9

.

%0L-' '

:Y)m

%,.

Portland General Electric CompanyTrojan Nuclear I'lant71760 Columbia River Hwy Apri1 2, 1991

- Rainier. Oregon 97048 WRR-077-91(50.h 55 M 713

U. S. Nuclear Regulatory CommissionDocument Control DeskWashington DC 20555

Gentlemen:

Licensee Event Report No. 91-006 is attached. This report disecreca an eventin which the failure of an inverter, which supplies a 120 VAC preferredinstrument panel, resulted in a Plant shutdown per Trojan TechnicalSpecifications.

Sincerely,

t .I 0 b t uaca t..W. R, Robinson'

General ManagerTrojan Nuclear Plant

WRR/LGr

i c: Mr. John B Martinl Regional Administrator, Region V

U, S. Nuclear Regulatory Commission

Mr. David Stewart SmithState 'of OregonDepartment of Energy

Mr. R. C, Barr

USNRC Resident inspectorTrojan Nuclear Plant

iLER Distribution

|

/' f/ \

9104050277 9:lO402 '

PDR ADOCK 05000344S PDR

.

.

NRC PO/dn 3eg U.S. NGCti AA RtGutA704v Counsassaoa14491

Apenovto OMG NO 31604104t,su .....

tsvtuaf t0 SURoth Pta misPON50 TO COMPtv wfM isail,

LICENSEE EVENT REPORT (LER) eC o "E ,,'v't Uo*A.'0,'*l.' " 0#fif'i. A ft'ro "?!s'a t C7*0i* ' * " ' ' " ' ' ' *.

ANO ntPOR f 3 MANAG4W98st BA A#eCM iP 430s u 8 NUCLE AR

P 74 Ripto mi flON P J il to 04 0 iOF WANAGlutNT AND 9VOcit.wASMemof 0N OC 70603.

PLCitif t 8eAmet 41B - 00Catf neuksetR til P AGE i3i

Trojan Nuclear Plant o |5 ; o io ; o | 3;4 |4 i jorj ois" ' " ' * Failure of Inverter Which Supplies 120 VAC Preferred Instrument Panel Results in Plant

Shutdown Per Technical Specifications4 VENT DAf h :$1 tta seVheet h Ig; etPO81f OA f t (FI Of Min P ACluf tt$ INvotyt0 see

MONTH DAY 70A4 vtAA "0M L'' UL*M MON f as Oat vtAm ' Acsu rv = Auss 00C a t i Nvwet nisi

N/A 0 15}0|0|0| | |

0| 3 d3 91 9|1 0 |0 | 6 0| 0 0|4 0| 2 ob ot 5 to 1 0r oi i !~ -

THis stPomf 14 sveMetft O PuntuANT 70 twa atouantutNil of 19 CPII { ICAsee .ae w *we .'sae r.u.aese (1HOP W NM004 m 1 30 402M 20 eetles 90 PhosaHet T3J1tal

_ _

powsa M 4884eH1H4 94 JetsHt) 94.734eH2 Het f1316sl

",".P-

10;0! n eHum so mi.iai unwie:H . ofu t a n.~ - A...-, .4

*||>'^"~''"""''""' \~~

n aasuH,Hn X sani.,ana uns.,aH HAs n

N esseeH1Hevi to 73tsH2Hal to 73isH2HousHei

to de54sif1 Het - 9433 eH2He# to 73:eH2Hel

(scl8stal CONT ACT PGA YM'S tt R 1121

NAM 4 TittPuoNG NVuetaAnteC00t

Lansing G. Dusek5 5 | 21 45|Oi3 515|6 i -t 1

CoasPttit 044 LINT PoM E ACH COur0Ntari 8 Astung DCSC8sS40 est twe8 Repost (136

W AM AC- 8,f,Aj$U CAv84 8vif tu Cou'ONENT "("h0' "y ,',[g'I*CAvat SY3fEW COwPONENT

o

X E i F I IN;V T E2 1 0|9 Y i , , i ; i iI 1

l ! I I I I I I I -! I I I Isu uwe=? At at oaf ExPicf to nei woNTM OAv i vtan

s''s'u'iEoN~

u ' " " ' '7 v4 v,. errecreo sumwo= oAfri Tl No | j ;

Auf.ACT u ,.,, ,e m . . <,.. ,a, - .,v -~ ,o..

On March 3,1991, the Plant was' in liode 1 at 100 percent rated thermal power.'At 0720, an inverter trouble alarm was received in the Control Room. It was.found that=one of the 125-V de-backed inverters supplying a 120-V ac preferredinstrument panel had automatically transferred the panel to the 120-V acbypass source. The preferred instrument panel was declared inoperable and aneight-hour Technical Specification action statement was entered. The Plantwas shut down to Mode 5 because invettigation and correction of the cause ofthe automatic transfer and noted inverter circuit damage was not accomplishedwithin the time requirements of the action statemant. An investigationdetermined that the most probable scenario is that-the automatic transfer ofthe inverter was initiated by a random component failure of an integratedcircuit on a logic board in the inverter. It is postulated that the automatictransfer was accompanied by a current surge which damaged inverter circuit-components that may have been stressed by transfers occurring at excessivephase angle differences. The inverter was investigated, repaired, tested, andreturned to service. Synchronization checks were also performed on the threeremaining inverters. An adjustment was made on one of the three inverters,and adjustments will be made on the other two inverters during the 1991Refueling Outage. Additional sets of printed circuit boards will be acquiredfor each of the inverters, calibrated in_ situ, and stored as spares so that

; they are available to replace the sets in the inverters if future inverter

|. circuit failures occur,t

i

NAC P.ca Joe 16491

{ '

. . . _ . .-- - - - - - - - .- - _. -

g,,.m =a u. JZnown,co ._ , , , , , , , , _

. osan m ,. -.

LlCENSEE EVENT REPORT (t'W 'Sg,^",D,o'yM,g"J'.83"li,N."'#,' .T.",l"x's.

TEXT CONTINUATlON f.,"",',".;'."1",^", Of, ?,,yNM,'c'"','M ;",' 'Mf!*

'

of MAhAGlutNT A40 0900&Y,stasmi.f"n= 9?,ciMt",'#,i",JoR"."a'vi;'a'%"EsCTON. 0C 30603

#LCakif y haut ni occattsvuega ut tt A huMelt tal P&Ot (31

d'' ws a e, wa e

Trojan Nuclear Plant o |6 jo ;s io | 3|4 | 4 9|1 0 |0 | 6 3 |0 0| 2 or o |gta r a . a e ,.,,,, w., on

i

EVENT DESflurt10R

Ba.chground

The 120-V ac Preferred Instrument System supplies uninterruptible power toengineered safety features (ESF) Train A and Train 11 equipment, ReactorProtection System Channels A, B, C, and D, and essential Plant instrumentationand control equipment required for startup, operation, and shutdown. Thesystem is comprised of four preferred instrument panels designated Yll, Y13, |Y22, and Y24, and four inverter assemblies designated Y15, Y17, Y26, and Y28, '

which supply power to the panels (See Figure 1).

A preferred instrument panel is normally powered from an associated ESF 125-Vde-backed 7.5 kVA inverter. Upon loss of the 125-V de source or failure ofthe' inverter, the preferred instrument panel is automatically transferred toan associated 120-V ac bypass-source via a static switch that is part of theinverter assembly. The 120-V ac bypass source is supplied from an ESF 480-Vac motor control center bus through a 480:120. 7.5 kVA transformer that isalso part of the inverter assembly. During normal operation of the inverter,output frequency is maintained synchronous with that of the 120-V ac bypasssource so that automatic transfers of the preferred instrument panel to thebypass source are accomplished without interrupting the power supply to thepanel. The preferred instrument panel can also be transferred to the 120-V acbypass source without passing through tb static switch by using a manualbypass switch. The preferred instrument panel can also be manually shifLed toan associated non-ESF 208/120-V ac instrument bus.

Deacriplion_of_Accurrence

on March 3, 1991, the Plant was in Mode 1 (Power Operation) at 100 percentrated thermal power. At-0720, the PREFER-AC Y-26/Y-28 TROUBLE alarm wasreceived in the Control Room. An Operator was dispatched to investigate thecause of the alarm. It was found that Inverter Y28 had automatically-transferred Preferred lastrument Panel Y24 to the 120-V ac bypass source.There were no indications of the cause of the transfer. At 0722 PreferredInstrument Panel'Y24 was declared inoperable because of the loss of its

-redundant ESF power supply, and the action statement of Trojan TechnicalSpecification (TTS) 3.8.2.1, "Onsite Power Distribution Systems, A.C.Dintribution - Operating", was entered.

