05000296/LER-1983-026, Supplemental LER 83-026/03X-4:on 830411,while Attempting to Establish EECW Flow Rate to Emergency Diesel Generator 3 Coolers,Head on HX Found Cracked.Caused by Mfg Defect.Cast Iron Head Replaced

Supplemental LER 83-026/03X-4:on 830411,while Attempting to Establish EECW Flow Rate to Emergency Diesel Generator 3 Coolers,Head on HX Found Cracked.Caused by Mfg Defect.Cast Iron Head Replaced

ML20082P157
Person / Time
Site:	Browns Ferry
Issue date:	11/25/1983
From:	Green H TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
LER-83-026-03X, LER-83-26-3X, NUDOCS 8312080111
Download: ML20082P157 (10)

LER-2083-026, Supplemental LER 83-026/03X-4:on 830411,while Attempting to Establish EECW Flow Rate to Emergency Diesel Generator 3 Coolers,Head on HX Found Cracked.Caused by Mfg Defect.Cast Iron Head Replaced

Event date:
Report date:
2962083026R00 - NRC Website

text

-___ ._ _

% - +, ._

80#, 0T08022 d :SI 92/II PREVIOUS REPORT - November 21, 1983 APPSOV E D UV C.AD i

'C8hs ase u o nuc6sa. naouta,o.v couweasson ano son NyC,,d LICENSEE EVEf4T REPCM ko< r so IPLE ASE PRINT oR TYPE ALL REQUIRED INFORMATioNi CONTROL BLOCK; l ( j jl l J

@ l A I L I B l R l Fl 3l@l0 l 01 - l.c... 0 l Ol.Of au-... O! 0 l - l O! 0l@l4 .. .. l 1 l u1 l l l 1l@l.. .l j @

u....n.. . , . .

, .. u......c... .. ..

CO*(T

d. "' U' l L l@l.0 ! 5 l0 l 0101219l 6l@[0 l 4 l 1l 1l 8l 3l@[1 l ,, . . . . . , . , . ..

_l EVENT DESCntPTION AND PROB ABLE CONSEQUENCES O10During normal op j o )2 l l

_j

[TTa'lI flow rate to the 3 ED Emergency Diesc1 Generator Coolers following a modi-The j Q l fication, a head on the heat exchanger was found to be cracked.

]

[TITl l_6enerator was rendered inoperable and unit 3 placed in an Lc0 (T.S. 3 9.B.2).

j There was no_ danger to the health

[oj ej l_ Redundant systems were proven operable. _

l

[oII]l and safety of the pub 1_ic.

I IoIalI

'u".~ qu: .::n:. .. .... ,.... .::::.. .::n:.

lobl. I E is l e L,BJ @ L,J,. u @ 1". IT I E l X l C l H j @ J. @ l..Z l@ ..

. i.

~::::~~ ~nn' ~:::~

. . . , , . .  ::::: = ? l 4l

@ ['((*1 . . . l 813l [---]

u 10 l 2 l 6 l u ,.

Z, l0l ..

3i

.. L..xJ I-l

,, u

.:?:::,3'.,@

o

.,f:::,.',

'" nu~  ;",,n' ..";;T .. "'::.la;*-

' 2'u 'n'1"l -....

101010{@ lY ]_0 l 2 l 1 l lu Bl@W@ lZn ]@ W@ u n 0j

'"'W @ lYl@ U. @

.. n u

j

[,JT)lCAUSE DESCRIPTION ANo CORRECTIVE ACTIONS bitA Young Radiator Company heat The j g [ manufacturing defect which became apparent due to in-service stresses.

l

{T il l cast iron head was replaced on May 25. 1983 with a newly fabricated head, This was a random j ltI3}l_ tested, and the diesel generator was returned to service.

I

@l necurrence and no further action is required.

=': , . . . ..... .... - @ l=' ::[ Aj@lOperator Observation

@ j{

@ l_E_J $ l 0 l 9 l,9J@(_ NA " " "

$'.Tl:. ! h) .";.. . . . , , . . . . . . . . . ,

..........u... @

l L2Lil L2J @ LZJ8l NA @J "

i NA "l

' ' .:,u':[" '"!?5"" *.. . . ......., @ j 8,. L.0101 Ol@ll.j@l NA

'af/:."" '* nil;,.... @ e3120 eof 11 831125 DR ADOCK 05000 S

. Iilal10101Ol@l NA n:7 ".=.="'""e g7, 7 i!i _ _j I Il 91 I 7.lh[ NA q-

. . . .. Nac usE oNty .. !

