skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: FABRICATION OF THE MOLTEN-SALT REACTOR EXPERIMENT HEAT EXCHANGER CORE INVOLVES A NOVEL WELDED AND BACK-BRAZED JOINT DESIGN FOR TUBE-TO-TUBE SHEET JOINTS

Abstract

The INOR-8 tube bundle of the primary heat exchanger of the Molten-Salt Reactor Experiment contains 163 1/2 in. dia x 0.042 in. wall U-tubes welded to a 1 1/2 in. thick tube sheet 18 in. in dia. Procedures were successfully developed for welding and back brazing the 326 closely spaced tube-to-tube sheet joints in the unit, and the actual tube bundle was fabricated without incident. The welded and back-brazed design provides a double seal between the fuel and coolant salts and was used because of the necessity for high joint integrity. Trepan grooves were machined in the weld side of the tube sheet so that lowrestraint edge-type welds could be made. This technique greatly reduces the cracking problems associated with welding thin-walled tubes to thick tube sheets. Welding and assembly procedures were developed, which provided welds of high quality with a minimung of roll-over. The 82 Au--18 Ni (wt. %) brazing alloy used is corrosion resistant, ductile, and produces joints exhibiting satisfactory mechanical strength. A unique joint design incorporating a trepan groove and feeder holes was used for the braze side, the purpose being to prevent preferential flow of alloy on the relatively thin-walled tubes. After the determination of exactmore » welding and brazing conditions on several subsize and full-size mockup samples, the actual unit was constructed. Nondestructive inspection of the welds revealed no defects. Good general flow of the brazing alloy was evident, and ultrasonic examination of brazed joints showed only minor scattered porosity. The completed unit passed both helium leak and 800 psi hydrostatic tests. (auth)« less

Authors:
;
Publication Date:
Research Org.:
Oak Ridge National Lab., Tenn.
OSTI Identifier:
4083229
NSA Number:
NSA-18-010512
Resource Type:
Journal Article
Journal Name:
Welding J. (N.Y.)
Additional Journal Information:
Journal Volume: Vol: 43; Other Information: Orig. Receipt Date: 31-DEC-64
Country of Publication:
Country unknown/Code not available
Language:
English
Subject:
METALS, CERAMICS, AND OTHER MATERIALS; ALLOYS; BRAZING; CHROMIUM ALLOYS; COOLANTS; CORROSION; CRACKS; DEFECTS; DUCTILITY; FABRICATION; FUELS; FUSED SALTS; GOLD ALLOYS; HEAT EXCHANGERS; HELIUM; INOR-8; JOINTS; MATERIALS TESTING; MECHANICAL PROPERTIES; MOLYBDENUM ALLOYS; NICKEL ALLOYS; PLANNING; POROSITY; PRESSURE; QUANTITATIVE ANALYSIS; SEALS; SHEETS; STABILITY; THICKNESS; TUBES; ULTRASONICS; WELDING; WELDS

Citation Formats

Donnelly, R G, and Slaughter, G M. FABRICATION OF THE MOLTEN-SALT REACTOR EXPERIMENT HEAT EXCHANGER CORE INVOLVES A NOVEL WELDED AND BACK-BRAZED JOINT DESIGN FOR TUBE-TO-TUBE SHEET JOINTS. Country unknown/Code not available: N. p., 1964. Web.
Donnelly, R G, & Slaughter, G M. FABRICATION OF THE MOLTEN-SALT REACTOR EXPERIMENT HEAT EXCHANGER CORE INVOLVES A NOVEL WELDED AND BACK-BRAZED JOINT DESIGN FOR TUBE-TO-TUBE SHEET JOINTS. Country unknown/Code not available.
Donnelly, R G, and Slaughter, G M. 1964. "FABRICATION OF THE MOLTEN-SALT REACTOR EXPERIMENT HEAT EXCHANGER CORE INVOLVES A NOVEL WELDED AND BACK-BRAZED JOINT DESIGN FOR TUBE-TO-TUBE SHEET JOINTS". Country unknown/Code not available.
@article{osti_4083229,
title = {FABRICATION OF THE MOLTEN-SALT REACTOR EXPERIMENT HEAT EXCHANGER CORE INVOLVES A NOVEL WELDED AND BACK-BRAZED JOINT DESIGN FOR TUBE-TO-TUBE SHEET JOINTS},
author = {Donnelly, R G and Slaughter, G M},
abstractNote = {The INOR-8 tube bundle of the primary heat exchanger of the Molten-Salt Reactor Experiment contains 163 1/2 in. dia x 0.042 in. wall U-tubes welded to a 1 1/2 in. thick tube sheet 18 in. in dia. Procedures were successfully developed for welding and back brazing the 326 closely spaced tube-to-tube sheet joints in the unit, and the actual tube bundle was fabricated without incident. The welded and back-brazed design provides a double seal between the fuel and coolant salts and was used because of the necessity for high joint integrity. Trepan grooves were machined in the weld side of the tube sheet so that lowrestraint edge-type welds could be made. This technique greatly reduces the cracking problems associated with welding thin-walled tubes to thick tube sheets. Welding and assembly procedures were developed, which provided welds of high quality with a minimung of roll-over. The 82 Au--18 Ni (wt. %) brazing alloy used is corrosion resistant, ductile, and produces joints exhibiting satisfactory mechanical strength. A unique joint design incorporating a trepan groove and feeder holes was used for the braze side, the purpose being to prevent preferential flow of alloy on the relatively thin-walled tubes. After the determination of exact welding and brazing conditions on several subsize and full-size mockup samples, the actual unit was constructed. Nondestructive inspection of the welds revealed no defects. Good general flow of the brazing alloy was evident, and ultrasonic examination of brazed joints showed only minor scattered porosity. The completed unit passed both helium leak and 800 psi hydrostatic tests. (auth)},
doi = {},
url = {https://www.osti.gov/biblio/4083229}, journal = {Welding J. (N.Y.)},
number = ,
volume = Vol: 43,
place = {Country unknown/Code not available},
year = {Sat Feb 01 00:00:00 EST 1964},
month = {Sat Feb 01 00:00:00 EST 1964}
}