US 12,347,579 B2
Method for monitoring a nuclear core comprising a relaxation of a threshold, and associated programme, support and nuclear reactor
Christian Royere, Clamart (FR); and Christophe Lasne, Puteaux (FR)
Assigned to FRAMATOME, Courbevoie (FR)
Appl. No. 16/634,365
Filed by FRAMATOME, Courbevoie (FR)
PCT Filed Jul. 30, 2018, PCT No. PCT/EP2018/070608
§ 371(c)(1), (2) Date Jan. 27, 2020,
PCT Pub. No. WO2019/020836, PCT Pub. Date Jan. 31, 2019.
Claims priority of application No. FR 17 57237 (FR), filed on Jul. 28, 2017.
Prior Publication US 2021/0098139 A1, Apr. 1, 2021
Int. Cl. G21D 3/08 (2006.01); G21C 3/04 (2006.01); G21C 7/00 (2006.01); G21C 7/36 (2006.01)
CPC G21D 3/08 (2013.01) [G21C 3/047 (2019.01); G21C 7/00 (2013.01); G21C 7/36 (2013.01)] 19 Claims
 
1. A method for monitoring a nuclear reactor comprising a core in which fuel assemblies are loaded, each fuel assembly comprising nuclear fuel rods each including nuclear fuel pellets and a cladding surrounding the nuclear fuel pellets, the method comprising the following steps:
determining at least one operating time limit for an operation at a reduced power of the nuclear reactor, so as to avoid a rupture of at least one of the claddings, the reduced power being inferior or equal to 92% of a nominal power of the nuclear reactor;
operating the nuclear reactor at the reduced power for an actual time strictly less than the operating time limit;
measuring and/or calculating a distribution of a linear power at any point of the core as a function of time;
relaxing a threshold linear power of the nuclear reactor as a function of a difference between the operating time limit and the actual time, the threshold linear power being a threshold of the linear power at any point of the core below which a rupture by Pellet/Cladding Interaction is avoided; and
further operating the nuclear reactor at the reduced power according to the threshold linear power from the relaxing step.