• chws1b
• iter
• waterhammer

The aim of this work is to carry out a water hammer analysis for ITER Chilled Water System 1B (CHWS-1B). A complete methodology was developed to finalize this task. The first step of this methodology consists of deriving the most probable transient events, considering all the possible normal and severe water hammers that could occur at the nominal working conditions of CHWS-1B. This step is the so-called “screening analysis” that allows to derive a test-case matrix of all the scenarios that must be implemented and run inside the model developed inside AFT Impulse. In order to develop this model, some design parameters, important for transient conditions, must be derived. These parameters are of great importance for the correct simulation of the system behavior under transient conditions and, being transient parameters, they are not provided by any system components’ manufacturer. For this reason, this work will also provide a description on how to derive IV quadrants’ pumps characteristics, pumps with its motor inertia and valve closure characteristics, together with a brief description on how to implement them inside the code. Once the transient model is developed, it is, in a first step, run in steady state conditions to assess it, comparing the steady state results with those of other dedicated steady-state code such as AFT Fathom. All the test cases are then run by this code that, through the characteristic method, solves the water hammer equations and permits to derive the time evolution of the most important thermal-hydraulic parameters inside the system. Based on these results, it is evaluated the capability of the CHWS to withstand those transient events and, if, for any reason, design conditions are exceeded, suggestions for variations in the preliminary plant design are provided.