ML18153A413
| ML18153A413 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 06/02/1997 |
| From: | Saunders R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 97-216, NUDOCS 9706060330 | |
| Download: ML18153A413 (14) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 A
June 2, 1997 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY Serial No.97-216 NL&OS/GDM R1 Docket Nos. 50-280, 281 50-338, 339 License Nos. DPR-32, *37 NPF-4, 7 NORTH ANNA AND SURRY POWER STATIONS UNITS 1 AND 2 ASME SECTION XI RELIEF REQUESTS REACTOR VESSEL CLOSURE HEAD NUTS North Anna Power Station Units 1 and 2 are presently in the second ten year inservice inspection interval, and examinations are conducted to the requirements of the 1983 and 1986 Editions of ASME Section XI, respectively. Surry Power Station Units 1 and 2 are presently in the third ten year inservice inspection interval, and examinations are conducted to the requirements of the 1989 Edition of ASME Section XI. Pursuant to 1 O CFR 50.55a(g)(5), relief is requested from certain requirements of the ASME Section XI Code associated with Code required examinations.
The Code requirements for the Code Editions referenced above require a surface examination of the reactor vessel closure head nuts. However, the 1989 Addenda of ASME Section XI has changed the requirement from a surface examination to a visual (VT-1) examination.
Relief is requested from performing the Code:..required surface examinations of the reactor vessel closure head nuts.
The basis for the relief is provided in the attached relief requests.
Relief requests NDE-35 and NDE-37 for North Anna Units 1 and 2 are provided in Attachments 1 and 2, respectively. Relief requests SR-018 and SR-025 for Surry Units 1 and 2 are provided in Attachments 3 and 4, respectively.
I 111111111111111111111111111111111111111
- &&3158*
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, The relief requests have been approved by the applicable Station Nuclear Safety and Operating Committee.
If you have any questions concerning this request, please contact us.
Very truly yours, R. F. Saunders Vice President - Nuclear Engineering and Services Commitments contained in this letter:
- 1.
None.
Attachments cc:
U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303 Mr. R. A. Musser.
NRC Senior Resident Inspector Surry Power Station NRC Senior Resident Inspector North Anna Power Station
ATTACHMENT 1 ASME SECTION XI RELIEF REQUEST NO. NDE~35 NORTH ANNA POWER STATION UNIT 1
Virginia Electric & Power Company North Anna Power Station Unit 1 Second Ten Vear Interval Relief Request NDE-35 I.
Identification of Component:
Mark No.
N-01 through N-58 Component No.
1-RC-R-1 Drawing No.
Class 11715-WMKS-RC-R-1.4 1
The above are reactor vessel closure head nuts.
II.
Code Requirements:
The 1983 Edition, Summer 1983 Addenda of ASME Section XI Table IW8-2500-1, examination category 8-G-1, item number 86.10 requires a surface examination of the reactor vessel closure head nuts.
Ill.
Code Requirement From Which Relief Is Requested:
Relief is requested from performing the Code-required surface examination on the above identified reactor vessel closure head nuts.
IV.
Basis for Relief:
The 1989 Addenda of ASME Section XI Table IW8-2500-1, examination category 8-G-1, item number 86.10 has changed the requirement from a surface examination to a visual (VT-1) examination.
Extensive cleaning of these nuts is required for a surface examination to be performed. This extensive cleaning results in additional costs and the inefficient use of available manpower resources.
Due to design factors, the stripping areas of the female threads in a nut are approximately 1.3 times the areas of the mating male threads (see ASME 81.1, Unified Inch Screw Threads). Accordingly, if a defect were to be developed during service, they would occur in the threads of the bolt or stud before developing in the nut's threads because of higher stresses in the male threads.
When reactor vessel head fasteners are tightened for closure or loosened for opening, the studs are tensioned and the nuts are run on the threads with no load as the load is taken by the stud or bolt through the tensioning device.
I
, V.
Proposed Alternate Requirement:
It is proposed that the requirements of the 1989 Addenda of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number B6.10 (visual, VT-
- 1) be substituted for the Code surface examination. In addition:
- 1.
A visual (VT-2) examination will be performed during the normally scheduled system leakage test each refueling outage;
- 2.
Technical Specifications require that the reactor coolant system leak rate be limited to one gallon per minute unidentified leakage. This value is calculated at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; and
- 3.
The containment atmosphere particulate radioactivity is checked every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The proposed alternative examinations stated above will ensure that the overall level of plant quality and safety will not be compromised.
ATTACHMENT 2 ASME SECTION XI RELIEF REQUEST NO. NDE-37 NORTH ANNA POWER STATION UNIT 2
Virginia Electric & Power Company North Anna Power Station Unit 2 Second Ten Vear Interval Relief Request NDE-37 I.
Identification of Component:
Mark No.
N-01 through N-58 Component No.
2-RC-R-1 Drawing No.
Class 12050-WMKS-RC-R-1.4 1
The above are reactor vessel closure head nuts.
II.
Code Requirements:
The 1986 Edition of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number B6.10 requires a surface examination of the reactor vessel closure head nuts.
Ill.
Code Requirement From Which Relief Is Requested:
Relief is requested from performing the Code-required surface examination on.
the above identified reactor vessel closure head nuts.
IV.
Basis for Relief:
The 1989 Addenda of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number B6.10 has changed the requirement from a surface examination to a visual (VT-1) examination.
Extensive cleaning of these nuts is required for a surface examination to be performed. This extensive cleaning results in additional costs and the inefficient use of available manpower resources.
