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Title: Examination of stainless steel-clad Connecticut Yankee fuel assembly S004 after storage in borated water

Abstract

A Connecticut Yankee fuel assembly (S004) was tested nondestructively and destructively. It was concluded that no obvious degradation of the 304L stainless steel-clad spent fuel from assembly S004 occurred during 5 y of storage in borated water. Furthermore, no obvious degradation due to the pool environment occurred on 304 stainless steel-clad rods in assemblies H07 and G11, which were stored for shorter periods but contained operationally induced cladding defects. The seam welds in the cladding on fuel rods from assembly S004, H07, and G11 were similar in that they showed a wrought microstructure with grains noticeably smaller than those in the cladding base metal. The end cap welds showed a dendritically cored structure, typical of rapidly quenched austenitic weld metal. Some intergranular melting may have occurred in the heat-affected zone (HAZ) in the cladding adjacent to the end cap welds in rods from assemblies S004 and H07. However, the weld areas did not show evidence of corrosion-induced degradation.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest Lab., Richland, WA (USA)
OSTI Identifier:
6793529
Alternate Identifier(s):
OSTI ID: 6793529; Legacy ID: DE83000301
Report Number(s):
PNL-3828
ON: DE83000301
DOE Contract Number:
AC06-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; CONNECTICUT YANKEE REACTOR; SPENT FUEL ELEMENTS; DESTRUCTIVE TESTING; NONDESTRUCTIVE TESTING; BURNUP; CORROSION; EDDY CURRENT TESTING; EXPERIMENTAL DATA; FISSION PRODUCTS; FUEL ASSEMBLIES; FUEL RODS; GAMMA FUEL SCANNING; INSPECTION; MECHANICAL TESTS; METALLOGRAPHY; MICROSTRUCTURE; SPENT FUEL STORAGE; STAINLESS STEEL-304; ALLOYS; CHEMICAL REACTIONS; CHROMIUM ALLOYS; CHROMIUM STEELS; CHROMIUM-NICKEL STEELS; CORROSION RESISTANT ALLOYS; CRYSTAL STRUCTURE; DATA; ELECTROMAGNETIC TESTING; ENRICHED URANIUM REACTORS; FUEL ELEMENTS; FUEL SCANNING; GAMMA RADIOGRAPHY; HEAT RESISTANT MATERIALS; HEAT RESISTING ALLOYS; INDUSTRIAL RADIOGRAPHY; INFORMATION; IRON ALLOYS; IRON BASE ALLOYS; ISOTOPES; MATERIALS; MATERIALS TESTING; NICKEL ALLOYS; NUMERICAL DATA; POWER REACTORS; PWR TYPE REACTORS; RADIOACTIVE MATERIALS; REACTOR COMPONENTS; REACTORS; STAINLESS STEELS; STEELS; STORAGE; TESTING; THERMAL REACTORS; WATER COOLED REACTORS; WATER MODERATED REACTORS 210200* -- Power Reactors, Nonbreeding, Light-Water Moderated, Nonboiling Water Cooled

