Publication detail

TEM RADIATION DAMAGE INVESTIGATION OF NEUTRON IRRADIATED BAFFLE-TO-FORMER BOLT EXTRACTED FROM A DECOMMISSIONED WWER-440 REACTOR

MICHALIČKA, J. KEILOVÁ, E. KOČÍK, J.

Czech title

TEM radiačního poškození neutrony ozářeného šroubu ze spoje hraněný plech-hraněný pás vyňatého z odstaveného reaktoru WWER-440

English title

TEM RADIATION DAMAGE INVESTIGATION OF NEUTRON IRRADIATED BAFFLE-TO-FORMER BOLT EXTRACTED FROM A DECOMMISSIONED WWER-440 REACTOR

Type

conference paper

Language

en

Original abstract

This study shows results of a radiation microstructure investigation of the baffle-to-former bolt irradiated to 11.4 dpa in real in-service LWR conditions of decommissioned WWER-440 reactor from Greifswald, Germany. The influence of temperature and dose gradients along the bolt was taken into account in the investigation of radiation defects evolution. Since an irradiation temperature about 270C in the bolt head is expected, a significantly higher temperature about 398C is predicted in the end of the bolt due to gamma heating. Also a continuous decrease of neutron dose and dose rate from bolt head towards the bottom of the bolt is present. Three positions along the bolt shank were investigated by TEM: one in each side, and one in the middle of the shank, respectively. Each position was experienced by different irradiation conditions. The TEM observations showed a presence of several radiation-induced defects: Frank dislocation loops, cavities, and Ni-Si rich precipitates. Since the population of Frank loops showed saturated state in each position, the population of cavities and radiation-induced precipitates ascertained specific evolution relatively to irradiation conditions present in particular position of investigation.

Czech abstract

Tato studie pojednává o mikrostruktuře radiačního poškození šroubu ze spoje hraněný plech-hraněný pás ozářeného na neutronovou dávku 11.4 dpa v reálných provozních podmínkách LWR vyřazeného reaktoru WWER-440 z Geifswaldu, Německo. Při studii evoluce radiačních defektů byl brán zřetel na vliv gradientu ozařovací teploty a neutronové dávky. V hlavičce studovaného šroubu byla teplota kolem 270C, nicméně podstatně vyšší teplota kolem 398C byla výpočtem predikována na konci šroubu díky ohřevu gama zářením. Zároveň docházelo k postupnému poklesu neutronové dávky a dávkového příkonu směrem od hlavičky ke konci šroubu. Tři pozice podél dříku šroubu byly proto zkoumány pomocí TEM: jedna na každém konci a jedna uprostřed dříku. Každá pozice byla ozařována za různých podmínek. TEM pozorováním se zjistila přítomnost následujících radiačně indukovaných defektů: Frankových dislokačních smyček, kavit a radiačně indukovaných precipitátů. Frankovy smyčky byly v saturovaném stavu ve všech třech pozicích, nicméně u kavit a u radiačně indukovaných precipitátů byl zjištěna specifická evoluce relativně k ozařovacím podmínkám v příslušné zkoumané pozici.

English abstract

This study shows results of a radiation microstructure investigation of the baffle-to-former bolt irradiated to 11.4 dpa in real in-service LWR conditions of decommissioned WWER-440 reactor from Greifswald, Germany. The influence of temperature and dose gradients along the bolt was taken into account in the investigation of radiation defects evolution. Since an irradiation temperature about 270C in the bolt head is expected, a significantly higher temperature about 398C is predicted in the end of the bolt due to gamma heating. Also a continuous decrease of neutron dose and dose rate from bolt head towards the bottom of the bolt is present. Three positions along the bolt shank were investigated by TEM: one in each side, and one in the middle of the shank, respectively. Each position was experienced by different irradiation conditions. The TEM observations showed a presence of several radiation-induced defects: Frank dislocation loops, cavities, and Ni-Si rich precipitates. Since the population of Frank loops showed saturated state in each position, the population of cavities and radiation-induced precipitates ascertained specific evolution relatively to irradiation conditions present in particular position of investigation.

Keywords in Czech

TEM, neutronové ozařování, radiačně-indukované defekty, Frankovy dislokační smyčky, kavity, bobtnání, radiačně-indukované precipitáty, ozařovací teplota, dávka, dávkový příkon, gama ohřev

Keywords in English

TEM, neutron irradiation, radiation-induced defects, Frank dislocation loops, cavities, swelling, radiation-induced precipitates, irradiation temperature, dose rate, gamma heating

RIV year

2014

Released

04.04.2014

ISBN

9781510819238

Book

Proceeding of NACE 16th Environmental Degradation Conference of Materials in Nuclear Power Systems – Water Reactors

Edition number

1

Pages from–to

1–17

Pages count

17

BIBTEX


@inproceedings{BUT102652,
  author="Jan {Michalička} and Eliška {Keilová} and Jan {Kočík},
  title="TEM RADIATION DAMAGE INVESTIGATION OF NEUTRON IRRADIATED BAFFLE-TO-FORMER BOLT EXTRACTED FROM A DECOMMISSIONED WWER-440 REACTOR",
  booktitle="Proceeding of NACE 16th Environmental Degradation Conference of Materials in Nuclear Power Systems – Water Reactors",
  year="2014",
  month="April",
  pages="1--17",
  isbn="9781510819238"
}