Due to design factors, the stripping areas of the female threads in a nut are approximately 1.3 times the areas of the mating male threads (see ASME B1.1, Unified Inch Screw Threads). Accordingly, if a defect were to be developed during service, they would occur in the threads of the bolt or stud before developing in the nut's threads because of higher stresses in the male threads.
When reactor vessel head fasteners are tightened for closure or loosened for opening, the studs are tensioned and the nuts are run on the threads with no load as the load is taken by the stud or bolt through the tensioning device.
. V.
Proposed Alternate Requirement:
It is proposed that the requirements of the 1989 Addenda of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number 86.10 (visual, VT-
- 1) be substituted for the Code surface examination. In addition:
- 1.
A visual (VT-2) examination will be performed during the normally scheduled system leakage test each refueling outage;
- 2.
Technical Specifications require that the reactor coolant system leak rate be limited to one gallon per minute unidentified leakage. This value is calculated at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; and
- 3.
The containment atmosphere particulate radioactivity is checked every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The proposed alternative examinations stated above will ensure that the overall level of plant quality and safety will not be compromised.
ATTACHMENT 3 ASME SECTION XI RELIEF REQUEST NO. SR-018 SURRY POWER STATION UNIT 1
Virginia Electric & Power Company Surry Power Station Unit 1 Third Ten Year Interval Request for Relief No. SR-018 I.
- Identification of Component:
Mark No.
N-01 through N-58 Component No.
1-RC-R-1 Drawing No.
Class 11448-WMKS-RC-R-1.4 1
The above are reactor vessel closure head nuts.
II.
Code Requirements:
The 1989 Edition of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number B6.10 requires a surface examination of the reactor vessel closure head nuts.
Ill.
Code Requirement From Which Relief Is Requested:
Relief is requested from performing the Code-required surface examination on the above identified reactor vessel closure head nuts.
IV.
Basis for Relief:
The 1989 Addenda of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number B6.10 has changed the requirement from a surface examination to a visual (VT-1) examination.
Extensive cleaning of these nuts is required for a surface examination to be performed. This extensive cleaning results in additional costs and the inefficient use of available manpower resources.
Due to design factors, the stripping areas of the female threads in a nut are approximately 1.3 times the areas of the mating male threads (see ASME B 1.1, Unified Inch Screw Threads).
Accordingly, if a defect were to be developed during service, they would occur in the threads of the bolt or stud before developing in the nut's threads because of higher stresses in the male threads.
When reactor vessel head fasteners are tightened for closure or loosened for opening, the studs are tensioned and the nuts are run on the threads with no load as the load is taken by the stud or bolt through the tensioning device.
. V.
Proposed Alternate Requirement:
It is proposed that the requirements of the 1989 Addenda of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number B6.10 (visual, VT-
- 1) be substituted for the Code surface examination. In addition:
- 1.
A visual (VT-2) examination will be performed during the normally scheduled system leakage test each refueling outage;
- 2.
Technical Specifications require that the reactor coolant system leak rate be limited to one gallon per minute unidentified leakage. This value is calculated at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; and
- 3.
The containment atmosphere particulate radioactivity is.checked every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The proposed alternative examinations stated above will ensure that the overall level of plant quality and safety will not be compromised.
ATTACHMENT 4 ASME SECTION XI RELIEF REQUEST NO. SR-025 SURRY POWER STATION UNIT 2
Virginia Electric & Power Company Surry Power Station Unit 2 Third Ten Year Interval Request for Relief No. SR-025 I.
Identification of Component:
Mark No.
N-01 through N-58 Component No.
2-RC-R-1 Drawing No.
Class 11548-WMKS-RC-R-1.4 1
The above are reactor vessel closure head nuts.
II.
Code Requirements:
The 1989 Edition of ASME Section XI Table IW8-2500-1, examination category 8-G-1, item number 86.10 requires a surface examination of the reactor vessel closure head nuts.
Ill.
Code Requirement From Which Relief Is Requested:
Relief is requested from performing the Code-required surface examination on the above identified reactor vessel closure head nuts.
IV.
Basis for Relief:
The 1989 Addenda of ASME Section XI Table IW8-2500-1, examination category 8-G-1, item number 86.10 has changed the requirement from a surface examination to a visual (VT-1) examination.
Extensive cleaning of these nuts is required for a surface examination to be performed. This extensive cleaning results in additional costs and the inefficient use of available manpower resources.
Due to design factors, the stripping areas of the female threads in a nut are approximately 1.3 times the areas of the mating male threads (see ASME 81.1, Unified Inch Screw Threads). Accordingly, if a defect were to be developed during service, they would occur in the threads of the bolt or stud before developing in the nut's threads because of higher stresses in the male threads.
When reactor vessel head fasteners are tightened for closure or loosened for opening, the studs are tensioned and the nuts are run on the threads with no load as the load is taken by the stud or bolt through the tensioning device.
. V.
Proposed Alternate Requirement:
It is proposed that the requirements of the 1989 Addenda of ASME Section XI Table IWB-2500-1, examination category B-G-1, item number 86.1 O (visual, VT-
- 1) be substituted for the Code surface examination. In addition:
- 1.
A visual (VT-2) examination will be performed during the normally scheduled system leakage test each refueling outage;
- 2.
Technical Specifications require that the reactor coolant system leak rate be limited to one gallon per minute unidentified leakage. This value is calculated at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; and
- 3.
The containment atmosphere particulate radioactivity is checked every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The proposed alternative examinations stated above will ensure that the overall level of plant quality and safety will not be compromised.