Technical Context. Creating a roadmap for obtaining information from designated NPPs as they go through decommissioning is complementary to ongoing NRC research in developing technical information to support evaluating SLR as well as data collection and testing of ex-plant materials. Material degradation has traditionally been managed reactively in response to events and operating experience, rather than proactively to prevent failures. For the NPPs currently entering their first license renewal period from 40-60 years, and submitting SLR applications, it is necessary to evaluate potential degradation mechanisms out to 80 years of operation. Evaluation of material properties in SSCs from actual decommissioned NPPs will provide a basis for comparison with results of laboratory tests and calculations to resolve the four issues listed above. The proactive management of materials degradation (PMMD) information tool was originally created at PNNL for RES (POC: Xxx Xxxx) to give an expert opinion of the possible future degradation mechanisms on a subcomponent/material specific basis (PNNL-17779)i. Combined with the LER database, the PMMD information tool allows one to not only react to past events, but to anticipate future issues. The original PMMD information tool was based on NUREG/CR-6923, “Proactive Materials Degradation Assessment (PMDA),” for the first license renewal period, so it is now appropriate to integrate information from the excel databases from the recently-published five volumes of NUREG/CR-7153, “Expanded Materials Degradation Assessment (EMDA)” for SLR. At this juncture, there is demonstrated industry interest in NPP long-term operation (LTO) and regulatory interest in SLR.
Technical Context. The purpose of this task is to extend the lattice physics code assessment to assess the accuracy of Polaris/PARCS core modeling calculations. Full-core calculations will be performed with SCALE/GENPMAXS/PARCS and XX Xxxxx Carlo reference models to assess the accuracy of predictions of core-level quantities of interest through code-to-code comparisons and comparisons to plant data. Data sets to consider include Xxxxx Bar Xxxx 0, XXXXXX, Xxxxxxxxx, Xxxxxxx, and potentially Forsmark data or IRSN EDF data. This work will assess the accuracy of coupled SCALE/PARCS analysis to understand bias and trends at the core level. The assessment should provide insight to prioritize code development efforts to minimize biases and improve accuracy
Technical Context. The purpose of this task will be to integrate the Shift Monte Carlo capabilities in the SCALE code suite within Polaris. This is advantageous to the NRC review staff as it provides a reference tool for new designs with limited experimental data. In particular reference solutions for non-Light Water Reactor fuel designs (nodal cross section data for PARCS for example) can be computed via Shift from the same inputs as the Polaris multigroup approach, thereby providing confidence with the results and also decreasing review time with shorter model development times. NRC-HQ-60-14-T0004 “SCALE Lattice Physics Acceleration” focused on the development of Polaris for light water reactor (LWR) lattice physics calculations. This project will focus on the capability to call Shift from Polaris to perform Monte Carlo lattice physics calculations for non- LWR applications.
Technical Context. In the cellulose hydrolysis field, synergy refers to the phenomenon whereby catalysis is more effective when catalytic agents act in combination as compared to the case where they act separately. Synergy among functionally-distinct components of cellulase enzyme systems (e.g. endo and exo) has been observed many times. By contrast, synergy between cellulase enzyme systems and metabolically active cells – that is the proposition that a cellulase enzyme system is more effective when expressed on the surface of a metabolically active cell than when the enzyme system acts independently of cells - has been evaluated in only one paper for one organism (Lu et al., PNAS, 2006). Such “enzyme-microbe” synergy is however of great potential value in the context of cost effective processing of cellulosic biomass. Understanding PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE SECRETARY OF THE COMMISSION PURSUANT TO AN APPLICATION FOR CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [***] DENOTES OMISSIONS. enzyme-microbe synergy represents a significant challenge from an intellectual standpoint, and can be expected to be enlightening with respect to microbially-mediated cellulose hydrolysis as it occurs in both engineered and natural environments. Documentation of enzyme-microbe synergy will become a focus in year 2 once techniques for cellulase quantification (Activities 3A and 3C) are developed, with a broader range of organisms and conditions investigated than have been studied thus far. Thereafter, it is anticipated that our focus will shift to understanding the mechanistic basis of enzyme-microbe synergy. Quantitative evaluation of enzyme-microbe synergy will be undertaken by comparing cellulase-specific rates of cellulose hydrolysis for metabolically active microbial cultures and for simultaneous saccharification and purification with purified cellulase preparations obtained from these cultures. Archival paper on enzyme microbe synergy in C. thermocellum under a broader range of conditions than studied previously. Archival paper on enzyme microbe synergy of model organisms other than C. thermocellum.
Technical Context. As a continuation of the work in Activities 6 and 7, we will expand our understanding on the functional roles of different members of cellulose-utilizing consortia. This investigation will be carried out with microbial consortia enriched from a variety of environments (Activity 6A) as well as consortia designed in the lab (Activity 7A) by using a combination of functional genetic tools and the techniques developed in Activity 2B. The main goal will be to PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE SECRETARY OF THE COMMISSION PURSUANT TO AN APPLICATION FOR CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [***] DENOTES OMISSIONS. identify the breadth of functions that play an essential role in the performance of the consortia, and identify the relationship between these functions underlying the consortia’s ability to utilize cellulose.
Technical Context. NRC currently maintains the MELCOR computer code for both severe accident analysis and source term and the containment related design basis analysis. The MELCOR computer code represents the current state of the art in severe accident analysis which has been developed through the NRC and international research performed since the accident at Three Mile Island in 1979. MELCOR is a fully integrated, engineering-level computer code and includes a broad spectrum of severe accident phenomena with capabilities to model core heatup and degradation, fission product release and transport within the primary system and containment, core relocation to the vessel lower head, and ex-vessel core concrete interaction. The MELCOR code is composed of an executive driver and a number of major modules, or packages, that together model the major systems of a reactor plant and their generally coupled interactions. The various code packages have been written using a carefully designed modular structure with well-defined interfaces between them. This allows the exchange of complete and consistent information among them so that all phenomena are explicitly coupled at every step. The structure also facilitates maintenance and upgrading of the code. MELCOR modeling is general and flexible, making use of a “control volume” approach in describing the thermal- hydraulic response of the plant. No specific nodalization is provided, which allows a choice of the degree of detail appropriate to the task at hand. Reactor-specific geometry is imposed only in modeling the reactor core. MELCOR code development meets the following criteria: • Prediction of phenomena is in qualitative agreement with current understanding of physics and uncertainties are in quantitative agreement with experiments. • Focus is on mechanistic models where feasible with adequate flexibility for parametric models. • Code is portable, robust, and relatively fast running, and the code maintenance follows established Software Quality Assurance (SQA) standards. • Availability of detailed code documentation. The NRC supports and hosts a number of meetings annually to exchange progress in severe accident research and to report MELCOR code development and assessment status which are listed below:
