuses on the accident progression aspects of accident mitigation and does not address some of the more important consequences of coolant additions on fission product release and behaviour. There does not seem to be in the literature a corresponding analysis of the source term issues associated with coolant additions. 

Flooded release pathways created by coolant addition were responsible for the relatively modest radionuclide releases to the containment during the Three Mile Island accident. Gas flows through flooded pathways are broken into bubbles. Radioactive vapours and aerosols are removed from the bubbles by processes that are quite like those that occur in steam suppression pools. These removal processes are also discussed in Chapter V. 

On the other hand, coolant additions insufficient to quench the degrading reactor fuel may enhance the release of radioactivity from die reactor coolant system. Enhanced releases can come about because the enhanced availability of steam for reaction widi zirconiiun clad leads to higher fuel temperatures. Higher steam concentrations can make some radionuclides more volatile. Or, enhanced releases may be caused simply because higher steam production leads to more efficient mass transport through the reactor coolant system. 

The requirements for radiator tanks are good heat stability, vibration resistance, and resistance to coolant additives [18],... 

K. Sato, M. Yasukawa, A. Sagasaki, T. Wada, and Y. Kato, Fuel cell system including coolant additive and ion exchange resin and fuel-cell vehicle, US Patent 8951689, assigned to Suzuki Motor Corporation (JP) Showa Water Industries Co., Ltd. (JP), February 10,2015. 

Propellants, explosives, pyrotechnics. Initiators, ceramic additives, conductive coatings, coolant additives, high thermal conductivity materials, sintering additives... 

Space Nuclear Power Plant (SNPP) electric power output could be controlled on reactor outlet temperature and Brayton speed. Mass inventory control (system pressure) was not pursued based on increased complexity and the additional risks to spaceship performance introduced by such a system (e.g., inadvertent coolant addition, additional leak paths). 

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