RS-07-058, Amergen/Exelon Nuclear - Request for Relief - Use of the Boiling Water Reactor Vessel and Internals Project (BWRVIP) Guidelines in Lieu of Specific ASME Code Requirements

Amergen/Exelon Nuclear - Request for Relief - Use of the Boiling Water Reactor Vessel and Internals Project (BWRVIP) Guidelines in Lieu of Specific ASME Code Requirements

ML071140082
Person / Time
Site:	Dresden, Peach Bottom, Oyster Creek, Limerick, Clinton, Quad Cities, LaSalle
Issue date:	04/19/2007
From:	Cowan P AmerGen Energy Co, Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, NRC/NRR/ADRO
References
2130-07-20489, RS-07-058
Download: ML071140082 (15)

Text

AmerGen, Exelkn.

An Exelon Company www.exeloncorp.com Nuclear AmerGen Energy Company, LLC 4300 Winfield Road Exelon Generation Warrenville, IL 60555 4300 Winfield Road Warrenville, IL 60555 10 CFR 50.55a RS-07-058 2130-07-20489 April 19, 2007 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Clinton Power Station Facility Operating License No. NPF-62 NRC Docket No. 50-461 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 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-1 1 and NPF-1 8 NRC Docket Nos. 50-373 and 50-374 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353 Oyster Creek Generating Station Facility Operating License No. DPR-16 NRC Docket No. 50-219 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265

Subject:

Request for Relief - Use of the Boiling Water Reactor Vessel and Internals Project (BWRVIP) Guidelines in Lieu of Specific ASME Code Requirements Pursuant to 10 CFR 50.55a(a)(3)(i), Exelon Generation Company, LLC and AmerGen Energy Company, LLC are requesting relief from specific portions of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," on the basis that the proposed A -1w

Request for Relief - Use of the Boiling Water Reactor Vessel and Internals Project (BWRVIP)

Guidelines in Lieu of Specific ASME Code Requirements April 19, 2007 Page 2 alternative provides an acceptable level of quality and safety. Specifically, this proposed alternative concerns the use of the Boiling Water Reactor Vessel and Internals Project (BWRVIP) guidelines in lieu of specific ASME Code Requirements. Attachment A contains the relief request.

We request your review and approval of this relief request involving the Exelon/AmerGen BWRs by April 18, 2008.

If you have any questions, please contact Tom Loomis, 610-765-5510.

Very truly yours, Pamela B. Cowan Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC AmerGen Energy Company, LLC Attachments:

A)

Use of BWRVIP Guidelines in Lieu of Specific ASME.Code Requirements Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

B)

Comparison of Code Examination Requirements to BWRVIP Examination Requirements cc:

Regional Administrator - NRC Region I Regional Administrator - NRC Region III NRC Senior Resident Inspector - Clinton Power Station NRC Senior Resident Inspector - Dresden Nuclear Power Station NRC Senior Resident Inspector - LaSalle County Station NRC Senior Resident Inspector - Limerick Generating Station NRC Senior Resident Inspector - Oyster Creek Generating Station NRC Senior Resident Inspector - Peach Bottom Atomic Power Station NRC Senior Resident Inspector - Quad Cities Nuclear Power Station Illinois Emergency Management Agency - Division of Nuclear Safety Director, Bureau of Radiation Protection, Pennsylvania Department of Environmental Resources Director, Bureau of Nuclear Engineering, New Jersey Department of Environmental Protection Chairman, Board of County Commissioners of Dauphin County, PA Chairman, Board of Supervisors of Londonderry Township, PA Mayor of Lacey Township, Forked River, NJ R. I. McLean, State of Maryland

Attachment A Use of BWRVIP Guidelines in Lieu of Specific ASME Code Requirements Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

Clinton Power Station Dresden Nuclear Power Station, Units 2 and 3 LaSalle County Station, Units 1 and 2 Limerick Generating Station, Units 1 and 2 Oyster Creek Generating Station Peach Bottom Atomic Power Station, Units 2 and 3 Quad Cities Nuclear Power Station, Units 1 and 2

Attachment A Use of BWRVIP Guidelines in Lieu of Specific ASME Code Requirements Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)

1. ASME Code Component(s) Affected ASME Section XI, Class 1, Examination Categories B-N-1 (Interior of Reactor Vessel) and B-N-2 (Welded Core Support Structures and Interior Attachments to Reactor Vessels), Code Item Nos. B13.10 - Vessel Interior, B13.20 - Interior Attachments within Beltline Region, B13.30 - Interior Attachments beyond Beltline Region, and B13.40 - Core Support Structure.

2. Applicable Code Edition and Addenda

PLANT INTERVAL EDITION START END Clinton Power Station Second 1989 Edition, no addenda January 1,2000 December 31,2010 Dresden Nuclear Power 1995 Edition, through 1996 January 20, 2003 January 19,2013 Station, Units 2 and 3 Addenda LaSalle County Station, Third 2001 Edition, through 2003 October 1,2007 September 30, 2017 Units 1 and 2 Addenda Limerick Generating Third 2001 Edition, through 2003 February 1, 2007 January 31, 2017 Station, Units 1 and 2 Addenda Oyster Creek Generating Fourth 1995 Edition, through 1996 October 15, 2002 October 14, 2012 Station FAddenda 2001 Edition, through 2003 Peach Bottom Atomic Fourth Addenda November 5, 2008 November 4, 2018 Power Station, Unit 2 (Final edition to be determined) 2001 Edition, through 2003 Peach Bottom Atomic ForhAddenda PahBtoAtmc Fourth AdnaAugust 15, 2008 August 14, 2018 Power Station, Unit 3 (Final edition to be determined)

Quad Cities Nuclear 1995 Edition, through 1996 Power Station, Units 1 Fourth Addenda March 10, 2003 March 9, 2013 and 2 Addenda

3. Applicable Code Requirements

ASME Section Xl requires the examination of components within the Reactor Pressure Vessel. These examinations are included in Table IWB-2500-1 Categories B-N-1 and B-N-2 and identified with the following item numbers:

B 13.10 Examine accessible areas of the reactor vessel interior each period by the VT-3 method (B-N-i).

B 13.20 Examine interior attachment welds within the beltline region each interval by the VT-1 method (B-N-2).

B 13.30 Examine interior attachment welds beyond the beltline region each interval by the VT-3 method (B-N-2).

Use of BWRVIP Guidelines in Lieu of Specific Attachment A ASME Code Requirements Proposed Alternative Page 2 B 13.40 Examine surfaces of the welded core support structure each interval by the VT-3 method.

These examinations are performed to assess the structural integrity of components within the boiling water reactor pressure vessel.

4. Reason for Request

In accordance 10 CFR 50.55a(a)(3)(i), Exelon Generation Company, LLC (Exelon) and AmerGen Energy Company, LLC (AmerGen) are requesting a proposed alternative to the Code requirements provided above on the basis that the use of the BWRVIP guidelines discussed below will provide an acceptable level of quality and safety.

The BWRVIP Inspection and Evaluation (I&E) guidelines have recommended aggressive specific inspection by BWR operators to completely identify material condition issues with BWR components. A wealth of inspection data has been gathered during these inspections across the BWR industry. I&E guidelines focus on specific and susceptible components, specify appropriate inspection methods capable of identifying real anticipated degradation mechanisms, and require re-examination at conservative intervals. In contrast, the code inspection requirements were prepared before the BWRVIP initiative and have not evolved with BWR inspection experience.

Use of this proposed alternative will maintain an adequate level of quality and safety and avoid unnecessary inspections, while conserving radiological dose.

5. Proposed Alternative In lieu of the requirements of ASME Section Xl, the proposed alternative is detailed in attached Table 1 for Examination Category B-N-1 and B-N-2.

