NORM materials can pose a significant risk or a great opportunity. For example, in the building industry there is good potential in the reuse of NORM containing industrial by-products. The traditional deposition has its own risks as well, but the valorisation of the NORM, the design of new synthetic NORM based building materials is raising concerns among authorities, the public and scientists. The engineers and scientists are required to demonstrate that these materials do not pose significant risks to humans or the environment. In order to avoid the elevated risk an overall investigation procedure is required focused on the mobility of toxic components (leaching properties) and radiation exposure (gamma dose rate and radon/thoron exhalation).
Based on our earlier studies the “classic” gamma dose surplus “I index” is not enough to characterize the by-products. More comprehensive protocol is required.
The last decade in our institute the dominant parameters where studied to characterising the by-products eg. radon exhalation, leachability.
Based on our protocol different by-produtcs (red mud, manganese mud, coal ash, drilling mud, phosphogypsum etc) were characterized from building material reusability aspects.
According to the results the classic gamma dose surplus determination and “aeric” radon exhalation is not contain enough information due to the strong influence of the inner structure (microporosity) to the radon potencial. Therefore to get more reliable information to the radon potencial estimation more comprehensive study is necessary.
Other hand a leaching tests are a very important tool for the assessment of long-term environmental behaviour and environmental impact. In the EU in spite of encouraging tendencies for the standardisation of methods such as the LEAF protocols, or the harmonisation of protocols for waste evaluation, there are still no commonly accepted methods for the evaluation of the leaching characteristics of NORM materials.
To characterize the leaching behaviour three leaching procedures were applied and compared, Hungarian standard, the international CEN/TS and the Tessier 5-step method.
According to the results the standard method complementing with the Tessier speciation method gives better insight to which fraction the radioisotopes are bound to.