ML050770041
| ML050770041 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/16/2005 |
| From: | Abney T Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC MC1704, TAC MC1705, TAC MC1706 | |
| Download: ML050770041 (20) | |
Text
March 16, 2005 10 CFR 54 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop: OWFN P1-35 Washington, D.C. 20555-0001 Gentlemen:
In the Matter of
) Docket Nos. 50-259 Tennessee Valley Authority
) 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) - UNITS 1, 2, AND 3 -
LICENSE RENEWAL APPLICATION (LRA) - RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION ON REACTOR COOLANT PRESSURE BOUNDARY (RCPB) BOLTING CLARIFICATIONS (TAC NOS. MC1704, MC1705, AND MC1706)
By letter dated December 31, 2003, TVA submitted, for NRC review, an application pursuant to 10 CFR 54, to renew the operating licenses for the Browns Ferry Nuclear Plant, Units 1, 2, and 3. As part of its review of TVAs LRA, the NRC staff, through an informal request on February 25, 2005, identified additional clarification information for RCPB bolting.
U.S. Nuclear Regulatory Commission Page 2 March 16, 2005 If you have any questions regarding this information, please contact Ken Brune, Browns Ferry License Renewal Project Manager, at (423) 751-8421.
I declare under penalty of perjury that the foregoing is true and correct. Executed on this 16th day of March, 2005.
Sincerely, Original signed by:
T. E. Abney Manager of Licensing and Industry Affairs
Enclosure:
cc: See page 3
U.S. Nuclear Regulatory Commission Page 3 March 16, 2005 Enclosure cc (Enclosure):
State Health Officer Alabama Department of Public Health RSA Tower - Administration Suite 1552 P.O. Box 303017 Montgomery, Alabama 36130-3017 Chairman Limestone County Commission 310 West Washington Street Athens, Alabama 35611 (Via NRC Electronic Distribution)
Enclosure cc (Enclosure):
U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 Mr. Stephen J. Cahill, Branch Chief U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 NRC Senior Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611-6970 NRC Unit 1 Restart Senior Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611-6970 cc: continued page 4
U.S. Nuclear Regulatory Commission Page 4 cc: (Enclosure)
Margaret Chernoff, Project Manager U.S. Nuclear Regulatory Commission (MS 08G9)
One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Eva A. Brown, Project Manager U.S. Nuclear Regulatory Commission (MS 08G9)
One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Yoira K. Diaz-Sanabria, Project Manager U.S. Nuclear Regulatory Commission (MS 011F1)
One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Ramachandran Subbaratnam, Project Manager U.S. Nuclear Regulatory Commission (MS 011F1)
One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739
U.S. Nuclear Regulatory Commission Page 5 March 16, 2004 DTL:GLS:BAB Enclosure cc (Enclosure):
A. S. Bhatnagar, LP 6-C K. A. Brune, LP 4F-C J. C. Fornicola, LP 6A-C R. G. Jones, NAB 1A-BFN K. L. Krueger, POB 2C-BFN R. F. Marks, Jr., PAB 1A-BFN F. C. Mashburn, BR 4X-C N. M. Moon, LP 6A-C J. R. Rupert, NAB 1F-BFN K. W. Singer, LP 6A-C M. D. Skaggs, PAB 1E-BFN E. J. Vigluicci, ET 11A-K NSRB Support, LP 5M-C EDMS, WT CA-K s://Licensing/Lic/BFN LR Clarification RCPB Bolting TVA Response Letter.doc
ENCLOSURE TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, AND 3 LICENSE RENEWAL APPLICATION (LRA),
RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION (RAI),
RELATED TO INFORMAL REQUEST FOR RCPB BOLTING CLARIFICATIONS (SEE ATTACHED)
E-1 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, AND 3 LICENSE RENEWAL APPLICATION (LRA),
RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION (RAI),
RELATED TO INFORMAL REQUEST FOR RCPB BOLTING CLARIFICATIONS By letter dated December 31, 2003, TVA submitted, for NRC review, an application pursuant to 10 CFR 54, to renew the operating licenses for the Browns Ferry Nuclear Plant, Units 1, 2, and 3. As part of its review of TVAs LRA, the NRC staff, through an informal request on February 25, 2005, identified additional clarification information needed for RCPB bolting. The information concentrates on reactor water recirculation pump closure bolting, reactor recirculation valve closure bolting, and provides an update to the bolting portion of Table 3.1.2.4.
The following contains the response to the specific NRC requests for additional information and corrects several discrepancies identified by TVA.
- 1. Reactor water recirculation pump closure RCPB bolting clarification:
NUREG 1801 line items IV.C1.2-d, e, and f address aging of the reactor water recirculation pump closure bolting. The bolting material for the pumps is ASME A 540 Grade B23.