Exelon and AmerGen will satisfy the Examination Category B-N-1 and B-N-2 requirements as described in Table 1 in accordance with BWRVIP guideline requirements. This relief request proposes to utilize the identified BWRVIP guidelines in lieu of the associated Code requirements, including examination method, examination volume, frequency, training, successive and additional examinations, flaw evaluations, and reporting.

The particular guidelines that are applicable to those components are:

BWRVIP-18-A, "BWR Core Spray Internals Inspection and Flaw Evaluation Guidelines" BWRVIP-26-A, "BWR Top Guide Inspection and Flaw Evaluation Guidelines" BWRVIP-38, "BWR Shroud Support Inspection and Flaw Evaluation Guidelines" BWRVIP-41, Revision 1 "BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines" BWRVIP-42-A, "LPCI Coupling Inspection and Flaw Evaluation Guidelines" BWRVIP-47-A, "BWR Lower Plenum Inspection and Flaw Evaluation Guidelines" BWRVIP-48-A, "Vessel ID Attachment Weld Inspection and Flaw Evaluation Guidelines" BWRVIP-76, "BWR Core Shroud Inspection and Flaw Evaluation Guidelines" (replaced BWRVIP-01, -07, and -63)

Use of BWRVIP Guidelines in Lieu of Specific Attachment A ASME Code Requirements Proposed Alternative Page 3 The attached Table (Table 1) compares present ASME Examination Category B-N-1 and B-N-2 requirements with the above current BWRVIP guideline requirements, as applicable, to BWR/2 through BWR/6 units.

In addition, where guidance in existing BWRVIP documents has been supplemented or revised by subsequent correspondence approved by the BWRVIP executive committee, the most current BWRVIP approved guidance will be implemented. Therefore, the attached Table only represents a current comparison.

Any deviations from the referenced BWRVIP Guidelines for the duration of the proposed alternative will be appropriately documented and communicated to the NRC, per the BWRVIP Deviation Disposition Process. Current Exelon/AmerGen deviations from the subject guidelines above are summarized in Table 2.

Inspection services, by an Authorized Inspection Agency, will be applied to the proposed alternative actions of this relief request.

6. Basis for Use BWRs now examine reactor internals in accordance with BWRVIP guidelines. These guidelines have been written to address the safety significant vessel internal components and to examine and evaluate the examination results for these components using appropriate methods and reexamination frequencies. The BWRVIP has established a reporting protocol for examination results and deviations. The NRC has agreed with the BWRVIP approach in principal and has issued Safety Evaluations for these guidelines (see References 2 - 11 below). Therefore, use of these guidelines, as an alternative to the subject Code requirements, provides an acceptable level of quality and safety and will not adversely impact the health and safety of the public.

As additional justification, Attachment B ("Comparison of Code Examination Requirements to BWRVIP Examination Requirements") provides specific examples which compare the inspection requirements of ASME Code Item Numbers 813.10, B13.20, B13.30, and B13.40 in Table IWB-2500-1, to the inspection requirements in the BWRVIP documents. Specific BWRVIP documents are provided as examples. This comparison also includes a discussion of the inspection methods. These comparisons demonstrate that use of these guidelines, as an alternative to the subject Code requirements, provides an acceptable level of quality and safety and will not adversely impact the health and safety of the public.

7. Duration of Proposed Alternative

The duration of the alternative is for the remainder of the interval specified above for each affected unit.

8. Precedence A similar relief request was approved for Vermont Yankee Nuclear Power Station as discussed in Reference 1.

Use of BWRVIP Guidelines in Lieu of Specific Attachment A ASME Code Requirements Proposed Alternative Page 4

9. References

1.

Letter from U. S. Nuclear Regulatory Commission (USNRC) to Entergy Nuclear Operations, "Safety Evaluation of Relief Request RI-01, Vermont Yankee Nuclear Power Station (TAC NO. MC0690)", dated September 19, 2005

2.

Letter USNRC to BWRVIP, dated April 27, 1998, "Final Supplement to the Safety Evaluation of the Boiling Water Reactor Vessel Internals Project, BWRVIP-07 Report (TAC NO. M94959)"

3.

Letter USNRC to BWRVIP, dated October 6, 1999, "Staff Reevaluation of Table 1 in the BWRVIP-07 Report (TAC NO. M94959)"

4.

Letter USNRC to BWRVIP, dated September 6, 2005, "NRC Approval Letter of BWRVIP-1 8-A, "BWR Vessel and Internals Project Boiling Water Reactor Core Spray Internals Inspection and Flaw Evaluation Guideline" "

5.

Letter USNRC to BWRVIP, dated September 9, 2005, "NRC Approval Letter of BWRVIP-26-A, "BWR Vessel and Internals Project Boiling Water Reactor Top Guide Inspection and Flaw Evaluation Guidelines" "

6.

Letter USNRC to BWRVIP, dated July 24, 2000, "Final Safety Evaluation of the "BWR Vessel and Internals Project, BWR Shroud Support Inspection and Flaw Evaluation Guidelines (BWRVIP-38)," EPRI Report TR-108823 (TAC NO. M99638)"

7.

Letter USNRC to BWRVIP, dated February 4, 2001, "Final Safety Evaluation of the "BWR Vessel and Internals Project, BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines (BWRVIP-41)," (TAC NO. M99870)"

8.

Letter USNRC to BWRVIP, dated September 9, 2005, NRC approval letter of BWRVIP-42A, "BWR Vessel and Internals Project Boiling Water Reactor Low Pressure Coolant Injection and Flaw Evaluation Guidelines"

9.

Letter USNRC to BWRVIP, dated September 9, 2005, "NRC Approval Letter of BWRVIP-47-A, "BWR Vessel and Internals Project Boiling Water Reactor Lower Plenum Inspection and Flaw Evaluation Guidelines" "

10.

Letter USNRC to BWRVIP, dated July 25, 2005, "NRC Approval Letter of BWRVIP-48-A, "BWR Vessel and Internals Project Vessel ID Attachment Weld Inspection and Flaw Evaluation Guideline" "

11.

Letter USNRC to BWRVIP, dated August 20, 2001, "Final Safety Evaluation of the "BWR Vessel and Internals Project, Shroud Vertical Weld Inspection and Evaluation Guidelines (BWRVIP-63)," (TAC NO. MA6015)"

Use of BWRVIP Guidelines in Lieu of Specific ASME Code Requirements Proposed Alternative Attachment A Page 5 TABLE 1 Comparison of ASME Examination Category B-N-1 and B-N-2 Requirements With BWRVIP Guidance Requirements (1)

ASME.ItemApplicable 1t No. Table Component*

ASME Exam ASME Exam ASME BWRVIP BWRVIPBWRVIP WRVIP BWRVIP Frequency Scope Frequency.

Scope Exam IWB-2500-1

__Document_....

B13.10 Reactor Vessel Interior Accessible Areas VT-3 Each period BWRVIP-18, Overview examinations of components during BWRVIP (Non-specific) 26, 38, 41, 42, examinations are performed to satisfy Code VT-3 inspection 47, 48, 76 requirements.

B13.20 Interior Attachments Within Accessible Welds VT-1 Each 10-year BWRVIP-48 Riser Brace EVT-1 100% in first 12 Beltline - Riser Braces Interval Table 3-2 Attachment years, 25% during each subsequent 6 years Lower Surveillance Specimen BWRVIP-48, Bracket VT-3 Each 10-year Interval Holder Brackets Table 3-2 Attachment B13.30 Interior Attachments Beyond Accessible Welds VT-3 Each 10-year BWRVIP-48 Bracket VT-3 Each 10-year Interval Beltline - Steam Dryer Hold-Interval Table 3-2 Attachment down Brackets Guide Rod Brackets BWRVIP-48, Bracket VT-3 Each 10-year Interval Table 3-2 Attachment Steam Dryer Support BWRVIP-48, Bracket EVT-1 Each 10-year Interval Brackets Table 3-2 Attachment Feedwater Sparger Brackets BWRVIP-48, Bracket EVT-1 Each 10-year Interval Table 3-2 Attachment Core Spray Piping Brackets BWRVIP-48, Bracket EVT-1 Every 4 Refueling Table 3-2 Attachment Cycles Upper Surveillance Specimen BWRVIP-48, Bracket VT-3 Each 10-year Interval Holder Brackets Table 3-2 Attachment Shroud Support (Weld H9)

