NUC-402: NUCLEAR MATERIALS
This final project includes six cases. Read and evaluate each case and provide your responses.
You are an engineer at the Acme Nuclear Power Plant, and over the course of a very active year, you are presented with the following material engineering problems. Your final project is to solve these problems using course material. Please divide your responses up by event number, and please recognize that these are hypothetical cases intended to exercise your learning, and do not reflect actual nuclear plant operation.
F1: Your fuels group is experimenting with glassification of spent fuel. They want to know how much of the following constituents they need to buy to produce 1000 kgs of a glass containing 14% wt% Na2O, 7% wt% CaO, and 79% wt% SiO2: Na2CO3, CaCO3, and SiO2. (10 pts, CO9)
F2: During a refueling outage, workers discover black, soft material in the reactor core (obviously a Foreign Materials Exclusion Area breech). To help identify the breech source, you are asked to determine the material. You discover that it is ground up bits of PVC piping, but this material is used in several locations. Fortunately, you can narrow the search because the PVC piping comes from unique vendors each with their unique degrees of polymerization. By detailed measurement, you determine that the PVC molecular non-extended (i.e., coiled) length is 7 nm. What is the degree of polymerization? (10 points, CO10)
F3: While shutdown, the core accidentally went critical and the reactor pressure vessel rose in temperature and was hot for two hours, but all instrumentation has failed and no one is sure what the temperature was. Explain how examination of the materials in retracted instruments (that had been in the core and are now extracted via thimble tubes) could be used to estimate the temperature. Specifically, use the TTT curve for 1.13% C steel (Figure 10.15) and the observation that what had been a pure gamma phase was now only 50% gamma phase to estimate what the temperature had been (assume a constant temperature for the two hour period). (10 points, CO6)
F4: A new composite grappling hook was purchase for the overhead crane in the turbine building, but the manufacturer lost all records of the volume of fibers used in the process. He is able to say that the fibers are E-glass and the matrix is epoxy, but he doesn’t know the percent of fibers. While a density measurement could estimate the make-up, you decide to test the force at which 1% strain occurs. Carefully gripping the shaft of the hook (which is 4 cm in diameter), you find that a force of 630kN is necessary to create 1% strain. What is the fiber percentage in the material? (10 points, CO11)
F5: Copper Iodide (CuI) can form in either a table-salt like cubic lattice structure, or the complex structure shown below. In the salt-like structure, CuI is a good iodine supplement for the plant goats, who keep the grass on the hillside cut short (an important safety function credited in the FSAR to prevent loss of offsite power through grass fires). However, in the complex structure at right, the material can be fatal to your safety-related goats. Calculate the density of each phase, so that the purchasing department can verify that they are obtaining the correct form of CuI. Note: you would have to make some assumption in order to calculate the edge length of the unit cell at right, but let’s say that it is a cube and that the two interior atoms are at the bcc center position and the center of the bottom face, which is close enough for a rough density value. (10 points, CO2)
F6: A worldwide shortage of nickel has made Inconel unavailable for steam generator tube manufacturing. Describe the properties of steam generator tubes that are most important for use in a PWR. List the values of these properties that Inconel 690 (some will be quantified, some will be qualitative). Seek out another material to take the place of Inconel 690. Justify your material choice on the basis of its properties. (50 points, CO13, CO14)