Nuclear Toolkit

Nuclear Toolkit is a reference and calculation suite for nuclear engineers, health physicists, reactor operators, radiochemists, and students. Every dataset and formula is drawn from authoritative sources and cited in-app, so you can trust the numbers and check the reference.

INTERACTIVE CHART OF NUCLIDES
• Explore all 3,383 nuclides from the IAEA Live Chart of Nuclides (NUBASE2020 / AME2020).
• Smooth pan-and-zoom canvas with decay-mode coloring.
• Filter by decay mode and half-life; search any isotope.
• Tap any nuclide for half-life, all decay branches with branching ratios, spin-parity, natural abundance, and a scrollable decay chain.

DECAY CALCULATOR
• Simple decay: A(t) = A₀·e^(−λt) with a dataset or custom half-life.
• Decay chains: full Bateman-equation solutions integrated across the chain, with a log-scale activity-vs-time chart and an activities-at-time table.
• Mixture activity: specific activity by component mass.
• Activity units: Bq, kBq, MBq, GBq, mCi, Ci.
• Export results as CSV or share the chart as an image.

REACTOR PHYSICS
• Xe-135 poisoning simulator: solves coupled I-135 / Xe-135 equations for shutdown (iodine pit), startup, step-down, and custom scenarios.
• Six-factor formula: k_eff = η·ε·p·f·P_NL with interactive sliders.
• Point kinetics: prompt-jump approximation, stable reactor period, and reactivity in dollars.

CONVERTERS & MIXTURES
• Unit converters: activity, absorbed dose (Gy/rad), dose equivalent (Sv/rem), dose rate, energy, and exposure.
• ICRP 103 radiation- and tissue-weighting-factor reference.
• Mixture calculator: convert between atomic and weight fractions and compute mixture density.

ACCURATE AND CITABLE
• Nuclide data: IAEA Live Chart of Nuclides (© International Atomic Energy Agency).
• Element densities: PubChem (NCBI/NIH).
• Formulas cited to canonical texts: Lamarsh "Introduction to Nuclear Engineering" and Duderstadt & Hamilton "Nuclear Reactor Analysis," with section numbers on each screen.

PRIVATE BY DESIGN
• No account, no sign-in, no ads.
• Works fully offline once installed.
• Optional anonymous usage analytics only; values you enter into calculators are never collected. See the in-app Privacy Policy for details.

Nuclear Toolkit is an educational and professional reference tool. It is not a substitute for official procedures, licensed software, or qualified judgment in safety-critical work.

Recent changes:
### Shielding and Activation — Corrected
* **Photon buildup:** Implemented ANSI/ANS-6.4.3 buildup factors for all materials over **15 keV–15 MeV**. Thick-lead shielding was corrected; for example, the calculated dose behind **10 cm of lead for Cs-137** is now approximately **half** the previous value.
* **Fast-flux monitors:** Added **Ni-58, Ti-46, S-32, and Cu-63** monitor reactions for **D–T neutron-generator** spectra.