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Storage that allows short-lived radioactive constituents to radioactive decay before subsequent handling or discharge. A clearance or discharge decision still requires the applicable measurement and acceptance criteria.

Temporary retention of radioactive gas so that nuclear radioactive decay lowers the radioactive activity released. A guaranteed minimum residence time, an average residence time and a tank filling time are different design quantities.

Control of radioactive wastes from generation through treatment, conditioning, storage and disposal. Concentrating a radionuclide in a smaller stream changes its location, not its radioactive decay law.

An idealized radiochemical neutrino counting model separates production, survival, recovery and readout. Suppose a freshly cleared target produces atoms at a constant rate $R$ during exposure $T$. Each atom has nuclear decay constant $\lambda =\log 2/h$, where $h$ is its half-life. The expected surviving population obeysThe proof is to multiply the differential equation by $e^{\lambda t}$ and apply integration. The expression also follows by summing the exponential decay survival probabilities of atoms produced at every earlier time. Production does not imply eventual recovery: atoms can decay during exposure.

Let $\eta$ be the fraction recovered instantaneously at extraction, $d$ the subsequent delay before counting, $ϵ$ the probability of recording a decay, and $W$ the counting duration. The expected signal pulses areWith constant background rate $b$, the expected total is $\mu ={\mu }_s+bW$. During counting, the expected instantaneous pulse rate is $s(t)+b$, with $s(t)=ϵ\eta \lambda N(T)e^{-\lambda (d+t)}$. Equal time windows therefore lose signal by the factor $e^{-\lambda \Delta t}$ while a constant background stays unchanged. Fitting the time dependence helps distinguish radioactive decay from that background; it does not recover individual capture times.

For an original worked example choose $Rh=20$, $T=W=h$, $d=0$, $\eta =0.8$, $ϵ=0.5$ and $bh=0.2$. These are illustrative assumptions. Then $N(T)=10/\log 2$, andDoubling the exposure does not double the surviving inventory: $N(2h)/N(h)=3/2$. A delay of one half-life halves the signal. At $\lambda T\ll 1$, $N(T)\simeq RT$; at long exposure it saturates at $R/\lambda$. These limits explain why a large target and repeated extraction can matter more than simply waiting longer. The model neglects time-dependent production, finite extraction duration, residual atoms between runs and time-dependent backgrounds.

Radiogenic heating is thermal energy deposited by radioactive decay. If its specific heating rate is $Q$ in watts per kilogram, the volumetric rate is $\rho Q$ and the heat input per horizontal area to a column of depth $H$ is $\rho QH$. The distinction between specific and volumetric rates matters in dimensional analysis of a convective heat flux law.

A thermoelectric generator whose heat supply comes from radioactive decay. The Seebeck effect converts part of a temperature-driven heat flow into electrical output. The source's thermal power and the electrical power delivered by the converter are distinct quantities.

A radionuclide is a species of atomic nucleus with an unstable nuclear state that undergoes radioactive decay. A sample's expected surviving population decreases with its nuclear decay constant. Carbon-14 is the radioisotope used in radiocarbon dating.

A pharmaceutical containing a radionuclide, with uptake and clearance chosen for imaging or treatment. Biological targeting and radioactive decay jointly determine its useful signal and tissue dose.

In 2001, $240.95$ live days, reconstructed radius below $5.50\mathrm{m}$ and effective electron kinetic energy above $6.75\mathrm{MeV}$ gave a CC neutrino flux of $1.75\times 10^6{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$ for the assumed boron-8 spectrum. Source calibrations measured $1.4\%$ instrumental-cut signal loss. SNO's own CC–ES difference was $1.6\sigma$; comparison with Super-Kamiokande's precise ES flux gave $3.3\sigma$ evidence for non-electron active neutrinos. This was not an NC measurement.^[ref]

In 2002 the pure-heavy water analysis used $306.4$ live days and a $5\mathrm{MeV}$ reconstructed kinetic-energy threshold. NC neutrons captured on deuterons emitted $6.25\mathrm{MeV}$ gamma rays, producing secondary electron light. The NC reaction threshold was $2.2\mathrm{MeV}$, a different quantity. Californium-252 calibrated $29.9\%$ capture efficiency, but only $14.4\%$ detection efficiency after fiducial and energy cuts. Assays constrained backgrounds from radioactive decay and photodisintegration.^[ref]

Energy, radius and direction relative to the Sun statistically separated channels. Assuming the standard boron-8 spectral shape, the NC total active neutrino flux was $5.09_{-0.43}^{+0.44}{(stat.)}_{-0.43}^{+0.46}(syst.)\times 10^6{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$, consistent with stellar structure predictions. The non-electron active component differed from zero by $5.3\sigma$. This established active flavour conversion, without individually tagging muon neutrinos and tau neutrinos. It did not exclude every sterile admixture.^[ref]

A continuous reactor with uniform contents. At steady state for first-order radioactive decay, $a_{\mathrm{out}}/a_{\mathrm{in}}=1/(1+\lambda V/Q)$; young material can leave before the mean residence time.

Western blot transfer moves separated proteins out of the gel onto a Western blot membrane, using an electric field across the gel thickness. Maintaining close contact preserves the lane pattern. Contact gaps, incomplete removal from the gel and passage through the receiving sheet can change how much protein is retained.

The original 1979 experiment pressed a wetted, $0.45\mu \mathrm{m}$-pore nitrocellulose Western blot membrane against the gel between scouring pads and plastic pipette-tray grids, held by elastic bands. The urea-gel assembly faced the cathode in acidic solution, with $6V/cm$ applied for one hour; the SDS-PAGE variant reversed polarity and used a glycine/methanol buffer solution. Stained gel/blot pairs checked pattern preservation. Corresponding labelled ribosome protein spots from two gels were compared through radioactive decay readouts after combustion. The stained gel remaining after transfer supplied a removal check; a second receiving sheet revealed breakthrough on overloading. These tests supported recovery for the examined urea-gel proteins, within experimental variation, while the SDS-PAGE results showed unequal staining recovery. Preserved band positions therefore did not establish universal quantitative transfer. ^[ref]

The reduction of reactor reactivity caused by neutron absorption by xenon-135. In a simplified model its abundance is fed by radioactive iodine decay, while its removal is by radioactive decay and neutron capture. Changes in these pathways can delay its response to a change of neutron flux.