ML20199C360
| ML20199C360 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 11/04/1997 |
| From: | Wetzel B NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20199C365 | List: |
| References | |
| NUDOCS 9711190320 | |
| Download: ML20199C360 (20) | |
Text
.
~_ _.
- p# "b,S UNITED STATES p*
o i
.j NUCLEAR REGULATORY COMMISSION WAsHWGf oN, D.C. 30006 4 001 NORTHERN STATES POWER COMPANY DOCKET NO. 50 282 PRAIRIE ISLAND NUCLEAR GENERATING PLANT. UNIT NO.1 AMENDMENT.TO. FACILITY OPERATING LICENSE Amendment No.132 License No. DPR-42 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Northem States Power Company (the licensee) dated November 27,1996, as supplemented August 15, September 2, and October 3,1997, complies with the stand &rds and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (1) that ;be activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. DPR-42 is hereby amended to read as follows:
l L
l
i
+
a r
2 l
Technical Soecdications I
The Technical Specifications contained in Appendix A, as revised through Amendment No. 132, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
l 3.
This license amendment is effective as of the date of issuance, with full implementation within 30 days.
FOR THE NUCLEAR REGULATORY COMMISdlON N.
Both A. Wetzel, Senior Project Manager Project Directorate lil 1 Division of Reactor Projects Ill/IV Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of lasuance: November 4. 1997
\\
4-e
.~
i I
ATTACHMENT TO LICENSE AMENDMENT NO.132 i
FACILITY OPERATING LICENSE NO. DPR-42 DOCKET NO. 50 282 i
Revise Appendix A Technical Specifications by removing the pages identified below and inserting the attached pages. The revised page,s are identified by amendment number and contain vertical lines indicating the area of change.
REMOVE lNSERT TS 4.12-1 TS 4.12 f TS 4.12 2 TS 4.12 2 TS 4.12-4 TS 4.12 4 TS 4.12 5 TS 4.12 5 Table TS 4.12 2 B 4.121 B 4.121 B 4.12 2 B 4.12 2 e
t m
--,..,e
~r
-,,v,.,
,-n a-
+s
= ---
4 TS.4.12 1 4.12 STEAM CENERATOR TURE SURVEILIANCE Acolicability Applies to inservice surveillance of the steam generator tubes.
Obiective To assure the continued integrity of the steam generator tubes that are a part of the primary coolant pressure boundary.
Egeeification Steam generator tubes in each unit shall be determined operable by the following:
A.
Steam Cenerator Sa= ale Seirytion and Insoection Each steam generator shall be determined operable in accordance with the in. service inspection schedule in Specification 4.12.C.
The in service inspection may be limited to one steam generator en a rotating schedule encompassing 64 of the tubes in the single steam generator, provided the previous inspections indicated that the two steam generators are performing in a like manner.
B.
Steam Cenerator Tube Samole Selection and Insoection.The steam generator tube minimum sample size, inspection result classification, and the corresponding action required shall be as specified in Tables TS.4.12 1 and TS.4.12 2.
The in service l
inspection of steam generator tubes shall be performed at the frequencies specified in Specification 4.12.C and the inspected tubes shall be verified acceptable per the acceptance criteria of Specification 4.12.D.
The tubes selected for each in. service inspection shall include at least 34 of the total number of tubes in all steam generators and at least 20% of the total number of sleeves in service in both steam generators; the tubes selected for these inspections shall be selected on a random basis except:
1.
Where experience in similar plants with similar water chemistry indicates critical areas to be inspected, then at least 50% of the tubes inspected shall be from these critical areas.
l Prairie Island Unit 1 Amendment - No.,36$ 132 (Prairie Island Unit 2' Amendment No.,2ST 124
~
c TS.4.12 2 i
2.
The first sample of tubes selected for each in service inspection (subsequent to the preservice inspection) of each steam generator shall include:
(a) All tubes that previously had detectable wall penetrations
(>204) that have not been plugged or sleeve repaired in the affected area.
(b) Tubes in those areas where experience has indicated potential problems.
(c) A tube inspection (pursuant to Specification 4.12.D.1.(h))
shall be performed on each selected tube.
