7. Water of high degree of purity, especially free from chloride ions, is necessary to minimize corrosion 8. The fuel material should be resistant to radiation damage that can lead to dimensional chan ges,e.g, by swelling, cracking, or creep. <oSx</o 9. The fuel material should have a high melting point and there should be no phase transform ations, which would be accompanied by density and other changes, below the melting point. <o </O 10. Uranium dioxide, ceram ic which is the most common fuel material in commerc ial power r eactors, has the advantage of high-temperature sta bility and adequate resistance to radiation. <o ②<O 1. The pellets are ground to specified dimensions and are loaded into thin zircaloy tubes whi h serve as cladding <o 12. The small annular gap between the fuel pellets and cladding conta ins helium gas to impro ve the heat transfer characteristic UNIT 10 REACTOR SAFETY<OO</oes 1. In general, the goals of reactor safety are to reduce the probability of an accident and to hi mit the extent of the radiological hazard oOx</oe7. Water of high degree of purity, especially free from chloride ions, is necessary to minimize corrosion.<O ></O > 8. The fuel material should be resistant to radiation damage that can lead to dimensional chan ges, e.g., by swelling, cracking, or creep.<O ></O > 9. The fuel material should have a high melting point and there should be no phase transform ations, which would be accompanied by density and other changes, below the melting point.<O ></O > 10. Uranium dioxide, ceramic which is the most common fuel material in commerc ial power r eactors, has the advantage of high-temperature stability and adequate resistance to radiation.<O ></O > 11. The pellets are ground to specified dimensions and are loaded into thin zircaloy tubes whi ch serve as cladding.<O ></O > 12. The small annular gap between the fuel pellets and cladding contains helium gas to impro ve the heat transfer characteristic UNIT 10 REACTOR SAFETY<O ></O > 1. In general, the goals of reactor safety are to reduce the probability of an accident and to li mit the extent of the radiological hazard.<O ></O >