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2 Background on Japanese and U.S. Nuclear Plants
Pages 31-71

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From page 31...
... (The reactors at the Fukushima Daiichi nuclear plant were BWRs.) • Sections 2.3 and 2.4 describe nuclear plants and regulation of nuclear power in Japan and the United States, respectively.
From page 32...
... The reactor core is enclosed in a robust steel pressure vessel, the reactor pressure vessel (RPV) (Figure 2.2)
From page 33...
... The control rods are moved into and out of the reactor core to control its power.
From page 34...
... 34 LESSONS LEARNED FROM THE FUKUSHIMA NUCLEAR ACCIDENT FIGURE 2.2 Schematic of a BWR/5 or BWR/6 reactor pressure vessel.
From page 35...
... . Reactor power is regulated by manipulating the positions of the control rods in the reactor core.5 The reactor can be "started" by partially withdrawing the control rods from the core.
From page 36...
... (Top) Boiling water reactor.
From page 37...
... 7  Prior to the Fukushima nuclear accident, there were 442 operating power reactors in 30 countries (World Energy Council, 2012)
From page 38...
... This is exactly the scenario that occurred in Units 1, 2, and 3 at the Fukushima Daiichi plant following the March 11, 2011, earthquake and tsunami. Fission product releases, which normally constitute the largest fraction of radioactivity released during a severe accident, are usually in the form of gases (xenon and krypton)
From page 39...
... Venting BWR containments through the suppression chamber is preferred because the vent gases can be passed through the suppression pool to scrub out aerosols. The reactor building, which serves as a secondary containment, can also be used to reduce aerosol releases when the containment is bypassed or develops a leak as happened at the Fukushima Daiichi plant (see Chapter 4)
From page 40...
... FIGURE 2.4  Estimated thermal power output of reactor cores at the Fukushima Daiichi plant following shutdown. SOURCE: Based on methodology used in Gauntt et al.
From page 41...
... If cooling is lost, the suppression chamber can be vented to the atmosphere to reduce pressures and temperatures. The suppression pool water can be used to filter out radioactive material before venting (Sidebar 2.2)
From page 42...
... ECCS = emergency core cooling system, HPCI = high-pressure coolant injection, HPCS = high-pressure core spray, RFP = reactor feedwater pump, RCIC = reactor core isolation cooling, and SRV = safety relief valve. SOURCE: Information taken from Boiling Water Reactor GE BWR/4 Technology Advanced Manual (available at http://pbadupws.nrc.gov/docs/ML0230/ML023010606.pdf)
From page 43...
... BWR/2, Mark I with IC Nine Mile Point 1 New York Oyster Creek New Jersey BWR/3, Mark I with IC (similar to Fukushima Daiichi Unit 1) Dresden 2 Illinois Dresden 3 Illinois BWR/3, Mark I with RCIC Monticello Minnesota Pilgrim 1 Massachusetts Quad Cities 1 Illinois Quad Cities 2 Illinois BWR/4, Mark I (similar to Fukushima Daiichi Units 2-4)
From page 44...
... . In BWRs, gases can be vented through the suppression pool prior to release to "scrub out" some of their radioactive constituents.
From page 45...
... . NOTE: D/W = drywell, PCV = primary containment vessel, RPV = reactor pressure ves sel, S/C = suppression chamber, SRV = safety relief valve.
From page 46...
... • Reactor core isolation cooling (RCIC) system: Used in BWR/4s, including Units 2-4 at the Fukushima Daiichi plant, BWR/5s, BWR/6s, and the Advanced Boiling Water Reactor.
From page 47...
... Once closed, the valves inside containment cannot be reopened unless AC power is available.13 This system logic affected the operation of the valves for the IC in Unit 1 of the Fukushima Daiichi plant during the accident (see Chapter 4)
From page 49...
... residual heat removal (RHR) system for Units 2 and 3 at the Fukushima Daiichi plant.
From page 50...
... Black indicates valve closed during normal operations; white indicates valve open during normal operations. Power sources to operate the valves (AC or DC power)
From page 51...
... system for Units 2 and 3 at the Fukushima Daiichi plant. Valves are indicated by connected triangles.
From page 52...