If any selected tube does not permit the passage ol' the eddy current probe for a tube inspection, this shall be recorded and an adjacent tube shall be selected and subjected to a tube inspection.
3.
In addition to the sample required in Specification 4.12.8.2.a through c, all tubes which have had the P* criteria applied will be inspected in the F* regions of the roll expanded region.
The roll expanded region of those tunes may be excluded from the requirements of 4.12.8.2.a.
4.
The tubes selected as the second and third samples (if required by Tables TS.4.121 or TS.4.12 2) during each inservice inspection may be subjected to a partial tube or sleeve inspection provided:
(a) The tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperf=ctions were previously found.
(b) The inspections include those portions of the tubes or sleeves where imperfections were previously found.
The results of each sample inspection shall be classified into one of the following three categories:
Category Inspection Results C1 Less than 5% of the total tubes inspected are degraded tubes and none of the inspected tubes are defective.
C2 One or more tubes, but not more than it of the total tubes inspected are defactive, or between St and 10%
of the total tubes inspected are degraded tubes.
C-3 More than 10% of t'..o total tubes inspected are degraded tubes or more that it of the inspected tubes are defective.
Note: In all inspections, previously degraded tubes must exhibit significant.(>104) further wall penetrationa to be included in the above percentage calculations.
Prairie Island Unit J-Amendment No.,767.146',132 Prairie Island Unit 2 Amendment No. JMJ, Jlli 124
TS.4.12 4 i
D.
Acceptance Criteria 1.
As used in this Specification:
(a)
ImoerfectiED means an exception to the dimensions, finish or contour of a tube from that required by fabrication drawings or specifications. Eddy current testing indications below 20% of the nominal tube wall thickness, if detectable, may be considered as imperfections.
l (b)
Derradation means a service induced cracking, wastage, wear or general corrosion occurring on either inside or outside of a tube.
(c)
Derraded Tube means a tube containing imperfections k20% of the nominal wall thickness caused by degradation.
(d) t Derradation means the percentage of the tube wall thickness affected or removed by degradation.
(e)
Defect means y imperfection of such severity that it exceeds the repair limat. A tube containing a defect is defective.
(f) genair Limit means the imperfection depth at or beyond which the tube shall be removed from service by plugging or rep 2 ired by sleeving because it may become unserviceable prior to the next inspection and is equal to 50% of the nominal tube wall thickness.
If significant general tube thinning occurs, this criteria will be reduced to 406 wall penetration. This definition does not apply to the portion of the tube in the tubesheet below the F* distance provided the tube is not degraded (i.e., no indications of cracks) within the F*
distance for F* tubes.
The repair limit for the pressure boundary region of any sleeve is 31% of the nominal sleeve wall thickness.
(g)
Unserviceable describes the condition of a tube if it leaks or contains a defect large enough to affect its structural integrity in the event of an Operating Basis Earthquake, a loss of coolant accident, or a steam line or feedwater line break.
(h)
Tube Insoection means an inspection of the steam generator tube from the point of entry (hot leg side) completely around the U. bend to the top support of the cold leg.
(i)
Sleevine is the repair of degraded tube regions using a new A11tv 60S tubing sleeve inserted inside the parent tube ano siq<a at each end by welding or by replacing the lower veld in a full depth tubesheet sleeve with a hard rolled joint. The new sleeve becomes the pressure boundary spanning the original degraded tube region.
Prairie Isinnd Unit 1 Amendment No.,7&T 116~, 132 '
Pietrie Island Unit 2 Amendment No. A91 1111 124 L
l t
~_
TS.4.12 5 (j)
F* Distance is the distance from the bottom of the hardroll transition toward the bottom of the tubesheet that has been conservatively determined to be 1.07 inches (not including 3ddy currant uncertainty).
(k)
F* Tube is a tube with degradation, below the F* distance, equal to or greater than 406, and not degraded (i.e., no indications of cracking) within the F* distance.
2.
The steam generator shall be determined CPERABLE after completing the corresponding actions (plug or repair by sleeving all tubes exceeding the repair limit and all tubes containing through wall cracks or classify as F* tubes) required by Tables TS.4.12 1 and TS.4.12 2.
