In conjunction with each refueling or other significant reactor core alternation, reactor startup physics tests are required to determine if the operating characteristics of the core are consistent with the core design calculations (pre-calculated). Therefore key nuclear safety parameters must be also verified experimentally during physics tests at low power.
Key nuclear safety parameters are selected as a minimal set of parameters that describes the behaviour of a reactor core during transients and accidents assumed in safety analyses (SAR).
The set of key nuclear safety parameters selected for low power physics tests includes:
- Reactivity balance
- Measurement of critical boron concentration
- Flux symmetry measurements
- Reactivity coefficients such as:
- Reactivity control:
- Control rod worths
- Immediate reactivity after reactor trip
Following the low power physics tests, the power distribution must be verified. Power distribution tests are performed at higher power levels (e.g. between 30% – 50% of rated power).
See also: Initial Test Programs for Water-cooled Nuclear Power Plants, Regulatory Guide 1.68, U. S. Nuclear Regulatory Commission, June 2013.
See also: Reload startup physics tests for pressurized water reactor, American National Standard, ANSI/ANS – 19.6.1-2011, January 2011.