ML20141J405

Proposed Tech Specs Revising Surveillance Specification for Once Through Steam Generator Inservice Insp for TMI-1 Cycle 12 Refueling (12R) Exams Applicable to TMI-1 Cycle 12 Operation

ML20141J405
Person / Time
Site:	Three Mile Island
Issue date:	08/12/1997
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20141J403	List: ML20141J398 ML20141J405
References
NUDOCS 9708200042
Download: ML20141J405 (5)

Text

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4.19.2 Specification (Continued)

C-2 One or more tubes, but not more than 1% of the total tubes inspected in a steam generator are defective, or 1 etween 5% and 10% of the total tubes inspected are degraded tubes.

C-3 More than 10% of the total tubes inspected in a steam generator are degraded tubes or more than 1% of the inspected tubes are defective.

NOTES: (1) In all inspections, previously degraded tubes whose degradation has not been spanned by a sleeve must exhibit significant increase in the applicable degradation size measurement (> 0,6 volt bobbin coil amplitude increase for inside diameter IGA indications or > 10%

further wall penetration for all other degradation) to be included in the above percentage calculations.

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,_ (2) Where special inspections are performed pursuant to 4.19.2 a.4, defective or i degraded tubes found as a result of the inspection shall be included in determining the Inspection Results Category for that special inspection but need l not be included in determining the Inspection Results Category for the general l steam generatorinspection.

I 4.19.3 Inspution Frequencies The required inservice inspections of steam generator tubes shall be performed at the following i frequencies:

a. The first (baseline) inspection was performed after 6 effective full power months but within 24 calendar months ofinitial criticality. The subsequent inservice inspections shall be performed not more than 24 calendar months aller the previous inspection. If the results of two consecutive inspections for a given group of tubes encompassing not less than 18 calendar months all fall into the C-1 category or demonstrate that previously observed des adation has not continued and no additional degradation has occurred, the inspection interval for that group may be extended to a maximum of once per 40 months.

b. If the results of the inservice inspection of a steam generator conducted in accordance with Table 4.19-2 at 40 month intervals for a given group of tubes

• fall into Category C-3 the inspection frequency for that group shall be increased to at least once per 20 months. The increase in inspection frequency shall apply until the subsequent inspections satisfy the criteria of Specification 4.19.3.a; the interval may then be extended to a maximum of on'ce per 40 months.

' A group of tubes means:

(a) All tubes inspected pursuant to 4.19.2.a.4, or (b) All tubes in a steam generator less those inspected pursuant to 4.19.2.a.4 9708200042 9708th PDR P

ADOCK 05000289 PDR 4-79 Amendment No. A7,153 (12-22-78)

4.19.3 Inspection Frequenqy(Continued)

c. Additional, unscheduled inservice inspections shall be performed on each steam generator in accordance with the first sample inspection specified in Table 4.19-2 during the shutdown subsequent to any of the following conditions:

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1. A seismic occurrence greater than the Operating Basis Earthquake.

2. A loss of coolant accident requiring actuation of engineering safeguards, or

3. A major main steam line or feedwater line break.

d. After primary-to-secondary tube leakage (not including leaks originating from tube-to-tube sheet welds) in excess of the limits of Specification 3.1.6.3, an inspection of the afTected steam generator will be performed in accordance with the following criteria:

1. If the leak is above the 14th tube support plate in a Group as defmed in Section 4.19.2.a.4(1) all of the tubes in this Group in the affected steam generator will be inspected above the 14th tube support plate. If the results of this inspection fall into the l C-3 category, additional inspections will be performed in the same Group in the other

steam generator.

2. If the leaking tube is not as defined in Section 4.19.3.d.1, then an inspection will be performed on the affected steam generator (s) in accordance with Table 4.19-2.

4.19.4 Acceptance Criteria

a. As used in the Specification:

1. Itnperfection means an exception to the dimensions. finish, or contour of a tube from that required by fabrication drawing or specifications. Eddy current testing indications less than degraded tube criteria specified in a.3 below may be considered imperfections.

2. DegradatiDD means a service-induced cracking, wastage, wear or general corrosion occurring on either inside or outside of a tube.

3. Degraded Tube means a tube containing :

(a) an inside diameter (I.D.) IGA indication with a bobbin coil indication 3 0.5 volt or 3 0.13 inches axial extent or 3 0.28 inches circumferential extent (for 12R outage examinations and Cycle 12 operation only), or (b) imperfections 2 20% of the nominal wall thickness caused by degradation.

4. %Eeuradation means the percentage of the tube wall thickness affected or removed by degradation.

4-80 Amendment No. 4M,149,153

4 4.19.4 - Acceptar.ce Criteria (Continued)

' 5.

Dsftq.1 means an imperfection of such severity that it exceeds the repair limit. A tube containing a defect is defective.

6. Repair Limit means the extent of degradation at or beyond which the tube shall be repaired or removed from service because it may become unserviceable prior to the next inspection.

This limit is equal to 40% of the nominal tube wall thickness. For Outage 12R examinations and Cycle 12 operation only, inside diameter IGA indications shall be repaired or removed from service if they exceed an axial extent of 0.25 inches, or a circumferential extent of 0.57 inches, or a through wall degradation dimension of > 40% if assigned.

7. Unserviceable describes the condition of a tube ifit leaks or contains a defect large enough to afTect its structural integrity in the event of an Operating Basis Earthquake, a loss of coolant accident, or a steam line or feedwater line break as specified in 4.19.3.c.,

above.