3.
Tube repair, after October 1, 1997, using Combustion Engineering welded sleeves shall be in accordance with the methods described in the following:
CEN.629.P. Revision 2, " Repair of Westinghouse Series 44 and $1 Steam Generator Tubes Using Leek Tight Slesves";
CEN.629.P Addendum 1 Revision 1, " Repair of Westinghouse Series 44 and $1 Steam Generator Tubes UJing Leak Tight Sleeves" E.
Reports
- 1. Following each in service inspection of steam generator tubes, if there are any tubes requiring plugging or sleeving, the number of tubes plugged or sleeved in each steam generator shall be reported to the Commission within 15 days.
- 2. The results of steam generator tube inservice inspections shall be included with the summary reports of ASME Code Section XI inspections submitted witnin 90 days of the end of each refueling outage.
Results of steam generator tube inservice inspections not associated with a refueling outage shall be submitted within 90 days of the completion of the inspection. These reports shall include: (1) number and extent of tubes inspected, (2) location and percent of wall thickness penetration for each indication of an imperfection and (3) identification of tubes plugged or sleeved.
- 3. Results of steam generator tube inspections which fall into Category C 3 require notification to the Commission prict to resumption of plant operation, and reporting as a special report to the Commission within 30 days. This special report shall provide a description of investigations conducted to determine cause of the tube degradation and corrective measures taken to prevent recurrence,
- 4. The results of inspections performed under Specification 4.12.B for all tubes that have defects below the F* distance, and were not plugged.
shall be reported to the Commission within 15 days following the inspection. The report shall include:
a.
Identification of F* tubes, and b.
Location and extent of degradation.
Prairic Island Unit 1 Amendment No. J6,,118, 132 Prairie Island Unit 2 Amendmen t No.,69,141', 124
27 mn n m*.
Table TS.4.12-2 oe Steam Generator Tube Sleeve Inspection i
B 4 h4 35 mo 1st Sample Inspection 2nd Sample Inspection ms
- a. o.
7E Sample Size Result Action Regt: ired Result Action Required XX 9 miniatus of 20% of C-1 None N/A N/A g-Tube Sleeves (1)
C-2 Inspect all remaining tube C-1 None sleeves in this S.C. and plug or repair defet.tive sleeved tubes.
C-2 Plug or repair defective sleeved tubes C-3 Perform action for C-3 I
result of first sample C-3 Inspect all tube sleeves in this The other None S.C., inspect 20% of the tube S.G. is C-1 sleeves in the other S.C.,
and The other Perform action for C-2 plug or repair defective sleeved tubes S.C. is C-2 results of first sample j
The other Inspect all tube sleeves in S.C is C-3 each S.C. and plug or repair defective sleeved tubes i
(1) Each type of sleeve is considered a separate population for determit Icion of scope expansion mo 3 D O. O.
t EE y
zz g
.O.O ww nu
- N p
N i
we 1
e==
+e-
8.4.12 1 4.12 STEAM CENERATOR TUBE SURVEILLANCE Bases The Surveillanas Requirements for inspection of the steam generator tubes ensure that the structaral integrity of this portion of the RCS will be maintained. The program for inservice inspection of steam generator tubes is based on a modification of Regulatory Guide 1.83, Revision 1.
In service inspection of steam generaeor tubing is essential in order to maintain surveillance of the conditions of the tubes in the event that i
there is evidence of mechanical damage or progressive degradation due to design, manufacturing errors, or in. service conditions that lead to corrosion.
In. service 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.
At the request of the NRC, a requirement for in service inspection of at least 20% of the total number of sleeves in service in both steam generators was added to TS 4.12.8.
In addition Table TS.4.12 2 was added to provide sample expansion requirements based on the results of the initial sample inspection similar to Table 4.121 This type of sample size and expansion requirement is consistent with the EPRI PWR Steam Generator Examination Guidelines. The sample selection is applied to each type of sleeve, Types of sleeves are categorized by such characteristics is the installation vendor, the sleeve material, the type of joint such as lower edge weld or lower hard roli joints, the sleeve location such as tube support plate or tubesheet and whether not the welded joints hJee received post weld heat treatment.
