ML20024G403

Application for Amend to License DPR-22 Re Limiting Condition for Operation & Surveillance Requirements

ML20024G403
Person / Time
Site:	Monticello
Issue date:	01/26/1976
From:	Wachter L NORTHERN STATES POWER CO.
To:
Shared Package
ML20024G401	List: ML20024G400 ML20024G403 ML20024G404
References
A00L-760126, AL-760126, NUDOCS 9102110430
Download: ML20024G403 (9)

Text

{{#Wiki_filter:- -. ~... -,- -- UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50 263 REQUEST POR AMENIMENT TO OPERATING LICENSE NO. DPR-22 (License Amendment Request Dated January 26, 1976) Northern States Power Company, a Minnesota corporation, requests authorization for changes to the Technical Specifications as shown on the attachments labeled Exhibit A and Exhibit B. Exhibit A describes the proposed changes along with reasons for the change. Exhibit B is a set of Technical Specification pages incorporating the proposed changes. This request contains no restricted or other defense information. NORTHERN STATES POWER COMPANY By 6I IN/

1. f J Wachter Vice President, Power Production &

System Operation On this 26th day of innnnev , 1976 , b' fore me a notary e public in and for said County, personally appeared L J Wachter, Vice President, Power Production & System Operation, and first being duly sworn acknavledged that he is authorized to execute this document in behalf of Northern States Power Company, that he knows the contents thereof and that to the best or i:is knowledge, information and belief, the statements made in it are true and that it is not interposed for delay. db/wrh lb4/M&t

• )

h, # DENISE E. BRANAU NOTARY PUsUC-MtWSUT4 HENNEPIN COUNTY My Commission Empires Oct.10,IIst m m :::::::.. - l 9102110430 760126 PDR ADOCK 05000263 P PDR .2 . _ _ ~ _ _ _

t EXHIBIT A MONTICELLO NUCLEAR CENERATING PLANT DOCKET No. 50-263 LICENSE AMENDMENT REQUEST DATED JANUARY 26, 1976 PROPOSED CHANGES TO TECHNICAL SPECIFICATIONS APPENDIX A 0F PROVISIONAL OPEP.ATING LICENSE NO. DPR-22 Pursuant to 10 CFR 50.59, the holders of provisional operating license DPR-22 hereby propose the following changes to Appendix A Technical Specification: PROPOSED CHANGE This proposed change supersedes in its entirety our License Amendment Request Dated June 9,1975 on the same subject. TS 4.3. A.2 (Page 76) - Replace the sentence, "Each partially or fully withdrawn ~6perable control rod shall be exercised one notch at 1 cast once each week.", with the sentence, "Each partially or fully withdrawn operable control rod shall be exercised one notch at least once cach month." REASON FOR CHANGE In long term studies of fuel behavior, reactor fuel damage has been associated with rapid increases in power, particularly if the ultimate power level is a substantial fraction of its thermal limit and/or ruddenly exceeds the level at which it was recently operated. Operating practices have been established to avoid potentially damaging rapid local power increases. Analytical studies show that the current Technical Specification surveillance requirements, when performed as intended, result in such potentially damaging power increases. The weekly notch surveillance exercise requirement involves an insertt on followed by a withdrawal of one control rod notch (a 6" step). It has historically been assumed that the notch insertion would cause a local power de crease while the return to the initial rod location would result a power in-crease to the original level, allowing the notch exercise surveillance to be com-pleted without reducing power. Recent analytical studies show that control rod insertion reduces power near the tip of the blade significantly. The reduced power decreases voiding (increases sub-cooling) in that channel which is a positive reactivity feedback resulting in a small but significant increase in power at some higher elevation in the fuel channel. Figures 1 and 2 show charac-teristic power redistributions for partially and fully withdrawn control rod exercises. The analytical studies are supported by observations from previous cycles which showed a gross trend wherein the offgas emission rate from the fuel increased linearly with the integrated number of control rod notches moved. The cycle A-1

