Utredning av högnivålarm i dränagetank på Ringhals 1
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The problem with high water level alarm that led to power shutdown did first occurred on the 3rd of May 2008 at Ringhals 1. In the beginning there was a theory that boiling triggered the measurement system that consists of a floating switch, it has not been verified if the alarm was triggered by steam or liquid.During the investigation process data was collected from Vattenfalls’ information systems and a RELAP5 model of the drainage system. This model was built with the purpose of simulating different scenario and to gather data that Vattenfall was lacking.It was first stated from Vattenfall that power shutdown was avoided on the 9th of May due to opening a valve more gradually. Analyzes comparing the cases 3rd of May and 9th of May show that the conditions was not equal enough to make the conclusion.Model simulations show that both super heaters take half of the mass flow (assuming negligible differences) from the high pressure turbine under all circumstances, therefore the crossflow pipe takes the other half in cases on the 3rd and 9th of May 2008. A theory that one of the super heaters at 3rd of May was overloaded is not the case according to the model.Liquid that was accumulated and dumped from pipe systems and then triggered the high level alarm was investigated. Results show that the pipe system after the drainage tank can acquire enough water if it is assumed that the water is pushed up into the tank from a back flow.The main goal should be to examine the measured data that occurs more than 3 hours before the high level alarm is triggered and caused a power shutdown at 3rd of May. This due to the fact that no unusual data for the 9th of May was observed.
Place, publisher, year, edition, pages
2013. , 100 p.
Teknik, Ringhals, dränagetank, kärnkraft, reaktor
IdentifiersURN: urn:nbn:se:ltu:diva-57134Local ID: dd3254c9-4566-4199-a77b-9cffe66a377aOAI: oai:DiVA.org:ltu-57134DiVA: diva2:1030521
Subject / course
Student thesis, at least 30 credits
Mechanical Engineering, master's level
Validerat; 20130612 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved