ANSWERS Seminar - 2015

The ANSWERS Seminar, 19th-21st May 2015

The 2015 ANSWERS Seminar was the 30th Anniversary of the Seminar in its current form. Held once again at the Haven Hotel in Sandbanks, Poole, it was attended by over 100 delegates from across the UK and Europe.

The three day event covered Shielding, Reactor Physics and Criticality, with a technical programme including presentations from both ANSWERS staff and customers, on the development and application of ANSWERS software.

Day 1: Radiation Shielding

The 2015 ANSWERS Seminar started on Tuesday 19th May with Radiation Shielding. Pat Cowan, the ANSWERS Applications Area Manager for Radiation Shielding, introduced the programme for the Shielding day, which included a variety of presentations on the recent developments in the ANSWERS Shielding codes and supporting tools, and a number of applications using the ANSWERS codes. The day was split into four sessions.

The first session was hosted by Pat Cowan and started with a presentation given by David Picton (Amec Foster Wheeler) entitled "Release of MCBEND11A_RU1". He described the code enhancements and error corrections included in Release Update 1. The second presentation, "CAD Developments – Improved IGES Import Option within MCBEND" was given by David Long (Amec Foster Wheeler), who described the latest developments and future work in CAD link capability. The last presentation of the first session was given by Simon Shaw from EDF Energy Nuclear Generation Ltd, entitled "Advanced Gas-Cooled Reactor (AGR) Dosimetry". This presentation described the methodology underpinning the AGR Dosimetry programme and EDF's current methods in AGR Dosimetry calculations.

After the morning break, the second session was hosted by Adam Bird. This started with a presentation by Oisin O'Sullivan (Amec Foster Wheeler) entitled "MCBEND Validation Against Neutron Flux Measurements Within an AGR Side Reflector", describing the need for revising original calculations and applying modern methods and their subsequent validation with measurements. The next presentation, "Use of the GRID Option in a Multi-Stage Linked Calculation", was given by Kim Vignitchouk (Amec Foster Wheeler), providing an update on the use of the MCBEND GRID option with multi-stage linked calculations. The next presentation was given by Jayne Eratt from Rolls Royce, entitled "Comparison of Attila with MCBEND11 using CAD input". She compared MCBEND CAD input results with MCBEND FG models and ATTILA models using SolidWorks. The final presentation of the morning, "Labyrinth Calculations in MCBEND" by Christophe Murphy (Amec Foster Wheeler), described the different modelling strategies used to extend the validation of MCBEND to a labyrinth shielding benchmark case.

After lunch, the third session of the day was hosted by George Wright. This session consisted of four presentations on FETCH2 (an unstructured finite element code for solving the Boltzmann neutron transport equation) with the view of combining deterministic and Monte Carlo codes for shielding applications. The first was given by Andrew Buchan, from Imperial College, with a presentation entitled "Radiation Transport Modelling: FETCH2 Recent Advances". He focused on the improvements to existing technologies with the new sub-grid scale formulation and new POD methods. The next presentation was given by Steven Dargaville, from Imperial College, on "Multigrid and Parallelisation of FETCH2". He described the development of space/angle multigrid technology. This was followed by a presentation from Chris Baker (Amec Foster Wheeler) on "Coupled Deterministic and Monte Carlo Calculations (Using FETCH2 with MCBEND)" where he demonstrated that the same geometry could be used across various modelling codes such as FETCH2 and MCBEND, thus providing a mechanism to couple codes together for complete analysis. The next presentation, given by Geoff Dobson (Amec Foster Wheeler), "Coupled Deterministic / Monte Carlo Calculations" described the options available for coupling deterministic calculations and MCBEND using tetrahedral geometry.

Following the afternoon break, the final session of the day was hosted by David Long. Adam Bird (Amec Foster Wheeler) started with a review of the features of Versions 3A and 3B of Visual Workshop, and introduced the latest developments to be included in Version 4. The final presentation of the Shielding day was given by Pat Cowan, "Shielding Area - Status and Future Plans", and briefly described the current status and future plans of the shielding codes MCBEND and RANKERN. The presentations were followed by a period of informal discussions with ANSWERS staff.

Day 2 : Reactor Physics

The Reactor Physics day of the 2015 ANSWERS Seminar was on Wednesday 20th May. The day was split into four sessions with separate hosts for each session. Session 1 was hosted by Peter Smith, Session 2 by Ben Lindley, Session 3 by Brendan Tollit and Session 4 by Dave Powney.

The first session began with a presentation by Ben Lindley (Amec Foster Wheeler). Ben presented work undertaken to establish a calculation route using WIMS and PANTHER for the modelling of BWRs. Pavel Mikolas from Skoda gave the next presentation, which described the analysis with WIMS10 of a benchmark to simulate the burn-up of UO2 fuel in a VVER-440 reactor. The following presentation was given by Dave Powney (Amec Foster Wheeler), who described developments to the GAM module in WIMS to allow the prediction of neutron and gamma heating in a Cartesian geometry, representative of PWR systems. The final talk of the session was given by Adam Bird (Amec Foster Wheeler). Adam reviewed the current status of Visual Workshop and described some new features, including the capability to compare and combine results from several different calculations.