was terminated short of the original design exposure for this reason; at the end of the cyc1g plant capacity was restricted to 577. of rated power by of fgas limi-tations. At that time all initial core fuel, which was believed be most subject failure, was prematurely discharged and replaced with fuel of an improved to design. This requested change is to maintain the demonstrated integrity of the new core which consists of all 8 x 8 fuel with the exception of 20 b"ndles of the improved 7 x 7 BWR design. Ar associated problem with the identified local power increase during surveillance is the increased potential to exceed the MAPLHGR limit momentarily, an event which has been declared reportabic with the issuance of a recent change to the Technical Specifications. The request to reduce the required surveillance frequency from weekly to monthly is supported by the safety evaluation presented below. An alternative mode of operation is to reduce power prior to conducting the weekly exercise test. This represents an unwarranted loss of plant capacity which was not initially assumed in the presently required Technical Specification surveillance program. SAFETY EVALUATION The initial step in evaluating a reduction in the frequency of conted rod notch exercising was to review the basis for the current program. Having reviewed the Technical Specification Bases and the FSAR and af ter discussions with personnel involved in the early stages of licensing, it appears that there is no clearly established basis for the notch exercise frequency being weekly, The judgement of those familiar with the control rod drive design was apparently that periodic movement was desirable to exercise components and to demonstrate operability. The exercise program was arbitrarily required weekly of initial plants having the same CRD design as Monticello, perhaps to accumulate performance data on that design, and has been required for all similar plants since that time. It has been common practice to establish an arbitrary but conservative surveillance frequency in areas where data is not available to quantify a more appropriate frequency. A corollary to that philosophy is to adjust the surveillance frequency as supporting data becomes available. In the case of instrument su rveillance, there are, in fact, provisions in the Technical Specifications to reduce the frequen-cy automatically as favorable experience accumulates. This puts into practice the theoretical concept of an optimum surveillance frequency which neither degrades the reliability by under-testing nor wears out equipment by over-testing. In five years of operation, approximately 25,000 notch movement tests have been performed at Monticello without a si.ngle failure. Having established a data base, one might either proceed to calculate a surveillance f requency based on an ultimate reliability design objective, or to propose a reason-abic surveillance frequency and to verify that it results in a sufficiently high reliability. The latter approach was chosen. The control rod sequence is exchanged approximately bi-monthly making that a convenient frequency for control rod exercise testing since power is generally reduced significantly to accommodate the rod exchange. Rather than moving from weekly to bi-monthly exercising, discretion suggests an in-A-2

n. .~ l termediate step to accumulate additional data; therefore a monthly exercise program is proposed. The applicable criterion in decemining the acceptable level of reliability is that the probability of an unanalyzed event must be less than 10-6 per year. Another Technical Specification requirement is that the core must be cap-able of being made subcritical at all times with one inoperable control rod. Therefore, a probability of two or more rods being inoperable must be less than 10-6 Furthermore, it has been the experience at Monticello that the core remains subcritical with two rods withdrawn if the two rods have a mini-mum separation. The method of evaluating the probability of an inoperable rod is based on WASH-1270, with the units redefined as appropriate. A sum-mary of the probabilistic approach is as follows: p1 5 (Equation 1) where g the probability of an individual rod failing to insert when as J challenged, N as the number of surveillance tests per year and ha the mean failure rate (year ~1), where h = n/ JT and M= (Equations 2 & 3) ax av a.a with AE a the true mean between failures (years) as opposed to the apparent mean, m = T/.st 7 the accumulated test time (years), (ror 5 years of testing for the m l 121 Monticello control rods, T = 605 years.) l l Jt Is the failures observed during T, and the area under the tail of the chi square distribution curve. sa Combining Equations 1, 2, and 3 results in the following equation: a 1 tI (Equation 4) ^ 4 ll N T l i A-3 = - -..