... 4"li.'l. .. .. @ J l l l l l l l l l [_l_ l,,l Agl NJ@[ ,-

NA

[ "~

OT080h[

t 0 #. z Tom M E Tennessee Valley Authority BY U S Browns Ferry Nuclear Plant 2/19/82 LER SUPPLEMENTAL INFORMATION a

8 3026R4 Technical Specification involved 3 9.D.2 _ _ _ _

BFRO-50 296 /

Reported Under Technical Specification 6 7 2.b(2)

• Date Due NRC Event Narrative:

units 1, 2, and 3 were operatin6 at 81-percent power, 85-percent power and 99-percent power respectively, only unit 3 was affected by this event.

Af ter performing modification work on the 3 ED Emergency Diesel-Generator Cooler, one of the heat exchanger heads was found to be cracked, apparently duo to a manufacturing defect, when the flow rate to the EECW cooler was establiohed. The generator was declared inoperable and unit 3 was placed in an LCO (Technical Specification 3 9.B.2) .

The cast iron head was replaced on May 25, 1983 with a newly fabricated head, tested, and the diesel-generator returned to servico. This was a random occurrence and no further action is required.

Toero was no danger to Redundant and backup systems were proven operable. .

the health and safety of the public.

TVA has performed a design ant. lysis on the diescl generator cooler heat The calculations inCicate '

exchanger aholl flanges, tube sheet, and tubes.180, 190, and 1200 psig respectively.

that the rated pressures of these are All of these pressures are above the normal eystem oporating pressure range of 80 - 120 psig and the maxt:aum actual pressure obtained during an accident

.(135 psig; 2 EECW pumps starting or,each taader).

Section II hydrostatic tests have been performed on the EECW side 'of these coolers, which includes the bonnet and bonnet flanges. Unit 1 and 2 diesc1 coolers were tested in February 1980 and unit 3 diesel coolers were tested in

~

November 1978. Test pressures ranged from 142 - 168 psig. This is 118 -

140% above the maximum normal system operating pressure (120 peig) and 105 -

1245 of the EECW accident pressure (135 psig). Modification to'all 16 of the diesel-generator engine coolers will be completa by August 1984 to assure- 15 9818 operation pressure of the diesel-generator engine coolers is below Based on theso design calculat'.ons and hydrostatio test data, there is no immodiato operating concern.

A detailed report and analysis is attached.

e Previous Aimilar Eventa!

None Retention: Period - Lifetime; Responsibility - Document Control Supervisor yM

• Revision:

e .....

?: ~

0108022

~

9 0 #. ..i:Si o 92/11 Page 1 (LER ALBRF 50 296/83026)

DETAILED REPORT AND ANALYSIS The diesel Senerator engine cooler heat exchangers have 'aen manufactured by Young Radiator Company to company standards for 75 psig design pressure. However, the Tennessee Valley Authority's Division of Engineerin5 Design has performed calculations on the tubes, tube sheet, and shell flanges using calculation procedurcs established by ASMB Section VIII or Tubuler Exchange Manufacturer Association (TEMA) and a comparison of These bonnot and bonnet flango assembly (head) to AWWA fittings.

calculations and comparisons are attached. The dimensions and material of all parts subject to ecoling water pressure have been compsred to ANSI and In addition, the TEMA standards for similar components in water service.

heat ezchanger bonnets (heads) are east iron. Cast iron does not exhibit fatigue failuro which is the type of failure that would occur with repeated overpressurization.

The diesel generator engine cooler heat exchangers have been in service for 10-years. During these 10-years, the heat exchangere have operated at EECW 100-120 pressures of 60-120 psig (normally in the upper part of the range, psig). Those pressures are obtained with one pump on each main EECW header. During tests with two pumps on each header, the maximum pressure was found to be 135 poig. The four pump pressure, two pumps par header, is the maximum operating pressure the EECW system will see since there are only four EECW pumps that would start from an accident signal to the diesel generators.

The EECW flow to each EECW system component is set by manual throttle valves which are locked in af ter being set for the required flow.

