Numerical analysis for microstructure change of a light water reactor fuel pellet at high burnup

Journal Article · Wed Jun 01 04:00:00 EDT 1994 · Nuclear Technology; (United States)

OSTI ID:7039867

Kameyama, Takanori; Matsumura, Tetsuo; Kinoshita, Motoyasu ^[1]

---

1. Central Research Institute of Electric Power Industry, Tokyo (Japan)

The peripheral region of a high burnup light water reactor (LWR) fuel pellet shows a microstructure that is different from the as-fabricated microstructure. The region where the microstructure change occurs (the rim region) is highly porous, and the original grains in the rim region are divided into much smaller subgrains. The electron probe microanalysis data of high burnup fuels indicate fission gas depletion in the rim region as well as in the central region. The burnup in the rim region is enhanced by built-up plutonium derived from a [sup 238]U self-shielding effect, which is called a rim effect. The rim effect accelerates microstructure change in the peripheral region. The authors developed a detailed burnup analysis code ANRB computing the rim effect in LWR fuels. The authors have verified the ANRB code performance with the data of the High Burnup Effects Program. The analysis shows that the microstructure change occurs where local burnup gets to the threshold burnup of 70 to 80 MWd/kg U in both pressurized water reactor and boiling water reactor types of fuels. The threshold burnup never changes with the plutonium/uranium burnup ratio or fission rate during the irradiation. The storage of radiation damage is expected to cause the microstructure change.

• OSTI ID: 7039867
• Journal Information: Nuclear Technology; (United States), Journal Name: Nuclear Technology; (United States) Vol. 106:3; ISSN 0029-5450; ISSN NUTYBB
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100* -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
210200 -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
A CODES
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BURNUP
BWR TYPE REACTORS
COMPUTER CODES
ENERGY SOURCES
ENRICHED URANIUM REACTORS
EVEN-EVEN NUCLEI
FUEL PELLETS
FUELS
HEAVY NUCLEI
ISOTOPES
MATERIALS
MICROSTRUCTURE
NUCLEAR FUELS
NUCLEI
PELLETS
PHYSICAL RADIATION EFFECTS
POWER REACTORS
PWR TYPE REACTORS
RADIATION EFFECTS
RADIOISOTOPES
REACTOR MATERIALS
REACTORS
SPONTANEOUS FISSION RADIOISOTOPES
THERMAL REACTORS
URANIUM 238
URANIUM ISOTOPES
WATER COOLED REACTORS
WATER MODERATED REACTORS
YEARS LIVING RADIOISOTOPES