ML20097B293

NRC Regulator of Nuclear Safety

ML20097B293
Person / Time
Issue date:	04/30/1992
From:	NRC
To:
References
NUREG-BR-0164, NUREG-BR-164, NUDOCS 9206050015
Download: ML20097B293 (26)

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NRC NRC-REGULATOR OF NUCLEAR SAFETY The U.S. Nuclear Regulatory Com-WHY REGULATE 7 mission (NRC) was formed in 1975 to regulate the various commercial and in.

The nuclear industry is strictly regu-stitutional uses of nuclear energy, in.

lated because of the potential hazards ciuding nuclear power plants. The involved in using radioactive materials.

agency succeeded the Atomic Energy These radioactive materials give off Commission, which previously had re-

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sponsibility for both developing and regulating nuclear activities, Federal re-search and development work for all en-ergy sources, as well as nuclear weap-ons production, is now conducted by the Department of Energy.

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tals, academic activities at educational K$ *,.[N E institutions, research work, and such in-dustrial applications as gauges and i"i L

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The NRC places a high priority on keeping the public informed of its work.

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f hearings, public meetings in local areas, and discussions with individuals and organizations the agency recog-fnan"y' s o"$c e s""c"o"s"M[r"a" din [o"N a"eN.

nizes the interest of citizens in what it diation erom redioactive eiements in soti and rock, and radiation *rorn medical and dental v. rays and does.

other medical procedures.

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NRC radiation, which can be hazardcas to tion, the NRC requires users to take people if they are exposed to it in signifi-steps to keep exposures well below the cant amounts. The extent of the risk de-

limits, pends on the type and amount of radia-tion cmitted by the radioactive material, the distance between the source of the NRC ORGANIZATION rad;ation and a person, and the length of time a person is exposed to the rLdia.

The NRC is headed by a five-mem-tion.

ber Commission with Commissioners appointed to five-year terms by the The risks can be lessened by reduc-President of the United States with the ing any or all of these factors. The haz-confirmation of the Senate. A Chairman ard is less if there is a shielding material is designated by 'he President.

like lead or concrete to block some of the radiation, if a person moves farther The NRC sta'i numbers approxi-from the radiation source, or if tha expo-mately 3,3 ) with a budget of over $500 rnillion. Some two-thirds of the NRC em-sure time is reduced.

ployees work in the agency's Head-if radioactive materials are properly quarters in Rockville, Maryland, or handled and regulated, they do not nearby offices. The remainder are 10-pose a significant risk to the pubiic or to cated in five regional offices throughout

workers, the country or at resident inspection of-fices at each commercial nuclear power Radioactivity f rom natural sources is plant.

present throughout ine world. People are continually exposed to low-level radiation from radioactive materials in NRC REGULATIONS the earth and frorn cosmic rays from space. Exposure to natural radiation The NRC sets the rules that users of can be affected by geography as well as radioactive materials must fo!:ow.

lifestyle. For example, radiation levels These rules are intended to protect the are higher in the mountains, and travel persons using the radioactive materials by airplane contributes additional expo-and the general public from the poten-sure because of increased cosmic tial hazards of radioactivity. Many NRC radiation at high altitudes. Most people regulations have been established or also receive some radiation exposurn chcnged, as necessary, based on the from medical and dental x-rays and recommendations of the NRC staff.

other medical procedures.

Members of the public and interested organizations can also request changes The NRC's regulatory program es-in regulations.The views of the public, of tablishes lirnits for radiation exposure to the industry being regulaMd and of workers and the general public as a re-other interested parties are usually so-sult of the various uses of radioactive hcited before new rules or changes are materials licensed by the NRC. In addi-adopted.

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• rLMOIT Wit.Cftw f. Mire The 14RC Headquarters is located in Rockville, Maryland, outside Washington, D.C. There are five regional offices and also resident inspection offices at each nuclear power plant.

REGULATORY RESEARCH materials must obtain a license. The use of very small amounts of radioactive As part of its regulatory program, the materials-like the tiny radiation source NRC conducts an extensive research inside many smoke detectors-is ex-program to provide independent empt from licensing or is authorized by information and expertise to support its a general license, which does not re-safety decision-making and to assess quire active control to assure safety, potential tt.nicalissues. This NRC re-However,forthe manufacturing of these search is periormed by government and similar items a specific !; cense laboratories, universities, and other re-involving regulatory control is required.

search institutions. Topics of inquiry in-clude such subjects as the durability and integrity of reactor components, Licenses for nuclear power plants the impact of natural phenomena like and their operators are issued by the earthquakes and tornadoes on nuclear NRC. Licenses for other uses of radio-facilities, radioact:ve waste disposal active materials are issued either by the technology, and how workers react t NRC or by State governments under instruments and systems in nuclear fa-NRC-approvuJ regulatory programs.

cilities.

There are about 8,500 licenses for LICENSES radioactive materials under the jurisdiction of the NRC and 15,000 un-Any organization or individual in-der the jurisdiction of those States tending to possess or use radicactive known as Agreement States which 3

l NRC regulate certain radioactive materials Combined licenses also incorporate a under agreements with NRC.

program of icsts, inspections and re-lated acceptance criteria which are nec-States also have regulatory jurisdic-essary and sufficient to show that the tion over certain radioactive substances plant has beca prouerly built. These cri-which occur naturally (primarily radium teria must be met before operation caa and radon) or are produced by begin.

machines called particle accelerators.

This process prevides for public hearings on the certification of the stan-The NRC or State license specifies dard design. There would also be public the types and quantities of radioactive hearings on the site approval and on the materials that may be possessed and issuance of a combined construction used as well as any specific restrictions and operating license. As the plant on their use. Typically, licenses will de-nears completion, a public hearino scribe the location of use, the training could be held if there is a significarit and qualifications of workers, specific question on whether the criteria of the procedures for using the materials, and combined cor 'ruction and operating any special st iety precautions required.

license have t 1 met.

The license holder must follow the spe-cific license requirements as well as the The licen 3 for nuclear power more general NRC regulations.

plants are issued for a 40-year period.

Licenses for currently operating plants will begin to expire after the year 2000.

POWER PLANT LICENSES The NRC has developed criteria to be used if utilities seek to have the licenses For nuclear power plants, there have been two types of licenses-a Con-extended for an additional period.

struction Permit, which allows the facility Licenses for nuclear power plants to be built, and an Operating License, can be amended and updated as the re-which permits operation of the facility sult of operating experiences at that once it is completed, plant or at other plants. When neces-sary, the NRC can impose new regula-In 1989 the NRC adopted a stream ~

tions or require changes in operating lined licensing process which encour-procedures or equipment to improve ages the use of standardized and pre-the safety of nuclear power plant opera-approved designs for any future plant tions.

proposals and provides for the issu-anceof acombined constructionpermit in addition to licensing the facility, and operating license. Another feature the NRC also licenses the individuals of the streamlined process is possible who operate the controls of the reactor.

early approval of sites for nuclear plants.

There are two categories of licenses-This combined licensing process pro-Reactor Operator and Senior Reactor vides for the early resolution of virtually Operator. The second type is for all issues before construction begins.

supervisorv positions. Before Operator 4

NRC Ucenses are issued, individuals must The core of the NRC inspection pro-complete an extensive training program gram for nuclear power plants is per-conducted oy the utikty and pass forn,si by the resident inspectors, with license examinations administered by at least two inspectors assigned to each NRC examiners. Once licensed, the op-site.

erators continue to receive training and are periodically tested to show they re-main qualified to operate the plant, F l'1T'm~i

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activities comply with NRC regulations

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and the terms of their licenses. These in-

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quency according to the relative hazard of the authorized activities.Throughout

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the construction and operating life of a f,,l 'g;g

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cach year. A small medical or research Dh

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formed by teams made up of personnel from the regional offices and from NRC headquarters. Normal inspections con-sist of examination of a sample of the work being performed by a utility.11 evi-tmC retent inspectors are assigned to each dence of problems is found, the inspec-nuclear powe plant with additionalinspections tor will focus on that work area in more performed by specialists from NRc regional of-fices and headquarters.

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NRC OTHER USES OF RADIOACTIVE MATERIALS

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Radioactive materials are used Other commercial and industrial in a wide variety of applications be-uses, including testing devices and sides fuel for nuclear power plants.

gauges to 'casure such charac-teristics as soil density or levels of a These applications include:

substance in processing equip-Medical radiation therapy and ment.

diagnostic tests using radioac-tive pharmaceuticals.

Various research activities.

Consumer products like smoke Each of these uses requires an z

detectors, gas lamp mantles, NRC or Agreement State license, and static el,m,ination devices, and i

the activities are periodically inspected luminous watch dials.

by NRC or state personnel. Violations of Industrial radiography, using NRC requirements are subject to the sealed radiation sources to same enforcement options as nuclear make x ray-like pictures of power plants, although the level of fines heavy metal objects like pipes imposed are normaily substantiaily and valves.

lower.

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NRC The inspection specialists, based in For more serious violations or repeti-regional offices, review plant security, tive ones, the NRC may fine utilities and emergency

planning, radiation other licensees up to $100,000 a day for protection, environmental monitoring, each violation.

periodic testing of plant equipment and in cases where there are serious systems, fire protection, ccnstruction questions about the safety of NRC-activities, and other more specialized licensed activitien, the NRC may issue areas.

Orders requiring that licensed activities be ha'ted or an individuai removed from Durinq' the course of a year, there work involving NRC-licensed matenais.

may be 1O to 30 of these routine inspec-NRC Orders also may modify, suspend, tions by NRC specialists at each nuclear or revoke a license.

power plant, depending on the activities underway at the plants and problems Licensed activities,if halted, may not which may occur.

be resumed until the safety and man-agement problems are corrected, and 9

The special team inspections may the NRC approves the resumption of focus en a specific plant activity, like work.

maintenance or security, or a team may Alicensee orindividual who chooses be sent to the plant to look at a specific operating problem or accident.

to contest a fine or an Order has the right to a hearing before the NRC.

All inspections and the findings by The results of the NRC irispection the inspectors are documented in in-program for each nuclear power plant spection reports. These reports are are periodically compted with other sent to the facility to inform the utility of agency evaluations in a review called a the findings. Inspection reports are also Systematic Assessment of Licensee j

maintained for public review in a public Performance (SALP) report. These re-library near each plant site and :! the ports, issued every 12 to 24 raonths, are NRC Public Document Room in Wash-public documents and are reviewed ington, DC. (Certain sensitive informa-with the utility in a meeting open to th tion-principally on nuclear facility se-public.

curity-may be withheld from public disclosure.)

The NRC occasionally receives alle-gations of wrongdoing involving mis-When the inspections disclose viola-conduct by licensees or their contrac-tions of NRC requirements, the agency tors. Allegaf.ons of possible criminalac-has a range of enforcement actions.

tivities are handled by the orofeosional The basic step is a Notice of Violation, investigative staff of tn# ' Mice ofIn-which requires the licensee to correct vestigations. These investigations may

$5 the problem and take steps to prevent a result in civil enforcement action or recurrerne of the violation. This re-criminal prosecution against licensees, sponse must be acceptable to the NRC.

individuals, or others.

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Energyis rete ased when an atom splits Into smatter pieces. These smaller pieces strike other atoms, reteas-Ing more energy. This continuing splitting of atoms in a reactor is called a chain reection.

HOW A NUCLEAR The turbine is connected to a gen-POWER PLANT WORKS erator. As the turbine shaft spins, the generator turns and produces electric-ity. This electricity is then carried by Power plants change one form of wires to the homes, businesses, and in-energy into another. Electrical generat-stitutions which use the e!ectricity, ing plants convert heat, the energy of wind or falling water, or solar energy into (Electricity is one of the few forms of electricity, energy that can easily be moved from one place to another. Electri;al energy Anuclear power plantit one of those can be produced in large quantities at plants that converts heat into electricity.

one location and transported by wires to Other types of heat conversion plants many different places.)

burn coal, oil, or gas for a heat source which is used to produce electricity.

We can see coal, oil, or gas burn-ing-and we know from experience that The heat-no matter what the it produces heat. This is the same sort of sou.ce-is normally used io heat water energy many people use to heat their to the boiling point and produce steam.

homes. Some furnaces heat air, which This steam is then carried by pipes to a is blown through ducts into each room; turbine-which has a series of fan others heat water which is piped blades on a shaft. The force of the throughout the house into radiators steam pushes against the blades, turn-where the water gives off some of the ing the turbine.

heat it absorbed from the burning fuel.

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Nuclear energy-as it is used in a M

mrm nuclear power plant-cannot be seen.

4 s,m There is no burning of fuelin the usual

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sense. Rather, energy is given off by the "TNeu7

h. sm nuclear fuel as certain types of atoms 6

split intu pieces. This energy is in the form of f st moving particles and invis-ible radiation. As the particles and radia-tion move through the fuel and sur-

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rounding water, the energy is converted into heat.

The heat is the useful energy result-ing from the splitting of atoms. The ra-E

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tect people and the environment.

To understand this process let's

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look at a nuclear reactor-which is a large water-filled vessel containing the l#

W E;V) nuclear fuel. Water in the reactor is Ai l

heated by the nuclear reaction - and the j.7

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heat is carried off to spin the turbine.

_ FUEL CENTP

' ECD URANIUM FUEL 6

l The fuel of a nuclear plant is ura-The fuel rods in the reactor contain hundrods of nium, but only a certain type of uranium ceramic pellets of uranium fuel. Each rod is atom can be easily split to produce en-sealed to prevent radioactive byproducts from ergy. This type of uranium atom - called entering the cooling water which surrounds the fuei. m fuei r os are grouped into bundies or uranium-235-is less than 1 bercent of assemblies. Controt rods in the re actor regulate uranium as.t is m.ined. To make fuel for the energy being produced.

i reactors, the uranium ore is purified and then processed to increase the percent-age of uranium-235 to 2 to 4 percent of Uranium fuel is formed into small the uranium. This percentage is enough cylindrical pellets, about the size of a for a continuous splitting of uranium at-finger tip. These pellets are then loaded oms-but much less than the percent-into metal tubes about 12 feet long.

age necessary for a nuclear weapon These tubes, called fuel rods are which requires almost 100 percent pu-sealed and assembled into bund. s or rity of uranium-235. The low percentage assemblies. The fuel assemblies are of uranium-235 in reactor fuelis one of produced at several commercial the reasons a plant can never explode facilities for shipment to the nuclear like an atomic bomb.

plants to be loaded into the reactor 9

NRC When a uranium-235 atom splits-or " fissions," to use the technical term -

it gives off energy in the form of radiation d.h p "'mw,

and also fast-moving pieces of the origi-q h

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called a neutron, can collide with an-p!

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1 other uranium 235 atom and cause it to O

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enough to use as anenergy source.The pieces fly away too fast and don't cause the fission of another atom to occur. The A pressurized water reactor (PWF1) circulates water through the reactor under pressure, The pieces need to be slowed down so that heated water goes to a large cyiinder called a they can collide with another ura-steam penerator where it heats another water nium-235 atom and continue the chain system t make steam. ms steam spins the tur-bine-generator to make electricity, reaction.

Several types of materials can be two thirds of the reactors are pressur-used to slow down the atomic particles, ized water reactors with one third being but most nuclear power plants (int ad-boiling water reactors.

ing all of those now operating in the United States) use water as the " mod-The pressurized water reactor is a erator"-the. material which slows the two stage system which keeps the particles down to allow the chain reac-water in the reactor under high presstae tion to continue.

so that it does not boil. Piping carries this heated water to large cylinders To control the chain reaction-and called steam generators. The heated re-to stop it once it is started-reactors actor water flows through thousands of have control rods which can be inserted tubes in the steam generator. The tubes into the reactor to absorb the neutrons re surrounded by a secondary water as they are given off, thus slowing or cupply that boils and produces steam stopping the chain reaction.

which is camed away by pipes to spin the turbine generator.

TWO REACTOR TYPES The reactor cooling water then re-turns to the reactor to be reheated and There are two main types of reactors circulated back to the steam generator in operation in the United States-the again in a continuous loop.

pressurized water reactor (PWR) and The boiling water reactor is a single the boiling water reactor (BWR), About stage system which allows the water in 10

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the reactor, but only through the con-denser tubes to cool the steam after it sim M-+

goes through the turbine. There is no N*'

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f-Eued water and the reactor cooling water or RMfg;.,.j. c.g

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other types of power plants or industrial J

facihties use cooling towers, cooling gn takes or ponds, or other techniques to

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reduce the effects of discharging heated water directly back into the river, A boiling water reactor (DWm sends steam from lake, or ocean. With cooling towers the the reactor directly to thi ? tbine generator to Water, once cooled,.is usually pumped provide electricity. After pasek g through the tur-blne the tteam is cooled, becomlnt; water again.

baCk into the condenser to be used This water is then pumped back to f 4e reactor to again to Carry off heat. Only a smal por-be reheated.

tion of the water.is returned to the natu-ral water source.

the reactor to boil and produce steam Once the steam is produced, the which is then piped directly to the tur-process and equipment used to gener-bine generator.

ate electricity is similar in both nuclear In both types of reactors, once the power plants and fossil-fueled power steam loses its energy in spinning the plants. Fossil-fueled plants also dis-turbine, it flows intc a condenser. Be.

charge heated water to the environment cause not all the heat energy in the or use cooling towers or other means to steam can be converted into electricity, cool the water from the condenser.

the leftover heat must bn carried away by cooling water which is pumped RADIOACTIVE BYPRODUCTS through the condenser. The condenser co.itains thousands of tubes carrying Because the fission reaction pro-rcol water which causes the steam to duces radioactive materiab which can condense back to water. The water is be hazardous, nuclear power plants are collected in the condenser and pumped equipped with safety systems to protect back to be reheated, either in the reac-workers, the public, and the environ-tor itself for a BWR or in the PWR stearn ment.

generator.

Radioactive materials require careful The condenser cooling water is use because they produce radiation-a drawn from a lake, river, or ocean. This form of energy which can damage hu-water does not actually pass through man cells and, depending on the 11

NRC amount and duration of the exposure, Although the effects ol very low levels of can potentially cause cancer over long rad:ation are difficult to detect, the NRC

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periods of time. There are two possible I:m*ts are based on the conservative as-ways a person can be exposed to radia-sumotion that radiation exposures to tion. Intemal exposures occur if a radio-members of the pubhc should only be a active material is inhaled or ingested sma!I fraction of what they receive from and rernains deposited in the body.

natural environmental radiation.

External exposures can resu!t from a Experience has shown that nuclear person being close to a radioactive ma-lants typically reicase only a small por-tenal without adequate shielding.

tion of the NRC limits during normal op-In the reactor, rnost of these hazard-erations. A person spending a full year ous radioactive substances--called fis-at a nuclear plant boundary would re-sion by-products -are trapped within ceive a radiation exposure of less than 1 the fuel pellets themselves or the sealed percent of the radiation exposure every-metal tubes holding the fuel. Small one receives from naturally occurring amounts of these radioactive fission radiation. (Natural environmental radia-byproducts. principally gases, how-tion exposures average 300 millirems ever, become mixed with the water per year while the year-round exposure passing through the reactor. Other im-at the plant boundary is 1 to 2 millirems purities in the water are also made ra-or less.)

dioactive as they pass through the reac-The NRC also sets limits for radiation tor. The water is processed and filtered exposure to individuals working at nu-to remove these radioactive impunties e ear plants and other facihties using ra-and then returned to the reactor coolin0 dioactive materials. Because these indi-system. Some small quantities of radio-viduals receive the radiation exposure active gases and hquids are ultimately as part of their employment and be-released to the environment under con' cLuse they receive special training on trolled and monitored conditions.

radiation protection, the occupational Radioactive materials Irme their ra-limits are higher than those permitted dioactive properties over time-some for the general public. Radiation work-are short4ved and become non-ers must wear devices to measure the radioactive forms in seconds or m!n-radiation they are exposed to.

utes. Other radioactive elements take The envlronmentalimpact of routine much longer to lose their radioactivity, o erations at a nuclear plant is very This process is called radioactive de-small But because of the radioactivity cay.

remaining in the reactor fuel, there must The NRC has established limits for be effective safety systems to prevent the release of radioactivity during rou-an accident that would lead to a large tine operations. These limits are based amount of that radioactivity being re-on guidehnes set by the Environmental leased from the plant. The likelihood of Protection Agency and by national and such an accident is remote, but the pos-international standard setting groups.

sibihty that one could occur leads to 12

NRC 1.

