Random sampling of geosynthetics in Finland

NorGeoSpec is a Nordic system for certification and specification of geosynthetics and geosynthetic related products. Traffic authorities of the member states have composed the guidelines and agreed on a 5-class specification system for geotextiles used for filtration and separation. Recently the quality certification system has been extended to include the reinforcement function, too. The classification system has made the specification of geotextiles easy for the designer, thus increasing the use. The NorGeoSpec process includes a third-party quality control and audits, i.e. an inspection of the production process and testing of the products in an independent testing laboratory, in addition to the producers' continuous quality testing. Also, continuous surveillance including unannounced random product sampling and control checks is possible. With the support of NorGeoSpec, Finnish Transport Infrastructure Agency has carried out a random products sampling on geotextiles and reinforcing geosynthetics in 2015-2018. In addition, random sampling was made on roadside groundwater protection projects using geosynthetic clay liners and geomembranes. The random sampling project has increased the knowledge of geosynthetics. The results of random sampling have shown some deviations from requirements and the variation between laboratories. Based on the results, the requirements on sampling and testing prior the use at the project site to prove the compliance has been added to Finnish general quality requirements (InfraRYL).publishedVersionPeer reviewe

Effect of de-icing salt as winter maintenance for corrosion of steel piles on bridges

Corrosion can have significant long-term effects on the structural resistance of steel piles in ground. There is a possibility that this effect can be intense if ground contains chlorides, sulphites or other aggressive chemicals. Also de-icing salt (NaCl) used on roads during winter maintenance may have effect on the corrosion of steel piles. In this research project a series of site investigations and laboratory tests have been conducted to investigate the effect of de-icing salt for corrosion on steel piles. Totally 12 sites were investigated, partly from locations where de-icing salt has been used and partly where de-icing salt has not been used. Most of the piles were part of bridge structures, but the study includes also data from a few special test piles. Investigated steel piles have been in ground for five to 24 years. The results show that the corrosion and its rate are low. The detrimental effect of de-icing salt on corrosion is negligible.publishedVersionPeer reviewe

Fuel utilization improvement in PWRs using the denatured /sup 233/U-Th cycle

A number of changes in PWR core design and/or operating strategy were evaluated to assess the fuel utilization improvement achievable by their implementation in a PWR using thorium-based fuel and operating in a recycle mode. The reference PWR for this study was identical to the B and W Standard Plant except that the fuel pellets were of denatured (/sup 233/U//sup 238/U-Th)O/sub 2/. An initial scoping study identified the three most promising improvement concepts as (1) a very tight lattice, (2) thorium blankets, and (3) ThO/sub 2/ rods placed in available guide tubes. A conceptual core design incorporating these changes was then developed, and the fuel utilization of this modified design was compared with that of the reference case

Assessment of non-backfittable concepts to improve PWR uranium utilization

Seven non-backfittable improvements to light water reactors were assessed for Batelle/Pacific Northwest Laboratories in support of the Department of Energy's program on Advanced Reactor Studies. The objective was to provide industrial perspective as to which concepts have the best potential for development to improve fuel utilization. The concepts were rated against the assessment criteria while considering the key questions identified for each concept, and recommendations were made for further action on unresolved key questions. The concepts were subjectively ranked against each other in terms of relative investment potential. The ranking considered all criteria but, for example, weighted fuel utilization savings more heavily than development costs. Finally, conclusions and recommendations for future action were determined. The reference design for this study was the NASAP Composite Improved PWR