[en] OXIDE-3 is an evolving code developed to analyze the transient response of certain state variables of a High Temperature Gas Cooled Reactor (HTGR) during an accident involving the inleakage of steam and/or air into the helium primary coolant system. Primary tasks of the code are to calculate the primary coolant constituents as a function of time, their resultant chemical interaction with the graphite fuel elements, and their possible egress into the containment building. The report takes a critical look at certain aspects of the problem solving methods implemented in OXIDE-3 and gives estimates of the expected accuracy. Attendant to the latter finding, some of the calculated output may require careful interpretation since programmatical warnings are not given when an accuracy limitation is exceeded. The code has been used at BNL in an investigation to calculate the full power steady state impurity concentrations in the primary coolant system as a function of steam leak rate, steam graphite reaction rate, and the effective diffusion constant of steam in graphite. The results are in reasonable agreement with those obtained from the steady state oxidation code GOPTWO

[en] The observation of Cerenkov glow from a fuel assembly is an attractive method of detecting the presence of radioactive material. The simple, hand-held instrumentation is very easy to use and does not require penetration of the water in the spent fuel pool. An obstacle to routine use of the instrument arises in that the standard night vision devices have a broad band wavelength response which required the pool area to be darkened. Various techniques used to limit the bandwidth of the devices for use in viewing the Cerenkov glow in the presence of facility illumination have furthered implementation. A properly specified, commercially available instrument has been used to make narrow band observations at two power reactors without interference from the facility illumination. Problems of interpretation of the observations persist. The technique has no useful role to play in the verification of an assembly at the rod level. As an item, the assembly can be verified as containing radioactive material in many instances; however some ambiguous situations were encountered

[en] The nature of impurity iron in PGX graphite has been examined and its role during oxidation by steam has been clarified. The iron exists as mobile clusters which are accessible to H₂ and H₂O. It can be easily maintained in a reduced or oxidized state by variation of H₂/H₂ pressures. In the reduced state, iron is an active catalyst which can produce high localized rates of oxidation and form clearly defined etch pits

No abstract available

[en] A thermochromatographic technique has been developed to investigate the chemical states of fission products from irradiated fuel as well as in fission product simulation studies. Some recent work on iodine transport and on release of fission products from irradiated fuel kernels will be discussed

[en] The nature of impurity iron in PGX graphite has been examined and its role during oxidation by steam has been clarified. The iron exists as mobile clusters which are accessible to H₂ and H₂O. It can be easily maintained in a reduced or oxidized state by variation of P sub(H₂)/P sub(H₂O). In the reduced state, iron is an active catalyst which can produce high localized rates of oxidation and form clearly defined etch pits. (author)

[en] A thermochromatographic technique has been developed to investigate the chemical states of fission products from irradiated fuel as well as in fission product simulation studies. Some recent work on iodine transport and on release of fission products from irradiated fuel kernels will be discussed. (author)

[en] The United States Programme of Technical Assistance to IAEA Safeguards (POTAS) has been providing technical support to the IAEA Department of Safeguards for 18 years. POTAS was proposed by the United States President Ford in February 1976. From its inception, POTAS has provided support in all relevant areas of need identified by the IAEA. Functions of POTAS, its past and current initiatives are described. 1 fig