The plant is expected to be oporated in a manner such that the secondary coolant will be maintained within those parameters found to result in negligible corrosion of the steam generator tubes.
If the secondary coolant chemistry is not maintained within these parameters, localized corrosion would most likely result in stress corrosion cracking.
The extent of cracking during plant operation would be limited by the limitation of steam ganarator leakage between the primary coolant system and the secondary coolant system (primary.co secondary leakage -
1.0 gpm). Cracks having a primary to secondary leakage less than 1.0 gpm during operation will have an adequate margin of safety against failure due to loads imposed by design basis accidents (Aeference 1).
Operating plants have demonstrated that primary to. secondary leakage as low as 0.1 gpm will be detected by radiation monitors of steam generator blowdown. Leakage in excess of 1.0 gpm will require plant shutdown and an unscheduled eddy current inspection, during which the leaking tubes will be located and plugged or sleeved.
Wastage type defects are unlikely with proper chemistry treatment of secondary coolant. However, even if this type of defect occurs it will be found during schedult.d in service steam generator tube inspections.
Repair or plugging will be_ required of all tubes with imperfections that could develop defects having less than the minimum seceptable wall thickness prior to the next inservice inspection which, by the definition of Specification 4.12.D.1.(f), is 50% of the tube or sleeve nominal wall thickness. Wastage type defects having a wall thickness greater than 0.025 inches will have adequate margins of safety against failure due to.
Ioads imposed by normal plant operation and design basis accidents (Reference 1).
Steam generator tube inspections of operating Prairie Island Unit 1 Amendment No. J9fl 132 Prairie Island Unit 2.
Amendment - No. Jkr, 124
t B.4.13 2 4
4.12 STEAM CENERATOR TUBE SURVEIUANCF, Bases continued plants have demonstrated the capability to reliably detect wastage type defects that have penetrated 204 of the original 0.050 inch wall thickness (Reference 2).
Plugging or sleevin6 is not required for tubes meeting the F* criteria.
The f* distance will be controlled by a combination of eddy current inspection and/or process enntrol.
For a new additional roll expansion, the requirement will be at least 1.2 inches of new hard roll.
This is controlled by the length of the rollers (1.25 inch effective length). The distance from the original roll transition zone is also controlled by_the process in that the lower end of the new roll expansion is located one E
inch above the original roll expansion.
In the case of the new roll, eddy current examination will confirm there are no indications in the new roll region and that there is a new roll region with well defined upper and lower expansion transitions.
When eddy current examination, alone, must determine the P* distance, such as in the existing hard roll region, or when multiple lengths of additional hard rolls have been added, the eddy current uncertainty is qualified by testing against knovo standards. That value is expected to be 0.18 inches. Therefore, the F* distance measured by eddy current (sum of 1.07 and 0.18) will be conservatively set at 1.3 inches.
When more than one Alternate Repair Criteria are used, the summation of leakage from all tubes left in service by all repair criteria must be less than the allowable leakage for the most limiting of those Alternate Repair criteria.
Whenever the results of any steam generator tubing in service inspection fall into Category C 3, these results will be promptly reported to the Commission prior to resumption of plant operation.
Such cases will be considered by the Commission 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.
Degraded steam generator tubes may be repaired by the installation of sleeves which span the section of degraded steam generator tubing. A steam generator tube with a sleeve installed meets the structural requirements of tubes which are not degraded.
The following sleeve designs have been found acceptable by the NRC Staff:
- a. Westinghouse Mechanical Sleeves (WCAP 10757)
- b. Westinghouse Brazed Sleeves (WCAP 10820)
- c. Combustion Engineering Leak Tight Sleeves (CEN 294 P for sleeves installed prior to October 1, 1997)
- d. Combustion Engineering Leak Tight Sleeves (CEN 629 P, for sleeves installed after October 1, 1997)
,Prairic Island Unit 1 Amendment No. ;9f', J4ff 132 1
Prairie Island Unit 2 Amendment No. JWF, 141, 124
~
- - ~ _. _.. -..
i 0 ' *%
6 y*
-t UNITED STATES NUCLEAR REGULATORY COMMISSION i
WASHINGTON. O.C. SOMHo01
.%,e...*
NORTHERN STATES POWER COMPANY DOCKET NO. 50,3QQ PRAIRIE ISLAND NUCLEAR GENERATING PLANT. UNIT NO.?