Ir.vestigation of Inverter Y28 was performed via an urgent maintenancerequest. Early in the investigation, Preferred Instrument Panel Y24 wasmanually shifted to the non-ESF 208/120-V ac instrument bus, YO2.Approx 1'nately five to ten minutes af ter opening the inverter cabinet doors,the inverter SYNC LOSS lamp began to light intermittently. Measurementsindicated the existence of a phase angle difference of approximately

NAC Perm JUGA 66498

_ - _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ ___-____ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _

.~. _ . . _

; ego.- u,veumnvu ru, no....o.,, , , , , , , , , , , , , , _

t XPCf $. 4/10/MILICENSEE EVENT REPORT (LERI St*,'!,%'fMJP,J'!;411,'%c ".y ,%",,'*'j-

.

TEXT CONTINUATION f,.t'"4".'o'.",1*'", TJUt"d"'.". ','jjf $"| "'c@'

'

70".W%R""ata',a",PA& Mess 0704 DC 20603."h''n?"#J"#17.'a.OFMAh&QlutNTANOevoQft

''C'W "aast m DOCst,T a.v.sa n uiU N mumet R las paos @

...a j- @ ty'f 6 |af{,*go,

Trojan Nucicar Plant o |5 |010 | 0 l 314 | 4 9 |1 0 | 0| 0 0| 0 0| 3 OF 0|8- -

rm in . = = .c , au .mn

12 degrees at no load between the 120-V ac bypass source and the inverteroutput. Raising the temperature a few degrees in the vicinity of printedcircuit boards inside the inverter cabinet was noted to result in the SYNCLOSS lamp remaining unlighted. It was surmised by personr.el involved with theinvestigation that cooling from the extra ventilation provided by the openinverter cabinet doors was responsible for the intermittent lighting of theSYNC LOSS lamp. After the inverter cabinet doors were shut, the SYNC LOSSlamp remained unlighted. The investigation revealed no other problems. Afteradditional maintenance and operational checks proved satisfactory, thepreferred instrument panel was shifted back to the 120-V ac bypass source andthen transferred to the inverter. After approximately two minutes, an acridodor and wisps of smoke were noted to be coming from the invertar. Thepreferred instrument panel was shifted back to the non-ESF 208/120-V acinstrument bus and the inverter was secured. Craftsmen investigated thesource of the odor and smoke and determined that a resistor had overheated.

At 1522 preparations to shutdown the Plant were commenced in accordance withthe action statement of TTS 3.8.2.1. At 1750 an Unusual Event was declared,and power reduction was begun. At 1755 notification of the NuclearRegulatory Commission was made concerning the declaration of the UnusualEvent, in accordance with Title 1G of the '' ode of Federal Regulations,Part 50.72(a)(1)(1), and concerning the initiation of the Plant shutdownrequired by Technical Specifications, in accordance with Title 10 of the Codeof Federal Regulations, Part 50.72(b)(1)(1)(A). At 0310 on March 5, 1991, thePlant entered Mode 5 (Cold Shutdown) and secured f rom the Unusual Event.

The resistor which overheated is designated R4 in the inverter fault sensecircuitry (See Figure 2). Other components in the inverter fault sensecircuitry were also determined to have sustained damage. Resistor R131 wasopen circuited, and Zener Diode CR115 was shorted.

During normal operatica, the inverter f ault sense circuitry monitors forfaults in the wave generation section of the inverter, via CurrentTransformer CT1. A fault is realized as an increase in voltage acrossResistor R134. A fault of sufficient magnitude results in enough increase inthe voltage across Resistor R134 to cause the associated operational amplifierto operate. Operation of the operational amplifier initiates an automatictransfer of the preferred instrument panel from the inverter to the 120-V acbypass source.

