ML22145A493

8-6-its-been-a-busy-year-r1

ML22145A493
Person / Time
Issue date:	03/08/2022
From:	Office of Nuclear Reactor Regulation
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Download: ML22145A493 (8)

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Its Been a Busy YearRecent Major Updates for the NRCs Accident Consequence Code System (MACCS)

Office of Nuclear Regulatory Research NEW Code Documentation

• Theory Manual

• User Guide

• Additional MACCS studies and reference documents NEW Code Models

• Near-Field Modelingevaluation, guidance, and new models to support modern siting applications

• HYSPLIThigh fidelity, state-of-the-art, atmospheric transport and dispersion modeling

• RDEIMalternate offsite cost estimation using gross domestic product (GDP) modeling NEW Postprocessing Capability

• AniMACCSplume segment animation and mapping utility 4.1 1

What Is MACCS and How Is It Used?

MACCS Code Suite WinMACCS 4.1MACCS Windows graphical user interface (GUI)

SECPOP 4.3.0population and economic data utility MelMACCS 2.0.1MELCOR radioactive source term input utility AniMACCS 1.3plume segment animation and mapping utility The MACCS code was developed and is used to evaluate the offsite consequences of radioactive releases to the environment

• MACCS models atmospheric transport, emergency and long-term protective actions, radioactive exposure pathways, dosimetry, health effects, and economic consequences

• MACCS outputs capture a variety of metrics, including dose, health effects, fatality risk, economic losses, and land contamination

• MACCS uses include regulatory and cost-benefit analyses, environmental reports and impact statements, plant-specific evaluations of severe accident mitigation alternatives, U.S. Department of Energy documented safety analyses, probabilistic risk assessments, and numerous research studies such as the State-of-the-Art Reactor Consequence Analysis (SOARCA) Project 2

AniMACCS

• MACCS added the capability to graphically visualize atmospheric results

• AniMACCS displays plume movement and ground and air concentration over a site map

• AniMACCS allows user flexibility to modify map scale, contour colors, zoom in or out, take screen captures, and export animation to video AniMACCS Ground Concentration Animation from SAND2020-8732 The AniMACCS User Guide (SAND2022-0403) was published in January 2022 3

Near-Field Modeling Benchmark and Improvements A. Ground-level, time-integrated /Q versus distance for AERMOD2, ARCON96, and QUIC compared with bounding MACCS calculations (Figure 5-8 from SAND2020-2609)

B. QUIC time-averaged air concentration for a vertical plane at building centerline (Figure 4-24b from SAND2020-2609)

C. QUIC time-averaged air concentration for a horizontal plane at 1 meter elevation (Figure 4-24a from SAND2020-2609)

• Recent near-field modeling improvements support computer code readiness to evaluate advanced reactors

• In 2020, MACCS 3.11.6 was compared to other codes, including QUIC, ARCON96, and AERMOD2 (SAND2020-2609)

• Comparison showed MACCS can be used within 500 meters (~0.3 miles) from the release location to model near-field results

• MACCS 4.1 enhancements added plume meander and building wind-effect models to simulate or bound near-field assessments of other codes A

B C

Near-Field Code Comparison 4

HYSPLIT and RDEIM Economic Model HYSPLIT

• MACCS added NOAAS HYSPLIT as an optional atmospheric transport and diffusion model

• HYSPLIT is a complete system for simulating complex atmospheric transport with both puff and particle tracking dispersion models

• Users can choose between the traditional MACCS Gaussian plume segment model or the higher fidelity HYSPLIT model Regional Disruption Economic Impact Model (RDEIM)

• MACCS added RDEIM to estimate offsite economic costs using current state-of-practice economics

• RDEIM includes income losses due to land restrictions in the directly affected area, national supply chain disruptions, and economic gains due to national recovery

• Users can select the new RDEIM model, which replaces the MACCS loss-of-use cost output with the GDP-based capability HYSPLIT Model Deposition Map 5

MACCS GUI RDEIM Model Selection RDEIM Model Document (SAND2020-5567)

Updated MACCS User Guides, Theory Manual, and Verification Report MACCS 3.10 and 4.0 User Guides (SAND2021-1588, SAND2021-8998)

• User guides published corresponding to new code releases

• User guide is intended to assist analysts in understanding both the WinMACCS GUI and MACCS inputs and outputs

• Provides guidance on getting started, parameter screens, tutorials, and required auxiliary input such as the site, meteorological, and dose conversion factor files MACCS Theory Manual (SAND2021-11535)

• Updates the previous theory manual from 1990 (NUREG/CR-4691, Vol. 2)

• Captures software improvements since MACCS 1.5

• Consolidates model descriptions contained in various historical documents

• Presents the current mathematical modeling and assumptions for MACCS modules and output results MACCS Verification Report (ADAMS Accession No. ML22026A461)

• Documents the systematic testing and verification of MACCS equations and algorithms

• Verification began with MACCS 4.0 and resulted in minor upgrades to MACCS 4.1, ensuring simulation consistency with analytic results 6

Numerous documents published 2019-2022

• AniMACCS User Guide (SAND2022-0403)

• MACCS Theory Manual (SAND2021-11535)

• MACCS 4.0 User Guide (SAND2021-8998)

• Nearfield Consequence Analysis Implementation (SAND2021-6924)

• MACCS 3.10 User Guide (SAND 2021-1588)

• MACCS Verification Report (ADAMS Accession No. ML22026A461)

• Nearfield Model Evaluation (SAND2020-2609)

• RDEIM Economic Model Description and Benchmark (SAND2020-5567)

• SOARCA Project, Sequoyah (NUREG/CR-7245)

MACCS Documentation 7

Contact Information MACCS Code Distribution AJ NosekCode Distribution Manager U.S. NRC, Office of Nuclear Regulatory Research, Accident Analysis Branch https://maccs.sandia.gov/getcode.aspx

Contact:

MACCSCodes@nrc.gov MACCS Code Support https://maccs.sandia.gov/default.aspx

Contact:

wg-maccs-entity@sandia.gov 8