ML123250319

Supplement to the Dresden Nuclear Power Station Fifth Inservice Inspection Interval Relief Request I5R-01

ML123250319
Person / Time
Site:	Dresden
Issue date:	11/19/2012
From:	Simpson P R Exelon Generation Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RS-12-202
Download: ML123250319 (4)

Text

RS-12-202 November 19, 2012 10 CFR 50.55a U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR

-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249

Subject:

Supplement to the Dresden Nuclear Power Station Fifth Inservice Inspection Interval Relief Request 15R-01

Reference:

Letter from D. M. Gullott (Exelon Generation Company, LLC (EGC)) to U. S.

NRC, "Dresden Nuclear Power Station, Units 2 and 3, Fifth Interval Inservice Inspection Program Plan and Relief Requests," dated September 28, 2012 In the referenced letter, EGC submitted relief requests associated with the fifth inservice inspection (ISI) interval for Dresden Nuclear Power Station (DNPS), Units 2 and 3. Upon further review of Relief Request 15R-01, it became apparent that 10 CFR 50.55a (a)(3)(ii) is the appropriate relief criterion for this request. Therefore, EGC requests to supersede the version of 15R-01 in the referenced letter with the version in the attachment to this letter in its entirety.

EGC continues to request approval of this relief request by September 28, 2013, to support examination of components during the DNPS, Unit 2 Fall 2013 refueling outage which falls within the fifth 10-year ISI interval.

There are no regulatory commitments contained within this letter.

Should you have any questions concerning this letter, please contact Mr. Mitchel A. Mathews at (630) 657-2819.

Patrick R. Simpson Manager - Licensing Exelon Generation Company, LLC

Attachment:

10 CFR 50.55a Request Number 15R-01, Revision 1 1 RS-12-202 November 19, 2012 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed FacilityOperating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249 10 CFR 50.55a

Subject:

Supplement to the Dresden Nuclear Power Station Fifth Inservice Inspection Interval Relief Request 15R-01

Reference:

Letter from D. M. Gullott (Exelon Generation Company, LLC (EGC>> to U. S. NRC, "Dresden Nuclear Power Station, Units 2 and 3, Fifth Intervallnservice Inspection Program Plan and Relief Requests," dated September 28,2012 In the referenced letter, EGC submitted relief requests associated with the fifth inservice inspection (lSI) interval for Dresden Nuclear Power Station (DNPS), Units 2 and 3. Upon further review of Relief Request 15R-01, it became apparent that 10 CFR 50.55a (a)(3)(ii) is the appropriate relief criterion for this request. Therefore, EGC requests to supersede the version of 15R-01 in the referenced letter with the version in the attachment to this letter in its entirety.

EGC continues to request approval of this relief request by September 28, 2013, to support examination of components during the DNPS, Unit 2 Fall 2013 refueling outage which falls within the fifth 10-year lSI interval.

There are no regulatory commitments contained within this letter. Should you have any questions concerning this letter, please contact Mr. Mitchel A. Mathews at (630) 657-2819.

Patrick R. Simpson Manager -Licensing Exelon Generation Company, LLC

Attachment:

10 CFR 50.55a Request Number 15R-01, Revision 1 ATTACHMENT 10 CFR 50.55a Request Number 15R

-01, Revision 1 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(ii)

--Hardship or Unusual Difficulty without Compensating Increase in Level of Quality and Safety--

1.ASME Code Component(s) Affected:

1 IWB-2500, Table IWB-2500-1 B-D83.100 Inspection of Standby Liquid Control Nozzle Inner Radius Unit 2: N12-1 Unit 3: N12-1 Unit 2: ISI-128, Sheet 3 Unit 3: ISI-125, Sheet 3 2.

The Dresden Nuclear Power Station (DNPS), Units 2 and 3 Inservice Inspection Program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2007 Edition through the 2008 Addenda.

3.Applicable Code Requirement:

IWB-2500 states that components shall be examined and tested as specified in Table IWB-2500-1.

Table IWB-2500-1 requires a volumetric examination to be performed on the inner radius section of all reactor pressure vessel nozzles each inspection interval.

4.

Pursuant to 10 CFR 50.55a(a)(3)(ii), relief is requested on the basis that conformance with the Code requirements impose hardship without a compensating increase in the level of quality and safety.

The Standby Liquid Control (SBLC) nozzle, as shown in Figure 15R-01.1, is designed with an integral socket to which the boron injection piping is fillet welded. The SBLC nozzle is located near the bottom of the vessel in an area which is inaccessible for ultrasonic examinations from the inside of the vessel. Therefore, ultrasonic examinations would need to be performed from the outside diameter of the vessel. As shown in Figure 15R-01.1, the ultrasonic scan would need to travel through the full thickness of the vessel into a complex cladding/socket configuration. These geometric and material reflectors inherent in the design prevent a meaningful examination from being performed on the inner radius of the SBLC nozzle.

In addition, the inner radius socket attaches to piping which injects boron at locations far removed from the nozzle. Therefore, the SBLC nozzle inner radius is not subjected to turbulent mixing conditions that are a concern at other nozzles.

