ML19308B942
| ML19308B942 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Crane  |
| Issue date: | 09/23/1970 |
| From: | Hendrie J US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Seaborg G US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8001170650 | |
| Download: ML19308B942 (5) | |
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ADVISORY COMMITTEE ON REACTOR SAFEGUARDS i
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UNITED STATES ATOMIC ENERGY COMMISSION WASHINGTON. D.C. 2G545 September 23, 1970 o
11onorable Glenn T. Seaborg i-Chairman U. S. Atomic Energy Commission Washington, D. C.
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REPORT ON OCONEE NUCLEAR STATION UNIT NO.1
Subject:
Dear Dr. Seaborg:
17-19, 1970, the Advisory Committee During its 125th meeting, September f the on Reactor Safeguards completed its review of the ap 1
'Ihe Committee met with the Station at power levels up to 2568 Mf(t).
13-15, 1970 and Subcomm t ee it applicant during its 124tF reeting, Augustat the site and on Ju y 31, 1970 l
meetings were held on June 23, 1970, In the course of the review, and September 9,1970, in Washington, D. C.
i and the Committee had the benefit of discuscions with representat ves h Bechtel consultants of the applicant, the Babcock and Wilcox Comp g-M.
Corporation, listed.
The Oconee Station is located in a rural area of Oconee County, South The nearest population center is Anderson, 21 miles south, The minimum exclusion distance for Carolina.
with a populatien of about 41,000.
h Low Popu-the completed three-unit power station will be one mi The ted by e
water supply for the plant is taken from Lake Keowce which the applicant.
pected to attract a transient population to the area.
lies The application covers Oconee Units 1, 2, and 3, but th e
l two-loop, four-pump, pressurized' water reactor, nuclear l
only to Unit r.
The Committee j,
facilities and services are shared in various arrangements.
systems.
has reviewed the temporary arrangements necessitated by operat l
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It is believed that the while Units 2 and 3 are still under construction.
h proposed physical measures and administrative procedures to isola L.;
I operating unit from construction activities are adequate.
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'_e Glenn T. Seaborg September 23, 1970 The Committee reported to you on the construction permit application for this power station on July 11, 1967. At that time the proposed operating power was to have been 2452 MJ(t); the current proposal for operating at powers as high as 2568 MN(t) is justified by the applicant, primarily on the basis of a flatter power distribution.
Prior to operation at the higher power level, reactor operation should be reviewed by the Regulatory Staff.
The prostressed concrete containment building is similar to those for the Palisades and Point Beach plants which have been reviewed recently for operation.
The Committee recommends that the applicant accelerate his studies of means of preventing common failure modes from negating scram action and of design featur as to make tolerable the consequences of failure to scram when required during anticipated transients. As solutions develop and are evaluated by the Regulatory Staff, appropriate action should be proposed and taken by the applicant on a reasonable time scale. The Committee wishes to be kept in-formed.
The applicant has proposed using a power-to-flow ratio signal as a diverse means to cause shutdown of the reactor if emergency core cooling action should be initiated. The Comnittee believes it is necessary that either the
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equipment associated with this signal be demonstrated to be able to survive the accident environment for an adequate time or a dif terent, diverse trip signal be employed. This matter should be resolved to the satisfaction of the Regulatory Staff.
The Committee suggests that davolopnental techniques, such as neutron noise analysis and use of accelerometers, be considered as an aid in ascertaining displacements, changes in vibration characteristics, and the. presence of loose parts in the primary systems.
The Committee notes the desirability of the continuing use of some thermocouples in the core.
The conmittee has commented in previous reports on the development of
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systems to control the buildup of hydrogen in the containment which might follow in the unlikely event of a loss-of-coolant accident. The applicant proposes to make use of a purging technique after a suitable time delay sub-sequent to the accident. Relatively high off-site doses possibly could result folloving p'eging of the containment. The Committee recommends that purging systems be incorporated in the plant but that the primary protection in this regard should utilize a hydrogen control method which keeps the hydrogen concentration within _ safe limits by means other than purging. The e
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.: September 23, 1970 IIono.able Glenn T. Scaborg yk v n contro* system and provisions for containment atmosphere mixing sad sampling should have redundancy and instrumentation suitabic for an eagineered safety feature; these should be made available within the first The Committee wishes to be kept informed of j-two years of power operation.
the resolution of this matter.
The applicant stated that the amount of radioactivity in liquid wastes nor-mally will not be greater than one percent of 10 CFR'Part 20 limiting con-centrations after dilution with the minimum flow (30 cfs) below the Keowee Larger flows will have proportionately smaller limiting concentrations.
The mean annual discharge from the Keowee dam is expected to be 1,100 cu. f t./
dam.
ne off-gas system has holding tank and filtering capability and gas re-Icase rates are not expected to exceed a few percent of 10 CFR Part 20 limits.
sec.
In order to protect against the postulated consequences of the accidental the applicant has stated that either, he will j.
dropping of a fuel element, l
install filters in the fuel pool building exhaust system, or the equivalent This matter should control and protection will be assured by another method.
be resolved to the satisfaction of the Regulatory Staff within the first year of power operation.
Improved calculational techniques are being applied to the analysis of the k
ef ficacy of the emergency core cooling system in the unlikely event of a loss-Interlm results appear to be acceptable, but further of-coolant accident.
calculations are needed and some phenomena important to the course of the 9
accident require further study. This matter should be resolved in a manner The Commit-l satisfactory to the Regulatory Staff prior to operation at power.
i tee wishes to be kept informed.
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%e reactor is calculated to have a positive moderator coefficient of reactiv-1 I
ity at power which will become negative as boron is removed from the coolant l
n e-applicant
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concurrent with build-up of fission products and fuel burnup.
plans to perform tests.to verify that divergent azimuthal xenon oscillations The Committee recommends that the Regulatory cannot occur in this reactor.
Staff follow the measurements and analyses related to these tests.
A conservative method of defining pressure vessel fracture toug1 mess should e employed that is satisfactory-to the Regulatory Staff.
Other problems relating to large water reactors which have been identified by the Regulatory Staff and the ACRS and cited in previous reports to you chould be dealt with appropriately by the Staff and applicant in the Oconce g,
j Unit 1 power plant 'as suitable approaches are developed.
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23, 1970 September
, DT. Scaborg if due believes that, satisfac-on Reactor Safeguardstioned above, and su ing there is to bject operated tn to the items menand preoperational test 1 can be lth and (ommittee lear Plant Unitt undue risk to the hea of construction surance the Oconee Nucup to 2568 MN(t) withou an jls h public.
Sincerely yours,
/s/
Joseph M. llendrie Chairman d below:
W. R. Stratton are presente any the
, comments by Dr.
which are stated to accompcalculations overly which high off-site doses are based onI believe to besituation, should used purging operation of assumptions which is my opinion that the and that the pro-number the ude a adequate protection for severe It f ervative.
much less fore hver arise, would beld provide in this regard and therei ed by this ed purge system wouIth and safety of the publ ccontrol equipment requ r i
additional hydrogennot necessary."
.ter is List of References tent:
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Ybb 11onorable Glenn T. Seaborg September 23, 1970
References:
1.
Amendment No. 7 to Duke Power Company Application for Oconee Nuclear Station, Units 1, 2, and 3, consisting of Final Safety Analysis Report, Volumes I and II, received June 4, 1969 2
Amendments Nos. 8 through 21 and Revised Ataendment No. 13 to the License Application.
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