05000301/LER-1980-002, Updated LER 80-002/01T-1:on 800227,during Normal Operation, Indication of Increasing primary-to-secondary Leak in a Steam Generator Noted.Caused by Leaking Tube in a Steam Generator Position R18C37

Updated LER 80-002/01T-1:on 800227,during Normal Operation, Indication of Increasing primary-to-secondary Leak in a Steam Generator Noted.Caused by Leaking Tube in a Steam Generator Position R18C37

ML19309F443
Person / Time
Site:	Point Beach
Issue date:	04/16/1980
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19309F440	List: 05000301/LER-1980-002, Updated LER 80-002/01T-1:on 800227,during Normal Operation, Indication of Increasing primary-to-secondary Leak in a Steam Generator Noted.Caused by Leaking Tube in a Steam Generator Position R18C37
References
LER-80-002-01T-01, LER-80-2-1T-1, NUDOCS 8004290469
Download: ML19309F443 (4)

LER-1980-002, Updated LER 80-002/01T-1:on 800227,during Normal Operation, Indication of Increasing primary-to-secondary Leak in a Steam Generator Noted.Caused by Leaking Tube in a Steam Generator Position R18C37

Event date:
Report date:
3011980002R00 - NRC Website

text

UPDATED REPORT - PREVIOUS REPORT ' SUBMITTED MARCH 12,U.S NUCLE AR GY99ATO%Y COMMISSION NRC FORM 366 0

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8 60 61 DOCK ET NOVSE R ha 63 EVENT DATE 74 76 REPORT D ATE BU EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h 1o l2l l During normal operation, indication of an increasing primary-to-J io ;3l l secondary leak in the "A"

SG was noted on 02-27-80.

The decision was l

1 o 14 l I made to shut the unit down at 2 340 hours0.00394 days <br />0.0944 hours <br />5.621693e-4 weeks <br />1.2937e-4 months <br /> on 02-27-80 and the unit was l

10 I s i l of f line at 02 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> on 02-28-80.

Chemistry results of a sample l

loIsii taken at 0010 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> on 02-28-80 quantified a primary-to-secondary l

10 l 7 l l leak rate of 1,420 gallons per day.

This event is reportable per l

toisil T.S.

15.6.9.2. A. 3 and is similar to previous LER's.

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JJ 34 34 36 31 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l i t o l 1 A orimary-to-secondary leak test cerformed on 03-01-80 revealed a l

Ii li i l leakina tube in the "A"

SG at oosition R18C37.

Eddv current testina I

g l began in both SG's on 03-03-80 and was completed on 03-09-80.

One l

1iI3l l degraded (41% defect) tube was found in the "B" SG and six defective l

ii t4i l (>50%) tubes and 18 tubes with pluggable (40% to 49%) defects were found 9 g the "A"

steam generator.

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ATTACHMENT TO LICENSEE EVENT REPORT NO. 80-002/0lT-1 Wisconsin Electric Power Company Point Beach Nuclear Plant Unit 2 1

Docket No. 50-301 Unit 2 was taken off line at 0225 hours0.0026 days <br />0.0625 hours <br />3.720238e-4 weeks <br />8.56125e-5 months <br /> on February 28, 1980 following confirmation of primary-to-secondary leakage in the "A" steam generator.

The leak had begun as a slight indication about noon the previous day and gradually increased to 70 gallons per day (estimated) by 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> on February 28.

The decision was made to shut down at 2340 hours0.0271 days <br />0.65 hours <br />0.00387 weeks <br />8.9037e-4 months <br /> upon a further large increase in the air ejector radiation monitor reading.

A static head leak check identified the leaking tube at position R18C37 and a subse-quent eddy current inspection placed the defect at eight to ten inches above the tube end, i.e.,

13 to 15 inches deep in the crevice of the tubesheet.

The previously scheduled refueling outage steam generator eddy current inspection was performed during the outage.

