05000285/LER-1980-011-03, /03L-0:on 800528,during 1980 Refueling Outage Type B & C Containment Leak Rate Tests,Total Leakage Exceeded 0.6La Limit.Caused by Leaking Fuel Transfer Tube, Electrical,Mechanical Sleeve & Piping Penetrations

/03L-0:on 800528,during 1980 Refueling Outage Type B & C Containment Leak Rate Tests,Total Leakage Exceeded 0.6La Limit.Caused by Leaking Fuel Transfer Tube, Electrical,Mechanical Sleeve & Piping Penetrations

ML19318D131
Person / Time
Site:	Fort Calhoun
Issue date:	06/16/1980
From:	Connolley J, Core M OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19318D123	List: 05000285/LER-1980-011, Forwards LER 80-011/03L-0 05000285/LER-1980-011-03, /03L-0:on 800528,during 1980 Refueling Outage Type B & C Containment Leak Rate Tests,Total Leakage Exceeded 0.6La Limit.Caused by Leaking Fuel Transfer Tube, Electrical,Mechanical Sleeve & Piping Penetrations
References
LER-80-011-03L, LER-80-11-3L, NUDOCS 8007070385
Download: ML19318D131 (7)

LER-1980-011, /03L-0:on 800528,during 1980 Refueling Outage Type B & C Containment Leak Rate Tests,Total Leakage Exceeded 0.6La Limit.Caused by Leaking Fuel Transfer Tube, Electrical,Mechanical Sleeve & Piping Penetrations

Event date:
Report date:
2851980011R03 - NRC Website

text

NRC Fo;M 366 U.S. NUCLEAR REGULATORY COMMISSICN i

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3 60 61 COCK ET NUMBER 68 69 EV ENT DATE 74 75 AERORT O ATE So EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l o l 21 l During the performance of the type B and C Containment Leak Rate Tests durina the I

iOi3i l 1980 Refueling Outage, it was noted that the total leakage exceeded the 0.6L, I

l0lal l limit of 62,951 secm.

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33 J4-35 36 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CCRRECTIVE ACTIONS h l1 I o i I All penetrations rhnt showed s M a of a w ass i n nleun were repaired and retested.

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LER 80-011 Omaha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 i

Attachment No. 1

Safety Analysis

l The local leak rate test performed during the 1980 Refueling Outage indicated a total "as found leakage of 299,496.34 seem (standard i

cubic centimeters per mimite). The types of penetrations tested and j

amounts of leakage "As Found" are tahalated below:

a)

Electrical: 42.85 scem b)

Fuel Transfer Tube Flange:

2100 seem c)

Mechanical Sleeves: 129,642.78 seem d)

Mechanical Piping: 167,710.70 seem The single worst mechanical sleeve penetration, M-95 (main steam line), was not open to containment atmosphere. The outer bellows was

' repaired and again tested for leakage. The leak rate on M-95 was re-duced from 123,457 seem to 0.0 seca.

Since the bellows in containment was intact, no containment atmosphere could have leaked out of M-95.

Af te: all repairs on mechanical sleeves, the "As Left" leakage was 6,435.78 scem.

f The single worst mechanical piping penetration M-13 (Steam Generator Blowdown), is also not open to containmant atmosphere. 'The line_is on the secondary side of the steam generators and is filled with water.

Two containment isolation valves, HC7-1388 A & B, were rebuilt and retested for leakage. The leak rate on M-13 was reduced from 147,247.6 seem to 0.0 secm.

f i

The mechanical piping penetration listed below also had detectable I

l' leaks but would not contribute to containment atmosphere leakage for reasons given.

"As Found" readings are also provided:

Penetration As Found Reason Not Contributing No.

Leakage to.6L r

1) M-91 (Aux. Feedwater) 28.96 seem Secondary Side, Filled with water

2) M-97 (Aux. Feedwater) 80.0 seem Secondary Side, Filled with water

3) M-94 Ofain Steam) 4500 seem Secondary Side, Steam /

Water' i

4) M-95 (Main Steam) 5.17 seem Seconcary Side, Steam /

Water i

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5) M-10 (Steam Generator 800 seem Secondary Side, Filled Blowdown) with water i-

LER 80-011 Omaha Public Power District Forr Calhoun Station Unit No. 1 Docket No. 05000285.

The total "As Found" leakage from these five penetrations is 5414.13 scem. To find the total leakage of containment atmosphere through penetrations, the following fornula is used:

Total "As Found" Leakage - leakage from M-95 sleeve - leakage from mechanical piping penetration M-91, M-97, M-94, M-95, M-10 and M-13. The equation then becomes:

299496.34 - 123,457 - 28.96 - 80.0 - 4500 - 5.17 - 800 - 147247.6 =

23,377.61 scem.

Since total allowable leakage of containment atmosphere is 62,951 scem, the "As Found" leakage was 39,573.39 seem below the limit.

Penetration M-45, Reactor Coolant Sample, was found to leak 2000 seca. The limit for the applicable surveillance test ST-CONT-3, is 1000 Although this leakage did not contribute significantly to.6La, secm.

it is over the allowable leak rate for this penetration.

If, during an accident situation, the two isolation valves involved, HCV-2504 A & B, failed to hold, the penetration could be isolated by closing SL-160, SL-191, SL-159 in the sample room. All valves and piping involved are ASME Section III NC (II).

The corrective action and tabulations of "As Lef t" leakage is listed in Attachment 2.

