[en] The aim of this paper is to describe the health physics efforts to bring the shot peening work at Ringhals to an ALARA goal. The complete scheme from the first plant visits, through training, modifying of equipment, follow up of lessons learned will be discussed, to show that the main part of dose reduction is accomplished during the preplanning stage

[en] Ringhals Nuclear Power Plant in Sweden comprises one Boiling Water Reactor and three Pressurised Water Reactors. This paper describes the experience in monitoring fuel failures and discusses the criteria for shutting down to avoid excessive contamination. (UK)

[en] It is well known that good control of the primary chemistry in a PWR is essential in order to minimize material problems and fuel damages. It has also been well established that the water chemistry has a great influence on accumulation of corrosion products on the fuel and the radiation build-up on primary system surfaces. Ringhals was one of the pioneers to increase operating pH in order to reduce radiation build-up and has now been operating for ten years with pH at 7.4 or (in later years) 7.2. Our experience is favourable and includes low radiation levels in the new (1989) steam generators of Ringhals 2. Ringhals 4 has operated almost its whole life at pH 7.2 or higher and it remains one of the cleanest PWRs of its vintage. In addition to strict adherence to a stable operating chemistry, Ringhals is now working on a program with the aim to find optimum shut-down and start-up chemistry to reduce activity levels in the primary systems. A particular goal is to use the shut-down and start-up chemistry at the 1994 outage in Ringhals 3 in order to reduce doserates in preparation for the planned steam generator replacement in 1995. The paper summarizes the experience to date of the established operating chemistry, on-going tests with modified shut-down and start-up chemistry and other measures to limit or reduce the activity build-up

[en] Refueling and steam generator work were chosen for this presentation, because these tasks are major contributors to the annual dose and because they are easily identified. However, it is important not to neglect the majority of low individual doses where dose saving can be accomplished, sometimes with very limited expenses in technical measures. Our experience is that most technical measures taken have proved to be successful, although they were based on professional judgement only, and not a formal optimization procedure. It is also significant that this paper describes technical measures taken, and their justification. Not the routine health physics work, which at a nuclear power plant, is the cause of most of the collective dose saved. But as recognized in ICRP 37, the scenario is very complicated and the actions must to a great deal, by necessity, be based on professional judgement and intuition