The basic design of the pressurized water reactor includes such requirement that the coolant (water) in the reactor coolant system must not boil. Subcooling margin is very important safety parameter of PWRs, since the boiling in the reactor core must be excluded. Temperature in the pressurizer can be maintained at 350 ☌ (662 ☏), which gives a subcooling margin (the difference between the pressurizer temperature and the highest temperature in the reactor core) of 30 ☌. Pressure in the primary circuit of PWRs is maintained by a pressurizer, a separate vessel that is connected to the primary circuit (hot leg) and partially filled with water which is heated to the saturation temperature (boiling point) for the desired pressure by submerged electrical heaters. The exhausted steam is at a pressure well below atmospheric, and is in a partially condensed state (point F), typically of a quality near 90%.Ī pressurizer is a key component of PWRs.Ī pressurizer is a component of a pressurized water reactor. The reheater heats the steam (point D) and then the steam is directed to the low-pressure stage of steam turbine, where expands (point E to F). The steam must be reheated in order to avoid damages that could be caused to blades of steam turbine by low quality steam. In these turbines the high-pressure stage receives steam (this steam is nearly saturated steam – x = 0.995 – point C at the figure) from a steam generator and exhaust it to moisture separator-reheater (point D). Typically most of nuclear power plants operates multi-stage condensing steam turbines. Saturated liquid water, which has no latent heat and therefore 0% quality, will therefore only contain sensible heat. In the case of dry steam (100% quality), it contains 100% of the latent heat available at that pressure. At constant pressure, an addition of energy does not changes the temperature of the mixture, but the vapor quality and specific volume changes. Between these two states, we talk about vapor-liquid mixture or wet steam (two-phase mixture). On the other hand, when the vapor quality is equal to 1, it is referred to as the saturated vapor state or dry steam (single-phase). When the vapor quality is equal to 0, it is referred to as the saturated liquid state (single-phase). This course will most likely only use the ‘Default for fluid’ convention.Dry Steam – Saturated Vapor Phase diagram of water.ĭry steam, or saturated steam, is characterized by the vapor quality, which is equal to unity. Select the desired standard state convention. For a constant pressure system, select ‘Isobaric properties’.ĭ. For an isothermal system, select ‘Isothermal properties’. In Step 3, choose what kind of data you’re looking to obtain. Choose the steam table units you’d like to work with, in step 2.Ĭ. Select ‘Water’ from the ‘Please select the species of interest:’ drop-down menuī. Scroll through this section to find desired dataĪ.On the substance homepage scroll down to the “Other data available” section and select “phase change data”.Select desired substance from the list provided if not brought to substance homepage immediately.Leave other options as default and search for substance.Scroll down to search options and choose, name, formula or other desired search criteria.Search for “NIST Chemistry Webbook” or go to.Appendix: Finding Chemical Property Data on NIST Finding Antoine equation parameters on NIST
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