1. COLLEGE OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING MENB 403 - INTRODUCTION TO NUCLEAR ENGINEERING GROUP ASSIGNMENT GROUP MEMBERS: MOHD DZAFIR TAJUL URUS ME086708 MOHD NOR QUIYYUM MAT JAMIL ME086654 MUHAMMAD RASHIDI MANSOR ME086651 LECTURER: ASSOC. PROF. DR. NASRI A. HAMID

2. PRESENTATION OVERVIEW -The assignment consists of 4 questions -The main topic is regarding the mechanism inside the reactor

3. 1) DESCRIBE THE TEMPERATURE DISTRIBUTION IN A FUEL PELLET Assumption: Axial heat conduction was negligible. Thermal conductivity in the fuel pellet and the cladding depended on the temperature. Volumetric heat capacity and density of fuel pellet and cladding were temperature dependent. Volumetric heat generation was uniformly distributed axially over the fuel pellet cross-section.

4. Heat Transfer Geometry in Nuclear Fuel Pellet

5. Evaluating radial heat conduction within the fuel pellet. Heat generated in fuel pellet radius R. Heat flows radially through the fuel, the pellet cladding gap, and the cladding to reach the coolant. Heat transfer through the cladding is achieved by conduction. The radial flow of heat in a cylindrical fuel tube was obtained by considering a heat balance; thickness and unit length. As the reactor been shut down, the radial temperature distribution decayed as function of time. (H = 0)

6. 2) EXPLAIN HOW HEAT IS TRANSFERRED FROM FUEL SURFACE TO THE COOLANT AND MODERATOR  Heat conduction is transferred the thermal energy released by fission in the fuel rods to the surface of the rod and then by convection to the coolant that circulates around the rods.  Fissionable material which is used to heat a thermal transfer fluid undergo chain reaction that will generate energy.  In the reactor core, nuclei that are unstable and heavy will break down into lighter fission outcomes from the bombardment fissile of neutrons. From the collisions of lighter nuclei with other atoms, it generates heat.

7.  The coolant fluid passing through the core functions as a prevention of overheating and act as thermal reservoir to remove and transfer heat to the turbines.  Moderator is being used to have a higher reaction of fission. It decreases the speed of neutron by absorbing its energy and the heat is transferred.  Heat conduction is then transferred to the surface of the rod. Besides that, there is another heat conduction occur through cladding.  Finally, heat is transferred to the coolant circulating through the core which around the rods by heat convection.

10. 3) HOW THERMAL ENERGY IS DELIVERED TO THE EXTERNAL LOOP IN A PRESSURIZED WATER REACTOR (PWR) SYSTEM. Thermal energy is delivered to the external loop in a Pressurized Water Reactor (PWR) system by the steam generator. Steam generators are heat exchangers used to convert water into steam from heat produced in a nuclear reactor core. They are used in pressurized water reactors (PWR) between the primary and secondary coolant loops.

11. PRIMARY LOOP Heat transfer takes place between the reactor core and the circulating water and the coolant is then pumped through the primary tube side of the steam generator by coolant pumps before returning to the reactor core. This is referred to as the primary loop.

12. SECONDARY LOOP That water flowing through the steam generator boils water on the shell side to produce steam in the secondary loop that is delivered to the turbines to make electricity.

13. TERTIARY LOOP The steam is subsequently condensed via cooled water from the tertiary loop and returned to the steam generator to be heated once again. The tertiary cooling water may be recirculated to cooling towers where it minimize waste heat before returning to condense more steam