BWRVIP-38, Weld H912 1

EVT-1 or UT Maximum of 6 years 3.1.3.2, for EVT-1, Maximum Figure 3-5 of 10 years for UT Shroud Support Legs (H12)

(Rarely BWRVIP-38, Weld H12 Per BWRVIP-When accessible Welds Accessible) 3.2.3 38 NRC SER (7/24/00),

inspect with appropriate method

Use of BWRVIP Guidelines in Lieu of Specific ASME Code Requirements Proposed Alternative Attachment A Page 6 ASME Item Applicable ASME Exam ASME BWRVIP Exam BWRVIP No. Table Component ASME Exam BWRVIP BWRVIP Frequency IWB-2500-1 ScoumentFrequency Exam B13.40 Welded Core Support Accessible VT-3 Each 10-BWRVIP-38, Shroud Support EVT-1 or UT Based on as-found Bi

.4 Wede Coe upprtSurde Structure year Interval 3.1.3.2, and Leg Welds conditions, to a Figure 3-5 maximum 6 years for one side EVT-1, 10 years for UT or 2 side EVT-1 Shroud Horizontal welds BWRVIP-76, Welds H1-H7 EVT-1 or UT Maximum 10 years 2.2.1 Shroud Vertical welds BWRVIP-76, Vertical and EVT-1 or UT Maximum 6 years for Figure 3-3 Ring Segment one-sided EVT-1, 10 ShroudRepairs_(3)

_Welds years for UT Shroud Repairs (3)

BWRVIP-76, Tie-Rod Repair VT-3 Per repair designer Section 3.5 recommendations per BWRVIP-76.

NOTES:

1) This Table provides only an overview of the requirements. For more details, refer to ASME Section XI, Table IWB-2500-1, and the appropriate BWRVIP document.

2) In accordance with Appendix A of BWRVIP-38, a site specific evaluation will determine the minimum required weld length to be examined.

3) Shroud repairs are currently installed on both units at Dresden and Quad Cities, and on the single units at Oyster Creek and Clinton.

Use of BWRVIP Guidelines in Lieu of Specific ASME Code Requirements Proposed Alternative Attachment A Page 7 TABLE 2 BWRVIP Deviations PLANT BWRVIP DOCUMENT LETTER DATE TO USNRC DEVIATION APPLICABILITY LaSalle County BWRVIP-76 Letter from S. R. Landahl (Exelon 100% of the accessible areas of the This deviation does Station, Unit 1 Generation Company, LLC) toU. S.

LaSalle County Station Unit 1 core not impact the basis nuclear Regulatory Commission, dated shroud was not examined in the for use of this relief April 27, 2006 L1 R 11 outage in February 2006.

request.

However, sufficient coverage of the accessible areas were examined, an engineering evaluation was performed and the results indicate the Unit 1 shroud retained sufficient structural margin and should be re-examined in six years.

Oyster Creek BWRVIP-76 To be submitted at a later date Per BWRVIP-76 re-inspection This deviation does Generating Station guidelines, a one-sided visual not impact the basis examination technique requires for use of this relief reexamination in 6 years as compared request.

to a two-sided visual or volumetric technique, which can achieve a 10-year reexamination frequency.

Contrary to this requirement, the four vertical welds were not reexamined in 1 R21 (2006) as required by the BWRVIP-76 guidance for single-sided examination.

Attachment B Comparison of Code Examination Requirements to BWRVIP Examination Requirements Clinton Power Station Dresden Nuclear Power Station, Units 2 and 3 LaSalle County Station, Units 1 and 2 Limerick Generating Station, Units 1 and 2 Oyster Creek Generating Station Peach Bottom Atomic Power Station, Units 2 and 3 Quad Cities Nuclear Power Station, Units 1 and 2

ATTACHMENT B COMPARISON OF CODE EXAMINATION REQUIREMENTS TO BWRVIP EXAMINATION REQUIREMENTS The following discussion provides a comparison of the examination requirements provided in ASME Code Item Numbers B13.10, B13.20, B13.30, and B13.40 in Table IWB-2500-1, to the examination requirements in the BWRVIP guidelines. Specific BWRVIP guidelines are provided as examples for comparisons. This comparison also includes a discussion of the examination methods.

1. Code Requirement - B13.10 - Reactor Vessel Interior Accessible Areas (B-N-i)

The ASME Section Xl Code requires a VT-3 examination of reactor vessel accessible areas, which are defined as the spaces above and below the core made accessible during normal refueling outages. The frequency of these examinations is specified as the first refueling outage, and at intervals of approximately 3 years, during the first inspection interval, and each period during each successive 10-year Inspection Interval. Typically, these examinations are performed every other refueling outage of the Inspection Interval. This examination requirement is a non-specific requirement that is a departure from the traditional Section Xl examinations of welds and surfaces. As such, this requirement has been interpreted and satisfied differently across the domestic fleet. The purpose of the examination is to identify relevant conditions such as distortion or displacement of parts; loose, missing, or fractured fasteners; foreign material, corrosion, erosion, or accumulation of corrosion products; wear; and structural degradation.

Portions of the various examinations required by the applicable BWRVIP Guidelines require access to accessible areas of the reactor vessel during each refueling outage. Examination of core spray piping and spargers (BWRVIP-18-A), top guide (BWRVIP-26-A), jet pump welds and components (BWRVIP-41, Rev. 1), interior attachments (BWRVIP-48-A), core shroud welds (BWRVIP-76), shroud support (BWRVIP-38), LPCI couplings (BWRVIP-42-A),

and lower plenum components (BWRVIP-47-A) provides such access. Locating and examining specific welds and components within the reactor vessel areas above, below (if accessible), and surrounding the core (annulus area) entails access by remote camera systems that essentially perform equivalent VT-3 examination of these areas or spaces as the specific weld or component examinations are performed. This provides an equivalent method of visual examination on a more frequent basis than that required by the ASME Section XI Code. Evidence of wear, structural degradation, loose, missing, or displaced parts, foreign materials, and corrosion product buildup can be, and has been observed during the course of implementing these BWRVIP examination requirements. Therefore, the specified BWRVIP Guideline requirements meet or exceed the subject Code requirements for examination method and frequency of the interior of the reactor vessel. Accordingly, these BWRVIP examination requirements provide an acceptable level of quality and safety as compared to the subject Code requirements.

2. Code Requirement - B13.20 - Interior Attachments Within the Beltline (B-N-2)

The ASME Section XI Code requires a VT-1 examination of accessible reactor interior surface attachment welds within the beltline each 10-year interval. In the boiling water reactor, this includes the jet pump riser brace welds-to-vessel wall and the lower surveillance specimen support bracket welds-to-vessel wall. In comparison, the BWRVIP

Comparison of Code to BWRVIP Requirements Attachment B Page 2 requires the same examination method and frequency for the lower surveillance specimen support bracket welds, and requires an EVT-1 examination on the remaining attachment welds in the beltline region in the first 12 years, and then 25% during each subsequent 6 years.

The jet pump riser brace examination requirements are provided below to show a comparison between the Code and the BWRVIP examination requirements.

Comparison to BWRVIP Requirements - Jet Pump Riser Braces (BWRVIP-41, Rev. 1 and BWRVIP-48-A)

The ASME Code requires a 100% VT-1 examination of the jet pump riser brace-to-reactor vessel wall pad welds each 10-year interval.

