Occupational Radiation Protection at Swedish Nuclear Power Plants: Views on Present Status and Future Challenges Ingemar Lund et al. Department of Occupational and Medical Exposure Swedish Radiation Protection Authority

Contents of Presentation oThe Swedish nuclear programme oExternal factors oRP status at Swedish NPPs in the early 90’s oActions to reduce radiation doses & levels oPresent situation oThe future – an outlook o Conclusion and catchwords

External Factors Influence Radiation Protection at NPPs National laws and regulations (safety and RP) International influence De-regulated electricity market (1996) –Cost-effectiveness, investments, organizations –Taxes, fees Phase-out of nuclear energy Protection of the environment –Best available technique (BAT) –New optimisation technique needed, risk transfer

Doses and Dose Rates at the NPPs in the Beginning of the 90’s Higher radiation doses at BWRs –Increase in collective and individual radiation doses –More workers with ”high” doses (> 15 mSv) Main reasons & drivers –Non-destructive testing –Refurbishment activities …Improvement of emergency core cooling systems …Modernization of Oskarshamn 1 –(Fuel damages, operation parameters, etc.)

BWR: Collective Dose Per Reactor (manSv)

PWR: Collective Dose Per Reactor (manSv) SG Exchange

Average Individual Doses for some Work Categories

Actions to Reduce Doses and Radiation Levels - I Research and development –Laser based alternatives to Stellite 6, fuel damages, oxide layers build-up, zinc & iron injection, decontamination, operation parameters SSI regulations, June 1994 –Dose limit: max. 20 mSv as an average under five consecutive years –Extended RP training –ALARA-programmes

Actions to Reduce Doses and Radiation Levels - II Exchange of information –Benchmarking (WANO, INPO, OSART) –Experience feedback (ISOE, national and regional meetings) Improved planning –Health physicians involved in the pre- planning and planning –Improve: communication and work planning with external firms

Actions to Reduce Doses and Radiation Levels - III Technical issues Reactor systems (construction, position) Material (Stellite) Fuel damage strategies (cleanness, identification) Water chemistry & flow Moisture content of steam Outage work

Present Situation at Swedish NPPs SPRINT-R1 MOD-O1

Present: Swedish NPPs in Collective dose: ~ 10 manSv/year Average individual dose: ~ 2,5 mSv Maximum individual dose 20 – 35 mSv # persons with eff. dose > 20 mSv: ~10 Intakes, Committed eff. dose > 0,25 mSv: ~ 2 / year

Recent and Future Work at the NPPs Barsebäck: Primary systems of B2 (2002) Forsmark: Moderator vessels, core grid, water clean-up systems (2000 – 2001) F1 – F3  Change of low-pressure turbines (2004 – 2006) Oskarshamn: Large project MOD 01 (2002), Refurbishment of O2 (2003 – ) Ringhals: R1 – Moderator vessel lid (2003), ”Safe End” reparations (R3/R4, 2002 – 03)  Reactor pressure vessel lids of R4/R3 (2004 – 2005)

Outlook for the Future Safety first! Refurbishment activities Organization (staff and contractors) Competence and education Maintenance vs. economy & dose load Political factors (close the brackets…..?)

Conclusion and Catchwords Considerable improvements  Halved collective doses & Lower radiation levels Conditions are good but should be maintained! – And improved? Competence Experience feedback Preventive measures Long-term planning