Some of these bolts are chrome plated (mostly Unit 2) and some are not chrome plated. The BFN aging management review took no credit for the chrome plating preventing any aging effect. Therefore, reactor water recirculation pump closure bolting, both plated and non-plated, was evaluated as carbon steel bolting. Wear, stress relaxation, and fatigue aging effects identified by NUREG 1801 were identified as aging effects requiring management for the period of extended operation. These aging effects are included in lines 1, 2, and 3 of Table 3.1.2.4. In each of these line items, the 8th column should read None as the material is not consistent with NUREG 1801.
In addition, line item 3 will include a new note identifying that fatigue is addressed as a TLAA in Section 4.3 of the LRA. See lines 1, 2, and 3 of the attached partial Table 3.1.2.4.
E-2 In addition to the aging effects listed in Section IV of NUREG 1801 discussed above, the BFN evaluation also addressed loss of material due to general corrosion and cracking due to cyclic loading and stress corrosion cracking (SCC).
Loss of material was not identified as an aging effect requiring management for the period of extended operation as the reactor water recirculation pump closure bolting is normally at greater than 212°F. This temperature prevents moisture from accumulating and causing general corrosion.
Since the specific class of ASME A 540 Grade B23 bolting can not be identified in all cases, the assumption is made that some bolting may be Class 1, which has yield strength greater than 150 ksi. Note that ASME A 540 Grade B23 Class 1 bolting was not identified in those applications where the ASME A 540 Grade B23 bolting class was specified. SCC requires a combination of high stress (both applied and residual tensile stresses), a corrosive environment, and a susceptible material. Carbon steel bolting with yield strength greater than 150 ksi is a susceptible material. However, SCC of high yield strength bolting in BWRs requires a corrosive environment typically attributed to a wet environment and the presence of thread lubricant containing MoS2 (molybdenum disulfide). While there is a small probability that ASME A 540 Grade B23 Class 1 bolting is present at BFN, the operating environment for this bolting is a nitrogen atmosphere without the presence of MoS2 thread lubricant, as MoS2 thread lubricant is not utilized for bolted connections at BFN. Therefore, SCC of reactor water recirculation pump closure bolting does not require aging management for the period of extended operation.
Crack initiation and growth due to cyclic loading is not considered a license renewal concern due to high cycle fatigue since it would be discovered during the current license period and corrected. In addition, cyclic primary loads are evaluated against conservative stress limits and are not a contributor to fatigue due to the few number of stress cycles postulated (e.g., earthquake and fluid transient loads). Therefore, cracking due to cyclic loading of bolting does not require aging management for the period of extended operation.
E-3 Based on the above discussion, loss of material (due to general corrosion) and cracking (due to cyclic loading and SCC) are not aging effects requiring management for reactor water recirculation pump closure bolting during the period of extended operation. Thus, no line items were included in the LRA to address these aging effects.
NUREG 1801 line items IV.C1.3-e, -f, and -g address aging of the carbon steel RCPB valve closure bolting. The bolting material for these valves is either ASME SA 193 Grade B7 or ASME A 540 Grade B23. Wear, stress relaxation, and fatigue should have been identified as aging mechanisms requiring management for the period of extended operation. Wear was included in current line item 4 of Table 3.1.2.4. In line item 4, the 7th column should read IV.C1.3-e. Line items 5 through 8 were added to address NUREG 1801 line items IV.C1.3-f and -g that were inadvertently excluded from the LRA.
In addition to the aging effects listed in Section IV of NUREG 1801 discussed above, the BFN evaluation also addressed loss of material due to general corrosion and cracking due to cyclic loading and stress corrosion cracking.
Loss of material was not identified as an aging effect requiring management for the period of extended operation as this bolting is normally at greater than 212°F. This temperature prevents moisture from accumulating and causing general corrosion.
The ASME SA 193 Grade B7 bolting has a yield strength less than 150 ksi and is not susceptible to stress corrosion cracking. Since the specific class of ASME A 540 Grade B23 bolting can not be identified in all cases, the assumption is made that some bolting may be Class 1, which has yield strength greater than 150 ksi. Note that ASME A 540 Grade B23 Class 1 bolting was not identified in those applications where the ASME A 540 Grade B23 bolting class was specified. SCC requires a combination of high stress (both applied and residual tensile stresses), a corrosive environment, and a susceptible material. Carbon steel bolting with yield strength greater than 150 ksi is a susceptible material. However, SCC of high yield strength bolting in BWRs requires a corrosive environment typically attributed to a wet environment and the presence of thread
E-4 lubricant containing MoS2 (molybdenum disulfide). While there is a small probability that ASME A 540 Grade B23 Class 1 bolting is present at BFN, the operating environment for this bolting is a nitrogen atmosphere without the presence of MoS2 thread lubricant, as MoS2 thread lubricant is not utilized for bolted connections at BFN. Therefore, SCC of carbon steel RCPB valve closure bolting does not require aging management for the period of extended operation.
