Patent · US Expired

Element immersed in coolant of nuclear reactor

US4938918A · kind A · utility

5Cited by
12References
7Claims
0Family size

Assignee

Inventor

Key dates

Filing dateSep 11, 1989
Grant dateJul 3, 1990
Priority date
Expiry dateSep 11, 2009

Classification

  • Technology area (CPC Y)Emerging Cross-Sectional Technologies
  • CPC primaryY10T29/49929
  • WIPO fieldEngines, pumps, turbines
  • WIPO sectorMechanical engineering

Abstract

The zirconium cladding of a coolant-displacement rod of a nuclear reactor is precollapsed in the zirconium oxide stack of pellets which supports the cladding. Current is conducted through the cladding in an atmosphere at reduced pressure containing residual oxygen, to heat the cladding to a temperature at which its yield strength is reduced. Then, while the rod remains at this temperature, it is subjected to isostatic pressure which collapses the cladding uniformly. The formation, by reason of exposure to neutron flux, of a long unsupported gap in the cladding which might be collapsed under the pressure of the coolant is precluded. In addition, the rod retains its symmetry. The outer surface of the cladding is oxidized, facilitating the movement of the rod into its thimbles of the core and improving the resistances of the cladding to reaction with the coolant.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.