Actinide Behaviour during Severe Nuclear Accident Three Mile - PowerPoint PPT Presentation

Actinide Behaviour during Severe Nuclear Accident – Three Mile Island Andriy Sizov, PhD, Senior researcher/Technical Expert Institute for Safety Problems of NPPs/ENCO Joint ICTP-IAEA International School on 10 – 14 September 2018 1 Nuclear Waste Actinide Immobilization

TMI • Middletown, Pennsylvania • May 1968 Three Mile Island (TMI) Unit 1 Construction began • November 1969 TMI Unit 2 Construction began • Unit 1 began operation in September 1974 • Unit 2 started up in December 1978 • Within 90 days, on March 28, 1979, a nuclear meltdown occurred in TMI 2 • A non-nuclear failure led to a nuclear meltdown • Worst accident at a nuclear power plant in the history of U.S. commercial power plants Joint ICTP-IAEA International School on 10 – 14 September 2018 2 Nuclear Waste Actinide Immobilization

Location Joint ICTP-IAEA International School on 10 – 14 September 2018 3 Nuclear Waste Actinide Immobilization

Three Mile Island NPP Joint ICTP-IAEA International School on 10 – 14 September 2018 4 Nuclear Waste Actinide Immobilization

Reactor Joint ICTP-IAEA International School on 10 – 14 September 2018 5 Nuclear Waste Actinide Immobilization

Sequence Joint ICTP-IAEA International School on 10 – 14 September 2018 6 Nuclear Waste Actinide Immobilization

Sequence 2 Joint ICTP-IAEA International School on 10 – 14 September 2018 7 Nuclear Waste Actinide Immobilization

Sequence 3 Joint ICTP-IAEA International School on 10 – 14 September 2018 8 Nuclear Waste Actinide Immobilization

Sequence 4 Joint ICTP-IAEA International School on 10 – 14 September 2018 9 Nuclear Waste Actinide Immobilization

Sequence 5 Joint ICTP-IAEA International School on 10 – 14 September 2018 10 Nuclear Waste Actinide Immobilization

Sequence 6 Joint ICTP-IAEA International School on 10 – 14 September 2018 11 Nuclear Waste Actinide Immobilization

Sequence 7 Joint ICTP-IAEA International School on 10 – 14 September 2018 12 Nuclear Waste Actinide Immobilization

Actions Joint ICTP-IAEA International School on 10 – 14 September 2018 13 Nuclear Waste Actinide Immobilization

Physical and Chemical processes during the accident • Phase 1 of the accident: LOCA (estimated duration 100 minutes) • Phase 2 of the accident: core heating with the RCS and high- pressure SIS shut down (from 100 minutes to 174 minutes) • Phase 3 of the accident: partial reflooding of the core - formation of a debris bed (between 174 and 180 minutes) • Phase 4 of the accident: heating of the debris bed – development of the corium pool (between 180 and 200 minutes) • Phase 5 of the accident: total reflooding of the core - continued development of the corium pool (between 200 and 224 minutes) • Phase 6 of the accident: movement of core materials towards the reactor vessel’s lower plenum (between 224 and 226 minutes) • End of the accident: restoration of stable cooling (to 16 hours after the start of the accident) Joint ICTP-IAEA International School on 10 – 14 September 2018 14 Nuclear Waste Actinide Immobilization

Phase 1. Phase 1 of the accident: LOCA (estimated duration 100 minutes). Assumed state of the core after lower crust formation. Joint ICTP-IAEA International School on 10 – 14 September 2018 15 Nuclear Waste Actinide Immobilization

Phase 2. Phase 2 of the accident: core heating with the RCS and high- pressure SIS shut down (from 100 minutes to 174 minutes). Dose rate alarm. Relief valve is closed. Assumed state of the core 174 minutes after the start of the accident. Joint ICTP-IAEA International School on 10 – 14 September 2018 16 Nuclear Waste Actinide Immobilization

Phase 3. Phase 3 of the accident: partial reflooding of the core (23 m 3 )- formation of a debris bed (between 174 and 180 minutes). Joint ICTP-IAEA International School on 10 – 14 September 2018 17 Nuclear Waste Actinide Immobilization

Phase 4 and 5. Phase 4 of the accident: heating of the debris bed – development of the corium pool (between 180 and 200 minutes). Reopening pressurizer relief valve. Emergency situation declared. Phase 5 of the accident: total reflooding of the core - continued development of the corium pool (between 200 and 224 minutes) SIS is restarted. Joint ICTP-IAEA International School on 10 – 14 September 2018 18 Nuclear Waste Actinide Immobilization

Phase 6. Phase 6 of the accident: movement of core materials towards the reactor vessel’s lower plenum (between 224 and 226 minutes). Crust rupture. Joint ICTP-IAEA International School on 10 – 14 September 2018 19 Nuclear Waste Actinide Immobilization

End state. End of the accident: restoration of stable cooling (to 16 hours after the start of the accident). Hydrogen combustion occurred 9 hours 30 minutes after the start of the accident. Joint ICTP-IAEA International School on 10 – 14 September 2018 20 Nuclear Waste Actinide Immobilization

Decontamination and Defueling 21 Joint ICTP-IAEA International School on 10 – 14 September 2018 Nuclear Waste Actinide Immobilization

Why can it be dangerous? China syndrome Joint ICTP-IAEA International School on 10 – 14 September 2018 22 Nuclear Waste Actinide Immobilization

Environmental/Public Health Consequences • No fatalities or injuries • Radiation exposure ~ 0.3 - 0.6 rem • No conclusive evidence for an increase in cancer cases • Unit 2 not allowed to resume operation • Unit 1 not allowed to resume operations until 1985 • General Public Utilities paid $82 million as compensation • Negative media coverage • Property values dropped • Mistrust of Nuclear Industry • Loss of income for surrounding farms Joint ICTP-IAEA International School on 10 – 14 September 2018 23 Nuclear Waste Actinide Immobilization

Environmental/Public Health Consequences Joint ICTP-IAEA International School on 10 – 14 September 2018 24 Nuclear Waste Actinide Immobilization

Consequences of the accident: comparison with Chornobyl and Fukushima Joint ICTP-IAEA International School on 10 – 14 September 2018 25 Nuclear Waste Actinide Immobilization

Lessons Learned • New Regulations • Inherently Safer Design and Operation • Emphasis on Training and Transparency • Expect the Unexpected (PSA). More severe accidents than a LOCA Joint ICTP-IAEA International School on 10 – 14 September 2018 26 Nuclear Waste Actinide Immobilization

The PHEBUS FP programme Joint ICTP-IAEA International School on 10 – 14 September 2018 27 Nuclear Waste Actinide Immobilization

References / Useful Links • Missouri University of Science and Technology http://web.mst.edu/~dludlow/classes/ChE%20285%20S p12/Three%20Mile%20Island.pptx • Nuclear Power Reactor Core Melt Accidents. Current State of Knowledge. IRSN 2015 • Three Mile Island Nuclear Accident. March 28, 1979 at Three Mile Island, Pennsylvania, USA. Failure Knowledge Database • Three Mile Island Accident of 1979 Knowledge Management Digest. Overview. NUREG/KM-0001, Revision 1. Office of Nuclear Regulatory Research • Backgrounder on the Three Mile Island Accident https://www.nrc.gov/reading-rm/doc-collections/fact- sheets/3mile-isle.html Joint ICTP-IAEA International School on 10 – 14 September 2018 28 Nuclear Waste Actinide Immobilization

Thank you for your attention. Joint ICTP-IAEA International School on 10 – 14 September 2018 29 Nuclear Waste Actinide Immobilization