Session 2 began with a presentation by Dani Kotlyar from the University of Cambridge. Dani had performed analysis of I2S-LWR systems using WIMS and PANTHER. Such systems contain U3Si2 fuel. An equilibrium cycle had successfully been analysed, with WIMS/PANTHER results being in close agreement with those from other codes. Core designs for MOX and TOX fuel were also considered by Dani. Next, Max Shepherd (Amec Foster Wheeler) gave details of WIMS analysis of the NEA UACSA uncertainties benchmark. Max’s calculations used the SPRUCE tool to drive WIMS calculations examining a large range of sensitivities in a PWR lattice model. Max also presented the status of the integration of SPRUCE into Visual Workshop. Tom Taylor of EDF Energy gave the next presentation. Tom described initial WIMS/PANTHER analyses of RBMK critical experiments. EDF Energy intend to use these calculations to validate the methods used to model steam ingress in AGR cores. The final presentation of the session was given by Richard Seward (Amec Foster Wheeler). Richard discussed PANTHER analysis used to assess the inter-reactor transfer of fuel between the Wylfa Magnox reactors. This programme has successfully allowed for the continued operation of Wylfa after the exhaustion of fresh fuel stocks. As well as being a useful tool in preparing the safety cases for the programme, PANTHER continues to be used for regular core monitoring calculations at Wylfa.

The session following lunch consisted of three presentations about the Generation IV Molten Salt Reactor (MSR). The first talk was given by Ben Lindley (Amec Foster Wheeler), who described recent modifications made to the WIMS BURNUP and INTER modules towards developing a new modelling route. Using the WIMSECCO and SP3 modules Ben presented initial results to show the new MSR route working. The second talk was given by Olga Negri from the University of Manchester who described progress made on importing 3D CAD geometries of an MSR into MONK. Olga initially discussed the benefits of using imported CAD over FG/Hole geometry and then showed how the CAD geometry and mesh were generated using the Salome model. Olga showed initial results comparing the CAD and FG/Hole geometries for a burnup calculation and finally gave suggestions that may improve the runtime. The third and last MSR talk was given by Kevin Hesketh from NNL who described a recent analysis of an MSR using the ERANOS code.

The final session started with a presentation by Eddie Birkett of EDF Energy. As part of their acceptance process, Eddie had compared lattice k-infinities for PWR and AGR systems using WIMS10A_RU0 and WIMS9A_RU1. Eddie concluded that acceptable agreement between the variants of the code was found. The next talk was by Brendan Tollit (Amec Foster Wheeler) who described the latest developments to the SP3 flux solver in WIMS. The presentation concentrated on the new kinetics and thermal features in the SP3 solver and demonstrated examples of the new features. The final talk of the Reactor Physics day was by Glynn Hosking (Amec Foster Wheeler), who described the status of the WIMS code and future development plans. WIMS10A was released in Autumn 2014. The new features that are expected to be available in WIMS11 include: CACTUSOT, a method of characteristics solver for 3D systems with vacuum boundary conditions; SP3 a steady state and transient flux solver; an extension of the PERSEUS method to 3D; molten salt reactor refuelling features in INTER and BURNUP; P1 solution in CACTUS and CACTUSOT; and, a 64 bit version of the code.

Day 3 : Criticality

The Criticality day was held on Thursday 21st May, the final day of the ANSWERS Seminar. The first session was hosted by the lead MONK developer Simon Richards (Amec Foster Wheeler) who also presented first, with MONK Status and Future Plans. This presentation covered the recent MONK release, comparing execution times with MONK9A_RU1, and summarising outstanding error memos. The following presentation was by David Long (Amec Foster Wheeler) who talked about the latest CAD runtime improvements which will form part of the next MONK release. Next, Max Shepherd (Amec Foster Wheeler) talked about SPRUCE and the application of SPRUCE in an international benchmark. This was followed by Christopher Baker (Amec Foster Wheeler) describing another uncertainty quantification benchmark, looking at correlations between experimental configurations. Finally, Simon Ramzi (Amec Foster Wheeler) briefly described the upcoming customer release of SPRUCE which has now been converted into Java for quality assured release.

The second session, hosted by Nigel Davies, started with a presentation from Simon Richards about a benchmark on assessing the undersampling bias, and his experiences of running MONK on HPCs which looked very encouraging. This was followed by Jackie Martin from EDF Energy Generation talking about Criticality Modelling of the Sizewell B Dry Fuel Store, describing various fault studies. Dan Ayres from Imperial College, London then talked about Uncertainty Quantification using Methods of Polynomial Chaos concentrating on non-intrusive methods and comparing with using the sensitivity option in MONK. The final presentation in the late morning session was from Adam Bird and Tim Fry (Amec Foster Wheeler) who talked about the new features in Visual Workshop, including outstanding error memos, recapping of versions 3A and 3B and various new features such as combining MONK runs.

The third session, hosted by Max Shepherd, started with a talk by Ben Matthews and Brendan Tollit (Amec Foster Wheeler) about CRITEXUK developments and FETCH Modelling. CRITEXUK is intended to be released in the near future and the presentation described some of the recent code improvements and how CRITEXUK is being integrated with both WIMS and Visual Workshop. Brendan then talked about modelling the same validation benchmarks using the multiphysics code FETCH. The next presentation was by Greg O’Conner from the Office for Nuclear Regulation on Criticality Safety Modelling Assumptions for Uranium Oxide Powder. Greg challenged the assumptions used which utilises homogeneous modelling for the uranium oxide powder and asking whether it was realistic or not. Greg compared this to analogies of looking at milk and flower and lumpy porridge and generated much interesting discussion. The final presentation of this session was from William Philpott (Amec Foster Wheeler) about Water Moderated Critical Experiments at Sandia National Laboratories which he recently attended.

The fourth and final session, hosted by Christopher Baker, started with Max Shepherd (Amec Foster Wheeler) talking about Burn-up credit analysis in MONK and the recent developments to improve the burn-up option for burn-up credit calculations. This was followed by a presentation by Paul Holloway from AWE on the Effects of Moisture Content and Distribution on Radiation Transport in Concrete, looking at dose assessments for criticality warning systems. The final presentation of the session, and of the seminar, was from Nigel Davies (Amec Foster Wheeler) summarising a bespoke course organised by ANSWERS on modelling reprocessing plants with MONK.

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