Soak Times:
Soak times might be needed while heating up the PCS, especially while huge limiting parts are included in the heatup. Soak times are used so in which heats could be carefully controlled. By this manner thermal stresses are minimized. An instance of a soak time is to heat the reactor coolant to a specified temperature and to stay at in which temperature for a specific time period. This permits the metal in huge parts, such as the reactor pressure vessel head, to heat more evenly from the hot side to the cold side, therefore limiting the thermal stress across the head. Soak time becomes extremely significant while the PCS is at room temperature or below and extremely close to its RTNDT temperature limitations.