i Note the important characteristics of the final equation for pi. All pre-vious testing at thg respective frequency is embodied in T which is the data base used in the X analyses. The time between tests in.the future is rep-resented by N; or more properly, 1/N, since N is the number of tests per year. If a failure is to occur, the most probable duration of inoperability prior to detection is one-half of the time between tests, that is (1/2) x (1/N). Hence equation 1. The individual rod exercise test is designed to identify the inoperability of the manual directional control of any individual control rod independent of all other rods. The highly unlikely situation of control rod inoperability not restricted to the inoperability of individual rods is the subject of WASH-1270, which evaluates the reliability of the entire reactor protection system based on a monthly surveillance frequency. For purposes of this evaluation, how-ever, the inoperability of a given rod is independent of the status of all other rods. Being independent, the statistical probability of two inoperabic rods is the product of the probability of each individual rod being inoperable, 2 that is, pt, 2 Evaluating the >C term for the number of failures observed (rr 0) and the normally acceptable gonfidence level of 95% ( cc =.05), standard statistical tables indicate ?(.05;2=6.0, Remembering that T = 605 years for Monti-cello, the probability of an individual inoperable rod pi can be calculated for any projected number of surveillance tests per year N. The results are as follows: 2 Surveillance pt, Probability of Frequency N, year ~1 Two Inoperable Rods Weekly 52 2.27 x 10~9 year ~1 ~1 Monthly 12 4.27 x 10~8 year Bi-monthly 6 1.71 x 10~7 year"I The probability of two inoperable rods cicarly meets the criteria of being less than 10-6 even for the bi-monthly case. An addi ional factor of con-servatism rests in the fact that the core can be made subcritical with two rods out, unless the second inoperable rod is one of 20 of the remaining 120 Monticello rods, resulting in a factor of six conservatism. Another fac-tor to note is that if inoperable rods are found during operation, there is no immediate ef fect on continued steady state operation. The problem is the inability to bring a local region of the core to a cold, xenon-free shut-down condition. Should this situation exist, the core can be made suberiti-cal using the Standby 1,1 quid Control System, which is required by Technical Specifications, having a design objective of making the reactor suberitical in a cold, xenon-free condition, assuming all rods are withdrawn from the core. A-4

~. l 1 i The potential for control rod inoperability due to a cracked collet housing has received widespread attention in the past few months. A September 24, 19".i Safety Evaluation on this subject by the NRC Staff, identified four re-acters similar to Monticello in which such cracks were observed, none of which resulted in inoperable control rods. It was found that the net strength of the collet housing was still far greater than necessary to perfonn the intended function. No cracks have been observed to date during the routine preventative maintenance program for Monticello control rod drives. This includes a thorough dye penetrant inspection specifically for collet housing { cracking on 32 drives after learning of the experience at other sites. Prob-able causes of the cracks have been reviewed and steps to mitigate the potential ) for cracking have either been implemented or remain under investigation. j Ex-perience at Monticello, as well as the industry as a whole, indicates that the current preventative maintenance inspection practices have identified the po-tential for cracked collet housings well in advance of crack propagation to the extreme of control rod inoperability. The inspections for the start of crack propagation, and not the control rod exercise surveillance tests to verify operability, have been the most valuable surveillance program in maintaining a highly reliable control rod drive system. We concur in the staff finding that " Distribution of failures of similar specimens generally follow a log normal pattern, with one to two orders of magnitude in time or cycles between failures of the first and failures of the last spacimen. As no collet housing has yet failed, we are confident that there would be very few, if any, fail-ures during the next time period corresponding to the total service life to date." The question of collet housing cracking is theref sre not an overriding issue in establishing the control rod exercise frequency. In conclusion, there is currently data available to quantify a reasonabic surveillance frequency for control rod notch exercising in place of the present overly conservative arbitrary Technical Specification requirements. Certain elements of conservatism have been identified in quantifying the newly proposed surveillance frequency. due to collet housing cracking has been considered.The potential-for CRD inoperability It has always been our objective to establish and maintain a surveillance program which in our best engineering judgement provides the optimum balance between reliable, economical service to the area with the utmost regard to the health and safety of the general public. Since it is believed that the testing frequency presently required by the Technical Specifications is not necessary and increases the potential for fuel damage and reduced plant capacity, immediate approval of the above change is urged to meet this objective. l t I i A-5

