ML19319A778
| ML19319A778 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/11/1967 |
| From: | Palladino N Advisory Committee on Reactor Safeguards |
| To: | Seaborg G US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19319A777 | List: |
| References | |
| TASK-TF, TASK-TMR NUDOCS 7912050875 | |
| Download: ML19319A778 (3) | |
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ADVISORY COMMITTEE ON REACTOR SAFEGUARDS UNITED STATES ATOMIC ENERGY COMMISSION W*~SHINGTON. D.C. 20545
'JUL 1 1 1967 '
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Honorable'Glenn T. Seaborg Chairman U. S. Atomic Energy Comission Wachington, D. C.
Subject:
REPOJT 03 OCOMEE NUCLEAR STATICU, UNITS 1, 2, AND 3 Daar Dr. Secborgt At its eighty-sixth meeting, on June 8-10, 1967, and its cichty-seventh meeting, on July 6-8, 1967, the Advisory Committco on Reactor Safeguards reviewed the proposal of the Duko Power Company to construct the Oconee 4
Nucient Station, Units 1, 2, and 3, at a site near C1cason, South Carolina.
This project was revicwed by an ACRS Subcoc:mittee on May 2,1967, at the site and at Cicsson and on May.31 and June 23. 1967, in Wochington, D. C.
The Comittea had the benefit of diccussions with representatives of the
..Duka Power Company and its consultants, The Babcock and Wilcox Company, Bechtel Corporation, and the AEC Regulatory Staff, and of the documents listed.
Each unit of the Oconea Station includes a precourized-water reactor rated
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at 2452 Imt. Ecch unit is to be provided with en escrgency core cooling system (ECCS), including two core flooding tcnks, thrca high-pressure in-jection pumps, cud three low-pressure injection and recirculation pumps.
The_ applicant proposes not to operato a unit with a core flooding tank valved off. The Co==ittee rococmends that the negulatory Staff review the detailed design of the ECCS and the analysis of its performance for the entiro spectrum of break sizes, as soon as this information is avail--
able. In this respect:
1.
The Regulatory Staff should review analyses of possible effects, upon pressure-vessel integrity, arising from thermal shock induced by ECCS operation.*
- 2.
The effects of blowdown forces on core and other primary l'
system components.shoild be analyzed more fully as de-L tailed design proceeds.*
3.
Further evidence should be obtained to show that fuol-rod failure in loss-of-coolant a:cidents will not affect significantly the ability of the ECCS to prevent clad melting.*
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Ilenorable Glenn T. Saaberg 2-JUL11 w67
!4., The applicant has proposed adding swing-check valves in
~ the core barrel to ensure obtaining adequate height of cooling water in the core under all circumstances of ECCS'oporation.-~This featura should be further reviewed s
,to ensure that no new problems are introduced.
5.
The cpplicant will explore further possibilitics for improvement, particularly by diversification, of the
. instrumentation that initiates ECCS action.
E=orgency po7er sources for the ECCS and other safeguards are:
(a) the other Oconee units (each unit can withstand and will be tested to with-stand instantaneous loss of load without a reactor trip or a turbine 1
trip);- (b) two hydroelectric: units at Keowca station loss than one mile away, with independent overhead and underground transmission lines; and (c) a gas-turbine unit ' thirty miles away with independent transmission lina,. transformer, and switchyard -- all in addition to the usual multi-
. ple ties to the_ power transmission grid. The applicant stated that switching and sequencing of sources, buses, and loads would be such that no sincia failura would ic: pair systes availability.
The applicant stated that the cucire primary system of each unit, includ-ing. the insido and outside of the reactor vessel, will be accessible for inspection over the life of the plant.
The O=mitteo continues to emphasizo the importance of quality assurance in fabrication of the primary system as uc11 as inspection during servica
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- life, and reco= mends that the applicant i=plement those improvements in primary system quality that aro practient with current technology.*
The moderator coeffiEientiof reactivity is eniculated to be positive at the beginning. of coro life, for the first core. The applicant is acking
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detailed studios of tho' offect of this coefficient on the course of postu-lated. accidents; if necessary, the coefficient will bo mado-mora negativa by the addition of solid poison shims to the-coro.-
Further evidenco should be obtained concerning the ability of the fuel to withstand. expoetad. transients -at the end of its ' anticipated lifetime.*
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' The applicant is investigating further the stability margin for xenon
, oscillations.
The containment' structures are similar to those for the Turkey Pofut re-actors previously reviewed. f Consideration should be given to improved inspection'of wolds ;in the steel liner of such containments, because an-acceptance pressurizationE test does not stress.the liner to postulated accident conditions.
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JUL 11 1967 Honorablo Glenn T. Seaborg 3-Power for the reactor protection systems and the safeguards protection systems for all thrco units is provided by a syste:a of six batteries, static inverters.and six buses. The sama batteries, via other inver-ters and buses, provida power to the contro?. systems for cll three unita.
The Co=mitteo urges the applicant to review the design of thoso systems with respect to independence of each unit from troubles in the others.
l The applicant proposes to construct a subscrged earthen weir in the in-tako canal to assuro a heat sink in the event Keouce Roservoir is drcwn down enecacively. The Co=mittoo believes that careful ettention is neces-scry in tho design cnd construction of this voir to cvoid hydraulic crosion and soil instability, particularly in caso of rapid draudown.
The f.dvisory Co=mittee on Reactor Safeguards believes that the items men-tioned abovo can be resolved by tho applicent and the Regulatory Staff during construction of the reactors. On the basis of the forcaoing com-ments, the Co=mittcc believes that the proposed Oconco nuclear Station can be constructed with reasonabic assurance that it can bo operated without unduo risk to the health and safety of the public.
Sincerely yours, ORIGIEIJ. SIC :D B'l H. J. PALLADIHC l
N. J. Palladino -
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Chairman
- The cc= ittee believes that these catters are significant for all large i
vatcr-cooled power reactors, and warrant careful attention.
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References:
1.
Dehe Power Company, Oconce Nuclear Station, Units 1 and 2, Preliminary Safety Analysis Ecport, Volumas I and II, undated, roccived Deccabar 5 1966.
2.
I.m:ndment no.1, dated April 1,1967.
3.
Amendment No. 2, dated April 18,.1967.
4.
Amendment No. 3, dated April 29, 1967.
5.
Amend: ent No. 4, dated May 25, 1967.
6.
Amend =ent No. 5, dated Juna 16, 1967.
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