REACTOR FACILITIES GROUP

FAST BREEDER TEST REACTOR (FBTR)

Description Components Safety Radiological Safety Construction, Commissioning & Operation Summary Reactor Vessel Internal Inspection History of FBTR

Construction, Commissioning and Operation Summary

Components were manufactured by Indian industries, and were installed in 1984. Commissioning was done in phases. Initially, the primary and secondary sodium systems were commissioned, without the steam generators in place. The reactor was made critical on 18th October 1985 and low power physics experiments were conducted. Steam generator modules were then connected to the secondary sodium circuits.

Reactor was operated up to a maximum power of 1 MW t till 1992 for intermediate power physics and engineering experiments. The steam?water circuit was commissioned, steam generators were put in water service and power was raised to 8 MW t in January 1993. After completing high power physics and engineering experiments, power was raised to 10.2 MW t, generating superheated steam suitable for admission to the turbine-generator. After completing the commissioning activities of TG and auxiliaries, power was raised to 11.5 MW t and the turbine-generator was synchronised to the grid in July 1997.The reactor has operated upto a power level of 27.2 MWt/5.8MWe

Mixed carbide fuel, being a unique fuel of its kind without any irradiation data, it was decided to use the reactor itself as the test bed for this driver fuel. Hence, the core was redesigned as a small carbide core. As against the original design of 65 MOX fuel subassemblies rated for 40 MW t, the small carbide core had 22 fuel subassemblies with 70% PuC and 30% UC composition (designated as Mark-I fuel) during first criticality. This small carbide core was rated for 10.2 MW t, with the peak linear heat rating limited to 250 W/cm. The core has since been progressively enlarged by adding fuel subassemblies to compensate for reactivity loss due to burn-up.

With a view to raise the reactor power to 40 MW t, it was decided, in 1995, to go in for a full carbide core of 78 fuel subassemblies. The fuel composition chosen was 55% PuC + 45% UC (designated as Mark-II fuel). Fuel subassemblies of Mark-II composition were inducted in 1996. A gradual transition to the full carbide core was envisaged. The Mark-I fuel in the centre was retained to continue the irradiation for assessing its ultimate burn-up capability before phasing it out. Mark-II fuel was added at the periphery. The allowable peak linear heat rating of the Mark-I fuel has also been revised up to 400 W/cm and burn-up limit of 25GWd/t was raised to 155GWd/t based on the fuel performance. Eight high Pu MOX SAs (44% PuO2 + 56% UO2) were inducted into the core in 2007. In 2008 three of the seven tubes in each SG module were blanked to achieve near design temperatures with nominal power of 18.6MWt. Reactor was operated at 18.6MWt with reduced feed water flow and core outlet Na temperature of 482C could be achieved during the 15th irradiation campaign. Performance of the systems was satisfactory at design conditions.

The only fuel clad failure till date occurred in Feb 2011 at the end of 17th irradiation campaign in a MK-I SA in the 3rd ring outer radius with burn-up close to the target burn-up at the end of the 17th campaign. The incident provided an opportunity to ascertain the effectiveness of failed fuel detection system and validate procedures for identification of failed fuel.

25th irradiation campaigns have been completed so far. 25th campaign which was started on 30th June 2016 ended on 14th March 2017.

25th irradiation campaign was significant as the highest reactor power of 27.2MWt so far has been achieved with 52 fuel SA (38 MK-I, 5 MK-II, 8 MOX & 1IFZ100) core. Table 2 gives the cumulative performance statistics of the reactor as of 01st March 2017. 25th irradiation campaigns have so far been completed.

Milestones

18 thOctober  1985 First criticality
November  1989 Sodium valved in into SG
January 1993 Water valved in into SG
December 1993 Power raised to 10.5 MWt
1994-1995 Safety related Engineering Experiments
May 1996 Mark-I burn-up of 25 GWd/t
July 1997 TG synchronized to grid
1998 -1999 Zr-Nb irradiation for PHWR
April 1999 Mark-I burn-up of 50 GWd/t
March 2002 Power raised to 17.4 MWt
September 2002 Mark-I burn-up of 100 GWd/t
July 2003 Start of PFBR Test Fuel Irradiation
October 2005 Mark-I burn-up of 150 GWd/t
July 2006 Mark I burn-up of 155 GWd/t without failure
The PFBR test fuel burn-up of 59.5GWd/t
Feb 2007 to Jan 2008 8 High Pu MOX SAs inducted into the core
The PFBR test fuel burn-up of 80.76GWd/t
validation of DND
PFBR single pin irradiation for studing
Grid plate flux measurement
Grid plate material irradiation
Testing of Kalman filter technique
PFBR neutron detector testing in detector pit
Irradiation of D-9 (Continuing)
September 2008 A special SA (IFZ-100) for trial production of the medical isotope Sr89
March 2009 The PFBR test fuel burn up of 85.3GWd/t
The SG was operated with three water tubes blanked.
Based on the PIE of the SA MK-I burn-up of 160GWd/t
TG connected to grid, generating a maximum power of 18.6MWt / 3MWe
Dec 2009 PFBR test fuel to its target burn up of 112GWd/t at LHR of 450W/cm
Closing of fast reactor fuel cycle as one of the fresh fuel SA has pins made of the recycled from FBTR SA.
Feb 2010 to Oct 2010 Testing of PFBR in-core detector
Measurement of neutron flux in experimental canal using foil irradiation measurement of gamma inside CCP.
Testing of detector of 16MWt and 400kWt
July 2011 to Jan 2012 Irradiation of Yttria in IFZ100
Testing of High Temperature Fission Chamber for PFBR
Testing of Kalman filter based instrument for drop time measurement of DSRDM of PFBR
Initiation of irradiation of test pins of sodium bonded metallic fuel
2013-2014 Irradiation of Yttria
Irradiation of Natural U-Zr sodium bonded metal fuel pins
Irradiation of Capsule with Ferro-Boron
Impact specimens of 304LN & 316LN for low does irradiation
Irradiation of 14.3% EU metal pins
Short term irradiation of the sphere pack fuel
HTFC Testing
Kalman filter reactivity meter testing
Irradiation of Ternary fuel pin U-Pu-Zr.
Dec 2015 - March2017 Yttria for production of 90Sr isotope
Sodium bonded Ternary fuel 14.3% EU and Natural U-Zr metal fuel pins
Impact specimens of 304LN& 316LN for low dose irradiation
Continuation of long term irradiation of D-9
March2017 to Feb 2018 SG Replacement
March 2018 Power raised to 30 MWt

Table -2
Summary of performance statistics from 1985 (up to 25th irradiation campaign)

Parameter Cumulative value since first criticality
Maximum power (MW t/MWe) 27.2/5.8
Maximum linear heat rating (W/cm) 400
Bulk sodium temperature (deg.C) 490
Operating time (h) 54,234
Thermal energy produced (MWh) 6,28,738
Electrical energy generated (Million Units) 59.37
TG synchronisation time (h) 19652
Peak burn-up (GW d/t) 155
Longest operating campaign (d) 120 days (2016)
No. of lowering of rods 309
No. of scrams 169