1 ~ ~ -._ - ( Ie i i. I e i 4 l l4 1 I ~__. ~. -- ...I... e i I i I

i,'

!.t t! .j{*I t 1- ,t rl, - } 'i f I i i,,.. ._..-._J -4 I ;. f - t.,.... t t ,s 4 , j i 1. ! I .j i 1 ,e t .t J .1 -1 1 l 1.' t j ' ji{, i l I p i i gs L.. ,0 -i ,4 ... ~. 4 + i

• =

H i a. 1 o i p 48 <1 11 l 6 0, e 0 y .l-n. ~ ~. _. .' *dor qi f 0 48.d ~!, '4 *s o ,I g o .j s L o ae O I .o 4 h d 8 0 QH { ,h & t b f.. l.. ._.... ( p._. aj.. Li .-.4. -. ~... g e u e d T3 E. .O 3 !=

1. t.. c a

0 0 00 4 3 m ~. I b .3 H 0 I o r-1 44 4J 3 g .H t) ~^ 5 d i. 43 \\ \\ ec c a _ _. - - f]^ p' r.. 1 f.u.S. 3. l a O O b Z l + H C p

f. )

O l r-a l 1 L] .l. _.._.2L 4. s ,g i i ~ ..!j... I i l F,l i i iI ;

6

,j + 1 6 l q j i, 5 j 't trs i i gt.s I A 44 'O 10 r ) 4 (. I - r 4. 4 i i O 1 0 W^ i tZ 0 t w4 9 [ i _-.~* ... ~ n L. g y ga o%% L*j e-4 $-e ti .C U *+ + l, O d .*u d b 4 0 't ~. > k A.C M OC.; Q Z N v.M QO M ] i I i i i e 6 ,i I I ^ 1 l ? ? I l ! fl I A-6 1 m

1 3 ,i.l l4!j; 1 j

• c L

e* e .J l, e !....... r. l .l .;515l. 4 ..L 2. r t 1 .qr j ,), i L-l i1 ~ e ,i I, ,p j,. - 9.. '}. l i Ill .c _j r -l'.4 !(! , i 4 - i, i t L -e 4. ( i,. j I a 4 e

l.

j j i,(l_I l.,,. i t. ..LHJ} j 9 a4

1.3

.j.. .} 1l. ..p .I, L '. L! L..J i i i 'j I., y..' - . R.I.f.. {

4. H.q.- l p '. ;

i i L n -8 1 ! '...J - - i l-L 4 iJ ! l-l JL.! a.".'.-.- jl~}Jb.{u}, h'4 la ! a l. ; , Ll. ,J L _.tJ...H 1. p I_ *{ - { - ~ 1 Qq, J. ;. .It.it ll;, +(5 p, .i. q.[ j. i e p.

qei, i

g..

3,

8 .c 1 !l' !F p;- - i ..p'_.f'.j.L {.f.l. ]'. )i 'il . )! I; i ;.1 o.;. ' i i J.i a., H .i !..J. I .1 l .4. I ! _. t LJ I h{ } }! ' _-].1 ..f, }.. 1ii , Ul. !l } 'j jl 6 1 i ( )I 6 l _! !.! L ...L L; l 1 4

aq )7]

q. . j..h..;! .q.. 3.,.., _..q ,.g s u

j... p

.} ; j.,i. _ _...f.,, ). i 4 .3... ,-I-1 .a. I {3.. i. s. q. . l..!.),. ; l. 1

3. p

.j., p:.. j4 a;l; .. 4 .. ;p _. 4 .L43 I q.J { l. J.. .l t. J 4 e i v. g d. i j l. 4 hjl.]-!- 2 j ij q 7 ,..q.._.. p.3 s 4 l..;.7.i,. -i i .o.._ - l.- j. i g i.l.). l L i ,7 . u i.. J i o J. 1 + 4 ..p. a l.;.i e ~ .-. ; c.. . p; .. ! 1. q . M i .:.J i.at i

., 7

.j a 1 p F .-Ph+ 3 t f [.cN .y4 . [4 :. 7 . i..I b.t I .4..J b Od '.g;,..l.7 1.j-q .2 g ._ i i 1 ,J. .i g .. L 0 +3.d p _. 3 4 L2. ..L 2.: p f

j. ! l

.p k]3M

!.kq. . {.4.L U b [ ..4..J b _4. ., _J . I.).4_ O .l J j_ cc a p .-u. .i u. i .I ..L ;. i 1.,.p! } [g 4 . p..9 g q

• 1..

