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TRACE Modeling Guidelines

Welcome to the TRACE modeling guidelines. This resource provides plant-system guidance for creating TRACE code input decks for Pressurized Water Reactors (PWR), Boiling Water Reactors (BWR), and future reactor designs.

This site supplements the TRACE manuals — it does not replace them

The TRACE V5.0 User's Manual, Volume 2: Modeling Guidelines (ADAMS ML120060402) is the authority on what each TRACE component does and how its input is specified. A later Patch 02 revision exists at ML102230226, which is not a public document. It is organised by code component and applies to any plant. The Theory Manual (ML120060218) covers the field equations and physical models.

This site is organised by plant system for a given reactor type, and covers what those manuals cannot: which designs a practice applies to, the nodalization actually recommended and the reasoning behind it, initialization and acceptance criteria, and known failure modes. Read it alongside the manuals, not instead of them.

All seven volumes are published as one public ADAMS package — Final — TRACE V5.0 Manuals (ML120060403) — and are listed with their accession numbers under References.

What is TRACE?

TRACE (TRAC/RELAP Advanced Computational Engine) is a thermal-hydraulic analysis code developed by the U.S. Nuclear Regulatory Commission (NRC) for analyzing transient and steady-state behavior of light water reactor systems.

Purpose of These Guidelines

These guidelines are designed to:

  • Standardize modeling approaches across different reactor types
  • Document best practices and lessons learned
  • Provide practical examples and validation cases
  • Support both experienced and new TRACE users
  • Enable consistent and reliable safety analyses
  • Complement the TRACE manuals rather than duplicate them — component input specification belongs in the manuals and is cited here, not restated

Quick Navigation

  • PWR Modeling

    Comprehensive guidance for Pressurized Water Reactor components including pressurizer, steam generators, and primary loops.

    PWR Guide

  • BWR Modeling

    Detailed instructions for Boiling Water Reactor systems including jet pumps, reactor vessels, and steam lines.

    BWR Guide

  • Research and Test Reactors / Experimental Facilities

    Placeholder outline for collecting modeling experience, references, and proposed guidance.

    Research and Test Reactor Outline

  • Future Reactors

    Emerging guidance for Small Modular Reactors (SMR) and advanced reactor designs.

    Future Designs

  • General Resources

    Best practices, validation approaches, references, and frequently asked questions.

    Resources

Getting Started

New to TRACE?

Start with our Getting Started Guide to understand the basics of TRACE modeling and input deck creation.

Experienced User?

Jump directly to the component-specific guidance for PWR or BWR systems.

Key Features

Comprehensive Coverage

Detailed guidance for all major reactor components and systems

Validation Examples

Real-world validation cases with documented results

Code Snippets

Ready-to-use TRACE input deck examples

Best Practices

Industry-standard approaches and recommendations

Regular Updates

Continuously updated with new insights and techniques

Document Structure

graph TD
    A[TRACE Guidelines] --> B[General]
    A --> C[PWR Modeling]
    A --> D[BWR Modeling]
    A --> E[Future Reactors]
    A --> F[Research and Test Reactors / Experimental Facilities]

    B --> B1[Overview]
    B --> B2[Getting Started]
    B --> B3[Best Practices]
    B --> B4[Validation]

    C --> C1[Components]
    C --> C2[Examples]

    D --> D1[Components]
    D --> D2[Examples]

    E --> E1[SMR]
    E --> E2[Advanced Designs]

Contributing

These guidelines are a living document. This is an internal repository: changes are made on a branch here and merged through a pull request. Do not fork — a pull request from a fork cannot be merged. If you have suggestions, corrections, or additional content to contribute, please:

  1. Review the contribution guidelines
  2. Ask a maintainer for write access, then clone the repository
  3. Create a feature branch, make your changes, and preview locally with mkdocs serve
  4. Sync your branch with the latest main and resolve any conflicts before requesting review
  5. Push the branch and open a pull request (or open an issue for small corrections)
  6. Contact the TRACE modeling team if you need help

We use small, focused pull requests and coordinate if multiple people are editing the same page.

Version Information

Document Status

This documentation is currently under active development. Some sections may be incomplete or subject to revision.

Current Version: 2.0.0
TRACE Version: Compatible with TRACE V5.0 and later

Each page shows its own last-updated date in the footer, taken from the commit history — there is no site-wide date to keep in step by hand.

Support and Contact

For questions, issues, or support:

Developed by NRC Research

Licensed under MIT License