AMENDMENT TO FACILITY OPERATING LICENSE Amendment No.124 License No DPR-60 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Northern States Powu Company (the licensee) dated November 27,1996, as supplemented August 15, September 2, and October 3,1997, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the C 'mmission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
T, sere is reasonable assurance (1) that the activities authorized by this an endment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of tnis amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
- 2. '
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility
- Operating License No. DPR-60 is hereby amended to read as follows:
-, - + - < -
.,e
,w--
.r1 r
e.-
v-
=.
2 Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 124, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
3.
This license amendment is effective as of the date of issuance, with full implementation 4
within 30 days.
FOR THE NUCLEAR REGULATORY COMMISSION N.
Beth A. Wetzel, Senior Project Manager Project Directorate lil 1 Division of Reactor Projects lil/lV Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance. November 4,1997 i
1 P
,--,,,-rm-
.--_-~..,m-.-.w...-we--.
w
,,-,--y-yr-,-
y e..-,
~
g
,.-s,,,
,-,,,m m.
i,e.
i ATTACHMENT TO LICENSE AMENDMENT NO.124 h
FACILITY OPERATING LICENSE NO. DPR 60 i
DOCKET NO. 50-306 i
Revise Appendix A Technical Specifications by removing the pages identifed below and inserting the attached pages. The revised pages are identifed by amendment number and contain vertical lines indicating the area of change.
REMOVE INSERT t
i TS 4.12-1 TS 4.12-1 TS 4.12 2 TS 4.12-2 i
TS 4.12-4 TS 4.12-4 TS 4.12 5 TS 4.12 5 Table TS 4.12 2 B 4.121 B 4.12-1 i
B 4.12 2 B 4.12 2 r
1 i
t
,,,-..,m,.
---3 vr + - - -w T-
""s-
- -w'-"T'-"'
" ' " - ^ - -'" ' " " ' - ' ~
TS.4.12 1 4.12 STEAM CENERATCR TUBE SURVEILIECE Acolicability Applies to inservice surveillance of the steam generator tubes.
Obiwetive To assure the continued integrity of the steam generator tubes that ere a part of the primary coolant pressure boundary.
i Specification Steam generator tubes in each unit shall h6
<termined operabis by the following:
A.
11eam Generator Samole Selection and Insoection.Each steam generator shall be determined operable in accordance with the in service inspection schedule in Specification 4.12.C.
The it..ssrvice inspection may be limited to one steam generator r.n a rotating schedule encompassing 6% of the tubes in the si'.gle steam generator, provided the previous inspections indicated that the two steam generators are performing in a like manner.
B.
Steam Generator Tube Sa=nle Selection and Insoection.The steam generator tube minimum sample size, inspection result classification, and the corresponding action required shall be as specified in Tables TS.4.12 1 and TS.4.12 2.
The in. service l
inspection of steam generator tubes shall bo performed at the frequencies specified in Specification 4.12.C and the inspected tubes shall be verified acceptable per the acceptance criteria of Specification 4.12.D.
The tubes selected for each in service inspection shall include at least 3% of the total number of tubes in all steam generators and at least 20% of the total number of sleeves in service in both steam generators; the tubes selected for these inspections shall be selected on a random basis except:
1.
Where experience in similar plants with similar water chemistry indicates critical areas to be inspected, then at least 50% of the tubes inspected shall be from these critical areas.
3(I132 Prairic Island Unit 1 Amendment No.,2SG 124 Prairie Island Unit 2 Amendment No.,
l l
t
- = _ -
_ =. - - _ - - -
TS.4.12 2 2.
The first sample of tubes selected for each in service inspection (subsequent to the preservice inspection) of each steam generator shall include:
(a) All tubes that previously had detectable wall penetrations
(>206) that have not been plugged or sleeve repaired in '.he affected area.
(b) Tubes in those areas where experience has indicated potential problems.
(c) A tube inspection (pursuant to Specification 4.12.D.1.(h))
shall be performed on each selected tube.
