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| Program name | Package id | Status | Status date |
|---|---|---|---|
| IFPE/DEMO-RAMP-I | NEA-1597/01 | Arrived | 09-MAR-2001 |
| IFPE/DEMO-RAMP-II | NEA-1597/02 | Arrived | 09-MAR-2001 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NEA-1597/01 | Many Computers | |
| NEA-1597/02 | Many Computers |
The STUDSVIK DEMO-RAMP I Project, an internationally sponsored research project, investigated the Pellet Clad Interaction (PCI) behaviour of specially designed remedy test fuel rods when subjected to fast power ramping.
The design of the five identical fuel rods comprised a combination of three candidate design PCI remedies e.g.
- Annular, short length fuel pellets.
- Nb2O5 doped fuel for controlled large grain size.
- Helium prepressurisation of the fuel rods.
The five rods were base irradiated through two consecutive fuel cycles in the commercial Ringhals I BWR at heat ratings in the range 16 to 29 KW/m to burnups in the range 14 to 17 MWd/kgU.
The power ramp tests were performed in the research reactor R2 at Studsvik, Sweden, utilizing the special experimental facilities available.
The rods underwent a thorough examination program.
The project has produced results that can be summarized as follows:
- The objective to demonstrate an improved PCI failure resistance has been attained as none of the fuel rods failed when ramped to power levels between 46 and 61 KW/m.
- Differences in the way the power ramps were performed (staircase ramp, one step ramps, two different ramp rates) gave differences in the rod behaviour.
- Rods power ramped with about the same ramp rate gave consistent results.
PROJECT SCOPE:
The program power ramped five individual test fuel rods of identical design. The rod were designed according to EPRI specifications, comprising a combination of three candidate design PCI remedies.
The technical programme consisted of a number of principal activities:
- Fabrication and pre-irradiation characterization of the five test fuel rods. This part of the program was performed by BNFL, England, under to contract.
- Assembling of the test rods to one full stringer rod and positioning the stringer into a fuel assembly for the Ringhals I reactor.
- Base irradiation of the experimental fuel rods in the power reactor Ringhals I, Sweden.
- Non-destructive examinations of the base irradiated fuel rods at Studsvik, Sweden, utilizing the pool-side facilities at the R2 reactor.
- Power ramp irradiation in the R2 reactor, utilizing a pressurized water loop operated at BWR conditions.
- Post-ramp examinations at Studsvik, Sweden, comprising pool-side examinations and hot cell examinations.
The STUDSVIK DEMO-RAMP II Project was an internationally sponsored research project which investigated the Pellet Clad Interaction (PCI) behaviour of power reactor irradiated BWR test fuel rods when subjected to fast power ramps. In particular the Project studied the PCI failure process, and its pre-stages at the proximity of the failure threshold.
Eight rods were base irradiated through three consecutive fuel cycles at heat ratings in the range of 16 to 30 kW/m to burn-ups in the range of 25 to 29 MWd/kgU in the commercial Wurgassen Boiling Water Reactor in FR Germany.
The power ramp tests were performed in the research reactor R2 at Studsvik, Sweden, utilizing the special experimental facilities available.
The rods underwent a thorough examination program, comprising characterization prior to the base irradiation, examinations interim to base and ramp irradiations and examinations after the ramp irradiation. The principal objective of the DEMO-RAMP II Project was to make a substantial contribution to the understanding of the pellet-clad interaction (PCI) defection process and its pre-stages at the proximity of the failure threshold under fast power up-rating of standard type BWR 8 x 8 test fuel rods, which in a commercially operating power reactor through three fuel cycles to a burn-up of approximately 25 MWd/kg U.
The main technical objectives of the Technical Program were the following:
- Establish through experiments the PCI failure threshold and determine the associated time to fission product detection of failed fuel rods. The results were to be compared with those of the INTER-RAMP Project study as to location of the failure threshold, reproducibility and consistency in, for example, time to failure indication.
- Study by interrupted ramp tests the failure incidence above the failure threshold as function of ramp terminal levels and hold times representative of postulated ATES (Anticipated Transients Without Scram).
- Quantify and characterize by interrupted ramp tests the failure process and pre-stages in terms of fission gas release, restructuring of the pellets, residual cladding deformation etc. and possibly also identify incipient stress corrosion cracks at the cladding inside surface.
- Produce well documented reference information for comparison of the power ramp performance of similar fuel rods at lower or higher irradiation exposures.
PROJECT SCOPE
The program power ramped eight individual test fuel rods of identical design.
The rods were base irradiated as constituents of two full size stringer rods, each consisting of seven segments. The test fuel was base irradiated during three consecutive operating cycles in the BWR-type power reactor Wurgassen, FR Germany. In addition to the eight test fuel segments mentioned above, the four end segments were included as spares in the program for the purpose of possible reference examinations. The burn-up levels ranged from 25 to 29 MWd/kg U achieved at heat ratings of 16 to 23 KW/m (time and rod average).
| Package ID | Status date | Status |
|---|---|---|
| NEA-1597/01 | 09-MAR-2001 | Masterfiled restricted |
| NEA-1597/02 | 09-MAR-2001 | Masterfiled restricted |
Keywords: experimental data, fuel elements, fuel rods, fuel-cladding interaction.