Crack initiation and growth due to cyclic loading is not considered a license renewal concern due to high cycle fatigue since it would be discovered during the current license period and corrected. In addition, cyclic primary loads are evaluated against conservative stress limits and are not a contributor to fatigue due to the few number of stress cycles postulated (e.g., earthquake and fluid transient loads). Therefore, cracking due to cyclic loading of bolting does not require aging management for the period of extended operation.
Based on the above discussion, loss of material (due to general corrosion) and cracking (due to cyclic loading and SCC) are not aging effects requiring management for reactor water recirculation pump closure bolting during the period of extended operation. Thus, no line items were included in the LRA to address these aging effects.
- 3. Carbon steel non-RCPB bolting clarification:
NUREG 1801 line items V.E.2-a, V.E.2-b, VII.I.2-a, and VII.I.2-b identify loss of material due to general corrosion and cracking due to cyclic loading and stress corrosion cracking aging effects for the carbon steel non-RCPB bolting in the Reactor Recirculation System boundary.
The bolting material for these valves is ASME SA 193 Grade B7. General corrosion was identified as the temperature of this bolting is less than 212°F. The current line items 5 and 7 are now shown in line items 9 and 11.
The aging management review determined that this bolting is not susceptible to SCC as the yield strength of the ASME SA 193 Grade B7 bolting is less than 150 ksi. Crack initiation and growth due to cyclic loading is not considered a license renewal concern due to high cycle fatigue since it would be discovered during the current license period and corrected. In addition, cyclic primary
E-5 loads are evaluated against conservative stress limits and are not a contributor to fatigue due to the few number of stress cycles postulated (e.g., earthquake and fluid transient loads). The absence of crack growth due to cyclic loading and stress corrosion cracking identified in current line items 6 and 8 is now shown in line items 10 and 12.
In addition to the aging effects listed in Section V and VII of NUREG 1801 discussed above, the BFN evaluation also addressed wear, stress relaxation, and fatigue.
Bolting degradation due to wear could potentially occur at locations of repeated relative motion of mechanical component bolted joints. Wear of bolted joint components is generally not a concern as demonstrated by industry operation experience and is not an aging effect requiring management for the period of extended operation. For License Renewal purposes only, wear is assumed as a potential mechanism only for critical bolting applications. Critical bolting applications constitute reactor coolant pressure boundary (RCPB) components where closure bolting failure could result in loss of reactor coolant and jeopardize safe operation of the plant. Thus, for non-RCPB bolting, wear is not a potential aging effect.
Stress relaxation is a thermal effect that results in loss of preload for the valve closure bolting. Stress relaxation is addressed during installation, early during component service, or during subsequent maintenance of the joint and appropriate actions would be taken to prevent recurrence. Installation procedures are in place that specify proper bolting installation practices and bolt torque values. Therefore, stress relaxation in a bolted joint is considered a design driven effect and is not considered an applicable aging effect for carbon steel non-RCPB valve closure bolting.
Based on the above discussion, wear and stress relaxation are not aging effects requiring management for carbon steel non-RCPB valve closure bolting during the period of extended operation and no line items were included in the LRA to address these aging effects.
Fatigue is applicable as an aging effect for non-RCPB valve closure bolting. Fatigue is addressed as a TLAA in Section 4.3 of the LRA.
E-6
- 4. Stainless steel reactor water recirculation pump closure bolting clarification:
There is no stainless steel reactor water recirculation pump closure bolting. Therefore, current line items 9, 10, and 11 have been deleted.
- 5. Stainless steel RCPB valve bolting clarification:
NUREG 1801 line item IV.C1.3-e addresses aging of the stainless steel RCPB valve closure bolting. The bolting material for these valves is ASME SA 193 Grade B8. Wear was included in current line 12 of Table 3.1.2.4. In current line item 12, the 7th column should read IV.C1.3-e and the 8th column should read 3.1.1.26. Current line item 12 appears as line item 13 in the attached partial Table 3.1.2.4.
In addition to wear listed in Section IV of NUREG 1801 discussed above, the BFN evaluation also addressed stress relaxation, fatigue, loss of material due to corrosion and cracking due to cyclic loading and stress corrosion cracking.
Stress relaxation is a thermal effect that results in loss of preload for the valve closure bolting. Stress relaxation is addressed during installation, early during component service, or during subsequent maintenance of the joint and appropriate actions would be taken to prevent recurrence. Installation procedures are in place that specify proper bolting installation practices and bolt torque values. Therefore, stress relaxation in a bolted joint is considered a design driven effect and is not considered an applicable aging effect for stainless steel RCPB valve closure bolting.