... In the case of an extended loss of AC power, such as occurred at the Fukushima Daiichi plant following the tsunami, the RCIC system may stop operation for the following reasons: • DC power for the failsafe logic control has failed, causing the system's valves to close (if motive power for the valves is still available)
From page 53...
... system for Units 1-3 at the Fukushima Daiichi plant. Valves are indicated by connected triangles.
From page 54...
... Consequently, it is essential to protect the batteries and circuits used to carry DC power through the plant so that these will continue to function even when AC power is lost. 2.3  NUCLEAR PLANTS IN JAPAN Prior to the Fukushima Daiichi accident, Japan had 54 operating nuclear power reactors at 16 sites (see Figure 2.10 and Table 2.3)
From page 55...
... All nuclear reactors in Japan must undergo a safety review by the new nuclear plant regulator (Nuclear Regulation Authority; see next section) before they can be restarted.
From page 56...
... TABLE 2.3  Operating Nuclear Plants in Japan Prior to the Fukushima Daiichi Accident 56 Reactor and Thermal Capacity Commercial Plant Name Unit Containment Type (MWt) Operation Licensee Fukushima Daiichi 1 BWR-Mark I 1,380 1971 TEPCO 2 BWR-Mark I 2,381 1974 3 BWR-Mark I 2,381 1976 4 BWR-Mark I 2,381 1978 5 BWR-Mark I 3,293 1978 6 BWR-Mark II 1979 Fukushima Daiini 1 BWR-Mark II 3,293 1982 TEPCO 2 BWR-Mark II (Improved)
From page 57...
... Kashiwazaki-Kariwa 1 BWR-Mark II 3,293 1985 TEPCO 2 BWR-Mark II (Improved) 3,293 1990 3 BWR-Mark II (Improved)
From page 58...
... SOURCES: Nuclear Regulation Authority, written communication; IAEA (2014b)
From page 59...
... 35,000 30,000 25,000 20,000 15,000 10,000 5,000 0 J F M A M J J A S O N D J F M A M J J A S O N D J 2011 2012 2013 Month FIGURE 2.11  Electrical generating capacity from operating Japanese nuclear power plants prior to and following the Fukushima Daiichi accident. SOURCE: Electrical generating capacity from Nuclear Regulation Authority, written communication; Figure 2-11 reactor shutdown dates from NRA (2013a)
From page 60...
... ; they will not be allowed to return to METI or MEXT in the future because they were hired by the NRA under a "no-return" rule. 2.4  NUCLEAR PLANTS IN THE UNITED STATES There are 100 nuclear power reactors currently licensed to operate at 65 sites in 31 states (Figure 2.13, Table 2.4)
From page 61...
... BACKGROUND ON JAPANESE AND U.S. NUCLEAR PLANTS 61 FIGURE 2.13 Locations and names of currently operating nuclear plants in the United States.
From page 62...
... Operation Licensee Arkansas Nuclear 1 PWR-DRYAMB 2,568 1974 Entergy 2 PWR-DRYAMB 3,026 1980 Beaver Valley 1 PWR-DRYAMB 2,900 1976 FirstEnergy 2 PWR-DRYAMB 2,900 1987 Braidwood 1 PWR-DRYAMB 3,587 1988 Exelon 2 PWR-DRYAMB 3,587 1988 Browns Ferry 1 BWR-Mark I 3,458 1974 Tennessee Valley Authority 2 BWR-Mark I 3,458 1975 3 BWR-Mark I 3,458 1977 Brunswick 1 BWR-Mark I 2,923 1977 Carolina Power & Light 2 BWR-Mark I 2,923 1975 Byron 1 PWR-DRYAMB 3,587 1985 Exelon 2 PWR-DRYAMB 3,587 1987 Callaway PWR-DRYAMB 3,565 1984 Union Electric Calvert Cliffs 1 PWR-DRYAMB 2,737 1975 Calvert Cliffs 2 PWR-DRYAMB 2,737 1977 Catawba 1 PWR-ICECND 3,411 1985 Duke Energy Carolinas 2 PWR-ICECND 3,411 1986 Clinton 1 BWR-Mark IIIa 3,473 1987 Exelon Columbia 2 BWR-Mark II 3,486 1984 Energy Northwest
From page 63...