If any selected tube does not permit the passage of the oddy current probe i
for a tube inspection, this shall be recorded and an adjacent tube shall be selected and subjected to a tube inspection.
3.
In addition to the sample required in Specification 4.12.5.2.a through c, all tubes which have had the r* criteria applied will be inspected in the F* regions of the roll expanded region. The roll expanded region of these tubes may be excluded from the requirements of 4.12.8.2.a.
4 T6 e u kes selected as the second and third samples (if required by Tables T5.4.121 or TS.4.12 2) during each inservice in.ipection may be subjected to a partial tube or sleeve inssectior provided:
(a) Ine tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperfections were previously found.
(b) The inspections include those portions of the tubes or sleeves where imperfections were previously found.
The results of each sample inspection shall be classified into one of the following three categories:
Category Inspection Results C1 Less than 5% of the total tubes inspected are degraded tubes and none of the Anspected tubes are defective.
C2 One or more tubes, but not more than in of the total tubes inspected are defective, or between 54 and 10%
of the total tubes inspected are degraded tubes.
-C3 More than 10% of the total tubes inspected are degraded tubes or more that 14 of the inspected tubes are defective.
Note: In all inspections, previously degraded tubes must exhibit significant (>106) further wall penetrations to be included in the above percent;;e calculations.
Prairie Island Unit 1.
Amendment No.,?67 24ff,132 Prairie Island Unit 2 Amendment No. Jkt.1tT,124 l
TS.4.12 6 D.
Acceptance Criteria 1.
As used in this Specification:
(a)
Imoerfection means an exception to the dimensions, finish or contour of a tube from that required by fabrication drawings or specifications. Eddy current testing indications below 20% of the nominal tube wall thickness, if detectable, may be considered as imperfections.
(b)
Derradation means a service induced cracking, wastage, wear or general corrosion occurring on either inside or outside of a tube.
(c)
Derraded Tube means a tube containing imperfections t20% of the nominal wall thickness caused by degradation.
(d) t Derradation means the percentage of the tube wall thickness affected or removed by degradation.
(e)
Defect means an imperfection of such severity that it exceeds the repair limit. A tube containing a defect is defective.
(f)
Eggair Limit means the imperfection depth at or beyond which the tube shall be removed from service by plugging or repaired by sleeving because it may become unserviceable prior to the next inspection and is equal to 50% of the nominal tube wall thickness. If significant general tube thinning occurs, this criteria will be reduced to tot wall penetration. This 2
definition does not apply to the portion of the tube in the tubesheet below the P* distance provided the tube is not degraded (i.e., no indications of cracks) within the F*
distance for P* tubes. The repair limit for the pressure boundary region of any sleeve is 31% of the nominal sleeve wall thickness.
(g)
Unserviceable describes the condition of a tube if it leaks or contains a defect large enough to affect its structural integrity in the event of an Operating Basis Earthquake, a loss of coolant accident, or a steam line or feedwater line break.
(h)
Tube Insoection means an inspection of the steam generator tube from the point of entry (hot leg side) completely around the U bend to the top support of the cold leg.
(i)
Sleevinz is the repair of degraded tube regions using a new Alloy 690 tubing sleeve inserted insiste the parent tube and sealed at each end by welding or by replacing the lower veld in a full depth tubesheet sleeve with a hard rolled joint. The new sleeve becomes the pressure boundary spanning the original degraded tube region.
Prairie Island Unit 1 Amendment No. )41 116',132 Prairie Island Unit 2 Amendment No. 644 lif',124 l
.-- ~
TS.4.12 5 l
1 (jf r* Distance is the distance from the bottom of the hardroll trcnsition toward the bottom of the tubesheet that has been conservatively determined to be 1.07 inches (not including eddy current uncertainty).
(k)
F* Tube is a tube with degradation, below the F* distance, equal to or greater than 404, and not degraded (i.e., no indications of cracking) within the F* distance.
2.
The steam generator shall be determined OPERABLE af ter completing the corresponding actions (p1v3 er repair by sleeving all tubes exceeding the repair limit and all tubes containing through wall cracks or classify as F* tubes) required by Tables TS.4.12 '. and TS.4.12 2.
