Published 2015 | Version v1
Miscellaneous Restricted

Fission gas release of MOX with heterogeneous structure

Creators

  • 1. Nuclear Energy System Safety Division, Japan Nuclear Safety Organization, Toranomon Towers Office, 4-1-28, Toranomon, Minato-ku, Tokyo, 105-0001 (Japan)
  • 2. Studiecentrum voor Kernenergie, Centre d'Etude de l'Energie Nucleaire, Boeretang 200, B-2400 MOL (Belgium)
  • 3. Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1, Iwado Kita, Komae-shi, Tokyo 201-8511 (Japan)
  • 4. Japan Nuclear Energy Safety Organization, 17-1, Toranomon 3-chome, Minatu-ku, Tokyo 105-0001 (Japan)

Description

It is very useful for fuel integrity evaluation to accumulate knowledge base on fuel behavior of uranium and plutonium mixed oxide (MOX) fuel used in light water reactors (LWRs). Fission gas release is one of fuel behaviors which have an impact on fuel integrity evaluation. Fission gas release behavior of MOX fuels having heterogeneous structure is focused in this study. MOX fuel rods with a heterogeneous fuel microstructure were irradiated in Halden reactor (IFA-702) and the BR-3/BR-2 CALLISTO Loop (CHIPS program). The 85Kr gamma spectrometry measurements were carried out in specific cycles in order to examine the concerned LHR (Linear Heat Rate) for fission gas release in the CHIPS program. The concerned LHR is defined in this paper to be the LHR at which a certain additional fission gas release thermally occurs. Post-irradiation examination was performed to understand the fission gas release behavior in connection with the pellet microstructure. The followings conclusions can be made from this study. First, the concerned LHR for fission gas release is estimated to be in the range of 20-23 kW/m with burnup over 37 GWd/tM. It is moreover guessed that the concerned LHR for fission gas release tends to decrease with increasing burnup. Secondly It is observed that FGR (fission gas release rate) is positively correlated with LHR when the LHR exceeds the concerned value. Thirdly, when burnup dependence of fission gas release is discussed, effective burnup should be taken into account. The effective burnup is defined as the burnup at which the LHR should be exceed the concerned value at the last time during all the irradiation period. And fourthly, it appears that FGR inside Pu spots is higher than outside and that retained (not released) fission gases mainly exist in the fission gas bubbles. Since fission gases in bubbles are considered to be easily released during fuel temperature increase, this information is very important to estimate fission gas release behavior during not only normal operation, but also accident such as reactivity initiated accident - RIA

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Additional details

Identifiers

URL
http://www.iaea.org/INIS/contacts/;

Publishing Information

Imprint Pagination
36 p.
Report number
INIS-FR--15-0410

Conference

Title
Conference on Contribution of Materials Investigations and Operating Experience to LWRs' Safety, Performance and Reliability
Acronym
Fontevraud 8
Dates
15-18 Sep 2014
Place
Avignon (France)

INIS

Country of Publication
France
Country of Input or Organization
France
INIS RN
46081707
Subject category
S21: SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS;
Resource subtype / Literary indicator
Conference
Descriptors DEI
FISSION PRODUCT RELEASE; KRYPTON 85; MIXED OXIDE FUELS; PLUTONIUM DIOXIDE; POST-IRRADIATION EXAMINATION; WATER COOLED REACTORS
Descriptors DEC
ACTINIDE COMPOUNDS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CHALCOGENIDES; ENERGY SOURCES; EVEN-ODD NUCLEI; FUELS; HOURS LIVING RADIOISOTOPES; INTERMEDIATE MASS NUCLEI; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; KRYPTON ISOTOPES; MATERIALS; MICROSECONDS LIVING RADIOISOTOPES; NUCLEAR FUELS; NUCLEI; OXIDES; OXYGEN COMPOUNDS; PLUTONIUM COMPOUNDS; PLUTONIUM OXIDES; RADIOISOTOPES; REACTOR MATERIALS; REACTORS; SOLID FUELS; TRANSURANIUM COMPOUNDS; YEARS LIVING RADIOISOTOPES

Optional Information

Notes
8 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS website for current contact and E-mail addresses: http://www.iaea.org/INIS/contacts/