... B Robinson 2 PWR-DRYAMB 2,339 1971 Carolina Power & Light Hope Creek 1 BWR-Mark Ib 3,840 1986 PSEG Nuclear Indian Point 2 PWR-DRYAMB 3,216 1974 Entergy 3 PWR-DRYAMB 3,216 1976 J
From page 64...
... TABLE 2.4  Continued 64 Reactor and Thermal Capacity Commercial Plant Name Unit Containment Type (MWt) Operation Licensee LaSalle 1 BWR-Mark II 3,546 1984 Exelon 2 BWR-Mark II 3,546 1984 Limerick 1 BWR-Mark II 3,515 1986 Exelon 2 BWR-Mark II 3,515 1990 McGuire 1 PWR-ICECND 3,411 1981 Duke Energy Carolinas 2 PWR-ICECND 3,411 1984 Millstone 2 PWR-DRYAMB 2,700 1975 Dominion 3 PWR-DRYSUB 3,650 1986 Monticello 1 BWR-Mark I 1,775 1971 NSP Minnesota Nine Mile Point 1 BWR-Mark I 1,850 1969 Nine Mile Point Nuclear 2 BWR-Mark II 3,988 1988 North Anna 1 PWR-DRYSUB 2,940 1978 Virginia Electric & Power 2 PWR-DRYSUB 2,940 1980 Oconee 1 PWR-DRYAMB 2,568 1973 Duke Energy Carolinas 2 PWR-DRYAMB 2,568 1974 3 PWR-DRYAMB 2,568 1974 Oyster Creek 1 BWR-Mark I 1,930 1969 Exelon Palisades PWR-DRYAMB 2,565 1971 Entergy Palo Verde 1 PWR-DRYAMB 3,990 1986 Arizona Public Service 2 PWR-DRYAMB 3,990 1986 3 PWR-DRYAMB 3,990 1988
From page 65...
... E Ginna Nuclear Saint Lucie 1 PWR-DRYAMB 3,020 1976 Florida Power & Light 2 PWR-DRYAMB 3,020 1983 Salem 1 PWR-DRYAMB 3,459 1977 PSEG Nuclear 2 PWR-DRYAMB 3,459 1981 Seabrook 1 PWR-DRYAMB 3,648 1990 NextEra Seabrook Sequoyah 1 PWR-ICECND 3,455 1981 Tennessee Valley Authority 2 PWR-ICECND 3,455 1982 Shearon Harris 1 PWR-DRYAMB 2,900 1987 Carolina Power & Light South Texas 1 PWR-DRYAMB 3,853 1988 STP Nuclear 2 PWR-DRYAMB 3,853 1989 Surry 1 PWR-DRYSUB 2,857 1972 Virginia Electric & Power 2 PWR-DRYSUB 2,857 1973 65 continued
From page 66...
... NOTES: Reactor types: BWR = boiling water reactor; PWR = pressurized water reactor. Containment types: DRYAMB = dry, ambient pressure; DRYSUB = dry, subatmospheric pressure; ICECND = wet, ice condenser; Mark I = wet, Mark I; Mark II = wet, Mark II; Mark III = wet, Mark III.
From page 67...
... . Most of the currently operating nuclear plants in the United States have received or are seeking 20-year license renewals, which would extend their operating lives to 60 years.
From page 68...
... Hardened vents were also installed at all eight of the Mark I BWR plants in Japan. Following the Fukushima Daiichi accident, the USNRC issued a new order25 to Mark I and Mark II BWR licensees to design and install "Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions" (see Chapter 5 and especially Appendix F)
From page 69...
... This practice was adopted worldwide. Following the Fukushima Daiichi accident, the USNRC examined the need for additional hydrogen control measures but decided not to take immediate action (see Chapter 5)
From page 70...
... nuclear plants with multiple redundant AC power sources (e.g., 13 emergency diesel generators at the Fukushima Daiichi plant) and backup batteries (trains of battery-powered 125VDC and 250VDC power sources)
From page 71...
... and were incorporated into reactor designs that were being developed by Japanese vendors for sale in the United States.


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