ML19323B942
| ML19323B942 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/31/1979 |
| From: | NRC COMMISSION (OCM) |
| To: | |
| Shared Package | |
| ML19323B939 | List: |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8005140441 | |
| Download: ML19323B942 (4) | |
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D 8 0 0514 0 '/Yl NRC STATEMENT ON THE SAFETY OF NUCLEAR POWER PLANTS
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The NRC recognizes that nuclear power plants present some potential
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for accidents that can have large public consequences.
Because of
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this, it also recognizes the need for a comprehensive regulatory pro-cess to help ensure that no undue -isk to the health and safety of -
the public will arise from their operation, This process involves a well developed safety de, sign approach, the specification 'of safety design requirements to implement that approacL, and an extensive safety review and licensing process to ensure that
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plants meet established safety requirements. - A key element.behind
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these requirements and procedures is a recognition of the need for redundancy not only in the elements of plant hesign but also in
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the review process. The need for redundancy derives from the knowledge that, in spite of man's best efforts to achieve high quality' in-design, construction and operation of. nuclear ' power plants, these
, goals cannot be completely achieved.
l The safety record so far achieved in'the operation of nuclear power plants attests ts the validity of NRC's approach. Therb have been
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approximately 440 reactor years of operation of large commercial nuclear plants in the U.S. without an. accident of significant effect on the health and safety of the public.
The worldwide
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total of operating experience with large nuclear power plants (which s
ij follow essentially the same safety design approa6h as that in the
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.j U.S.) brings the total to about Sed'7
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reactor years.
While this lg experience is much less than that needed to confirm our belief that large reacter accidents have a low probability of occurrence, not. even the prec'ursors (such as large p. pe breaks or fuel over-i hiating) to potentially large accidents have occurred within 'this period of operating experience.
NRC's regulatory process has relied and will continue to rely on the 1 judgment?of.. highly, ski.1.ed, engineers a. n,d scientists as th'e principal 1
' basis for its safety decisions. While extensive strides have been.
made in the development of quantitative risk assessment techniques, and the careful use of such techniques can. provide added engineering insights about th'e safety of nuclear power plants, they are not yet -
sufficiently precise to be relied on except to supplement the other methods and procedures now used by the NRC to form i,ts safety judgments.
The safety design approach 'used by the NB,C emphasizes defense in depth.
In nuclear power plants, a series of phy.sical barriers is constructed between the large amounts of radioact'ivity contained in the nuclear fuel and the environment. The fuel is contained in a
' sealed, metal cladding; the clad fuel is contained in a sealed, steel e
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3 primary coolant system; and the primary coolant system is enclosed
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Since it is known that some l
types of failures in one of these barriers can also cause failure of the other barriers,, there are two other important factors' involved in the implementation of the defense in depth approach. These are, first, the specification of requirements to achieve high quality in the design, construction and operation of nuclear power plants to reduce the likelihood of failures that could potentialTy cause accidents; and, second, the use of engineered safety systems, with redundancy when needed, to prevent failures from progressing -into. accidents. These ~
requirements are outline'd in NRC' reg'ulations, standards 'and safety guides
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which are based on sound engineering prac'tices. established over the i
pa,st twenty years, and which are undergoing continuing improvement.
.The NRC also sponsors a comprehensive research program to provide the technical bases for. the confimation of NRC's safety decisions and for needed improvements.
The NRC's regulatory process for nuclear power plants consists of safety reviews by the staff of the Office of Nuclear Reactor Regulation a'nd
.by the statutorily independent Advisory Committee on Reactor Safeguards.
.i Public hearings of the results of the staff and ACRS reviews are held by an NRC Atomic Safety and Licensing Board. The results of these hearings can be appealled to an NRC Appeals Board and the Comnission.
I Beyond this, appeals can also b'e made to the courts. These
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reviews are conducted twice--once before the construction of a plant is a{
allowed to comence and again'before operation of the plant is if permitted. The reviews include environmental as well as health and safety considerations.
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.The NRC's Office of Inspection and Enforcement conducts inspect ons.
during construction of the plant to help ensure that the plant is being built in accordance with the safety design and guality requirements.
Inspections are'cantinued during the opera. ting life of the plant to '
help ensure that the requirements of NRC's licenses are adequately enfoh ed, tha$, problems arising'in operation-are well ' handled, and -
.' '.,f valuable feedback from operating experiences'is incorporated into the safety reviews of additional plants.
Furtherm' ore,.JRC licenses require utilities to test important safety systems periodically and to report l
failures of all safety relat,ed equipment to the NRC'. The results of
-NRC inspections and reports of equipment failures are routinely made public.
In summary, the NRC believes that, while nuclear power plants (or any
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other of man's technological endeavors) cannot achieve ' risk free.
operation, the current system has provided a sound basis to. ensure that nuclear pwer plants present no undue risk to the health and safety of the pubTic.
It also believes that the ex'cellent safety reco.rd so far achieved can be maintained if there is continued support for a I
technically strong and vigilant regulatory program.
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