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- 2 Ch Co==iscioner Johnson Coa.miscioner Lcrson CO::T20L OF CC:iSULTILL2 GitS CCCC#::TRA*fl01:S FOLLO:!I!!G A LOSS-07-C00Lf>tTf ACCIDL:r At nesuletory Infc=ction :fecting 422, on Septcaber 4,1970, the Cc.:1-cicsion cpproved for current r.nd future reactors the propocod rer.ulatory po::itien on recnu for providin ; control of ecebustibic gas cc.acentre-ticus folleuing design bauls icos-of-coolant accidents in ucter-cooled nuc1cer pv..'er plents, cc deceribed in Mr. Pricc's ccmorandum of September 2, 1970.
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Eriefly,,thp cpproved pocitien re eirec that a system cectin?, enginecred safety feature criteric be provideci for contro111na the hydronen con-
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centrction withotit relicnca en centcinzent purninn.
Dcchup hydroacn control ec;:bility by pur;in-the containacnt ntror:phere in a centrolled ocnner through filteru or other cypropricte radioactivity removal de-r i
vicco would c1co be required.
Enclosed is a discussion of heu uc nropone to cpply the neu position to reactors alracdy approved.
This position has been discucsed uith the /.CES, uhich 10 in tencral ccreccent, but hac rccerved the possi-bility of changing one or two reactors to different catc;;orica upon i
further conciderction.
The reactors under consideration are broken into four categories as folicas:
1.
_Reectors free F_crui 2 en to the future.
These are considered to be the current end future reacters".to which the regulatory position alrecdy approved by the Commicsion is to be applied.
1 2.
Eartier nl.antn b >twen Cowk ced flavic-nenec.
The public safety evaluations and ACRS letters for these plants discuss or refer to the hydrogen probica; thus, all thece applicanto are aircady on notice that this probica r.uct be resolved. Uc believe that these picnto r.hould all conforn to the regulatory position by the time they go into operation or as soon thereafter as practical.
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2 Commissioners i
3.
Still carlier nienrrt fre., Ginnzi to ncunung.. These picnts have full performance e;,crgency cora coolin3 syste:ns, but in general are not en notice rensrdin?, the:cor.bustible 3:s probica. Each of theco licenoces should be c:hed to furnish information regard-i ing the cciculated doco frca purging eftcr a loss-of-coolant accident,-using the reguletory position occumptions. Plants for.
vhich the esiculatcd rurgo doun cre greater then 2-1/2 rom tholo body or 30 rem thyroid, ce the site boundcry, thould fustell conbustibic gas control cyste:.c on rccconchle schedules.
4.
The n1 Art : 1 nt n ny 4.or to fM r,a. The er.cracncy-coro. cooling sys-tems of t'.:ct.a o*.crccin*; pl::ncs are not concidered to ht.ve full perfore:nce capability by.Procer.t criteria.. The ccabustibic gas control requirements for these rients r.:ur.t be censidered esce-by-cano either curin, the reviw for full-term oport. ting licence or, for thors picats uith full-term operatin', licences,. during.
the forthccaina review of the upgr:dic:: pro:; rams for their-cocr-geucy core cooling cystens.
j The increment in sefety obtained fren bcchritting combuctihte gas control-cc,elq=ent. in the virtesi clininatica of the cupor,ure to the 'public froa the radioactive pas released duri:.g pur3ing.
Conc typical calculated pur3c doceu are c'.to::n in Tt.bic I of the cttnched discuncica; they reuse up to thoer.nnds ;f ren. *1h: cost of providis"; conhuntibic ces control I
equirraent is coticated to renae frca b2%,000 for' the la t,o containments J
to teverci rdilion for the reallect contrinacnts. Accordingly, the proposed backfittir.3 tchen into account the cciculated purge doses for the reactors in Groupo 2, 3, cnd 4.
l The reguletory staff cnd' the ACRS believe that the backfitting pro;,oced
' uill provide substentici odditional protection which is required for public health and saicty.
I uould like to diccuso this matter with the Commission at en early
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Information l'ceting.
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.I Ilarold L. Price ec:i General Manager (2)
Director of Regulation General Counsel (2)
Enclosure:
Secretary (2)
- Discussion of Backfitting for
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DI wSS10N OF BACKFITTING CONSIDEIL _ _ONS j
IN Tile CONTROL OF COMBUSTIBLE CAS CONCENTRATIONS IN Tile CONTAINMENT FOLLOWING A LOSS-OF-COOLANI ACCIDENT 4
A.
Introduction f'
..I The regulatory position alt' ey approved for cur' rent _and future. reactors requires that a, system be provided f or controlling the hydrogen concentra-tion uithout reliance on containment purging.
This system. should meet the design, quality assurance,. redundancy, energy source, and instruments-tion requirements for an engineered safety feature; moreover, the-system should not itself introduce safety problems that might affect. containment integrity.
Backup hydrogen control capability by purging the contain-'
q ment atmosphere in a controlled manner through. filters or. other appropriate.
radioactivity removal devices vould also be required.