.t i 7 ..,a .., _. _, c J. g t0 O n4 $ n g., C _. H

• -4

.l_ L ec i.. 1 i l l,_ ]td

---

l-hJ f_.

._l 4 ..y..+ s%, u 3g ,g. p o 3 _..-g H O O .a-t O 2 + ! _ n 4WH j .i 4 p

1. ;

t,. H O R 9 ei 3 g yp -4 q 4t 't D N M- MD0 C P y gaya m, y .- _1 a j. - ;. 9,_. x ~ e g.,.. _., _ i q..p ,g . y { GL . q. i.,. _ L. !. ' fp.. l. 4 . q p 7_ a... .._L t7 _.2_ {. y 4

.a a

.,7 g p 7. o 4 .f .) 6 i _. .-6 .l ... J. -4. g 4 a H. 7.. _ j _.2 H p 8 _,_ . g. 4.- i. a .. 4..a e .;,jy_ q .qg, .g ,e.. _. ., fw. r j. .; g. a, 3 )

p.. y,3. J..gm.4.,.a.j j.

m; y-m. . y p., p ~ p a g r,,. g ;,,,, q

m.,

q -a 1 ... _}. ,1, m 4 L ,7.- _ g.4 L j ;....-... .i ILidd'p j'b.. j t.i g, '..k,i l--"-'- . _l .,. ;_, J .r-~- b bI U p.3. i,. J .1 -*--*.-*-~,'.,.a .,._ lu _ -d--- ..r i J U .,e i ; t l. 7 . m 4,o F ,o 7 is i J -.l.. a.f. 9 s-- + -. --f r + L +3 { b ! g"-t {. - t-. .~ ..c. o....,, t r-p {.- b. i f. ! j, j.., i -.., 1,1 I -{ Hj

i

-l j -!, i IO ; .q.! j, eu J r.. _,4.m. p ..y y q ,.., a. u. Lt 1. ,. I. y 3.. L -. - '.L]l..,p 'f {. l i 4 , l,_. y e. t 4. f.. l.. ,.._.4_,I' 'I it QA + j ,J: ) + a b-*;'. - -. ~.i' } ' t

• 1 I

i f c c4 L ,4 d d,C O % '!1- -i 1-I t r-i -L d 0 H O LN ~ i. 1 Ot 3 dL4 e 's L .L - 4 t .a. .g. .. 4 ).l.. _.. .-l, 3 . _... mbt" .4_ o , +d l ~e'l ', m m' q.}' a'L i m.p ' '

• r 3 ' T' --~ ~

.q.}.t. ]- ~ d - ' ~' ,I t l.1 ~ *-- .llq,.,. .l l . j p., _ 7 j j t j e i. i. p{1i; f . gl - s e r., p. o m._. .,i. {.1 . a j 9.i ; i..j,, i e J.o..{ w ;. ~3- . i i .i . - l, i ;# j g .4 -] f,-j j. j q-{f I ] l - l h j,. ,3 i _f.. i l-Lf ,;ijHf j -- p t i j l. JI 4 A-6

i ? 4 I L 3 -LH253A e p' i 'u-

._... _.a. m

. u. a.u a __ _ u u.. 4u 2 . _.u u _ t a.. u.z?.L ' i ; p.,t__l- .._3.. Lmi i ti,1-u' m L"' = 2-h 2 - t +-- ALL .;2ALaa.LH_._p' u.A._ _. L i L 2 31 LL' i a d._1, LA "-

