ML20094H491

Proposed TS 15.4.2.A,allowing Use of Repair Roll (Reroll) & F* (F-star) Acceptance Criterion as Repair Option

ML20094H491
Person / Time
Site:	Point Beach
Issue date:	11/09/1995
From:	WISCONSIN ELECTRIC POWER CO.
To:
Shared Package
ML19317C086	List: ML20094H481 ML20094H491
References
NUDOCS 9511140206
Download: ML20094H491 (2)

Text

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1 Cateaory C-1: Less than 5% of the total number of tubes examined l are degraded but none are defective.

Cateaory C-2: Between 5% and 10% of the total number of tubes examined are degraded, but none are defective E one tube to not more than 1% of the sample is defective.

Cateaory C-3: More than 10% of the total number of tubes examined are degraded, but none are defective g more than 1% of the sample is defective.

1 In the first sample of a given steam generator during any inservice l inspection, degraded tubes not beyond the plugging limit detected by '

the prior examinations in that steam generator shall be included in the above percentage calculations, only if these tubes are demonstrated to j have a further wall penetration of greater than 10% of the nominal tube l wall thickness. '

(c) Tubes shall be selected for examination primarily from those areas of the tube bundle where service experience has shown the most severe tube degradation.

(d) In addition to the sample size specified in Table 15.4.2-1, the tubes examined in a given steam generator during the first examination of any inservice inspection shall include all non-plugged tubes in that steam generator that from prior examination were degraded. l (e) In addition" t6'the~samfpli'sifeFiquifid"is:Specifidtions"15 4'.^2TAl2[if '

through (d), all F* tubes shall, be inspected in the F* region, The results of F* tube inspections are not to be'used as a basis for additional inspections,per, Table 15.4.2-1.' ' "~ '" ~ "~" ~ ~

(ef) During the second and third sample examinations of any inservice inspection, the tube inspection may be limited to those sections of the i tube lengths where imperfections were detected during the prior  !

examination.

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3. Examination Method and Reouirements l The examination method shall meet the intent of the requirements in ASME Section XI Appendix IV. This includes equipment, personnel and procedure l requirements, certification and calibration along with records and reports. )

The actual technique may be the latest industry accepted technique, provided the flaw detection capability is as good or better than the technique endorsed by the code in effect per Technical Specification 15.4.2.B.1.

This allows the use of improvements in inspection techniques that were not included in the code in effect. However, it means that word-for-word  !

compliance with Appendix IV of ASME Section XI may not be possible.

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~ i nj Uni t t 2 O Fol l owi ng iste aRgenegtodrep1 a cementd niMtj26th4 Eesuirementilsjnulfandivoidj Unit 1 - Amendment No. % 15.4.2-2 Augu:t 15, 1935 Unit 2 - Amendment No. 99 9511140206 951109 PDR ADOCK 05000266 P PDR

l Defect is an imperfection of such severity that it exceeds'the minimua ,

acceptable tube wall thickness of 50%. A tube containing a defect is

' defective.

Pluoaina limit is the imperfection depth beyond which the tube must  !

be removed from service or repaired, because the tube may become defective prior to the next scheduled inspection. The plugging limit is 40% of the nominal tube wall thickness. i F*~Distisce~fs ths~distisis~sf ~tWs~ipisded"p6FtToh"6f Tt~utWTdiid l provides a sufficient length of undegraded tube expansion to resist  ;

pullout of the tube from uhe tubesheet.i The F* distance is 0.88'"~'

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inches _Laot . including 3 ya;urrent_uncertajnty)r dd '

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oggreati ud hbt digraded isdi pacli@)$ethaM40llM}ff3y{(ance[~~g~~f~iy~dh lthi$the

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6. Corrective Measures I All tubes that leak or have degradation exceeding the plugging limit shall be, plugged or repaired by a process such as sleeving *1 o nclasiQ M Q6 { Q an ihs @'pectish condition.tulie' priorhaving Sleeved tubes to return to degradation sleeve power from a refueling or insel exceeding 40% of the nominal sleeve wall thickness shall be plugged.

7. Reports (a) After each inservice examination, the number of tubes plugged or repaired in each steam generator shall be reported to the Commission ,

as soon as practicable. '

(b) The complete results of the steam generator tube inservice inspection shall be included in the Annual Results and Data Report for the period in which the inspection was completed.

Reports shall include:

1. Number and extent of tubes inspected.

2. Location and percent of all thickness penetration for each indication.

1

3. Identification of tubes plugged or repaired. l (c) Reports required by Table 15.4.2 Steam Generator Tube Inspection shall provide the information required by Specification 15.4.2.A.7(b) and a description of investigations conducted to determine cause of  !

the tube degradation and corrective measures taken to prevent recurrence. The report shall be submitted to the Commission prior to resumption of plant operation.

28 Brazed joints shall not be employed. Tubes previously subject to explosive plugging shall not be sleeved.

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Unit 1 Amendment No. M 15.4.2-4 Augu ;t 15,1985 Unit 2 Amendment No. 99