Innovations on life management of VVER reactor pressure vessels

Jyrki Kohopää, Antero Tamminen, Matti Valo, Jussi Solin

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


    The embrittlement rate of the pressure vessel weld material is a dominating factor in life management of VVER reactor pressure vessels. In order to maintain adequate safety level, several backfitting measures have been performed in Loviisa. The neutron flux and embrittlement rate was reduced after receiving the first indications of anticipated problems. An increase of emergency core cooling water temperature and other process related changes followed to eliminate and reduce potential transients. Finally, the core weld of Loviisa 1 was successfully annealed in 1996. A current concern is to verify the post-annealing embrittlement rate in order to enable safe and economic life management of the RPV. Post-annealing re-embrittlement is governed by somewhat different mechanisms than the embrittlement of the first irradiation cycle. A new tentative approach for predicting the re-embrittlement rate has been proposed.
    Original languageEnglish
    Title of host publication Plant Life Management
    Subtitle of host publicationMidterm status of a R&D project
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    ISBN (Electronic)951-38-5728-X
    ISBN (Print)951-38-5727-1
    Publication statusPublished - 2001
    MoE publication typeA4 Article in a conference publication
    EventPlant Life Management: Midterm status of a R&D project - Espoo, Finland
    Duration: 1 Jan 20011 Jan 2001

    Publication series

    SeriesVTT Symposium


    ConferencePlant Life Management


    • innovation


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