• t - L; 1.-L W '

i Lii LL4

- u. y m _1 _.L1LLLL_LL

' ~ Li U !. ' L L-- 4-I '*21 Ni .t.L..< 4l

.L a{._

s. i 2'.,m _w u4 1 +*'* t' ^ sii w a r i !1i d. Iu 11j14L;1 i iii. o, r, rt ii Ji 1 1 - iI L LLL w it., Li.' iui .s. i y i - ' fi+ .L _LLLIAd *L _' i 11u '..L . ! q_LuJ.1 .Lu u_ Lu. ' _ ' +.H_._- - _J trtLL u_ .u..' :_Lu_. t L4 gJ.ya.L. a H LL g. + q_' 4 a._7 g j } F1gure 2. Char 4e in Average ._,_L m .__ _ J - Lu_Lt. s_ _,, ',,, -,., - H,,, a',_,'__, a "_-%. _,,, L._F ~. _ _ r, _,.a_--,_ _L u :_ g Ap.. _ .J. i ' p_ q.1..p4 L " /-i-' .._.m a Nodal Power during a Notch N4- -- L' ^ ' W 4u_t L__; + u, _.L_.2-.a a Exercise of a Partin117 u .u. q _1L..:- ,, i L. x, a_.n u.a .f.... _ _ .___o_ .__..L____ L i ,.__..2._._.4

: 1 4

+ +i, i,. r # -,i. Lv. t _u Withdrawn Control Rod ._,..__u.,_.___.a_. ._L.a t._'-*u...-.. a_1.. i ..,,,, 3.,_.__~i i i1 't ,,u L u. r,.___ <m_._. __..-t___._t + 7 _4. _i m _y _4 -

• Li i

Au;.1.L U_1 : . _u u_1M. L L1_ 2.4_LM 1LLLJ_.J -b. __. _ . _, -_ _ _ _.. l_ r_ _,,;. c_a,___; -j_ p E _..;_ _ L._ a_L J_J_ L;y_L. m,

4.AL 4._4.12. l L

.: u_LL.JJJ.. Lij J, i. l L, _,L,;, ,L7 .t,. ,,1_ lu :.1 a JJ.j_ u .a.g J A L. ' p L.. _L. a n_ u t 4. p.i.. 1, 2 4 4 - _L1 < i ' .A .2 L L..L t1.2.12 u.._u, L .i*- i /__LL..; A_ i i ! 8 7i

u_t,

_LiJ,._ _La..!

L.Ap LT' 4 . 21 / . 4_.1u_ ' _.p. _:. 4 _,g,p - _ r_ _-, __ __4. _. w. 4._._. __. J.. .._..;_ i l. i . _i _. 4 i t ..s._3_.,_.,._._1.. _ ~. pg7 ~.. _ _. " + -- H -+ - r,! Lj H !l l.l H+l r.. Y "W~M . _.J 1. ~- . _ ". _ _... -. _9.. H. ' ,'_',c- + i _.l.>_- _A Y_+_H_. '. '.L- - i i H ' '_. i l '.f._-.__ _ _.'. a_... .._,I Normni Control fiod Position i ___,i _.___._.,A.. . 6_L5_ n .t ... _., s. e ._ m._.. _,. .,,...a _. _. _...J... __r +l.._ t + 4 6 _. ~.. _._ ,e _ L. _..,. _ - a _..,. 4 i,_, a 1 ri,.r. n..._'. rm. (. _a___ _ a_._t.. > x._.'. ._1 .L ,H. - Control Rod Position During Exercise - _._.1_ S__+ : . c.. _a. +_ _- + . _. +., _.4_. t_. p ,.__g _.a ~. .t_. i y - - l - ' --F_. y.,__.M.,____2__ [ _. ",, .-l- -,' ' - -- + 8-l l 7 _1 ,_' z_i. _.. 1_ _L , ' _ _.... _. 1 -.4_... _..h__. l _ _. Avera6e H _..,. - y - ~ 1._r_ i Nodal . 4p m_. L_ / Power !._1.' 7-d yl !_.d,,- , ! '~ i - '. g, i.' O i _. -. ~.., " _., H-...r.' _ _ ~ _,.'-

