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

Abstract

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
Pages107-126
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

NameVTT Symposium
PublisherVTT
Number218
ISSN (Print)0357-9387
ISSN (Electronic)1455-0873

Conference

ConferencePlant Life Management
CountryFinland
CityEspoo
Period1/01/011/01/01

Fingerprint

Embrittlement
Pressure vessels
Innovation
Welds
Annealing
Neutron flux
Cooling water
Irradiation
Economics

Keywords

  • innovation

Cite this

Kohopää, J., Tamminen, A., Valo, M., & Solin, J. (2001). Innovations on life management of VVER reactor pressure vessels. In  Plant Life Management: Midterm status of a R&D project (pp. 107-126). Espoo: VTT Technical Research Centre of Finland. VTT Symposium, No. 218
Kohopää, Jyrki ; Tamminen, Antero ; Valo, Matti ; Solin, Jussi. / Innovations on life management of VVER reactor pressure vessels.  Plant Life Management: Midterm status of a R&D project. Espoo : VTT Technical Research Centre of Finland, 2001. pp. 107-126 (VTT Symposium; No. 218).
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Kohopää, J, Tamminen, A, Valo, M & Solin, J 2001, Innovations on life management of VVER reactor pressure vessels. in  Plant Life Management: Midterm status of a R&D project. VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 218, pp. 107-126, Plant Life Management, Espoo, Finland, 1/01/01.

Innovations on life management of VVER reactor pressure vessels. / Kohopää, Jyrki; Tamminen, Antero; Valo, Matti; Solin, Jussi.

 Plant Life Management: Midterm status of a R&D project. Espoo : VTT Technical Research Centre of Finland, 2001. p. 107-126 (VTT Symposium; No. 218).

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

TY - GEN

T1 - Innovations on life management of VVER reactor pressure vessels

AU - Kohopää, Jyrki

AU - Tamminen, Antero

AU - Valo, Matti

AU - Solin, Jussi

PY - 2001

Y1 - 2001

N2 - 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.

AB - 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.

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M3 - Conference article in proceedings

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BT -  Plant Life Management

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Kohopää J, Tamminen A, Valo M, Solin J. Innovations on life management of VVER reactor pressure vessels. In  Plant Life Management: Midterm status of a R&D project. Espoo: VTT Technical Research Centre of Finland. 2001. p. 107-126. (VTT Symposium; No. 218).