Studsvik offers core design and core tracking services using the CMS codes to ensure customers using fuel vendor-developed loading patterns fulfills the design criteria and acheives the best possible fuel cycle cost. The independent review and core tracking process can include any of the following components, or additional analysis that may be required.
Studsvik can review the planned core designs (loading patterns, boron letdown curves, control rod sequences), which includes control of cycle length, k-effective behavior comparison with other cycles, thermal margins, shutdown margins (both local and groupwise), burnup distributions, and evaluation of the margin to RIA safety limits. Separate flexibility studies to explore alternate cycle length and core reactivity can also be performed.
For BWR cores, this review may also include a review of burnable poison dimensioning and form factors having influence on the stability of the core during transients, as well as predictive stability calculations.
All verification calculations, technical notes, and results are documented and delivered to the customer as part of the design process.
Fuel assembly enrichment and burnable absorber layouts and core loading patterns are designed based on customer-specified cycle design requirements. Studsvik engineers use proprietary optimization tools when fine tuning enrichment and poison loading patterns to improve fuel economy and safety margins.
Fuel cycle cost, based on customer-provided data, could be delivered as part of separate flexibility studies with variation in cycle length and core reactivity.
Once the final core design is selected, Studsvik will update the core simulator model to the final core design and perform calculations to predict cold physics tests (cold criticals). The core simulator model can be depleted through the entire cycle based on operating data and measurement data provided by the plant.
During cycle operation, intermediate results like in-core and ex-core detector measurements and cycle length estimates will be evaluated to determine the fidelity of the core model. Direct operational support, such as control rod sequence adjustments or alternate boration strategy, can be provided upon request.
Fuel economy studies are typically based on a combination of transition and equilibrium cycle studies to consistently assess the effects of insertion of new fuel types, variation of cycle lengths, or power plant uprate. Studsvik can perform multi-cycle studies to analyze the impact on reactivity quantities, fuel loadings, and thermal margins to estimate fuel cycle costs under such circumstances.