ML19309G048

Revised LER 80-009/03L-1:on 800219,during Annual Insp of Containment Spray Heat Exchanges,Leaks Discovered in Four Heat Exchangers.Caused by Component Failure & Design.Heat Exchangers to Be Retubed W/Titanium

ML19309G048
Person / Time
Site:	Oyster Creek
Issue date:	04/22/1980
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19309G043	List: ML19309G042 ML19309G048
References
LER-80-009-03L, LER-80-9-3L, NUDOCS 8005020266
Download: ML19309G048 (4)

Text

{{#Wiki_filter:------~_ _ __ ____ __ __-_ _ I \ l I (PLEASE PRINT OR TYPE ALL R; . t R ED IN F O RMATION) h3. TROL Bt.OCK:1 l 121 I n '; 10 Ic IP l1 !@! O! O! -l 0l 0l 0 } O ! 0 l- l 026l 0 lhl 4! C6 I! ;I I! II@l 57 Cl 4 68\@ LICENSE TYPE 30 6 9 LI ErdSEE CODE 14 15 LICENSE NUMBEH DN'T >l'l 8 E*[R:"'IL\@]015l010101211 E 60 61 DOOKET NUMBER 19 l@l SS 69 012 EVENT l 1 l o l 810 l@lREPORT CATE 74 7b 01DATE4l 2l 71 80 8 l O l@ EVEN T DESCRIPTION AND PROBABLE CONSEQUENCES h 1 > I:1 l Durina the annual inspection of the containment snrav hant eveh,nnare 2 : 31 l it was discovered that the four heat exchancers had develooed leaks. I a 4 411 Tube leakage will result in the leakina of torus water into the emarg- I @; 'ency service water discharge line to the discharoe canal when each cont- I c is I i ainment spray system is operated twice a month for approximatelv 18s to 1 ETi'; i 30 minutes. The isotopic activity concentration af ter dilution in the 1 gl O discharge canal was calculated to be well below the allowable limit. I 80 E s C O*.i P. VALVE SYSTE M CAUSE CAUSE COLE CODE SUSC002 COMPONENT OCDE SUE: ODE EUECODE

@      G l S i B l@ l Bl@ l B l@ l Hl Tl El Xl C l H lh G            to          11            12            13                              Ig Wh d h 19              20 OCCUR RENCE           REPORT                    REVISION SEQUE NTI AL

_ EVENT YEA R REPORT NO. CODE TYPE N O.

            @ ;tzy.g              m ao I 81 0l                       l-l           101019 l                l/]             l o 13 l              l Ll          I-I 31 l 1l 32
                                          .,, 21          22          23           24             26       27              2E       29           30 AK                  A     O             ON PL NT           Mb                       HOURS 22          58 i             F     . B.      SU LIElk          MANU C RER l32X lgl34F lg                               l5    Z jg                         l 0 l0 l0 l0 l            l41 Yl@           lYl@             y@            l44 Ml 1l 8l 7lg 3                 l36Zl@ 37                            40                      42               43                               47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h
@]                             The cause of the occurrence is attributed to comoonent failure and to the                                                                                        1
@[                             c'esign of the heat exchangers.                                Tubes were removed and analvzed.                              An                                  I gl                            eddy current inspection of the tubes in one heat exchanger was perform-                                                                                          I gl                            ed.       Based on the extent of tube damage and the corrosion mechanism                                                                                         {

identified, the heat exchangers will be retubed with titanium tubes. l gl 83 8 9 SA S  % POWER OTHER STATUS 015 0 RY DISCOVERY DESCRIPTION Annual Inspection

 ] l Hl@ l 0 l 0 l0 l@l                                                      NA                    l   l B l@l                                                                                  l A TIVITY                    CO TENT RELEASE                                                    AMOUNT OF ACTIVITY                                                        LOCATION OF RELEASE Minimal                                   l                            To Discharoe Canal                                    l E l8 Ll  9
                  @D OF RELEASEW@l     10             11                                         44           45                                                                              go
                    *ER$0NNEL EXPOSURES N UVB E R                      TYPE         DESCRIPTION E l0  * '

10 l0 l@lZl@l NA l

                    , MON ~EL ,munS rsUveER                        oESCRIPTION
 ] l0 l0 l0 j@l                                    12 NA 80 l

8 9 11 LO;S 08 OR DAMAGE TO FACILITY Tv*E DESCRIPTION { NA l E (z_J@l b to 10 . 30 PUB L s CITY NRC USE ONLY l1IIIIIii*llll[ D g {5 ' EDQl ESCRi* TION Weekly news release - 3/20/80 1 10 CS 69 gg.3 g 9 Donald A. Ross 455-8754

• PHONE: 6 N AME OF PREPARER

     .          - - . . . . ..                            .                             _                                                                    B Q Q f)__Q fz_Q _ &

