TMI-12-152, Submittal of End of Interval Relief Request RR-12-01

Submittal of End of Interval Relief Request RR-12-01

ML12283A252
Person / Time
Site:	Three Mile Island
Issue date:	10/05/2012
From:	Jesse M Exelon Generation Co
To:	Document Control Desk, NRC Region 1
References
TMI-12-152
Download: ML12283A252 (32)

Text

10 CFR 50.55a TMI-12-152 October 5, 2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Three Mile Island Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-50 NRC Docket No. 50-289

Subject:

Submittal of End of Interval Relief Request RR-12-01 Attached for your review is Relief Request RR-12-01 which is associated with the third Inservice Inspection (lSI) interval for Three Mile Island Nuclear Station (TMI), Unit 1.

RR-12-01 concerns requirements for examination of pressurizer relief nozzle welds that were examined in the fall 2011 refueling outage. The TMI, Unit 1 third lSI interval complied with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 1995 Edition, 1996 Addenda. The third lSI interval concluded on April 19, 2012. We request your approval by October 5,2013.

There are no regulatory commitments in this letter.

If you have any questions concerning this letter, please contact Tom Loomis at (610) 765-5510.

Respectfully, Michael D. Jesse /j/j"~--

Director - Licensil;lg egulatory Affairs Exelon Generation Company, LLC

Attachment:

Relief Request RR-12-01 cc: Regional Administrator, Region I, USNRC USNRC Senior Resident Inspector, TMI USNRC Project Manager, [TMI] USNRC

Attachment Relief Request RR-12-01

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii) 1 of

1. ASME Code Component(s) Affected Code Class: 1

Reference:

IWB-2500, Table IWB-2500-1 Examination Category: B-D Item Number: B3.110

Description:

Limited Examination Coverage Component Number: See Table 1

2. Applicable Code Edition and Addenda

The third Inservice Inspection (lSI) interval is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 1995 Edition, 1996 Addenda.

3. Applicable Code Requirements This relief request addresses the limited examination of three (3) pressurizer relief nozzle welds at the Three Mile Island Nuclear Station (TMI), Unit 1 (see Table 1). The following are the ASME Code,Section XI, requirements for inspection of the pressurizer nozzle to head welds:

Table IWB-2500-1, Examination Category B-D requires volumetric examination of Item B3.11 0 (pressurizer nozzle-to-vessel welds).

Figure IWB-2500-7(a) depicts the required examination volume (A-B-C-D-E-F-G-H-I),

which includes the weld and adjacent base metal on either side of the weld extending to a distance of one-half the thickness of the wall from the extremities of the weld.

ASME Section XI, Mandatory Appendix I, requires ultrasonic examination of vessel welds greater than 2" thick to be conducted in accordance with ASME Section V, Article 4 as supplemented by Table 1-2000-1.

ASME Section V, Article 4 requires:

T-441.1.3 Extent of Scanning: Wherever feasible, the scanning of the examination volume shall be carried out from both sides of the weld on the same surface. Where configuration or adjacent parts of the component are such that scanning from both sides is not feasible, this fact shall be included in the report of the examination.

T-441.1.4 Angle Beam Scanning: Wherever feaSible, each examination shall be performed in two directions, i.e., approaching the weld from the opposite directions and parallel to the weld from opposite directions.

T -441.1.5 Scanning for Reflectors Oriented Parallel to the Weld: The angle beam search units shall be aimed at right angles to the weld axis, with the search unit manipulated so that the ultrasonic beams pass through the entire volume of weld

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iii) 2 of metal. The adjacent base metal in the examination volume must be completely scanned by two angle beams, but need not be completely scanned by both angle beams from both directions (any combination of two angle beams will satisfy the requirement).

T -441.1.6 Scanning for Reflectors Oriented Transverse to the Weld: The angle beam search units shall be aimed parallel to the axis of the longitudinal and circumferential welds. The search unit shall be manipulated so that the ultrasonic beams pass through all of the examination volume. Scanning shall be done in two directions 180 degrees to each other to the extent possible. Areas blocked by geometric conditions shall be examined from at least one direction.

TMI, Unit 1 has invoked ASME Section XI Code Case N-460, "Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1." Code Case N-460 states, in part, that when the entire examination volume or area cannot be examined a reduction in examination coverage may be accepted provided the reduction in coverage for that weld is less than 10%. NRC Information Notice 98-42, "Implementation of 10 CFR 50.55a(g)

Inservice Inspection Requirements," termed the reduction in coverage of less than 10% to be "essentially 100 percent." Information Notice 98-42 states, in part, that the NRC has adopted and further refined the definition of "essentially 100 percent" to mean "greater than 90 percent," which has been applied to examination of welds or other areas required by ASME Section XI.

