Passive residual heat removal systems for current and future light water reactors

Thesis (M.S., Mechanical Engineering) -- California State University, Sacramento, 2013.The main problem with nuclear power during a shutdown is that decay heat is still present and needs to be removed to prevent a number of problems. The traditional method of removing heat is through forced circulation via pumps. This setup works well unless the pumps are damaged or lose electricity. Therefore, there has been plenty of research conducted on Passive Residual Heat Removal Systems (PRHRS). These types of systems use multiple natural convection paths to dissipate the residual heat from both the reactor vessel and the containment structure before it can cause major problems. \ud The purpose of this thesis is to investigate the PRHRS for the Pressurized Water Reactor and the Boiling Water Reactor, and show where they stand in terms of future reactor design and possible retrofits for existing reactors.\ud Research showed that many nations are already implementing PRHRS in future designs. However, it is recommended that they retrofit existing reactors to prevent a similar Fukushima disaster and to fully utilize the lifespan of their investment. \ud Previously proposed retrofits involve levees and hydrogen ventilation. Newly proposed retrofits introduced in this investigation pertain to using the PRHRS and fuel rod bundle geometry. Both technologies have been used on reactors before, but they have never been considered for use as a retrofit. They both offer specific benefits to engineers in designing retrofits, as detailed in the study.Mechanical Engineerin