Page 1 of 3 Code Class:

Reference:

Examination Category:

Item Number:

==

Description:==

Component Number:

Drawing Number:

ATTACHMENT 10 CFR SO.SSa Request Number ISR-01, Revision 1 Proposed Alternative In Accordance with 10 CFR SO.SSa(a)(3}(ii}

--Hardship or Unusual Difficulty without Compensating Increase in Level of Quality and Safety--1. ASME Code Component(s)

Affected:

Code Class:

Reference:

Examination Category:

Item Number:

Description:

Component Number: Drawing Number: 1 IWB-2500, Table IWB-2500-1 B-D B3.100 Inspection of Standby Liquid Control Nozzle Inner Radius Unit 2: N12-1 Unit 3: N12-1 Unit 2: ISI-128, Sheet 3 Unit 3: ISI-125, Sheet 3 2. Applicable Code Edition and Addenda: The Dresden Nuclear Power Station (DNPS), Units 2 and 3 Inservice Inspection Program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2007 Edition through the 2008 Addenda. 3. Applicable Code Requirement:

IWB-2500 states that components shall be examined and tested as specified in Table IWB-2500-1.

Table IWB-2500-1 requires a volumetric examination to be performed on the inner radius section of all reactor pressure vessel nozzles each inspection interval.

4. Reason for Request: Pursuant to 10 CFR 50.55a(a)(3)(ii), relief is requested on the basis that conformance with the Code requirements impose hardship without a compensating increase in the level of quality and safety. The Standby Liquid Control (SBLC) nozzle, as shown in Figure 15R-01.1, is designed with an integral socket to which the boron injection piping is fillet welded. The SBLC nozzle is located near the bottom of the vessel in an area which is inaccessible for ultrasonic examinations from the inside of the vessel. Therefore, ultrasonic examinations would need to be performed from the outside diameter of the vessel. As shown in Figure 15R-01.1, the ultrasonic scan would need to travel through the full thickness of the vessel into a complex cladding/socket configuration.

These geometric and material reflectors inherent in the design prevent a meaningful examination from being performed on the inner radius of the SBLC nozzle. In addition, the inner radius socket attaches to piping which injects boron at locations far removed from the nozzle. Therefore, the SBLC nozzle inner radius is not subjected to turbulent mixing conditions that are a concern at other nozzles. Page 1 of 3 ATTACHMENT 10 CFR 50.55a Request Number 15R-01, Revision 1 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(ii)

--Hardship or Unusual Difficulty without Compensating Increase in Level of Quality and Safety--

Compliance with the applicable Code requirements would require an ultrasonic examination to be performed on the outside diameter of the reactor pressure vessel. Geometric and material reflectors would prevent a meaningful examination, resulting in inaccurate data.

Based on this, the Code requirements impose hardship without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(a)(3)(ii).

5.

As an alternate examination, Exelon Generation Company, LLC will perform a VT-2 visual examination of the subject nozzles at DNPS, Units 2 and 3 each refueling outage in conjunction with the Class 1 System Leakage Test.

6.Duration of Proposed Alternative:

Relief is requested for the Fifth Ten-Year Inspection Interval for Dresden Nuclear Power Station Units 2 and 3.

7.

DNPS, Units 2 and 3 fourth inspection interval Relief Request 14R

-01 was authorized in an NRC safety evaluation (SE) dated September 4, 2003. The fifth inspection interval relief request (i.e., 15R-01, Revision 1) utilizes a similar approach that was previously approved.Quad Cities Nuclear Power Station, Units 1 and 2 fourth inspection interval Relief Request 14R-01 was authorized in an NRC SE dated January 28, 2004.

Page 2 of 3 ATTACHMENT 10 CFR SO.SSa Request Number ISR-01, Revision 1 Proposed Alternative In Accordance with 10 CFR SO.SSa(a}(3}(ii}

--Hardship or Unusual Difficulty without Compensating Increase in Level of Quality and Safety--Compliance with the applicable Code requirements would require an ultrasonic examination to be performed on the outside diameter of the reactor pressure vessel. Geometric and material reflectors would prevent a meaningful examination, resulting in inaccurate data. Based on this, the Code requirements impose hardship without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(a)(3)(ii).

S. Proposed Alternate and Basis for Use: As an alternate examination, Exelon Generation Company, LLC will perform a VT-2 visual examination of the subject nozzles at DNPS, Units 2 and 3 each refueling outage in conjunction with the Class 1 System Leakage Test. 6. Duration of Proposed Alternative:

Relief is requested for the Fifth Ten-Year Inspection Interval for Dresden Nuclear Power Station Units 2 and 3. 7. Precedents:

DNPS, Units 2 and 3 fourth inspection interval Relief Request 14R-01 was authorized in an NRC safety evaluation (SE) dated September 4, 2003. The fifth inspection interval relief request (Le., 15R-01, Revision 1) utilizes a similar approach that was previously approved.

Quad Cities Nuclear Power Station, Units 1 and 2 fourth inspection interval Relief Request 14R-01 was authorized in an NRC SE dated January 28, 2004. Page 2 of3 ATTACHMENT 10 CFR 50.55a Request Number 15R-01, Revision 1 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(ii)

--Hardship or Unusual Difficulty without Compensating Increase in Level of Quality and Safety--Vessel (Mn-Mo)I.D.Cladding Safe-End (Stainless Steel)

Pipe(Mn-Mo)(Stainless Steel)

Nozzle 1 15/16" 1/8" Min 6 3/8" FIGURE 15R

-01.1: Two (2) Inch Standby Liquid Control Nozzle Page 3 of 3 ATTACHMENT 10 CFR 50.55a Request Number 15R-01, Revision 1 Proposed Alternative In Accordance with 10 CFR 50.55a(a}(3}(ii}

--Hardship or Unusual Difficulty without Compensating Increase in Level of Quality and Safety--Safe-End (Stainless Steel) Vessel (Mn-MO)\ Nozzle (Mn-Mo) 3/4" R Min FIGURE 15R-01.1:

Two (2) Inch Standby Liquid Control Nozzle Page 3 of3 1. D. Cladding