A method to quickly shut down a re-N actor and stop the fission chain re-

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cocuac, 4

WATEE - A

./(,2. Numerous systems to control reac-TDg tor pressure and to continue cool-ing the reactor fuel-that is, to carry

% pg ggg away the heat that continues to be

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E'ectrical, control, and instrument systems for the safety systems and 1

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to monitor reactor conditions.

1. 1 4.

Methods of containing radioactivity

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J M MLP/AD AlyJLlARY SOILDIN(5 SHUTDOWM SYSTEMS

((cMTAINMENT)

Each reactor has a system to insert the control rods into the reactor core A nuclear power plant includes 11e I,a!! ding hous-within seconds to stoP the fission reac-Ing the reactor and cooling system comfonents; the auxillary building with the controt room andlm.

tion. This immediate chutdown-called portant safety equipment; and the turbine building a re8CIOr " scram" or reactor " trip"- can where electricity is produced. Many nucleor plants be tri gered by a reactor operator or by-0 also have cooling towers to cool water which has been used to condense steam passing throu0h automatic controls which protect the the turbine. Water for this condensing function reactor frOm any unusual Conditions in comes from a river, take or ocean-and uoes not pass through the reactor itself.

the plant.

COOLING AND PRESSURE CONTROL SYSTEMS special care in design, construction,

. When a reactor is eperating, the heat and operation of nuclear power plants, energy from the fissrJn reaction is car-ried off in the cooling water.That energy

- REACTOR SAFETY SYSTEMS is used as steam to spin the turbine-generator, making electricity. A reactor A nuclearpower planthasfour major shutdown stops the fission reaction, but types of safety systems to prevent acci-there is se!! heat being generated by the dents and reduce their effects if one radioactive fission by-products which should occur:

have built up in the reactor fuel. There is 13

NRC much less heat being created than SAFETY SYSTEM POWER when the reactor is operating, but the heat is still sufficient to damags.he fuelif Most of the safety systems are pow-it is not cooled. As time passes after the cred by electricity, although some reactor shutdown, the amount of heat pumps do use steam to drive them in or-being produced in the f uel in the reactor der to have an alternate source of core decreases. Continued cooling of power. Because of this reliance on elec-the fuel remains necessary, however.

trical power, nuclear plants are required There are both normal cooling systems to have multiple sources of electricity.

and emergency coohng systems A nuclear plant uses a portion of the available. Each system has at least two powcr it generates to run plant equip-parallel parts so that if one fails, the ment. A plant also rnust have at least other part of the system would still be w c nne ons eu s cWcal available to continue to cool the reactor.

distribution system so that it can imtne-diately shift to offsite power sources if a shutdown occurs. Should there be a The Emergency Core Cooling' Sys.

Hum n Mshe powa connechons, tem (ECCS) consists of pumps and each plant has emergency diesel gen-valves and pipes which are independent erators installed onsite with sufficient ca-of the normal cooling system. The pacity to supply electricity to the entical ECCS includes equipment that can safety systema pump at high pressure to inject water into the reactor when the pressure in-The control and instrument systems side is at the high levels maintained dur-normally use direct current (DC) elec-ing operation. There are also low pres.

tricity, the kind of power found in batter-sure systems to pump water at lower ies. For these systems there are large pressures, such as might occur if a banks of batteries to provide DC power cooling water pipe broke and allowed if there is an interruption in the normal sources of electricity.

pressure inside the reactor to drop, The reactor systems also includ CONTA!NING RADIOACTIVITY I

valves which can be opened to reduce pressure by releasina steam. These re-lief valves open autorbatically if pressure There are three principal barriers to prevent the release of radioactivity-the gets too high in the reactor system.

S z aled fuel rods, the reactor vessel and Some of the valves can be opened us-associated components, and the struc-ing controls in the reactor control room.

ture housing the reactor, called the re-These pressure reduction systems can actor containment.

also be used to reduce reactor pressure so that the low pressure cooling sys-A serious reactor accident could tems can function.

damage the fuel rods, which form the 14

NRC first barrier, if adequate cooling does C.OMTAJMMEN7 not occur. Overheated fuel rods can p

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leak or break apart and eventually melt.

s Possible damage to the reactor cooling k,

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system piping could breach the second TORS

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barrier.

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Even with the failure of these first two I C 1

barriers, the reactor containment is de-

.) h signed to hold radioactive material that

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pressure suppression containment, gy has a large water-filled pool to cool the steam and reduce the pressure buildup WACTOR. VESSEL in the containment.