Citation Formats

Langstaff, D.C., Bailey, W.J., Johnson, A.B. Jr., Landow, M.P., Pasupathi, V., and Klingensmith, R.W. Examination of stainless steel-clad Connecticut Yankee fuel assembly S004 after storage in borated water. United States: N. p., 1982. Web. doi:10.2172/6793529.
Langstaff, D.C., Bailey, W.J., Johnson, A.B. Jr., Landow, M.P., Pasupathi, V., & Klingensmith, R.W. Examination of stainless steel-clad Connecticut Yankee fuel assembly S004 after storage in borated water. United States. doi:10.2172/6793529.
Langstaff, D.C., Bailey, W.J., Johnson, A.B. Jr., Landow, M.P., Pasupathi, V., and Klingensmith, R.W. Wed . "Examination of stainless steel-clad Connecticut Yankee fuel assembly S004 after storage in borated water". United States. doi:10.2172/6793529. https://www.osti.gov/servlets/purl/6793529.
@article{osti_6793529,
title = {Examination of stainless steel-clad Connecticut Yankee fuel assembly S004 after storage in borated water},
author = {Langstaff, D.C. and Bailey, W.J. and Johnson, A.B. Jr. and Landow, M.P. and Pasupathi, V. and Klingensmith, R.W.},
abstractNote = {A Connecticut Yankee fuel assembly (S004) was tested nondestructively and destructively. It was concluded that no obvious degradation of the 304L stainless steel-clad spent fuel from assembly S004 occurred during 5 y of storage in borated water. Furthermore, no obvious degradation due to the pool environment occurred on 304 stainless steel-clad rods in assemblies H07 and G11, which were stored for shorter periods but contained operationally induced cladding defects. The seam welds in the cladding on fuel rods from assembly S004, H07, and G11 were similar in that they showed a wrought microstructure with grains noticeably smaller than those in the cladding base metal. The end cap welds showed a dendritically cored structure, typical of rapidly quenched austenitic weld metal. Some intergranular melting may have occurred in the heat-affected zone (HAZ) in the cladding adjacent to the end cap welds in rods from assemblies S004 and H07. However, the weld areas did not show evidence of corrosion-induced degradation.},
doi = {10.2172/6793529},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Sep 01 00:00:00 EDT 1982},
month = {Wed Sep 01 00:00:00 EDT 1982}
}

Technical Report:

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  • Significant levels of fuel rod failures were observed in the batch 8 fuel assemblies of the Connecticut Yankee reactor. Failure of 304 stainless steel cladding in a PWR environment was not expected. Therefore a detailed poolside and hot cell examination program was conducted to determine the cause of failure and identify differences between batch 8 fuel and previous batches which had operated without failures. Hot cell work conducted consisted of detailed nondestructive and destructive examination of fuel rods from batches 7 and 8. The results indicate that the batch 8 failure mechanism was stress corrosion cracking initiating on the cladmore » outer surface. The sources of cladding stresses are believed to be (a) fuel pellet chips wedged in the cladding gap, (b) swelling of highly nondensifying batch 8 fuel and (c) potentially harmful effects of a power change event that occurred near the end of the second cycle of irradiation for batch 8.« less
  • To aid in the analytical design of the core for the power reactor for the Yankee Atomic Electric Company, measurements have been made of various reactor parameters in a cold clean critical assembly of design similar to the power reactor. In order to better simulate the effects of large temperature changes in the core, three core configurations were studied having water/uranium ratios of 2.19, 2.93, and 3.87. The following measurements were made: critical size, buckling and reflector savings, migration area, disadvantage factor, and cadmium ratios. The resonance escape probability and fast fission factor were measurcd in the 2.93 and 3.87more » W/U cores. The effects on core reactivity of temperature, voids, insertion of control rods and of stainless steel were also measured. Neutron flux distributions in the core were deterrained in the neighborhood of control rods and through gaps and slots in the fuel configuration. Where applicable, the results of these measurements are correlated with the water/ uranium ratio. (auth)« less
  • EPRI is continuing to investigate the application of borated stainless steel products within the commercial nuclear power industry through participation in code development and material testing. This effort provides documentation of the material properties of interest in design applications utilizing the borated stainless steel products as structural elements as well as serving as neutron absorbers. The properties of most concern in the design of spent fuel storage racks, shipping casks, and other containment type applications are the materials' ductility, tensile strength, corrosion resistance and resistance to degradation due to radiation and temperature. The data presented in this report indicate thatmore » practical designs can be achieved utilizing borated stainless steels and that the materials can be cost effectively applied.« less
  • EPRI is continuing to investigate the application of borated stainless steel products within the commercial nuclear power industry through participation in code development and material testing. This effort provides documentation of the material properties of interest in design applications utilizing the borated stainless steel products as structural elements as well as serving as neutron absorbers. The properties of most concern in the design of spent fuel storage racks, shipping casks, and other containment type applications are the materials` ductility, tensile strength, corrosion resistance and resistance to degradation due to radiation and temperature. The data presented in this report indicate thatmore » practical designs can be achieved utilizing borated stainless steels and that the materials can be cost effectively applied.« less