Investigation into the cause of the automatic transfer of Preferred InstrumentPanel Y24 from Inverter Yi8 to the 120-V ac bypass source and the damage notedin the inverter fault sense circuitry included assistance from an authorizedservice representative for the inverters. Analysis of the event determinedthe following scenario to be the most probable; however, due to the number offailed circuit components, proof of this scenario is not conclusive. Theintermittent operation of the SYNC LOSS lamp early in the investigation

we ,- ma .u,,-

_- _- __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _

-c,g =* u. wcum.Oum, co . ,o,,, , , , , , , , , , , , , , , , , ,

t EMtt 4/30>Tf 7

| LICENSEE EVENT REPORT ILER) "';n'|,0,o',fRyd'!;o"f,,'",!?"P.' 'g".,'."dj,

TEXT CONTINUATlON f,74%',,y*,^."fgi|Mf',M'd,*, ','M? '"Iu ' "Mf'-

MiW,',T.'Jt"."atina',Z"a;?"J!J'AM'f a'

of WANAGEwtNT AND SVDGtT e4&mwGT04. Oc 20603--

8& Calif T HAM 4 tu oggggj wyu,gn m

"etr :w.t:"-

Trojan Nuclear Plant n p n;n;n p ;4 4 9;1 0o 6 00 0 ;4 0g8gg yg _ _

ttmn . =c , am4m

supports that the immediate reason for the automatic transfer of Inverter Y28was the failure of the 4011 integrated circuit on the static switch logic

board. It is postulated that the automatic transfer was accompanied by acurrent surge in the innerter fault sense circuitry which resulted in ZenerDiode CR115 shorting and in Resistor R131 open circuiting. With the inverterfault sense circuitry damaged as described, the subsequent reloading of theinverter resulted in overheating Resistor R4 since it would have then beencarrying the full load of the circuitry.

The magnitude of the phase angle difference noted between the 120-V ac bypasssource and the inverter output indicates that transfers of Inverter Y28 mayhave occurred near the design limits of the inverter fault sense circuitrypotentially since installation of the inverter in 1988. Transfers in thiscondition possibly stressed components in the circuitry. Synchronizationchecks of Inverters Y15 and Y17 were performed following their installation in1987. Ilowever, based on satisfactory results from the checks of theseinverters, consideration that the test method being used for thesynchronization check presented a potential electrical shock hazard topersonnel, and absence of a requirement in the inverter technical manual toperform the checks, it was determined that synchronization checks of InvertersY26 and Y28 following their installation in 1988 were unnecessary.

The completion of the nucicar plant shutdown required by the plant's TechnicalSpecifications is being reported in accordance with the requirements ofTitle 10 of the Code of Federal Regulations, Part 50.73(a)(2)(1)(A).

CAUSE

Based on the scenario postulated above, the most probable cause of theautomatic transfer of Preferred Instrument Panel Y24 from Inverter Y28 to the120-V ac bypass source is random component failure of the 4011 integratedcircuit on the static switch logic board. Accordingly, the most probablecause of the damage noted in the inverter fault sense circuitry is inadequatepost installation testing of Inverter Y28, since a synchronization check andsubsequent adjustment were not performed following installation of theinverter.

CDRRE_CIIVLACIl0NS

Corrective actions that have been accomplished are as follows:

1. An extensive investigation, necessary repairs, and final maintenancetesting of Inverter Y28 were performed under the guidance of theauthorized service representative for the inverters. The as-left pht.cc

angle difference between the 120-V ac bypass source and the inverteroutput was approximately 5 degrees at no load.

we e-a u m

- .- - ..- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ . _ . __ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ . _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __

g. , , - . ~ve6 ..c..os. .. Co - - o-,,,,,,,, ,,,,,, ,,,,,,,,

8376283 sanct

LICENSEE EVENT REPORT (LER) f,,,'g*,',',%',vam,;t*o"'!;%*8,1,'cJo"'A' ,%",'Jj8-,

TEXT CONTINUATION c?"*4",2,*,15'* |*Waf',' U,'/*^,'M '",' Mf!., o u

a tfvN60m 3fgoc 04k oNihpaegawo08 WAha0tutNT AND SWOGtt,yba$MtNOTON.DC 7060L

eaci41,y haast ni poca t t NVh88 6 R L31(gn muesta 181 9&04 m

8 ' d',' [,' 6 ",'Jw'',y,''.t&a

Trojan Nuclear Plant o!6[o|o|0|3|4|4 31 Dj0|6 0 0 0; 5 or 0|8- ,_.

run a . we e ms..nm

2. The phase angle differences between the 120-V ac bypass sources and theoutputs of Inverters Y15, Y17, and Y26, were measured to ensure thedifferences were within the design limit of approximately 11.5 degrees.The phase angle difference between the 120-V ac bypass source and theoutput of Inverter Y26 was adjusted to approximately 44.8 degrees at noload.