3.
Tube repair, after October 1, 1997, using Combustion Engineering welded s1* eves shall be in accordance with the methods described in the following:
CEN 629 P. Revision 2. " Repair of Westinghouse Series 44 and 51 Steam Generator Tubes Using Leak Tight Sleeves";
CEN 629.P Addendum 1, Revision 1, ' Repair of Westinghouse Series 44 and 51 Steam Generator Tubes Using Leak Tight sleeves" E.
Renorts
- 1. Following each in service inspection of steam generator tubes, if there are any tubes requirins P uS5 ng or slesving, the number of tubes l
1 plugged or sleeved in each steam generator shall be reported to the commission within 15 days.
- 2. The results of steam generator tube inservice inspsetions shall be includsd with the summary reports of ASME Code Section XI inspections submitted within 90 days of the end of each refueling outage. Results of steam generator tube inservice inspections not associated with a refueling outage shall be submitted within P0 days of the completion of the inspection, These reports shall include: (1) number and extent of tubes inspected (2) location and percent of wall thickness penetration for each indication of an imperfection.and (3) identification of tubes plugged or sleeved.
- 3. Results of steam generator tube inspeccions which fall into Category C 3 require notification to the Commission prior to resumption of plant operation, and reporting as a special report to the Commission within 30 days. This special report shall provide a description of investigations conducted to determine cause of the tube degradation and corrective measures taken to prevent recurrence.
- 4. The results of inspections performed under Specification 4.12.B for all tubes that have defects below the F* distance, and were not plugged, shall be reported to the Consission within 15 days following the inspection.
The report shall include:
a.
Identification of F* tubes, and b.
Location and extent of degradation.
Prairie Island Unit 1 Amendment No. J61.J43, 132 Prairie Island-Unit 2 Amendment No.,69,141', 124 l
l
E i
??
EE Table TS.4.12-2 eo Steam Generator Tube Sleeve Inspection L
mm os e nn uo ist Sample Inspection 2nd Sample Inspection
- o. a.
EE Sample Size Result Action Required Result Action Required XX A minimum of 20% of C-1 None N/A N/A w
Tube Sleeves (1)
C-2 Inspect all remaining tube C-1 None sleeves in this S.C. and plug or repair defective sleeved tubes.
C-2 Plug or repair defecti_ve sleeved tubes C-3 Perform action for C-3 result of first sample C-3 Inspect all tube sleeves in this The other None S.G..
inspect 20% of the tube S.C. is C-1 sleeves in the other S.C., and plug or repair defective sleeved The other Perform action for C-2 tubes S.C. is C-2 results o.
first sample The other Inspect all twe sleeves in S.C is C-3 each S.C. and plug or repair defective sleeved tubes f
Each type of sleeve is considered a separate population for determination of scope expansion N N
,1) l nn l
I 33 O. Q.
EE y
o-22 U
C. C
~
L i
i 3.4.12 1 i
?
4.12 S'iEAM CENERATOR WSE SURVEILLANCE The Sune111ance Requirements for inspection of the steam generator tubes l
ensure that the structural integrity of this portion of the RCS will be i
maintained. The program for inservice inspection of steam generator tubes is based on a modification of Regulatory Guide 1.83, 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 mechanica*L damage or progressive degradation due to design, manufacturing errors, it in service conditions that lead to corrosion.
In. service inspect on of steam generator tubing also provides a means of characterizing the Asture and cause of any tube degradation so that corrective measures can be taken.
At the request of the NRC, a requirement for in service inspection of at least 20% of the total number of sleeves in service in both steam generators was added to TS 4.12.5.
In addition. Table TS 4.
2 2 was added to provide sample expansion requirements based on the results of the l
initial sample inspection similar to Table 4.12 1 This type of sample size and expansion requirement is consistent with the EPRI FWR Stena Generator Examination cuidelines. The sample selection is applied to each type of sleeve. Types of sleeves are categorized by such characteristics as the installation vendor, the sleeve material, the type of joint such as lower edge weld or lowcr hard roll joints, the sleeve location such as tube support plate or tubesheet and whether not the walded joints have received post weld heat treatment.