• • ~

a 7 7, c, _ _ _ ~ Change p--

- - --~ - ".

i_. ..__J...' - r i . A L,.u.4. During i. .i _L 1-'. 2 u... 2 -.a..n...1, + ^- +aj-2,--m.. i,.. '. a ---J. U. t_L . I .. a I ._ldd _L p Notch d'J'_'".I._L"' Aul nL .>.w-._ . t_ c l ij. "Li i I r- -- - --- m-I r . -F_ - r._: _ p __ - - - _.. _. I 21 4 42 E L.. ' ' 4" 4M +]."2; _ l_L _jL LH u4 4 u J"' '-f!i.2 _... Li._

• io H> - Exercise '

"- +i_,.A_.._.._c+, t.i. i F "_M + '2" ~'r'. _ '.4 i W.L (kv/ft) _g .1 p. t .J _y 4_. Lp LL__g. j -. _.... _.L. Elevation above Core Botton, feet " '+'

. a.J

_. LA u.1 . _.h.. t_La,- ..pL.._ I. (7_. U _ r ._ ~_~ i .t_ _w.1 1, _ ; _ '. j ; 4. L,. ;_ t .J

_i..

L._ m _, ./ J m. .g E .L n .

• a.

b !... )'WL i Al LL;L'- i L. o f h_S I _h. .. k-j .{ j p _.L;.1'1-. .t'.1 4 .a l id. ! !

• _.J_

1' m. L- .==a g J

• t, a -. -

L 2.ul?'. LLu....i_t.' i t a)t _i La!I . u.Lp t u > I-. - - t. i 'q4.'; _ Ep. s a 1' uo u u1u. __ . : L , 4 J. .L .1, L: t. ..' a _,2 ; u a i.: tut L 2- _ _.. _ f. __& l y* * -a _I._LL.' 'q L j _L _Q{.! '.pp si1 : : 1! # v.m._ p: j.p :I ' p; am t l..1!J i r t L t ? r-a_pf a g. Ld, 1 J.; .1 Ll _ L. } ; ' i. _. I l L.. a, ..T . _ _ ~ _. ( .,.-4 j imi;,r r; .L 4 !

• L ; g[.

._; y

~,l.

. n.J. , + 1_. ~r ; -..r. L m_., w ,*...c._r,J_g th.A_L;g t. m.1

2a r.t L1

,,e q. a._ ,y 1 a a l-j ii ,r l a t :.. j _LL1.j J -. ; L.t,- t_HJ _.._ r._ _7 ..L; i _. .a i gp'4 r/2 ~ a :_,'.. ,..... d _i t > _p n a... L .2 A; 1.;... J p .a_ ,iu

2 a

.a. . t .. t ~u.., 11 ' 2,_ m.,_ a 4J_g #um i a_uJr!]i> 1 .; 1 +. L'. p..t4 . i L 2 i L 1 ___t.1_ nLL m . L... 1. i,, L;, i ' '.' a! w.4 :_L i.pa!i.. l u.L u.t. . g L j_L u ..LL.; _2 L i. g Lui ' t

.L

. L : _:

At i L. [a ; t.

J-

- 1 J.;

a 4 a ... 4 tt-J.u i. U

1. y.

.a'. r. ,.. L _a, ; J _ i t. .r ,.a L M,._o n,/r_ t.; ;. M.. l.,L., - J. J 1 p2 m ._ L l.. ..i. i !. _ f. n. j..t_....__.. ....L&, :_14 a.', j L 7.J...., 4. .. L1.. i q.L. .3 .a a ; q a _,_4_+ ...i._...._,r.t.- i. i _4 1AJ.J11 j 3_.... - 2 4.j 2-, 4...' ._1;1.L4 LL _L. .w..._ j y, ....t j., q. qj i ' ql p ;. 2 ,4 J.3 tij 3 4 j.j g _&_j.,

L,;{

_-. :J.L 7._,,-l ra 7

4 f i _... a #. __ ,a ; .J i . a a I k i t I i et. .-}}