HPS N13.53:2009 (R2016)

This standard specifies dose limits and release criteria for the management of material, products, and waste containing technologically enhanced naturally occurring radioactive material (TENORM), namely uranium and thorium. TENORM is used to differentiate radioactivity present in some materials and processes from NORM contained in nearly all materials of mineral origins. The radioactivity in TENORM is due to a few predominant radionuclides associated with two radioactive decay series, namely uranium-238 (238U) consisting of thorium-234m (234mTh), protactinium- 234m (234mPa), 230Th, radium-226 (226Ra), radon-222 (222Rn), lead-210 (210Pb), and polonium-210 (210Po); and the 232Th series consisting of 228Ra, 228Th, 224Ra, and 220Rn. In some situations, the actinium decay series, starting with 235U, may need to be considered as well, especially if 238U concentrations are elevated even at natural isotopic abundances. The major decay products of 235U include 231Th, 231Pa, actinium-227 (227Ac), 227Th, 223Ra, and 219Rn. The isotopic distribution of natural uranium is given as 48.9% for 238U, 48.9% for 234U, and 2.2% for 235U, in terms of activity. Potassium-40 (40K) is also included because in some instances it may be isotopically enriched. Annex A presents the radioactive decay schemes for the uranium and thorium series and potassium.
In defining the objective of this standard, it should be recognized that the demarcation between NORM and TERNORM is not always well delineated; often, an industry using or receiving materials may not be capable of distinguishing materials that are TENORM, or even materials that may be subject to existing federal or state regulations. Given that it is not possible to catalog a priori all situations involving the use of TENORM, the standard provides a common theme and information with which to recognize practices that may result in unnecessary radiation exposures to workers and the public and possibly have an impact on the environment. In considering a specific practice, the information provided in this standard should be used to seek technical and regulatory advice from qualified regulatory agencies or experts in the appropriate disciplines. In this context, the standard recommends that industries routinely monitor rule-making activities as emerging issues involving TENORM are addressed by federal or state agencies. Finally, the standard may be adopted by industries and organizations as guidance in foreign countries where there are no TENORM regulations or guidelines.
The criteria are contained in Section 2.0, and Annex B presents the basis for the recommended criteria. Also, the standard offers further guidance to facilitate its implementation. Annex C presents background information for recognizing and evaluating practices that may have potential impacts on the public, workers, and the environment. Annex D describes various options for managing TENORM and also includes supporting technical information. The guidance presented in Annexes C and D is informative and not part of the requirements or criteria presented in Section 2.0. Annex E presents normative and informative references cited throughout the standard.