The reactor containment is a sealed reinforced concrete and steel structure which surrounds The NRC requires that the reactor the reactor. it is oesigned ta hold in radioactive containment be periodically tested to gases that might be released by a pipe break or thu rnajM reactor accident.

show it meets requirements to prevent leakage from inside the structure.

of radioactive gases through seals and While reactor containments were gaskets around the containment. The designed to cope with many types of se-molten fuel could also damage the con-rious reactor accidents, they may not crete base of the containment, leading withstand the conditions that result from to a possible release of radioactivity.

an extremely unlikely accident in which Even in these cases, however, most of all cooling capability is lost in the reac-the long-term hazardous radioactive tor. Under these circumstances, the en-material would remain inside the con-ergy produced by the radioactivity re-tainment structure.

maining in the fuel could cause the fuel in the only major commercial power to melt. Melting of the fuel could eventu-reactor accident in the United States, ally lead to a pressure buildup in the the Three Mile Island accident in 1979, containment that could cause leakage there was extensiw fuel damage.

15

NRC Radioactive gases and contaminated been prepared and the operators have cooling water filled the containment.

been trained in their use. In addition, Although there was some release of ra-most nuclear power plants use com-dioactivity to the atmosphere by an indi-puter-based simu!ators for training in rect route, the containment itself per-both routine and abnormal situations.

formed as designed and kept the radio ~

These simulators are laid out just like the activity safely bottled up inside. The ef' p ant's control room with all of the con-fectiveness of the containment was the trols and instrumentation. Computers major factor,n preventing release of i

e the operators practice dealing with large amounts of radioactive matenals endes as tW ont in m e to the environment, g

In 1986 a much more serious accident occurred at Chernobyl in the The Three Mile Island accident also Soviet Union. This plant used a much pointed out the need for improved plan-different type of reactor from those in ning by Federal, State, and local gov-the U.S. It had no containment system ernments to deal with possible reactor like that of U.S. plants. The Chernobyl accidents. The NRC now requires that accident severely damaged the reactor emergency plans be prepared for core, releasing large quantities of evacuation or other actions to protect radioactivity to the environment. Radio-the residents in the vicinity of nuclear active contamination was deposited in plants. These plans usually cover an nemby countries and was even detect-area about 10 miles in all directions able at very low levels in the U.S' around each nuclear plant. The utility has its own emergency plan to notify government officiais of a possib!e emer-WHAT IF?

gency and to provide them with infor-mation and recommendations. State and local governments have detailed Although a major reactor accident is plans for sheltering and evacuation of unlikely and each plam is equipped with residents if necessary. Federal emer-safety systems to prevent or cope with gency plans include Federal personnel, an accident, additional measures help equipment, and resources needed to protect the public heath and safety.

t espond to a nuclear power plant acci-The first is special training given to dent. The NRC would closely follow the the reactor operators in the handling of handling of an accident by a utility and emergency situations. One of the investigate the causes of the accident, lessons learned as a result of the Three Mile Island accident was that reactor op-These emergency plans are tested erators needed to practice how they through emergency exercises which would handle emergencies. Detailed simulate a serious reactor accident. Util-emergency operating procedures have ity personnel and government officials 16

NRC pt NUCLEAR INSURANCE 7

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Congress has estabhshed a system y

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coverage in the event of a major reactor

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known as the Price Anderson Act, com-l b.

bines commercial insurance and self-

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insurance by the nuclear industry.

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Large nuclear plants are required to

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have the maximum amount of liabihty in-y

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surance which is commercially avail-I T

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able, currently $200 million. In addition, t

each licensed reactor is liable for a $03 j

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v 61 million assessment to provide funds in mm y

y the event of a major accident at a plant in g

the U.S. (No reactor would be assessed y

more than $10 million in any one year.)

Each nuclear plant has a warning system to notif y With more than 11 nuclear power nearby residents of emergency conditions. In-lants n the U.S., the combination of structions in the event of an emergency would be provided by state and local officials using the commerClalinsurance and industry self-cmergency broadcast system.

insuranCO exceeds $7 billion. This is the total liability limit for an accident under follow their emergency plans in gather.

the Price-Anderson Act and no claims ing information, consulting with each are required to be paid in excess of this other, and issuing instructions to the amount, but Congress will consider the public. These emergency exercises need for providing an additional source sometimes include small-scale evacu-of funds should $7 billion prove inade-ation drills for schools, nursing homes, quate.

or other institutions.

The Price-Anderscn Act provides The NRC must determine that there liability insurance coverage for actual is reasonable assurance that evacu-damages incurred by anyone affected ation or other steps can be taken to by a major reactor accident. Besides protect c ea residents in the event of a major reactor accident. To make this the coverage for offsite public liability determination, the NRC reviews the claims, the NRC requires that utikties utility's plans, conducts inspections, maintain $1 billion in onsite property and considers the assessment of State damage insurance 'o provide funds to and local planning by the Federal Emer-deal with cleanup of the reactor site after gency Management Agency.

an accident.