The extent of the inspection was expanded during the outage as six tubes with greater than 50% through-wall indications, in addition to the leaking tube, were discovered in the "A" steam generator.

Eighteen tubes with indications between i

40 and 49% were also found.

The "A"

steam generator hot leg program was first expanded by a 2S sample then to 100% as required i

by the Technical Specifications.

The 25 defective or degraded tubes in the "A" steam generator were explosively plugged on March 10, 1980.

The

)

leaking tube was mechanically plugged on the inlet side.

This tube has been pulled during the April 1980 refueling outage for further examination.

Eight tubes which exhibited 39% defect indications were also explosively plugged as a conservative measure.

Two tubes, R22C62 and R9C54, also with 39% defects, were plugged on the cold leg only.

These tubes were mechanically plugged on the hot leg side during the April 1980 refueling outage.

An 800 psi hydrostatic test of the "B"

steam generator revealed no leaking tubes or plugs.

Approximately 700 tubes i

in each of the hot and cold legs of the "B" steam generator were examined and one cold leg tube was found to have a 41% defect l

indication.

The one 41% degraded tube in the "B" steam generator was explosively plugged on March 9, 1980.

Unit 2 was placed on line at 1802 hours0.0209 days <br />0.501 hours <br />0.00298 weeks <br />6.85661e-4 months <br /> on March 13, 1980.

i l

The average radioactive release rate via the Unit 2 l

air ejector during this event has been calculated to be 0.051%

of the allowable annual release rate of 0.2 Curies per second.

l 1

l This event is reportable per Technical Specification 15.6.9.2.A.3. _ _

a The approximate exposures recorded during the outage are as follows:

(All exposure data are based on dosimeter information.)

Steam Generator Manway Work 1.8 Man Rem Visual Inspections 0.8 Man Rem Eddy Current Inspections 14.7 Man Rem Tube Plugging 5.9 Man Rem Health Physics Coverage 3.4 Man Rem i

l l

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i

s EDDY CURRENT RESULTS FOR PLUGGED TUBES STEAM GENERATOR "A"

INLET Tube

% Defect Location R21C5F 42 Top of tubesheet*

R10C.3 39 Top of tubesheet R20Ci9 41 Top of tubesheet R21C59 39 Top of tubesheet R20C61 42 Top of tubesheet R20C63 51 Top of tubesheet R21C63 56 Top of tubesheet R10C64 42 Top of tubesheet R21C64 46 Top of tubesheet R19C65 51 Top of tubesheet R18C68 39 Top of tubesheet R12C73 43 Top of tubesheet R34C73 43 First support plate RllC74 39 Top of tubesheet R07C21 39 Top of tubesheet R13C19 40 Top of tubesheet R12C31 41 Top of tubesheet R13C34 43 Top of tubesheet R14C34 57 Top of tubesheet R14C35 42 Top of tubesheet R15C35 44 Top of tubesheet R13C36 42 Top of tubesheet R14C36 39 Top of tubesheet R10C39 45 Top of tubesheet R13C41 56 Top of tubesheet R18C37 100 9" above tube end R28C42 45 Top of tubesheet R20C4 3 39 Top of tubesheet R12C44 41 Top of tubesheet R20C4 7 39 Top of tubesheet R21C57 43 Top of tubesheet R22C57 42 Top of tui.,6ch::t R10C58 52 Top of tubesheet STEAM GENERATOR "B"

OUTLET R07C36 41 1 " above tubesheet I

• The notation " top of tubesheet" refers to defect indications which have been separated from the top of tubesheet eddy current signal using multi-frequene.:y

(

techniques.

Twenty-six of these top of tubesheet j

signals using a 400 khz eddy current frequency have been present since 1974.

The recent developmenc of l

the multi-frequency eddy current technique has allowed l

discrimination of defect indications from the top of tubesheet signal.

Evaluation of all data available at this time indicates that these top of tubesheet defect l

indications have been present but undetectable since 1974.