The plant is expectnd to be operated in a manner such that the secondary coolant will be maintained within thase parameters found to result in negligible corrosion of the steam generator tubes.
If the secondary coolant chemistry is not maintained within these parameters, localized corrosion would most likely result in stress corrosion cracking.
The extent of cracking during plant operation would be limited by the limitation of steam generator leakage between the primary coolant system and the secondary coolant system (primary.to. secondary leakage -
1.0 spa). Cracks having a primary to secondary leakage less than 1.0 gpa during operation will have an adequate margin of safety against failure due to loads imposed by design basis accidents (Reference 1).
Operating plants have demonstrated that primary.to secondary leakage as low as 0.1 spa will be detected by radiation monitors of steam generator blowdown. 14akage in excess of 1.0 gpa vill reautre plant shutdown and an unscheduled oddy current inspection, during which the leaking tubes will be located and plugged or sleeved.
Wastage. type defects are unlikely with proper chemistry treatment of
-secondary coolant. However, even if this type of defect occurs it will be found during scheduled in service steaa_ generator tube inspections.
Repair or plugging will be required of all tubes with imperfections that could' develop defects having less than the minteum acceptable wall thickness prior to the next inservice inspection which. by the definition of Specification 4.12.D 1.(f), is 504'of the tube or sleeve nominal wall thickness. Wastage type defects having a vall thickness greater than 0,025 inches will have adequate margins of safety against failure due to loads imposed by normal plant' operation and design basis accidents (Reference'1). Steam generator tube inspections of operating Prairie Island Unit 1 Amendment No.,96 132 Prairie Island Unit-2 Amendment No. JiW, 124 I
. ~.. -
-.L_.....,._
_,~..._...-__u.--_-
- = - _ _
i 8.4.12 2 4.12 STEAM.CENERATOR TURE SVRVEII.1ANCE
&agga continued plants have demonstrated the capability to reliably detect wastage type defects that have penetrated 20% of the original 0.0$0 inch wall thickness (Reference 2).
Plugging or sleeving is not required for tubes meeting the F* criteria.
The F* distance will be controlled by a combination of eddy current inspection and/or process control.
For a new additional roll expansion, the requirement will be at least 1.2 inches of new hard roll. This is controlled by the length of the rollers (1.25 inch effective length). The distance from the original roll transition zone is also controlled by the process in that the lower end of the new roll expansion is located one inch above the original roll expansion. In the case of ths new roll, ;4ty current examination will confirm there are no indications in the new roll region and that there 'is a new roll region with well defined upper and lower expansion transitions.
When oddy current examination, alone, must datermine the F* distance, such as in the existing hard roll region, or when multiple lengths of additional hard rolls have been added, the eddy current uncertainty is qualified by testing against known standards. That value is expected to be 0.18 inches. Therefore, the F* distance measured by eddy current (sum of 1.07 and 0.18) will be conservatively set at 1.3 inches.
When more than one Alternate Repair Criteria are used, the summation of leekage from all tubes left in service by all repair criteria mast be less than the allowable leakage for the most limiting of those Alternate Repair criteria.
Whenever the results of any stoma generator tubing in service inspection fall into Category C 3, these results will be promptly reported co tha Commission prior to resumption of plant operation. Such cases will be considered by the Commission 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.
Degraded steam generator tubes may be repaired by the installation of sleeves which span the section of degraded steam generator tubing. A steam generator tube with a sleeve installed meets the structurel requirements of tubes which are not degraded.
The following sleeve designs have been found acceptable by the NRC Staff:
- a. Westinghouse Mechanical Sleeves (WCAP 10757)
- b. Westinghouse Brated Sleeves (WCAP 1082C)
- c. Combustion Engineering Leak Tight Sleeves (CEN 294 P, for sleeves installed prior to October 1, 1997)
- d. Combustion Engineering Lesk Tight Sleeves (CEN 629 P, for sleeves installed after October 1, 1997)
Prairie Island Unit 1 Amendment No JR', J!s; 132 Prairie Island Unit 2 Amendment No. JMF, in,124 i
w
,v-
_y-u-w
- w
--m--+t
>-te+