Corrective actions to be accomplished are as follows:

-1. The phase angle differences between the 120-V ac bypass sources and theoutputs of Inverters Y15 and Y17 will be adjusted during the 1991Refueling Outage. l

.1

2. The inverter maintenance procedure will be revised to check the phase iangle difference between the 120-V ac bypass source and the inverter !

|output and to provide instructions for making adjustments. The revisionwill be completed by April 30, 1991.

3. To. enhance Plant safety and availability, a complete set of printedcircuit boards will be acquired for each of Inverters Y15, Y17, Y26, and 1

Y28. The sets will be calibrated in their respective-inverters and thenstored as spares so that they are available to replace the sets in theinverters if future inverter circuit failures occur. This action will becompleted by June 30, 1992.

SLGRIElCANCE OF OCCURREMCE<

The redundancy designed into the power sources to the preferred instrumentpanels mitigates the effect of a loss of any one source. In_this event

. uninterrupted ESF power was maintained to Preferred Instrument Panel Y24.Furthermore, power could have also been supplied to the panel from the non-ESF208/120-V ac instrument bus. Therefore, there was no effect on public healthand' safety. Even if a loss of offaite power had occurred concurrent with theinverter failure, the preferred instrument panel would have regained powerfollowing the start of the' Train B Emergency Diesel Generator which backs the120-V ac bypass source.

EREV10US SIMIIAILEVENIS

A review of Trojan Licensee Event Reports submitted since the initialinstallation of two of the invertets in 1987 revealed no occurrences ofsimilar failures of the inverters. A review of internel problem reportingdocumentation revealed that problems with overheated R4 resistors werepreviously encountered following-the completion of startup testing ofInverters Y26 and Y28. An investigation revealed that the R4 resistors in

M]tC Perm Je&A IH9

. - .

_ - _ - _ _ _ _ _ _ . _ _ - - _ _

.go==.. u . ~oca .. . .vs A, . , co-,.._ , , , , , , , , , , , , ,

j u...n ., ,.

LICENSEE EVENT REPORT (LER) f,'.';",,'i',o,AvaoOdi"J',7a**,',,'*,o f"'N ."o|JT!c.

TEXT CONTINU ATION $,",',"4'.% ^*,,3. *f"?'Ai!,'e',", ','!d? '''' UjNf!u.

M,P,'','o".'on"ra'A"',!"o'"fd?"oW", '':i.a0 WANA0tulNT AleC Sv0Gf t n46MINGTD8e DC 20603

. AC4ktit %Aut til DocatisevMataiJs 48. kuust a 14, | .aSt tai

"ttn.''-- ef,yr+=

Troj an Nuclear Plant 0 |6 |0 j o | 0 | 314 | 4 9| 1 0 | 0|6 0 j0 Oj6 OF 0| 8- -

rm in = . . .ei muv mi

Inverters Y15, Y17, and Y26 showed signs of overheating. The immediate causeof the overheating was determined to be that the R4 resistors installed in allfour inverters were of a different type than specified by the vendor. Theresistors were replaced with ones of the specified type. It is possible that

the phase angle difference between the 120-V ac bypass source and the inverteroutput may have been a contributing cause to the overheating of theR4 resistor in the case of Inverter Y26 since the inverter'8 phase angledifference was not checked following installation.

6075W

.

- - - _ - - - . _ _ _ _ - _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ - _ _ __ ___ ___

- _ - - . . - . - .. . - - . - . ~ . . - - - . - . - . _ . - . . -

1

|40220 Mu W& NUC6449 840W4A19av Comulletok ,,

i oi.. . w-.

