5. The term shut down margin is defined as the instantaneous amount of reactivity by whic a reactor is sub-critical or would be sub-critical from its present condition assuming all control rods are fully inserted except for and equilibrium xenon removed refers to the term. Multiple Choice c. a. the single control rod with the lowest integral worth b. the single control rod with the highest differential worth the single control rod with the highest integral worth d. any single control rod 6. Several factors may change during and after the shutdown of the reactor that affect the reactivity of the core. These include: soluble neutron poison concentration; temperature of the fuel and coolant; poisons (xenon & samarium);reactor pressure and Multiple Choice a. moderator to fuel ratio b. control rod position c. installed neutron source rate d. delayed neutron precursor half-life 7. About 7 percent of the 200 MeV produced by an average fission is released at some time after the instant of fission. After the reactor is shutdown this remaining energy is referred to as Multiple Choice a. C. delayed heat b. delayed neutron precursors shutdown margin d. decay heat 8. Search for and define the following terms: Materials Testing Reactor, TRIGA Reactor, Swimming Pool Reactor, Neutron Activation Analysis