Trantham_M3.3

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Excelsior University *

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246

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Mechanical Engineering

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Apr 3, 2024

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Course: Thermal Measurements Lab Section: Module 3 Instructor Name: Dr. Pashayi Name(s): Carlton Trantham __________________________________________________________________________ Title : In this lab, we measured various temperatures from the secondary side of the steam plant and performed a heat balance calculation for the steam generator. We also observed what happens when steam stops are rapidly shut while at power. __________________________________________________________________________ Abstract: Analyzing the steam generator as an open system, we can calculate the heat produced by the reactor since the steam generator is the reactor’s heat sink. This is an important ability for operators, as we need a method to verify power indications for the reactor. There are multiple methods for performing this calculation as well, but we used steam mass flow rate and multiplied that by the difference in enthalpy between the feed water and steam. Operators must understand plant responses to different operating conditions as well, which we demonstrated by predicting the results of the steam stops shutting and then testing those predictions in the simulator. __________________________________________________________________________ Introduction: According to the first law of thermodynamics, energy must be conserved within an analyzed system. This means that we can analyze various points of the reactor plant and compare those to the indications we see on a status board to prove the accuracy of the instruments. This is one of the major reasons calorimetrics are done on reactors. Utilizing a heat balance equation, we can compare the thermal power of the steam generator to the thermal power of the reactor, and with a certain amount of confidence prove the indicated power is accurate. __________________________________________________________________________ Methods: Navigate to the simulator start page. Begin the lesson by selecting “Lesson 2- IC002 100 MOL” and then run the simulation. Once operating, navigate to the MFW1 page. Here you will find various temperatures and pressures from the steam generators, as well as the feed system supplying feed water to the generators. From this page, you will record the 4 steam generator pressures, and average them together. When averaged, you will convert this pressure to an

absolute pressure. You will then add the 4 steam flows together. Next, locate the feed water temperature leaving the feed water heaters and record that value.

We have recorded all necessary values from the simulator but we need to find values for steam and feed water enthalpy. Using the saturated steam tables, input the feed water temperature and record its corresponding enthalpy. You will record only h f . Next, using the averaged steam generator pressure, input that value into the steam table and record h g , the saturated steam enthalpy. Now, using the equation Q S/G =ṁ stm × (h stm - h fw ) and covert this value to MW. With our calculated value, we can compare that to the indicated value on the simulator. Next, we will observe what happens when the steam generator isolation valves are shut unexpectedly. Navigate to the ESF1 screen, and click the average coolant temperature indication from the top panel. Click the visible chart to enlarge it and show a real-time graph. Then select “Actuate” beside Train 1, and select “Actuate” again from the pop-up menu. ________________________________________________________________________ Results: 9 a. 1053.3 psia 10 a. 17,959 KLBH 11 a. 449.9 F 14. You must use the change in enthalpy because the feed water is undergoing a phase change within the steam generator. Since latent heat is being absorbed by the feed water, only calculating thermal power with the temperature difference would fail to represent all of the energy being transferred within the steam generator.

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18 a. 430.09 BTU/lb 20 a. 1190.5 BTU/lb 21. 4,002.2 MW 22 a. 3983 MW 23. The first law of thermodynamics states that the system's internal energy difference is proportional to the heat added to the system subtracted by the work done by the system. If the steam stops are shut, you remove the system’s ability to do work. This would cause your feed enthalpy to decrease. However, the enthalpy of the steam would continue to increase since the reactor coolant pumps were unaffected. This would eventually cause steam generator relief valves to lift to relieve pressure. 24 a. 588.4 F 29. Average coolant temperature momentarily rose since the reactor lost its primary heat sink. This is aligned with what I predicted since heat was continuing to be added to the feed water with no ability for the steam to leave the generator. The automatic protective features prevented the steam generator relief valves from lifting. 30. I did not predict a change in average coolant temperature, but average coolant temperature rose sharply, and fell rapidly after the reactor was scrammed. _________________________________________________________________________ Discussion : Energy must be conserved within any thermodynamic system, as stated by the first law of thermodynamics. Using this law, we are given the ability to analyze different portions of a larger system to express the total energy within the system. By calculating the energy added to the feed water within the steam generator, we know that energy must have come from the reactor. It is also vital that operators understand plant responses to major equipment malfunctions, like the one we caused in this simulation. Shutting the main steam stops while at power is a very dangerous operation as evidenced by automatic protective features we observed. __________________________________________________________________________ Conclusion: Heat balance equations play a pivotal role in the safe operation of nuclear power plants by ensuring instruments are accurate within a reasonable tolerance. The first law of thermodynamics can also help operators predict how a system may respond when vital equipment fails or doesn’t perform as expected.

__________________________________________________________________________ References: 3 Key Student, (n.d.) PWR Simulator. https://www.3keystudent.com/ Engineering Fundamentals, (n.d.). Saturated Steam Table. https://www.efunda.com/materials/water/steamtable_sat.cfm