A. set of acceptable assumptions is provided for generation rates and flammability limits: to be '
j used in the evaluation of such systems.
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The present discussion considers the application of -this' regulatory posi -
tion to reactors already approved, or for which the revicu process is so far advanced that it would be unreasonable to require _-a change at the present time without backfitting consideration.
In dealing uith the com-bus _tibic gas problem, it is necessary to consider also the state of tfie 1
cmergency core cooling system capabilities for the various reactors,. since the amount of hydrogen potentially to be generated depends upon the _ effi-cacy of the emargency core cooling.
This is particularly true for the
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hydrogen generated in pctentici metal-unter reactions.
Eccrgency core cooling systems with capabilities not up to.present standards might permit more metal-water reaction to take place than needs.to be considered in 1
current applications.
Consideration has also been given to the fact that the combustible gas problem has been under. intensive discussion with vendors and applicants l-for over two years, and that some applicants are aircady on notice that this problem must be adequately resolved before their operation.
B.
Proposed Re$uire'ments The reactors in question have been grouped into four categories, based '
upon the capability of their emergency core. cooling systems, 'the status of consideration in each case of the combustible gas problem, and the
- status of regulatory review and construction or operation for each reactor.
A tabulation of the reactors in each category is-enclosed as Table-11.
l 1.
From Fermi 2 on to the future. - These are considered to be the'.
" current and future reactors," since Fermi 2 is already committed to do whatever is required and the future reactors are still under regulatory consideration.
These reactors must meet the new r_egu-latory position.
For the reactors where the regulatory review is 1
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c1most finished, there will not be time for the applicant to propose I
a program and a preliminary design in conformance with the new regulatory position, and so a suitable commitment will be adequate at this time.
llowever, for such' plants a preliminary design should be submitted by the applicant to the regulatory staff by September 1, 1971.
Although we are always op'en to discussion of assumptions different from those now in use, the assumptions in the
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regulatory position should be used unless approval is obtained from the AEC in the meantime to use different ones, j
I 2.
Earlier plants between Cook and Davis-Besse. - The public safety evaluations by the regulatory staff and the ACRS letters for these plan's discuss or refer to the combustibic gas problem.
All these t
licensees are on notice that this probicm must be resolved.
E: c'esed in Table I are some recently calculated doses from the purg-f l
inn effluent to a hypothetical person standing at.the site boundary j
I or the low population zone.
For these calculations, it was assumed that purging alone was used for combustible gas control.
All the General Electric small containments have unacceptably high predicted f
_ doses 'f rom such purging.
For the larger PUR containments, there l's a spectrum of predicted purging doses from very large (greater than j
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- Part 100) to small (essentially negligible). The great variability is caused by differences in containment size, site size and meteorol-i ngy, corrosive ma t erial s avail able for the generation of hydrogen; etc.
l These plants should all conform to the regulatory position by the time they go into operation or as soon thereaf ter as practicable.
It is recognized that for a few plants the calculated purge doses may truly be negligibic.
Exceptions to the above decision for i
such plants, if requested, should be. dealt with case-by-case on the basis of dos.es and man-rem.
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All these li'censees should be informed of this decision so they can begin work on the necessary designs.,
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3, Still earlier plants from Ginna to Kewaunee. - These plants have emergency core cooling systems designed for full performance.
The
- assumptions in the regulatory position are therefore applicable to.
' them.
In general, these licensees are not on notice with regard to the necessity for solving the combustible gas problem, although discussions have been held with a few of them.
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DEC!E E0!U 4
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4 3-Each of these licensees should be asked to furnish information to I
the regulatory staf f regarding the calculated dose from purging, using the. assumptions in the regulatory position.
Present re gulatory staff and ACRS thinking, which uc do not plcn to tell these licensees 3
at the present time, is that plants for which the calculated purge l
doses are greater than'2-1/2 rem whole body or 30 rem thyroid at the I
site boundary chould install combustibic gas control systems in ac-j cordance with the regulatory' position and on reasonable time scales, but not necessarily with the same redundancy and design require-monts as for.the later plants.
This should be decided on a case-by-case basis where necessary, in backfitting a plant which is built or i
almost so.
For borderline cases or highly populated sites, the man-rem 'should also be considered.
4 ',
The ol d e s t plants orior to Ginna. - These plants are in operation.
Their emergency core cooling systems performance capability falls short of nore,recent plants in varying' degrees.
The oldest plants, i
l for which the cmergency core cooling systems are seriously deficient, are being upgraded in this respect.
- The combustibic gas control requirements for these pl. ants must be considered case-by-case, and the consideration must include the planned upgrading in performance of the emergency core cooling sys-f tem.
Combustibic gas control systems for plants with provisional i
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operating licenses will be considered during the review for full-1 l
term operating licenses.
Those plants holding full-term operating licenses will be reviewed in this regard during the consideration j
of their emergency core cooling system upgrading programs.
