Method and device for operating a reactor in an unstable state

US5978429A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Dieter Kreuter · Rödermark, DE
• Godehard Rauch · Rodgau, DE
• Joachim Schulze · Soest, DE

Key dates

• Filing date: Nov 4, 1998
• Grant date: Nov 2, 1999
• Expiry date: Nov 4, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E30/30
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A transiently unstable state of a boiling-water reactor is damped by measuring the oscillating neutron flux and, after a first threshold value is exceeded over a plurality of oscillation periods, the rate of increase of the oscillation is determined. Depending on the slope of the increase, and after a further threshold value (in particular one dependent on the rate of increase) for the oscillating flux is exceeded, a selection is made which one of various stabilization strategies for damping the oscillation should be triggered before a SCRAM becomes necessary. A hierarchy of stabilization strategies is available: blocking a power increase, for instance, in the control system, controlled slow reduction of the power, or rapid power reduction by a "partial SCRAM". The monitoring of the unstable state is effected with a system of sensors strategically distributed throughout the core and which redundantly measure the flux in one region of the core. The sensors act on a plurality of redundantly operating systems, and the signal from each sensor is effective in only one of the redundant systems.