17

i NRC RADIOACTIVE WASTE pools at each reactor site and at one DISPOSAL storage facility in Illinois. From one-fourth to one-third of the reactor fuelis During normalop ns, a nuclear removed and replaced during refueling.

power plant generates,

types of ra-Reactors are normally refueled every 12 dioactive wastes-used fuel (usually to 18 months.

called spent fuel), which is considered high-level waste, and low-level wastes, Spent fuelis highly radioactive since which include contaminated equip-it contains the fission by-products that ment, filters, maintenance materials, were created while the reactor was and resins used in purifying water for the operating. One characteristic of radio-reactor cooling system. Other users of active material is that it decays or loses radioactive materials also generate low-its radioactivity at a set rate. Each radio-level wastes.

active component has a different rate of Each type of waste is handled differ.

decay called its half life-the time it takes the material to lose half of its

ently, radioactivity. Some fission by-products have a half life of a few seconds, while HIGH-LEVEL WASTE others have half-lives of hundreds or The spent fuel from nuclear power thousands of years.

plants is currently stored in water-filled When fuel is first removed from the reactor, the short-lived radioactive N % Sh:@%*h N,e-icuusasA.

u w-sw Rii y.

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Most of the highly-rad.oactive spent fuel removed from civilian nuclear power plants is stored in specially de signed water basins at the reactor rJtes. When a Federat high-level waste site becomes available the used fuel wl!I be moved there for perm:r.ent disposal.

18

NRC materials are still oresent. But over time, The Department of Ener6, (DOE) is these substances decay, leaving the developing plans for a permanent dis-longer-lived materials as the principal posal facility for spent fuel from nuclear substo ~ :es for disposal. These materi-power plants as well as for the high-level als include cobalt-60 (5-year half-life),

waste which has been produced by the cesium-137 (30-year half-life), and plu-nation's nuclear weapons production tonium-239 (24,400-year half-life),

activities.

Congress has directed DOE to fo-Special procedures are needed in cus on a proposed site at Yucca Moun-the handling of the spent fuel, since the tain in southern Nevada for tms waste radiation levels can be very dangerous disposal facility. Site studies are still un-without proper shielding. The water in derway to determine if the site is ade-the spent fuel storage pool provides quateforlong termdisposalof thehigh-adequate shielding for the radiation to level w ste.

protect workers in a nuclear plant. At some plants spent fuel is also stored in DOE would design, build, and oper-heavy metal or concrete containers ate the facility, which would be regu-placed on concrete pads adjacent to lated by the NRC. The NRC must ap-the reactor facility.

prove the site and design for the facility as well as inspect it during construction Although most of the spent fuel re-and operation.

mains stored at individual plants, there has been some shipment of spent fuel Although some nuclear plants have

~

to offsite storage facilities. One offsite adequate capacity to store the spent storage facility operates in Illinois.

fuel they generate until a DOE site is These shipments have used heavy available for disposal, other plants, par-shielded shipping con'ainers which are ticularly the older ones, may run out of designed to withstand the conditions storage space in their spent fuel pools in that might occur during a shipping acci.

the 1990s. DOE and the nuclear indus-dent. Spent fuel shipments have been trv are considering various options to both by rail and by truck. The NRC certi.

store additional spent fuel, including dry fies each shipping container that meets storage in large iron, steel, or concrete Federal requirements, and the Depart.

casks, construction of additional offsite ment of Transportation sets the rules for storage facilities, and techniques for actual transportation of the spent fuel.

storing more fuel in the existing spent fuel storage pools. Several utilities have Some of the components in spent recently begun using dry cask storage.

fuel remain hazardous for long periods of time. Permanent disposal of spent LOW-LEVEL WASTE fuel therefore requires a disposal f acility which provides reasonable assurance Low-level radioactive

waste, that the wcste will remain isolated for whether from a nuclear power plant or thousands of years.

from other users of radioactive material, 19

NRC WA U

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Commerciallow-level radioactive waste has been shipped for many years to sites in Washington, tievada, and south Carolina.

formanyyears has been shipped to one sites, or in some cases they'll use the of three licensed commercial disposal facilities that have been operating. The facilities. About 65 percent of the waste additional disposal facilities are volume is from nuclear power plants expected to be in operation in the and the remaining 35 percent is gener-1990s.

ated by hospitals, research institutes, and other users of radioactive materials.

These facilities in Nevada, South Caro.

TRANSPORTATION -

lina, and Washington are operated by commercial firms but are regulated by About 3 million shipments of rade.-

the states. At all three sites, the waste is active materials are made each year in packaged and placed in burial trenches the United States-by highway, by rail-and covered with soil.

r ad, by aircraft, and by ship. Regulat-ing the safety and security of these ship-l In 1980 Congress provided that ments is the joint responsibility of the l

- each state is responsible for assuring U.S. Department of Transportation and l

the availability of disposal capacity for the Nuclear Regulatory Commission.

L commercial low-level waste produced in the state. States could either provide The federal regulatory system pro-for disposal individually or by joining tects transport workers and the public together in a regional agreement. The by setting performance standards for individual states or state groups are in the packages and by setting limits on the process of selecting new burial the radioactive contents and radiation 20 1

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Y spent reactor fuelis carried in specially designed shipping containers 11.at are desI ned to withstand D

accident conditions without releasing their radioactive contents.

levels for packages and vehicles. Infor-tive materials each year. These ship-mation on radioactive shipments is pro-ments use packaging (classified as vided by package marking and label-Type A) that is expected to withstand ing, vehicle placards, and shipping pa-the rigors of normal transportation with-pers describing the materials.

out damage.

