Q1 (10 points) A reactor is fueled with pellets of uranium dioxide (UO2) which have a density of 10 g/cm3. The uranium is enriched to 3 w/o in U-235, with the remainder of the uranium in form U –238. The following additional information is provided. Nuclide Atomic weight σa {b} σf {b} U 235 235.0 680 580 U 238 238.0 2.70 0 0 16.00 0 0 Na = 0.6022 x 1024 atoms/mole, a)(2 points) What is the atomic weight of the uranium (U-235 & U-238 combined) in the pellets? b)(2 points) What is the percent by weight of the uranium in the fuel? c)(3 points) What is the macroscopic cross-section for fission in the fuel? d)(3 points) What is the average distance a neutron will travel in the fuel prior to absorption or fission? a) M(U) = __________________ b) w/o(U) = ________________ c) ∑f = __________________ d)λ a = __________________Q2 (5 points) Use the following information to answer the below questions. M(p) =1.007820 amu, M(n) = 1.008665 amu, M(235U) = 235.0449 amu Na = 0.6022 x 1024 atoms/mole, 1 Mev = 1.6 x 10-13 watt-sec, 1 amu = 930 Mev. a)(3 points) Compute the mass defect ∆ of  in amu b)(2 points) Compute the average binding energy per nucleon for U-235 in Mev. . a) ∆(235U ) = ______________ b) BE/A(235U) = ____________Q3 (5 points) The nuclide   emits either an alpha or beta particle with a half-life of 3.10 min. a) (2 point) Calculate the decay constant λ. λ = ________________ b) (3 points A sample has an activity of 100 µCi, how many atoms of nuclide   remain after one half life. Note: 1 ci = 3.7 x 1010 disintegrations per second. Atoms = ________________Q4 (5 points) Short answers and true false questions. a) (2 points) List three ways neutrons interact with matter b) (1.5 points) List three ways photons interact with matter. c) (1.5 points) List three types of radioactive decayELEC 307-01 EXAM #1 Spring 2011 75 minutes, 1 sheet of notes permitted Name __________________________________________ Notes: 1. All answers require correct units for full credit. 2. Please place answer in boxes where provided. Question # Points Grade 1 10 2 5 3 5 4 5 Total