- - - - - _ _ _ - _ _ _ _ _ _ b

908 otocou si:t1 um iN Page 2 Both the unit 1 and 2 (scuth header performed 1980) and unit 3 (both

< headers performed 1978) diesel generator engine cooler heat exchangers were hydrostatically pressure tested by procedures written to requirements of Section II of the ASME Boiler and Pressure Vessel Code. In accordance with these procedurcs, the EECW system is divided into six sootions (two sections per unit) and each of these scotion is individually hydrostat-ically tested. The two sections on unit 1 and the two sections on unit 3 contain the diosol generator engino coolers. To test each of these sections, the section under test is isolated from the rest of the EECW system by closing the appropriate EECW main header sect tonalizing valve and isolating each EECW component using its outlet isolation valve. Included in each of the unit 1 and unit 3 section's components are two diesel generator engine coolers. After isolation, both EECW pumps assigned to that header, plus one pump assigned to the other header, are started if they are not already running. The EECW pressures established durin6 the unit 1 and unit 3 hydrostatio tests were 112-168 1 peig.

d There has been only one failuro associated with the diesel generator engine coolers. The bonnet (head) on one heat exchanger failed during reassembly due to bolt-up stress and a possible canufacturing defect. It was detected immediately after the heat exchanger was placed back in service after modifications to the connecting EECW piping. Thore have been no failures on any of the 16 heat exchangers due to overpressurisatien.

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

s5 ". Fist _ . . .

204 010C022 6i:81 92/TT PCgo 3 From the calculations, comparisons to industry standards, and operating

• experience, it is evident that the diesel generator engine cooler heat exchangers can operate at the normal and accident pressure without degradation. Ilowever, to ensure tho satisfactory long-term operation of the heat exchangers, throttic valves will be installed in the inlet piping of each set of heat exobangers (two heat exchan6ers arranged in series in each diesel generator engine cooler). These throttle valves will be used to set the EECW pressure to each heat exchanger at levels that are calculated to be below the manufacturers design pressure of 75 poig. The schedule for completion of this modification is to have all eight diesel generator engine coolers complete by August 1984. The diesel generators are and will continto to be visually checked each day as documented in operating instructiona until the modification is complete.

? >

O O

m n _ _ _ _ _ _

T A G L E ,

A 4-28-83 4-1-83 4-1-83 Unit 1-1980 se.t 3 197a. .

1 Pump per Header 2 Pumps per Header 1 Pump per Header Hydrostatie Test osin ... psist .. osir nair-DI3SEL North South North South North South r:RarnRATOR E== der Hender Header Header Hader Header 1A 97 97 124 125 93 93 Scheduled for later date 1B 100 100 126 125 94 93 142 1C 101 100 125 124 92 92 Scheduled for later date 124 142 03 1D 98 98 123 92 89 3A 100 100 128 129 98 91 145 .$

3B 101 102 129 130 100 100 168 ,,, "

1 3c 100 100 128 131 101 100 145 3D 100 100 128 129 100 98 168 o"'

NORTH $

HEADER '

]

~ ;.

N/A ~~

Unit 1 99 129 93 Unit 3 98 127 94 145 SOUTH HEADER Unit 1 105 134 98 142 Unit 3 106 135 101 168 o

Cd k

e

% o OJ D N a

w=4 1

^

s i, .

c 1; ;- tayy . . . .

60# 0108022 02:81 92/II P;ge 5 ATTACHMENT a

Purpose - To evaluate the fitness for service of the coolers. Their nameplate pressure rating was 75 psig. The raw cooling water system pressure on the tube side was greater than 75 pais.

Method - The actual dimensions and materials in the cooler were compared to dimensions of standard pressure parts where applicable or calculations were performed where necessary to evaluate the cooler's pressure retaining capability against the raw cooling water pressure.

1 AAAA11a - Brctina Ferry Nuolear Plant personnel provided the information requested on the attached sketch of a cooler. The outline drawing and data sheet for the coolers provided overall dimensions, piping connection sizes and tubing information.

On the tube side of the coolers, the tubes, tubesheet, flanges, and bonnets were evaluated.

a. Flanges (1) Shell flanges were comparod to ANSI stool flanges,12-inch NFS, Class 150, low strength carbon steel.

ANSI Flange Pressure Rating - 215 psi f.NSI Flange Thickness 1/4 inch Cooler Flange thickness 1/16 inch ANSI)  : E(ANSI)

• (Cooler)

( E(Cooler)

P (Cooler) - approximately equal to 180 psi The cooler flange had 24 bolts, 5/8-inch diameter, the ANSI flange requires 12 bolts, 7/8-inch diameter - The 24 smaller bolts were judged sufficier.t. ~

9' r Q ary -~.

OIR 0T08022 12:81 92/11 Pasa 6

b. Bonnet Flanges to Sho11 and Bonnet (Head Assembly)

(1) Bonnat Flanges to Shell y Bonnet flanges were 1-inch thick. ASHE and American Water Works Association (AWWA) flanges with 165 or 150 psi ratings rsquire 1-1/4-icch flanges with 12 or 8 bolts. These flanges had 24 bolts and full face gaskets. 4/5 of 165 approximately equal to 130 pai.