Tne Department of Transpcrtation The containers for larger quantities (DOT) has regulatory jurisdiction over of radioactivo ma% rials are designed to radioactive shipments while the material withstand acciderit conditions without is in transit. DOT also establishes ship-releasing their contents. These pack-ping categories, sets the standards for ages, designated as Type B, are used labeling of radioactive shipments, and for shipping industrial irradiators, medi-establishes criteria for containers used cal radiation therapy devices, and sorne for smaller quantities of radioactive ma-shipments of radioactive w1stes. The terials. The NRC, which licenses the or-accident evaluation criteria for these ganizations shipping and receiving the containers include impact, puncture, radioactive materials, assures that its li-heat, and submersion in water.

censees meet the Department of Trans-A specializedType B container isthe portation shipping requirements. The s ent fuel shipping cask, whicn is used NRC also establishes the requirements to transport used fuel from nuclear reac-for design and manufacture of pack-tors. These large shipping casks are ages for larger quantities of radioactive carried on trucks or rail cars. Like all maten,als.

Type B containers, they are sealed to Typical of small quantity ship-prevent leakage ano heavily shielded to ments-using packages meeting DOT minimize the radiation levels.

requirements-are radioactive materi-The NRC also imposes security re-als for medical diagnostic tests and quirements on spent fuel shipments therapy.

and on shipments of larger quantities of These shipments comprise the ma-highly enriched uranium or plutonium.

jor portion of all shipments of radioac-These security measures include route I

l 21

l l

NRC evaluation, escort personnel and vehi-These regulations apply to nuclear cles, communications caoabilities. and powar plants and to other facilities emergency plans.

which handle radioactive materials in forms that may require cleanup proce-State governments are notified in dures w hen the f acility is closed. Careful advance of spent fuel shipments and radiation surveys must also be per-thoselarge quantity shipments of rad;o-formed before the site can be rele ased active waste which require Type B con-for other uses.

tainers.

During the operating life of a nuclear Tne regulatory system for transpor-power plant, many plant components tation of radioactive materials has been associated with the reactor become ra-successful in minimizing the safety im-

?oactive, either through contamination pact from accidents involving the ship-or as a result of the radiation from the fis-ments. There have been few accidents sion reaction. Therefore, care is needed involving shipments of radioactive ma-in the handling of decommissioning terials (averaging less than 50 a year out work, and contaminated materials will of 3 million shipments). Only a small have to be shipped to a low-level radio-number of those accidents have in-active waste disposal site for burial.

volved any release of the radioactive contents. In these instances, radioac~

The NRC has identified two principal tive contamination has been generally plans for decommissioning a nuclear minor with no public safety conse-power plant-immediate dismantling or quences.

safe storage for a period of 30 to 50 years followed by dismantling. A third option, called entombment may also be DECOMM9SIONING available in some cases. This would in-e seahng oH radoase compo-Decommissioning is the term used nents with concrete and steel. Entomb-for ending the operation of a nucl car fa-ment would require less maintenance c6ty. Nuclear power plants are beensed and security provisions than the storage for a term of 40 years. Some plants may o tion.

be closed before that time elapses, while others may seek an extension of The storage and entombment meth-the license penod.

ods allow for a reduction in the levels of A few srmll nuclear power plants radioactivity over time. NRC studies ave been decommissioned in the past have shown that after 50 Aars, the vol-and several others are currently await-ume of radioactively contaminated ma-ing decommissioning. The NRC has terial would be reduced to one-tenth of adopted extensive regulations for deal-the originC volume as a result of radio-ing with the technical and financial is-active decay Delay in dismantling a sues associated with aecommission-plant wculd also result in lower radiation ing.

exposures to the workers involved.

22

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-NRC Cost estimates for decommission-decommissioning of their plants.

ing a large nuclear plant are $100 million Sicnilar financial procedures are also or more, plus the cost of demolition of required for other tyoes of nuclear facili-non-contaminated materials. The NRC ties, including plants which prepare fuel decommissioning rules require utilities for nuclear power plants or process to establish funds to pay for the future radioactive materia',s.

For-additional:Infor_mation,

contact

Office of Public Affairs U.S. Nuclear Regulatory Commission Washington, D.C. 20555 (301) 504-2240 i

Regional Pt.buc Affairs O{fices Region i 375 Allendale Road Region ':1 799 Roosevelt Road King c' Fruscia, Pa.19400 Glen Ellyn,IL C0137 (215) 337-d330 (708) 790-5500 Region IV 611 Ryan Plaza Drive Suite 400 Arlington, TX 76011

- Region 11 101 Mariotta Street Suite 2000 Region V 1450 Maria Lane Atlanta, GA 30323 Walnut Creek, CA 94596-5368 (404) 331-4503 (415) 975-0200 23-

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