The BWRVIP requires an EVT-1 examination of the jet pump riser brace-to-reactor vessel wall pad welds the first 12 years and then 25% during each subsequent 6 years.

BWRVIP-48-A specifically defines the susceptible regions of the attachment that are to be examined.

The Code VT-1 examination is conducted to detect discontinuities and imperfections on the surfaces of components, including such conditions as cracks, wear, corrosion, or erosion.

The BWRVIP enhanced VT-1 (EVT-1) is conducted to detect discontinuities and imperfections on the surface of components and is additionally specified to detect potentially very tight cracks characteristic of fatigue and inter-granular stress corrosion cracking (IGSCC), the relevant degradation mechanisms for these components. General wear, corrosion, or erosion although generally not a concern for inherently tough, corrosion resistant stainless steel material, would also be detected during the process of performing a BWRVIP EVT-1 examination.

The Code VT-1 visual examination method requires (depending on applicable Edition) that at a maximum distance of 2 feet, a 1/32" black line can be resolved or a letter character with a height of 0.044 inches can be read. The BWRVIP EVT-1 visual examination method requires resolution of a 1/2 mil (0.0005 inch) wire on the examination surface. The jet pump riser brace configuration for each plant varies with vessel manufacturer (B&W, CB&I, etc.)

and generation (BWR/3-BWR/6). BWRVIP-48-A includes diagrams for each configuration and prescribes examination for each configuration.

The calibration standards used for BWRVIP EVT-1 exams utilize the Code characters and the 0.0005" wire, thus assuring at least equivalent resolution compared to the Code.

Although the BWRVIP examination may be less frequent, it is a more comprehensive method. Therefore, the enhanced flaw detection capability of an EVT-1, with a less frequent examination schedule provides an acceptable level of quality and safety to that provided by the ASME Code.

3. Code Requirement - B13.30 - Interior Attachment Beyond the Beltline Reqion (B-N-2)

The ASME Section Xl Code requires a VT-3 examination of accessible reactor interior surface attachment welds beyond the beltline each 10-year interval. In the boiling water reactor, this includes the core spray piping primary and supplemental support bracket welds-

Comparison of Code to BWRVIP Requirements Attachment B Page 3 to-vessel wall, the upper surveillance specimen support bracket welds-to-vessel wall, the feedwater sparger support bracket welds-to-reactor vessel wall, the steam dryer support and hold down bracket welds-to-reactor vessel wall, the guide rod support bracket weld-to-reactor vessel wall, and the shroud support plate-to-vessel wall. BWRVIP-48-A requires as a minimum the same VT-3 examination method as the Code for some of the interior attachment welds beyond the beltline region, and in some cases specifies an enhanced visual examination technique EVT-1 for these welds. For those interior attachment welds that have the same VT-3 method of examination, the same scope of examination (accessible welds), the same examination frequency (each 10 year interval) and ASME Section Xl flaw evaluation criteria, the level of quality and safety provided by the BWRVIP requirements are equivalent to that provide by the ASME Code.

For the core spray primary and secondary support bracket attachment welds, the steam dryer support bracket attachment welds, the feedwater sparger support bracket attachment welds, and the shroud support plate-to-vessel welds, as applicable, the BWRVIP Guidelines require an EVT-1 examination at the same frequency as the Code, or at a more frequent rate. Therefore, the BWRVIP requirements provide the same level of quality and safety to that provided by the ASME Code.

The core spray piping bracket-to-vessel attachment weld is used as an example for comparison between the Code and BWRVIP examination requirements as discussed below.

Comparison to BWRVIP Requirements - Core Spray piping Bracket Welds (BWRVIP-48-A)

The Code examination requirement is a VT-3 examination of each weld every 10 years.

The BWRVIP examination requirement is an EVT-1 for the core spray piping bracket attachment welds with each weld examined every four cycles (8 years for units with a two year fuel cycle).