(2) Bonnets All pressure bour.dary dimensions of both bonnets were at least as thick as required for AWWA, 12 inch, 150 pai rated piping. The radius area of the inlet / outlet bonnet was thickened and present no concern.

c. Tubesheet - Th6 tubesheet was assumed to be an unstayed flat head with ligament efficiency or 0.5. No staying effect of tubes was included.

t=d' kip /SE t 7/8 E = 0.5 d = 13 s = 12,500 x 1 5 P=t 2SE/d 2C P = 140 psi Later calculations in accordance with TEMA showed a maximum design pressure of 190 psi.

d. Tube Admirality - 3/8 inch X 23 BWG

. Allowable stress = 10,000 pci t = .0226 P - 2 SET /Do P e.1200 si Conclusions Hux. Press. Seen During comoonent Calculated Pressures Section II-Hydro

1. Shell Flanges 180 168" psig

2. Head Assembly 168" paig

a. Bonnet Flanges 130

b. Bcaneta 150

3. Tubesheet 190 168a psig

4. Tubes 1200 168' psig

~

l 5r .,..> _..

II JO IIR '0108022 '

12:81 92/11

y. ,, ;a c,p o s r)i5* '*'

'...)/E544.C".dt44TaL_coacwpw,4rgg y_ _

. --. /

CO AY M8Didr70) opf HerthJr's A/.}/id7~>  ? C-PT/

>w/d k X F-13 p J-TB.zR ]Q 'f <

q z >le Y3 IYW D * S '* I 7 (hh 012) eg

_ w_Csk

. a gg.

i~ "

g z. w fave,(sa g&l

.a 2

9 u e up r-onter

^

g 1 n .< - ~ __ rpm *WG ! .

f

( 94 - i > <a  :

, [W V _

~

,%LW'n,, e k .c w -

CCf Ap)V j k f.gpg.,s,).g$fMgQ, z-} { C j f Y /N ,,,

.x ap1wa ui_w r

~~

i

. . " . . . yo_.pyg. 11p: c's. . hiuNa

~

hA ' D 2. 42. :> /ds ! ;* '

73p,. ,

.kuur'ap_ym._,sa*w sac < -

l

'; y L u. -- D7672C -

-- =

1 p u n 6 .j.-.,sa.r.g.gi.ei m .- ...

) l . M ,7_

! b --MinWoE_- f~ FG4t_14iceatsr Sherb $E ed AW

....g.

. i.,

(p 1,.jz/ !T @ , . .-

,sy.'

[2.'C'sid

~ w ..s . .

W?D - :Ros?Q. r- .. -

3 m]T) .

,s9 --

l ~:. . ~ ..

AV' L . 72CI--

ff h $ ". .

(*. 4h .

' { {' *

/h . i

, Q ho6.s&'., \ i.a ,, ,}l$ -

.rc b...: . yl' V- '#

lf) j?) ,'ksr .T -

'sw'. -

??_1 * . ih . .

7 .,

(b . se :% 4 (D .nr

%.,4 ~

~. M  ; .

EB ..

AS '

-- - ) _ .. z.,.7',)s -

. r ;* ...--.-

-M ~ %,, 'e-),)Aiys . .

- . , .-- " y A,fiD f ^' :. -

b '

8: d W } & M' W - .B g,<=-fig 4QW}

l TENNESSEE VELLEY AUTHORITY CH ATTANOOGA, TENNESSEE 37401 1750 Chestnut Street Tower iI November 25, 1983 03MBNQ Al**

Mr. James P. O'Reilly, Director U.S. Nuclear Regulatory Commission Suite 2900 101 Marietta Street, NW.

Atlanta, Georgia 30303

Dear Mr. O'Reilly:

TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT UNIT 3 - DOCKET NO. 50-296 - FACILITY OPERATING LICENSE DPR REPORTABLE OCCURRENCE REPORT BFRO-50-296/83026 - REVIS10N 4 The enclosed report is a supplement to my letters to you dated May 9, 1983; June 16,1983; November 18, 1983; and November 21, 1983, concerning a defective heat exchanger head on the 3 ED emergency diesel-generator coolers. This report is submitted in accordance with Browns Ferry unft 3 Technical Specification 6.7.2.b(2).

Very truly yours, TENNESSEE VALLEY AUTHORITY

f i 8/.7/?

[H.J. Green Director of Nuclear Power Enclosure cc (Enclosure):

Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Records Center Institute of Nuclear Power Operations Suite 1500 1100 Circle 75 Parkway Atlanta, Georgia 30339 NRC Inspector, Browns Ferry ini A T . C

An Equal Opportunity Employer gg an

/t

_