Greifswald VVER-440 RPV investigations: Neutron dosimetry and material tests


Greifswald VVER-440 RPV investigations: Neutron dosimetry and material tests

Konheiser, J.; Viehrig, H.-W.; Rindelhardt, U.; Noack, K.; Gleisberg, B.

The Greifswald NPP was operated between 1973 and 1990. The units are of Russian WWER-440-230 type. Now trepans from the RPV were gained to investigate the post mortem properties of the material.
The paper describes the results of weld metal originating from the critical weld of the RPV of unit 1. The RPV of this unit was annealed after 14 years of operation, followed by two additional years of operation.
The neutron dosimetry was based on fluence calculations as well as retrospective Nb dosimetry. Both approaches are shortly described. A decrease of 60% through the thickness of the RPV was found by both methods.
The ongoing material test results comprise Charpy-V, tensile and fracture toughness parameters. The main interest is focussed on the comparison of assessment codes applied in Russia and other European countries where WWER-440 reactors are operated. An additional aspect is the comparison of results determined on sub-size Charpy specimens after the annealing procedure. The RPV of Greifswald Unit 1 is uncladded. After the annealing templates of weld metal were taken from the inner RPV wall. The toughness of the weld metal was measured with sub size Charpy specimens.

Keywords: Reactor pressure vessel; neutron embrittlement

  • Contribution to proceedings
    5th International Conference: Safety Assurance of NPP with WWER, 29.05.-01.06.2007, Podolsk, Russia
    Conference Proceedings, paper 137
  • Lecture (Conference)
    5th International Conference: Safety Assurance of NPP with WWER, 29.05.-01.06.2007, Podolsk, Russia

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