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Enclosures:
Tabic I l
Table II 1
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Japuary 19, 1971
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.Rev. February 11, 1971 TAB 1E I
.Available Pbrre Doce Calculations - Regulatory Position Assumptions 4
' Purge Purge Doses--rem Remarks
' Plant Initiation Site Bdy LPZ
'IName Time WB Thy UB Thy
-' Conn Yankee 120 days 1.1
.,008
.008 negl-
' neglected corros}cn Conn Yankee 30 1.1 7
.008
.04 degraded ECCS-207, };/U Davis-Besse 83
.9
.54
.08
.005 low'Al inventory
.26
.32 neglected corrosion Hutchinson I 51 H.B. Robinson 2 46
.4 8
.003
.7 1200 lb A1, NaOH l
Point Beach 44
.05
.15 500 lb A1, good meteo Dia blo 2 t(40
.8 8
neglected corrosion Indian Pt 2 35 2.2 14
.6 4
neglected corrosion N
Millstone 2 25
.2 2.7 neglected corrosion Tr**sn 18 4,1 74
. 8' 15 neglected corrosien
.Hidland 16 7.8 160 1
21 low A'1' Oconee 14 150 8
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~ Palisades 4
32 480 large corrosion
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Palisades 4
12 170 l
stack release i
Teuni 2 1.7 250 2700 18 190 no stack l
i Con Ed 4/5 2
1800 2400 site has poor me. tear.
Cooper
~2.4 10 120 2
20
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Dresden 3 3.2
~ 100
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TABLE 11 i
CATEGOR17ATION OF PLANTS FOR THE PURPOSE OF
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CONSIDERING COMBUSTIBLE GAS CONTT,0L Catenorf 1. - These are considered to be the " current and future reactors" to which the regulat::ry position aircady spproved is to be applied.
These plants have construction. permit applications.under review by the regulatory staff;
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except for Fermi 2, their ACRS revicus are not completed.
EUR PWR Fermi 2 San Onofre 2 6 3 Newbold Island 1 6.2 Farl ey Limerick 1 6 2 Forhed River Bail ly McGuire Hatch 2 Arkansas 2 l
LaSalle 1 6 2 Aguirre Wm. Zimmer Waterford All future applications ce tgarv 2. - The public safety evaluations and ACRS letters f or these plants discuss or refer to the hydrogen problem; thus, all these applicants are already on notice that this problem nust be resolved.
These plants should all conio'rm to the regulatory position by the time they go into operation or as soon there-after as practictl.
These picnts are licensed for construction or have aircady Ncen revicued by the ACRS for a construction permit; review of their operating
.icense applications has not begun; a few operating license applications have just been received.
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H,atch 1
.D. C. Coch,1 6 2 (ACRS 12/13/68)
Duane Arnold Three Mile Island 2 Fitzpatrick Hi11 stone 2 Shorcham Diablo Canyon 2 Brunsuick 1 6 2 Sequoyah 1 & 2'
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Hidland 1 6 2 1
North dnna 1 & 2 I
Troj an Hutchinson Island 1 Beaver Valley Calvert Cliffs 1 & 2 i
Indian Point 3 Davis-Besse Categorv_3. - These plants have full performance emergency core cooling systems, but in general are not on notice regarding the combustible gas probicm. Each of j
these licensees should be asked to furnish information regarding the calculated j
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i I TABLE II (Cont'd) t oose from pu'rging af ter a loss-of-coolant accident, using the regulatory position i
assumptions.
Plants for which the calculated purge dcces are greater ::an 2-1/2 l
rem whole body or 30 rem thyroid, at the site boundary, should install :ombust-ibic gas control systems on reasonable schedules.
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Monticello 1 Ginna Millstone 1 Point Beach 1 & 2 Pilgrim Arkansas 1 Dresden 2 H. B.
Robir. son 2 Dresden 3 Zion 1 & 2 Quad Cities 1 & 2 Indian Point 2 Maine Yanhec Palisades Cooper Station Oconee 1, 2, & 3 Peach Bottom 2 & 3
' Crystal River 3 Browns Ferry 1, 2 & 3 Turkey Point 3 & 4 VermontJankee
'Three Mile Island 1:
Prairic Isit d 1 & 2 Ft. Calhoun j
Diablo Cany:n 1 Ns Salem 1 & 2
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Rancho 'Seco 1 Surry 1 6 2 i
Kewaunee Categorv 4. - The emergency core cooling systems of these operating p1 tats are '
not considered to have full performance capability by present criteria. The combustible gas control requirements for these plants must be considered case-1
. by-case either during the review for full-term operati.ng license or, fer those
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plants with full-term. operating licenses, during the forthcoming review of the upgrading programs fcr their emergency core cooling systems.
Dresden 1 Haddam Neck l
Big Rock Point Indian Point 1 l
Lacrosse San Onofre 1 Oyster Creek 1 Yankee j
Nine Mile Point Saxton Humboldt Bay 3
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