4. Impracticality of Compliance Pursuant to 10 CFR 50.55a(g)(5)(iii), relief is requested on the basis that conformance with the specified Code requirement has been determined to be impractical.

Three (3) pressurizer relief nozzle welds were examined during the third period of the third lSI interval in accordance with ASME Section V, Article 4 requirements. The volumetric examination coverage for these nozzle welds was less than the required 90%

(see Table 1). The limitations are due to the nozzle configuration and adjacent obstructions on the pressurizer upper head. See Figures 1 thru 26 for configuration and limitations.

S. Burden Caused by Compliance The three (3) pressurizer relief nozzle welds were credited for volumetric examination during the third period of the third lSI interval even though the overall volumetric examination coverage was less than 90% (see Table 1). The welds listed in Table 1 were examined to the extent practical. The pressurizer head would need to be replaced with newly designed nozzles designed such that the required examination volume could be examined in order to achieve examination coverage >90%.

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iIi) 3 of

6. Proposed Alternative and Basis for Use Examination coverage for the nozzle inner radius (Table IWB-2500-1, Category D-B, Item Number B3.120) was greater than 90%. This examination would detect surface connected inside surface flaws. The areas of limited examination were mainly in the region of the outside surface weld radius between the nozzle and head. A supplemental VT-1 examination of this region was performed to supplement the limited examination in this region and no degradation was observed. Surface connected service induced degradation in this most highly unexamined region would be detected by the VT-1 examination method.

A supplemental 35 degree angle beam examination was performed to increase coverage in other locations. The UT examinations were performed to the maximum extent practical using the best available technology of the time.

7. Duration of Proposed Alternative Relief is requested for the third ten-year lSI interval for TMI, Unit 1. The third ten-year interval began on April 20, 2001 and ended on April 19, 2012 for these examinations.

8. Precedents Letter from H. K. Chernoff (U.S. Nuclear Regulatory Commission) to M. J. Pacilio (Exelon Generation Company, LLC), "Three Mile Island Nuclear Station, Unit 1 (TMI-1) -- Third Inservice Inspection Interval Relief Requests RR-11-01 and RR-11-02 (TAC Nos. ME5670 and ME5671 )," dated December 19, 2011

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iii)

(Page 4 of 30)

Table 1 Pressurizer Upper Head Nozzle Welds Weld 10 I Category Outage & Coverage Fabrication Section NDE limitation Indications Description litem No. Date Attained Materials XI Exam Method Description Identified Figure I Angles RCT0002PR0003N I B-O I T1R19, Fall 40.5% Ferritic Steel IWB- UT 10, Obstruction due to None Nozzle to Head Weld B3.110 2011 2500-7(a} 35,45, nozzle configuration, (See Figures 1 thru 8) 60 adjacent nozzle, adjacent lifting lug, and adjacent manway RCT0002PR0004N I B-O I T1R19, Fall 40.6% Ferritic Steel IWB- UT 10, Obstruction due to None Nozzle to Head Weld B3.110 2011 2500-7(a} 35,45, nozzle configuration, (See Figures 1 and 9 60 adjacent nozzles, thru 16) and adjacent lifting lug RCT0002PR0005N I B-O I T1R19, Fall 39.4% Ferritic Steel IWB- UT 10, Obstruction due to None Nozzle to Head Weld B3.110 2011 2500-7(a) 35,45, nozzle configuration, (See Figures 1 and 17 60 adjacent nozzles, thru 26) and adjacent lifting lug

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iii)

(Page S of 30)

Figure 1 Pressurizer Upper Head Nozzle Overview E[] Weld and/or tapered area x

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 6 of 30)

Figure 2 UT Examination Adjacent Obstruction Limitations for Nozzle RCT0002PR0003N Distance Scan(s) Length OBS Description from Weld Affected Affected 60 t 20° = 1.6" 0

1 Vent Nz. 8" 1 Vent Nz. 8" 45°j 15° = 1.2" 2 Manway 13.5" average 60°1 53° = 4.3" 0

3 Lifting Lug 11.5" average 60 t 55° = 4.4" 3 Lifting Lug 8" average 45°t 22° = 1.8"

(-:' Scan perimeter for 60° radial exam looking towards nozzle (j).

( ) Scan perimeter for 45° radial exam looking towards nozzle (i).

( ) Scan perimeter for 35° radial exam looking towards nozzle (t).