LICENSEE EVENT REPORT (LER) '.". o'".* ". ,o.o'h Co' *s "e v"io.". ".'t os"n t' o co** ' ' ."o="w'."n*osao o*.* u u x

TEXT CONTINUATION A h p A't >0n"f t 'w'a h 6 0 t u's"h ? D R A"NC m"* " 'o '"' "s'C a t anco** *" C ao''' "D'* c "o*aP 430s. U t N

agovtatomt COMweleom wasusmuich oc paste amp to - !

ing tapq mwont R8 DvCT#0h Pao;r ct otuaiO4i op e tCl |Of wAhAGlutNt AND tvDGit.walmaNotch DC Pmol i

Pactkity hawltu poca a t Nvutt h 63'

|gla kJaest e ite Pact (3'

.. ... :, . , f .. ..e. .-],,,, w.; . - n.

Trojan Nuclear Plant 0 p | 0 | 0 | 0 | 3| 4 |4 9| -l 0|0 | 6 0|0 0|/ OF o |8-

rartn-, . - ..c asuoon

tt.................1;R f :*m -

#-; 3 {ff""~|

c '

d 1- ti 7. ; /, .V :r

! S <+ - !. 5g:49(!!! !.

A.:

$ w.. ..

5 8i. . . . . .&. | ! ! B |, :..........

,V^ .| !( , . . . . . . . . . . . . . . . ,

A g & i! i k.,'

5.

eg. ,; 5"' ' .-

- ; &I NTv''' | , i tp| [y6; I

- .

8 g| E'

'E| egyf 8 | r9:

V*.

h, ; |

IfC 'si:;| AR:6 | [:qf...;N'.> -

G~; if 1 . . a

.; y e-- 2^. | [ $

W '

g n .

fit .' : : ms

.3.................. - ,h P'% #%

.. gm

ba',*g M

I. n

N# -aY. E 8m n

--

um = i

Y t e.*"

N $.

Gg w.

V ^

y. p u<

g >.

C= p 9n_ m

ECE................. y.e-

E$h h b~

: |,,a., e8 -e -

- 9- :g , )3 s . . . . . .v ; g- -

: e.

5 b ! rg Y ''! [! ! ! '+3 d .:.. - ng . [Y

e =E h:-*- -

(e : I.w - 7:| &~|

' * * * is.,,, E #.V 8 0^- -j | S Ii t.I ,! ,R:

;s.---. .-. , ,,, , .

,

Y YY^,

( .......... . .. - ,

8| g..''

8 ! u........ .......

h !f !E a

: | rs 8 :

:r: ff!5 5- ! r!.!.$ N

.: ~ ..3 i e c, +. \ i. 4 a X y ,s***,

Y ||

.

'.j.

'/[^ ga ss

g.) g,

' *g'

............. .

.

NIC f era JAGA 16491

. - . . . . . .. , . . . . . - , . . , . . . . .- - -- .

!1|)1!

--h.3uM I" : Ejj cE 8" aj E?

g ?;i- o egd- ,|

", 2 : ea ~.

e_Om2umm m<m24 3m]24 pm2 - r) 2 ;o 73; :m ?3s . nC$ 5 *b- -

. _7 3;5p'a7 :r, g ?* y325s *a E 5 c3-.

4mX4 ;o $ 3,2 3pE 3 5,*;;ox. I .O O Z4~z C y4 O2 gc .- -- - - 2 2 h0 m

;c 1g 8! p ic 5** ;o 8;- 2 8" :7a ? ato , $s - o. = Io c; E15 ;* c?; i- -. R .

eO aE~ - ' f i ! ; c- 5fti z- I* 4

* , j1' !!9c.

,,1 - * ' -

HnOawD zCoHru" m~40" o- - - - 2. E 1: * 0,, O3f-s ~

_C o m oO y.I|.z,* 3} ! e .j 24 E* { .:G..

- u4s

wwNo 5

'1363x'/ aF3 -

1

-

\'s -a

.

3 - %>| c4A

kW1 .

(,J-> j- I<

-reneZ5

11 vR5C, '1

.

, . '

fp

6myr

11 3 tC3 i

- ucr

- iCes

3 n3 a e1 1 SR 5, I

I.> , tl

uaF3oa ne3o

_ 1

i2 r12 r

u.P2e g2 e-

tr

r ef;,,' ' v. A n4r- n

~Ik

I_0E1_2r-1&- A $ .

ar, .i2

D erug

n i

r1

F4

e 4 3n R 1

r

#,dofsnori

ltinCe

-

er

uCp

U-

kco.L

=I yb ia-

t|<l||1I ii || |||!,( |l .