Description of double-shell tank selection criteria for inspection

Technical criteria for selecting double-shelf tanks`s (DST`s) for inspection are presented. Inspection of DST`s is planned to non-destructively determine the general condition of their inner wall and bottom knuckle. Inspection of representative tanks will provide a basis for evaluating the integrity of all the DST`s and provide a basis for estimating remaining life. The selection criteria recommended are tank age based on date-of-first fluid entry, waste temperature, corrosion inhibitor levels, deviations from normal behavior - involving sludge levels, hydrogen release and waste transfers - least waste depth fluctuation, tank steel type, other chemical species that could activate stress-corrosion cracking, and waste types

Program to develop acoustic emission-flow relationship for inservice monitoring of nuclear pressure vessels. Progress report, February 1 - July 1, 1977. [BWR; PWR]

The purpose of the program reported is to evaluate experimentally the feasibility of further assuring reactor safety by detecting and analyzing flaw growth in reactor pressure boundaries through continuous monitoring for acoustic emission (AE). Program objectives are: (1) characterize AE from a limited range of defects and material property conditions; (2) characterize AE from innocuous sources (including defects); (3) develop criteria for distinguishing significant flaws from innocuous sources; (4) develop an AE-flaw damage model to serve as a basis for relating inservice AE to pressure vessel integrity. Steel plate required for the program has been procured and test specimens are being fabricated. Specimen test system has been assembled and calibrated. A technique for rating AE monitor system sensitivity has been developed. An HSST pressure vessel test has been successfully monitored for AE, and data analysis is in progress

Materials evaluation for a transuranic processing facility

The Westinghouse Hanford Company, with the assistance of the Pacific Northwest Laboratory, is developing a transuranium extraction process for preheating double-shell tank wastes at the Hanford Site to reduce the volume of transuranic waste being sent to a repository. The bench- scale transuranium extraction process development is reaching a stage where a pilot plant design has begun for the construction of a facility in the existing B Plant. Because of the potential corrosivity of neutralized cladding removal waste process streams, existing embedded piping alloys in B Plant are being evaluated and new'' alloys are being selected for the full-scale plant screening corrosion tests. Once the waste is acidified with HNO{sub 3}, some of the process streams that are high in F{sup {minus}} and low in Al and zr can produce corrosion rates exceeding 30,000 mil/yr in austenitic alloys. Initial results results are reported concerning the applicability of existing plant materials to withstand expected process solutions and conditions to help determine the feasibility of locating the plant at the selected facility. In addition, process changes are presented that should make the process solutions less corrosive to the existing materials. Experimental work confirms that Hastelloy B is unsatisfactory for the expected process solutions; type 304L, 347 and 309S stainless steels are satisfactory for service at room temperature and 60{degrees}C, if process stream complexing is performed. Inconel 625 was satisfactory for all solutions. 17 refs., 5 figs., 8 tabs

Corrosion resistance of stainless steels and high Ni-Cr alloys to acid fluoride wastes

TRUEX processing of Hanford Site waste will utilize potentially corrosive acid fluoride processing solutions. Appropriate construction materials for such a processing facility need to be identified. Toward this objective, candidate stainless steels and high Ni-Cr alloys have been corrosion tested in simulated acid fluoride process solutions at 333K. The high Ni-Cr alloys exhibited corrosion rates as low as 0.14 mm/y in a solution with an HF activity of about 1.2 M, much lower than the 19 to 94 mm/y observed for austenitic stainless steels. At a lower HF activity (about 0.008 M), stainless steels display delayed passivation while high Ni-Cr alloys display essentially no reaction