8. Tube Inspection means an inspection of the steam generator tube from the bottom of the upper tubesheet completely to the top of the lower tubesheet, except as permitted by 4.19.2.b.2, above.

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9. Inside Diameter Inter-Granular Attack (IGA) ludication means a bobbin coil indication initiating on the inside diameter surface and confirmed by diagnostic ECT to have a volumetric morphology characteristic of IGA.

b. The steam generator shall be determined OPERABLE after completing the corresponding actions (removal from service by plugging, or repair by kinetic expansion, sleeving, or other methods, of all tubes exceeding the repair limit and all tubes containing tiiroughwall cracks) required by Table .19-2, 4.19.5 Reoorts

a. After the completion of each inservice inspection of steam generator tubes, prior to  ;

exceeding a reactor coolant system (RCS) temperature of 250 F, the NRC shall be '

notified of the following:

1) The number of tubes repaired or removed from service in each steam generator,

2) An assessment of growth ofinside diameter IGA degradation, and

3) Results ofin-situ pressure testing,if performed.

4-81 Amendment No. 47,83,91,103,129,149,153,157

0 4.19.5 Esp _gm (Continued) b' The complete results of the steam generator tube inservice inspection shall be reported to the '

NRC within 90 days following completion of the inspection and repairs. The report shall include:

1. Number and extent of tubes inspected.

2. Location and percent of wall-thickness penetration for each indication of an imperfection.

3. Location, bobbin esil amplitude, and axial and circumferential extent (if determined) for each inside d'aaeter IGA indication, and

4. Identification of tubes repaired or re noved from service.

c. Results of steam generator tube inspections which fall into Category C-3 require notification in accordance with 10 CFR 50.72 prior to resumption of plant operation. The written follow-up of this report shall provide a description ofinvestigations conducted to determine the cause of the tube degradation and corrective measures taken to prevent recurrence in accordance with 10 CFR 50.73.

Bases The Surveillance Requirements for inspection of the steam generator tubes ensure that the stmetural integrity of this portion of the RCS will be maintained.

The program for inservice inspection of steam generator tubes is based on modification of Regulatory Guide i.83, Revision 1. In-service inspection of steam generator tubing is essential in order to maintain surveillance of the conditions of the tubes in the event that there is evidence of mechanical damage or progressive degradation due to design, manufacturing errors, or inservice conditions. Inservice inspection of steam generator tubing also provides a means of characterizing the nature and cause of any tube degradation so that corrective measures can be taken.

The Unit is expected to be operated in a manner such that the primary and secondary coolant will be maintained within those chemistry limits found to result in negligible corrosion of the steam generator tubes. If the primary or secondary coolant chemistry is not maintained within these chemistry limits, localized ' corrosion may likely result.

The extent of steam generator tube leakage due to cracking would be limited by the secondary coolant activity, Specification 3.1.6.3.

The extent of cracking during plant operation would be limited by the limitation of total steam generator tube leakage between the primary coolant system and the secondary coolant system (primary-to-secondary leakage = 1 gpm). Leakage in excess of this limit will require plant shutdown and an unscheduled inspection, during which the leaking tubes will be located and repaired or removed from service.

4-82 Amendment No. 4h86A46,119,153

Hms (Continued)

Wastage'-type defects are unlikely with proper chemistry treatment of the primary or the secondary coolant. However, even if a defect would develop in service, it will be found during scheduled in-service steam generator tube examinations. For tubes with ID IGA indications, additional conservatism is being applied during the 12R Outage, for Cycle 12 operation, to evaluate chcumferential and axial dimensions for determining final disposition of the tube. For ID IGA indications through wall dimension will continue :9 be assigned to those indications where amplitude response permits measuring through wall oi.nension. Steam generator tube inspections of operating plants have demonstrated the capability to reliably detect degradation that has penetrated 20% of the originaSube wall thickness.

Removal from service by plugging, or repair by kinetic expansion, sleeving, or other methods, will be required for degradation equal to or in excess of 40% of the tube nominal wall thickness. For the 12R Outage examinations and Cycle 12 operation only, tubes with 1.D. initiated intergranular degradation may remain in service without % T.W. sizing if time degradation morphology has been characterized as not crack-like by diagnostic eddy current inspection and the degradation is oflimited circumferential and axiallength to ensure tube structural integrity. Additionally, serviceability for accident leakage under the limiting postulated Main Steam Line Break (MSLB) accident will be evaluated by determining that this I.D.

initiated degradation mechanism is inactive (e.g. comparison of the 12R Outage examination results with the results from past outages does not show growth greater than expected ECT repeatability variations) and by successful 12R in-situ pressure testing of a sample of these degraded tubes to evaluate their accident leakage potential.

Where experience in similar plants with similar water chemistry, as documented by USNRC Bulletins / Notices, indicate critical areas to be inspected, at least 50% of the tubes inspected should be from these critical areas. First sample inspections sample size may be modified subject to NRC review and approval.

Whenever the results of any steam generator tubing inservice inspection fall in.to Category C-3 on the first sample inspection (See Table 4.19.2), these results will be reported to NRC pursuant to the requirements of Specification 4.19.5.c. Such cases will be considered by the NRC on a case-by-case basis and may result in a requirement for analysis, laboratory examinations, tests, additional eddy current inspection, and revision of the Technical Specifications, if necessary.

4-83 Amendment No. 47-+29 (12-22-78)

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