'N.- . -4 79 T - - J:rs:y Contrzl P wer & Light Company a D-{

  "   71.*d   L,-

3 - f (-) Madison Avenue at Punch Bowl Road Morristown, New Jersey 07960 (201)455-8200 OYSTER CREEK NUCLEAR GENERATING STATION Forked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/80-9/3L-1 Report Date Update Report - April 22, 1980 Previous Report Date - March 19, 1980 Occurrence Date February 19, 1980 Identification of Occurrence During the annual inspection of the containment spray heat exchangers, it was discovered that the four heat exchangers had developed tube leaks. This event was recognized as a reportable occurrence on February 19, 1980. This event is considered to be a reportable occurrence as defined in the Techni . cal Specifications, paragraph 6.9.2.b.4. Conditions Prior to Occurrence The plant was shutdown for a refueling / maintenance outage. The reactor was subcritical. The reactor mode switch was locked in REFUEL. Tne cavity (;as flooded. The primary containment was not required. Description of Occurrence On January 24, 1980, while performing an inspection of containment heat exchanger 1-2, it was observed that water from the containment spray system (shell side) had collected on the emergency service water system (tube side) of the heat exchanger due to tube leakage. One tube was observed to be leaking at the time. On January 29, 1980, inspection of heat exchanger 1-4 revealed that tube leaks had developed in that heat exchanger also. Subsequent inspection indicated that heat exchangers 1-1 and 1-3 in the opposite loop were also leaking. Apparent Cause of Occurrence The cause of this occurrence is -ttributed to component failure and to the design of the heat exchangers. Jersey Centra! Power & Light Company is a Member of the Generaf Public Utilmes Systern

Reportable Occurrenca No. 50-219/80-9/3L-1 Pcga 2 Update Report - Previous Report Date March 19, 1980 April 22, 1980 Analysis of Occurrence The containment spray cooling system consists of two independent cooling loops, each loop capable of removing fission product decay heat from the primary con-tainment after a postulated loss of coolant accident. Each independent loop has two heat exchangers and two pumps. A review of containment spray system surveillance tests revealed the pressure on the containment spray side of the heat exchangers has been noted to exceed the pressure on the emergency service water side during operation. The operation of this system with tube leakage will, therefore, result in the leaking of torus water into the emergency service water discharge line to the discharge canal. Each containment spray system is operated approximately twice a month for about 15 to 30 minutes. During the time the system is in standby condition, there is no leakage of torus water because the service water system maintains a flow through the heat exchangers. The flow is at a higher pressure than the contain-ment spray side, in addition, torus water samples over the past few months indicate there was a rise in chloride concentration which verifies saltwater entered the torus. The exact amount of torus water that was released during the operation of the containment spray system was impossible to measure. However, calculations show that concentration of activity in the torus water leaking into the discharge canal did not approach the limits specified in 10CFR20 Appendix B Table 11. The worst case evaluation for seawater in leakage revealed a leak rate of 0.102 gpm. This is based on an increase in the chloride concentration of the torus water (volume-700,000 gallons) of 70 ppm over a one month period. Using the calculated in-leakage rate and the highest AP across the containment spray heat exchangers observed during system testing an outicakage rate of .228 gpm was determined. Using the calculated outleakage rate, a dilution rate of 710,000 gpm (4 circulating water pumps, one (1) dilution pump, one (1) service water pump and one (1) ESW pump) and the highest observed total isotopic activity concentration in the torus water; the concentration discharged was calculated to be 1.9E-09 pc/ml at the discharge point and 2.7E-ll pc/mi after dilution in the discharge canal. These concentrations are well below allowable limits for unidentified mixtures. Using the same outleakage rate and assuming a chromate concentration in the torus water of 900 ppm (highest observed during the period of time leakage was believed to have occurred) the concentration of chromates in the service water discharge was calculated to be 0.02 ppm (an undetectable concentration) and after dilution in the canal (assuming 710,000 gpm flow) the concentration is further reduced to 0.29 ppb. Corrective Action ' The leaking tubes were temporarily plugged, and the heat exchangers were completely drained. On February 14, 1980, one tube from heat exchangers 1-2 and 1-4 was re-moved for analysis of the cause for the tube failures. The analysis revealed that'

Reporteble Occurrsnce No. 50-219/80-9/3L-1 Paga 3 Update Report - Previous Report Date March 19, 1980 April 22, 1980 the tubes were perforated from the saltwater side by an apparent deposit attack. This mechanism forms pits underneath porous deposits via an oxygen differential cell. An oxygen aeration cell is formed with the oxygen deficient area below the deposit becoming the anode resulting in extensive corrosion underneath the deposit. Another form of deposit attack may have been caused by anaerobic bac-teria. These bacteria reduce the natural sulfate in seawater to sulfides. The sulfides then cause pitting by reacting with copper alloys to form a non protec-tive corrosion product. In parallel with this analysis, an eddy-current inspection of the tubes in heat exchanger 1-4 was performed to determine the extent of tube damage. A total of 650 tubes were inspected and revealed that 95 tubes (approximately 15%) were definitely bad with an additional 58 tubes showing signs of corrosion on the inside diameter. Based on the extent of tube damage and the corrosion mechanism identified, it has been decided to completely retube the containment spray heat exchangers with titanium tubes which are highly resistant to corrosion and erosion. The retubing is being completed during the current outage. Failure Data Manu facturer: McQuay-Perfex, Inc. Type: AFM Vertical Heat Exchanger Tubes: 90-10 CuNI S/N: 936101-1, 936101-2, 936101-3, 936101-4

                                    .}}