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LER 80-011 Omaha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 Attachment No. 2

Corrective Action

The types of penetrations and corrective actions for each type are tabulated below:

A)

Fuel Tranfer Tube:

"As Found" leakage was 2l00 scem., This test was performed prior to removing the flange. When the flange was replaced, the test was performed again and the leakage was found to be 0.0 scem.

B)

Electrical Penetrations:

The following penetrations had detectable leaks:

C-6, D-6, E-HCV-383-3A, E-HCV-383-3B, E-HCV-383-4A and E-HCV-383-4B.

Total con-tribution from all six penetrations was 42.85 secm.

It is felt that 42.85 seem is an acceptable leak rate from the electrical penetrations (71 total) and no corrective action was performed.

Final leak rate = as found leak rate = 42.85 secm.

C)

Mechanical Sleeves:

The leak rates from mechanical sleeves are as follows:

As Found As Left Penetration No.

Function Leakage Leakage HCV-383-3 Containment Recire.

2831.7 seem 2831.7 seem HCV-383-4 Containment Recire.

43.0 scem 43.0 scem M-11 Component Cooling to Nuclear Detector Wells 4.08 scem 4.08 seem M-45 Reactor Coolant Sample System 5.2 seem 5.2 seem M-48 Containment Relief 7.6 scem 7.6 sces M-49 Steam Generator Blowdown Sampling 18.4 seem 18.4 seem M-52 Containment Pressure Signal 39.72 'scem 39.72 sccm M-53 Containment Leak Test Supply Air 33.61 seem 33.61 seem M-62 Hydrogen Purge 4.0 secs 4.0 seem M-73 Instrument Air 0.77 seem 0.77 seem M-85 Component Cooling to Air Handlers 15.92 seen 15.92 seem M-90 Blanked Off (spare) 14.28 seem 14.28 sccm M-91 Aux. Feedwater to Steam Generator 17.5 sces 17.5 scem M-94 Main Steam 3150 seem 3400 scem M-95 Main Steam 123,457 seem 0.0 seem Totals 129,642.78 scem 6,435.78 scem Since the only significant contribution to leakage was from M-95, it was the only sleeve on which work was performed. The bellows on the secondary side was welded and leakage reduced to 0.0 scem.

LER 80-011 Omaha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285D)

Mechanical Piping:

The leak rates from mechanical piping are as follows:

Penetration As Found As Left No.

Function Note Leakage Leakage M-2 R.C. Letdown Heat Exchanger (3) 32.65 secs 15.9 scem (1) (3) 800 secs 0.0 sces M-10 Steam Generator Blowdown M-13 Steam Generator Blowdown (1) (3) 147,247.6 scem 0.0 scem M-14 R.C. Drain Tank Vent to W.D.S.

11.0 seem 11.0 sces M-15 Component Cooling to Nuclear Detector Wells 8.97 seen 8.97 sec=

M-16 S.I. & Shutdown Cooling 140.0 secs 140.0 seem M-18 Component Cooling to R.C. Motors (2) 0.0 secs 3.26 seem M-20 R.C. Drain Tank Pump to W.D.S.

0.82 scem 0.82 seem M-38 Containment Pressure 33.79 secs 33.79 secs M-42 N SuPP y (3) 1350 seem 1300 scem l

2 M-45 R.C. Sample System (3) 2000 sces 0.0 seem M-46 Containment Atmosphere Sampling 10.34 seem 10.34 secs M-48 Containment Relief (3) 1620 sces 0.0 scem M-50

• Containment Pres. Signal 138.27 sces 138.27 seem M-51 Containment Pres. Signal (2) 83.58 seem 83.58 seem M-52 Containment Pres. Signal (3) 80.69 sces 0.0 seem T-57 Hydrogen Pressure (2) 26.39 scen 24.99 scem M-58 Hydrogen Purge (2) 1.66 scan 1500 sces M-69 Hydrogen Purge (2) 3.61 seem 1.22 seem M-73 Instrument Air 4.61 seem 4.61 seem M-79 Make-up to Pressurizer Quench Tank 2.59 secs 2.59 seem M-87 Containment Purge Exhaust 6600 sccm 6600 scan M-91 Aux. Feedwater to Steam Generator (1) 28.96 scem 28.96 seem M-93 Feedwater 200 seem 200 scem M-94 Main Steam (1) 4500 scan 4500 seen M-95 Main Steam (1) 5.175 sces 5.175 seem M-96 Feedwater (1) 2700 scem 2700 sces M-97 Aux. Feedwater to Steam Generator (1) 80.0 seem 80.0 seem Total 167,710.7 scem 17,393.5 seem Notes:

1)

Penetrations that do not contribute to 0.6L.

These are penetrations a

on the secondary side of the steam generators and would not be exposed to containmer,t atmosphere in the event of an accident.

2)

Valves that were retested after the Integrated Leak Rate Test (ILRT).

3)

Valves on which maintenance was perfor=ed. The valves were rebuilt, stroked or bench set and then retested.

o LER 80-011 Omaha.Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285Each penetration was evaluated at the time of testing to determine whether or not repair was necessary.

Each valve that was repaired is documented by current plant procedures.

(i.e. maintenance order, procedure, etc.)

Due to the corrective action efforts,.the total leakage from all types of penetrations was reduced from 299,496.4 seem to 28,872.1 sces.

It is felt that this amount of leakage is acceptable. No further corrective action is anticipated.

1 1

LER 80-011 Omaha Public Power District Fort Calhoen Station Unit No. l' Docket No. 05000285 Attachment No. 3 I

Failure Data J

Previous LER's77-038 and 78-040 address penetration failures at Fort Calhoun Station.

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