Effective full power day

Mixed oxide (MOX) fuel, 21.0-wt% Pu in 18.0-wt% enriched uranium, was irradiated from the 16 to 35 cycle at the 3" row in the experimental fast reactor JOYO. Tire effective full power days were 1019.33, and the peak bumup was 143.8 GWd/t. Atotal of 1560 days have passed from the reactor shut down to analysis. 

Calculations of the 30-rod bank worths for other time points during the depletion show that the rod and RSC worths are a function of time in the cycle rather than which cycle it is (initial or equilibrium) even though the cycles differ greatly in length and fuel loading. (The initial cycle is all fresh fuel with a cycle length of 555 effective full-power days (EFPD) and a carbon-to-thorium atom ratio of 600, while the equilibrium reload has half new fuel and the remainder depleted fuel, loaded for 482 EFPD and a C/Th = 1000.)... 

The core incorporated a graded low-enriched uranium (LEU) and thorium (LEU/Th) fuel cycle with an equilibrium cycle in which fuel exposure reaches 964 effective full power days (EFPDs) (3.3 calendar years at 80% equivalent availability), with one-half of the active core being replaced every 482 EFPDs (1.65 calendar years at S0% equivalent availability). 

Note EC, equilibriuin cycle EFPD, effective full power days. Best estimate. 

Before this extensive use of thoria in Kakrapar was started, performance testing of thorium bundles in power reactors was done by loading four thorium bundles in the Madras Atomic Power Station in May 1985. These bundles were unloaded during the usual refueling operation. By then the thoria bundles had been in the core for 280 effective full-power days. The highest bumup was 1.7 MW d/kg HE. 

Fuel lifetime/period between refuellings in effective full power days (EFPD)... 

Operation cycle between refuellings, effective full power days 320 2 083 ... 

The fuel lifetime and the period between refuellings are both about 1800 effective full power days (EFPD), or more than 5 years. From the viewpoint of the neutronics, a 10-year (about 3650 EFPD) refuelling interval is possible but the integrity of the fuel cladding is not confirmed for more than 5 years of operation in the conditions similar to those of a PWR core. 

The fuel lifetime is equal to the period between refiiellings and constitutes 1750 effective full power days. 

The lifetime calculations were performed for the five variants highlighted above. For variants with uranium fuel (1, 4), the lifetime duration was presumed to be 2200 effective full power days (EFPD) for variants with plutonium fuel (2, 3, 5), the lifetime duration was presumed to be 3200 EFPD. The Keff changes over the lifetime are shown in Fig. XIX-3. 

Fuel lifetime / period between refuellings 4 200 effective full power days... 

EFPD= Effective Full Power Days FIG. XXIX-4. Keffvariation with fuel burn-up. 

The period between refuelling sis estimated to be 5500 effective full power days (EFPD). Design basis lifetime for reactor core, vessel and structures... 

Bum-up reactivity swing 0.001 dK/30 EFPD (Effective Full Power Days) Since the conversion ratio of FUJI is 0.97 and since fresh fuel is added to the core periodically (at every 30 EFPD), the bum-up reactivity swing is very small. The above value is applicable throughout the whole operation cycle... 

Period between refuelling in effective full power days (EFPD) Fissile feeding 2 kg of is supplied to the core in the form of LiF-UF4 (73-27 mol. %) at every 30 EFPD. Fertile feeding 67 kg of Th is supplied to the core in the form of LiF-BeF2-ThF4 (72-16-12 mol. %) at every 150 EFPD. 

Period between refuellings 600 effective full power days. 

The fuel lifetime is about 3800 effective full power days (EFPD) and the period between refuellings in is about 780 EFPD (about 25 months). 

The KAMADO refuelling concept is similar to that of other LWRs. Since the KAMADO concept has a simple plant system design, plant maintenance becomes easy too. Therefore shorter refuelling/outage time is expected. Assuming 360 effective full power days (EFPD) of operation and 40 days of refuelling, the load factor of 90% could be achieved. 

Fertile particle maximum, % FIMA Refuelling interval, effective full power days 7... 

The reactor has a provision for on-line refuelling. On average, 12 driver fuel assemblies about 11 blanket assemblies will be replaced assuming 310 effective full power days (EFPD) of operation per year, with an average residence time of the driver fuel assemblies and the internal blanket assemblies of the core being approximately 4.5 years, while it will be 9 years for the outer blanket assemblies. The average discharge burn-up of the driver fuel (without reconstitution) is 87.6 MW-d/kg U, and the maximum one is 120.7 MW-d/kg U. 

On average, 75 fuel assemblies will be replaced per year, assuming 330 effective full power days (EFPD) of operation per year and the average discharge bum-up of 75 MW-d/ kg. 

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