PRINCIPAL RESULTS OF EXPERIMENTAL-COMMERCIAL OPERATION OF VVER-440 FUEL OF 3-D GENERATION, V. Saprykin, I. Yasnopolskaya, A.
23rd SYMPOSIUM of AER
on VVER Reactor Physics and Reactor Safety
September 30 – October 4, 2013, Strbske pleso, Slovakia
PRINCIPAL RESULTS OF EXPERIMENTAL ?COMMERCIAL OPERATION OF
VVER-440 FUEL OF 3-D GENERATION
V. V. Saprykin. A. A. Gagarinsky
NRC Kurchatov Institute, Moscow
On the Kola NPP, Unit 4 trial operation of the 3-rd generation fuel continues. This fuel have a
number of design features, providing the best operational characteristics [1, 2]. Increasing of
efficiency of nuclear fuel usage will be achieved by reduction of the parasitic capture of thermal
neutrons in constructional materials (weight of zirconium is reduced), optimization of uranium
water relation (increase in fuel elements step), increasing of uranium loading (usage of fuel
pallets with increased diameter and without central hole in them).
The basic characteristics of the core with fuel of the 3rd generation are provided in work
3. In the present report, being addition to the report 4, gave new results of operation and the
short analysis of the obtained data is made. Experimental characteristics of WWER-440 reactor
core with fuel assemblies of the 2nd (FA-2) and 3rd (FA-3) generation of the enrichment
increased to 4.87% are submitted. Some questions of operation of FA-2 and FA-3 are discussed:
assessment of influence of cover absence on indications of thermocouples at joint operation of
FA-2 and FA-3, features and methods of core design.
2. Purposes of trial operation.
Trial Operation is carried out with the purpose of confirmation of operability FA-3 during 7 fuel
cycles. Use of only 12 RK-3 is planned. Placement of RK-3 by symmetrically RK-2 of identical
enrichment, for comparison of their characteristics for various positions in core is supposed. As
result of trial operation using of these FA in all WWER-440 reactors will possible.
3. Comparison results of experimental and calculated data on the energy release.
In the first fuel cycle FA-3 were established on the core periphery in 3 pieces conjointly in 4
sectors 60 of grad symmetry. In the remained 2 sectors FA-2 of 4.87% enrichment are located. In
the following fuel cycles placement of FA-3 and FA-2 in other characteristic positions of core is
supposed. In the 3-th fuel cycle FA-3 were placed near to working group of the control and
For determination of true power of FA-3 by the temperature measurements the great
value of influence of intra- and inter-assembly leakages of coolant can have. The assessment of
influence of lack of a assembly cover on indications of thermocouples is important for safe
operation since basic data of core there are indications of the temperature sensors located at the
exit from FA.
Calculations by the SC-15 program have shown that for the lack of assembly?s cover a
coolant flow which can participate in removal of heat of FA-3 is bigger than corresponding flow
for FA-2 on 10% 6. In conditions of absence of assembly?s cover, mixed value of coolant
temperature on going out of fuel bundle characterized FA-3 power only approximately. Design
features of FA-3 define nature of change of pin by pin energy release in these assemblies.