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 7 of 30)

Figure 3 45 Degree Angle Beam Limitations for Nozzle RCT0002PR0003N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(Iii)

(Page 8 of 30)

Figure 4 45 Degree Angle Beam Limitations (away from nozzle) for Nozzle RCT0002PR0003N I

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 9 of 30)

Figure 5 45 Degree Angle Beam Limitations (due to adjacent obstructions) for Nozzle RCT0002PR0003N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 10 of 30)

Figure 6 35 and 60 Degree Angle Beam Limitations (due to adjacent obstructions) for Nozzle RCT0002PR0003N

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 11 of 30)

Figure 7 35 and 60 Degree Angle Beam Limitations (away from nozzle) for Nozzle RCT0002PR0003N "0

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 12 of 30)

Figure 8 o Degree Angle Beam Limitations for Nozzle RCT0002PR0003N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iii)

(Page 13 of 30)

Figure 9 Adjacent Obstruction limitations for Nozzle RCT0002PR0004N UT Exam Limitations Distance Scan(s, Length OBS Description from Weld Affected Affected 1 Spray Nz. 13.5" average 60 t 0

=

30° 2.4" 60 t 22° = 1.8" 0

2 Relief Nz. "8" 14.5" average 3 Vent Nz. 8" 60 t 0

=

20° 1.6" 3 Vent Nz. 8" 45°t 15° = 1.2" 4 Lifting Lug 13.8" average 60 0 j 20° = 1.6"

( ) Scan perimeter for 60° radial exam looking towards nozzle (i).

( ) Scan perimeter for 45° radial exam looking towards nozzle (i).

( )scan perimeter for 35° radial exam looking towards nozzle (i).

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 14 of 30)

Figure 10 45 Degree Angle Beam Limitations for Nozzle RCT0002PR0004N

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 15 of 30)

Figure 11 45 Degree Angle Beam Limitations (away from nozzle) for Nozzle RCT0002PR0004N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iii)

(Page 16 of 30)

Figure 12 60 Degree Angle Beam Limitations for Nozzle RCT0002PR0004N u

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(Iii)

(Page 17 of 30)

Figure 13 35 and 60 Degree Angle Beam Limitations (due to adjacent vent nozzle) for Nozzle RCT0002PR0004N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iIi)

(Page 18 of 30)

Figure 14 3S and 60 Degree Angle Beam Limitations (away from nozzle) for Nozzle RCT0002PR0004N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 19 of 30)

Figure 15 o Degree limitations for Nozzle RCT0002PR0004N i

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 20 of 30)

Figure 16 45 Degree Limitations Due to Adjacent Obstruction for Nozzle RCT0002PR0004N I

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iii)

(Page 21 of 30)

Figure 17 Adjacent Obstruction Limitations for Nozzle RCT0002PROOOSN Distance Scan(s) Length OBS Description from Weld Affected Affected 1 Lifting Lug 4" average 60 0

r 61° = 4.9' 1 Lifting Lug 4" average 45°t 72° = 5.8' 2 Vent Nz. 8" 60 0 j 20° = 1.6' 2 Vent Nz. 8" 45°1 15° = 1.2' 60 t 22° = 1.8' 0

3 Relief Nz. "A" 14.5" average

(_) Scan perimeter for 60° radial exam looking towards nozzle (1).

(_) Scan perimeter for 45° radial exam looking towards nozzle (1).

(, 'Scan perimeter for 35° radial exam looking towards nozzle (i).

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 22 of 30)

Figure 18 45 Degree Angle Beam Limitations for Nozzle RCT0002PR0005N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 23 of 30)

Figure 19 45 Degree Angle Beam Limitation Due to Lifting Lug for Nozzle RCT0002PR0005N I

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 24 of 30)

Figure 20 45 Degree Angle Beam Limitations (away from nozzle) for Nozzle RCT0002PR0005N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iIi)

(Page 25 of 30)

Figure 21 60 Degree Angle Beam limitations for Nozzle RCT0002PR0005N

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 26 of 30)

Figure 22 35 and 60 Degree Angle Beam limitation Due to Lifting Lug for Nozzle RCT0002PR0005N

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR SO.SSa(g)(S)(iii)

(Page 27 of 30)

Figure 23 3S and 60 Degree Angle Beam limitation (away from nozzle) for Nozzle RCT0002PROOOSN

Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 28 of 30)

Figure 24 o Degree Angle Beam Limitation for Nozzle RCT0002PR0005N "0

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds In Accordance with 10 CFR 50.55a(g)(5)(iii)

(Page 29 of 30)

Figure 25 45 Degree Angle Beam Limitation Due to Vent Nozzle for Nozzle RCT0002PR0005N I

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Relief Request RR-12-01 for Pressurizer Nozzle to Head Welds in Accordance with 10 CFR 50.55a(g)(5)(lii)

(Page 30 of 30)

Figure 26 35 and 60 Degree Angle Beam Limitation Due to Adjacent Obstructions for Nozzle RCT0002PR0005N I