The BWRVIP examination method EVT-1 has superior flaw detection and sizing capability, the examination frequency is greater than the Code requirements, and the same flaw evaluation criteria are used.

The Code VT-3 examination is conducted to detect component structural integrity by ensuring the components general condition is acceptable. An enhanced EVT-1 is conducted to detect discontinuities and imperfections on the examination surfaces, including such conditions as tight cracks caused by IGSCC or fatigue, the relevant degradation mechanisms for BWR internal attachments.

Therefore, with the EVT-1 examination method, the same examination scope (accessible welds), an increased examination frequency (8 years instead of 10 years) in some cases, the same flaw evaluation criteria (Section Xl), the level of quality and safety provided by the BWRVIP criteria is superior than that provided by the Code.

4. Code Requirement - B13.40 - Inteqrally Welded Core Support Structures (B-N-2)

The ASME Code requires a VT-3 examination of accessible surfaces of the welded core support structure each 10-year interval. In the boiling water reactor, the welded core support structure has primarily been considered the shroud support structure, including the shroud support plate (annulus floor) the shroud support ring, the shroud support welds, and

Comparison of Code to BWRVIP Requirements Attachment B Page 4 the shroud support legs (if accessible). In later designs, the shroud itself is considered part of the welded core support structure. Historically, this requirement has been interpreted and satisfied differently across the industry. The proposed alternate examination replaces this ASME requirement with specific BWRVIP guidelines that examine susceptible locations for known relevant degradation mechanisms.

The Code requires a VT-3 of accessible surfaces each 10-year interval.

The BWRVIP requires as a minimum the same examination method (VT-3) as the Code for integrally welded Core Support Structures, and for specific areas, requires either an enhanced visual examination technique (EVT-1) or volumetric examination (UT).

BWRVIP recommended examinations of integrally welded core support structures are focused on the known susceptible areas of this structure, including the welds and associated weld heat affected zones. As a minimum, the same or superior visual examination technique is required for examination at the same frequency as the code examination requirements. In many locations, the BWRVIP guidelines require a volumetric examination of the susceptible welds at a frequency identical to the Code requirement.

Where shroud repair tie-rods have been installed (Dresden, Quad Cities, Oyster Creek and Clinton), the BWRVIP referenced examinations are the same as the Code requirements.

Shroud repair tie-rod examinations are recommended in BWRVIP-76 and have the same basic VT-3 method of examination, the same scope of examination (accessible surfaces),

the same examination frequency (each 10 year interval) and the same flaw evaluation criteria. Therefore, the BWRVIP requirements provide a level of quality and safety equivalent to that provided by the ASME Code. Additionally, the repair vendor has provided site-specific examination recommendations to address the unique features of each repair.

For other integrally welded core support structure components, the BWRVIP requires an EVT-1 or UT of core support structures. The core shroud is used as an example for comparison between the Code and BWRVIP examination requirements as shown below.

Comparison to BWRVIP Requirements - BWR Core Shroud Examination and Flaw Evaluation Guideline (BWRVIP-76)

The Code requires a VT-3 examination of accessible surfaces every 10 years.

The BWRVIP requires an EVT-1 examination from the inside and outside surface where accessible or ultrasonic examination of each core shroud circumferential weld that has not been structurally replaced with a shroud repair at a calculated "end of interval" (EOI) that will vary depending upon the amount of flaws present, but not to exceed ten years.

The BWRVIP recommended examinations specify locations that are known to be vulnerable to BWR relevant degradation mechanisms rather than "all surfaces". The BWRVIP examination methods (EVT-1 or UT) are superior to the Code required VT-3 for flaw detection and characterization. The BWRVIP examination frequency is equivalent to or more frequent than the examination frequency required by the Code. The superior flaw detection and characterization capability, with an equivalent or more frequent examination frequency and the same flaw evaluation criteria, results in the BWRVIP criteria providing a level of quality and safety equivalent to or superior to that provided by the Code requirements.