Stainless steel bolting is not susceptible to corrosion in an inside air environment.
The yield strength of the stainless steel bolting is less than 150 ksi. Therefore, cracking due to SCC of stainless steel bolting does not require aging management for the period of extended operation Crack initiation and growth due to cyclic loading is not considered a license renewal concern due to high cycle fatigue since it would be discovered during the current
E-7 license period and corrected. In addition, cyclic primary loads are evaluated against conservative stress limits and are not a contributor to fatigue due to the few number of stress cycles postulated (e.g., earthquake and fluid transient loads). Therefore, cracking due to cyclic loading of bolting does not require aging management for the period of extended operation.
Based on the above discussion, stress relaxation, loss of material due to corrosion, and cracking due to cyclic loading and stress corrosion cracking are not aging effects requiring management for stainless steel RCPB valve closure bolting during the period of extended operation and no line items were included in the LRA to address these aging effects.
Fatigue is applicable as an aging effect for non-RCPB valve closure bolting. Fatigue is addressed as a TLAA in Section 4.3 of the LRA.
- 6. Stainless steel non-RCPB bolting clarification:
NUREG 1801 identifies no aging effects for stainless steel non-RCPB bolting in the Reactor Recirculation System boundary. The bolting material for these valves is ASTM A 193 Grade B8.
The BFN evaluation of this stainless steel non-RCPB bolting addressed corrosion, cracking due to cyclic loading and stress corrosion cracking, wear, stress relaxation, and fatigue.
Stainless steel bolting is not susceptible to corrosion in an inside air environment.
The yield strength of the stainless steel bolting is less than 150 ksi. Therefore, cracking due to SCC of stainless steel bolting does not require aging management for the period of extended operation.
Crack initiation and growth due to cyclic loading is not considered a license renewal concern due to high cycle fatigue since it would be discovered during the current license period and corrected. In addition, cyclic primary loads are evaluated against conservative stress limits and are not a contributor to fatigue due to the few number of stress cycles postulated (e.g., earthquake and fluid transient loads). Therefore, cracking due to cyclic
E-8 loading of stainless steel bolting does not require aging management for the period of extended operation.
Bolting degradation due to wear could potentially occur at locations of repeated relative motion of mechanical component bolted joints. Wear of bolted joint components is generally not a concern as demonstrated by industry operation experience and is not an aging effect requiring management for the period of extended operation. For License Renewal purposes only, wear is assumed as a potential mechanism for critical bolting applications.
Critical bolting applications constitute reactor coolant pressure boundary (RCPB) components where closure bolting failure could result in loss of reactor coolant and jeopardize safe operation of the plant.
Stress relaxation is a thermal effect that results in loss of preload for the valve closure bolting. Stress relaxation is addressed during installation, early during component service, or during subsequent maintenance of the joint and appropriate actions would be taken to prevent recurrence. Installation procedures are in place that specify proper bolting installation practices and bolt torque values. Therefore, stress relaxation in a bolted joint is considered a design driven effect and is not considered an applicable aging effect for stainless steel RCPB valve closure bolting.
Based on the above discussion, wear, stress relaxation, loss of material due to corrosion, and cracking due to cyclic loading and stress corrosion cracking are not aging effects requiring management for stainless steel non-RCPB valve closure bolting during the period of extended operation and no line items were included in the LRA to address these aging effects. Table 3.1.2.4, current line items 13 and 14 were included in the LRA to address the absence of general corrosion in stainless steel non-RCBP bolting. Since stainless steel bolting is not identified in NUREG 1801, these line items are not required and current line items 13 and 14 have been deleted from the attached partial Table 3.1.2.4.
Fatigue is applicable as an aging effect for non-RCPB valve closure bolting. Fatigue is addressed as a TLAA in Section 4.3 of the LRA.
E-9
- 7. Stainless steel bolting in a treated water environment clarification:
There is no stainless steel bolting in a treated water environment in the scope of license renewal. Therefore, current line item 15 has been deleted.
E-10 Summary of changes to LRA Table 3.1.2.4:
Current LRA Revised LRA Line Addressed in Line Item Item (Subsequent Pages)
Above Section 1
1 1
2 2
1 3
3 1
4 4
2 5 (added) 2 6 (added) 2 7 (added) 2 8 (added) 2 5
9 3
6 10 3
7 11 3
8 12 3
9 (deleted) 4 10 (deleted) 4 11 (deleted) 4 12 13 5
13 (deleted) 6 14 (deleted) 6 15 (deleted) 7
E-11 Table 3.1.2.4:
Reactor Recirculation System (068) - Summary of Aging Management Evaluation Component Type Intended Function Material Environment Aging Effect Requiring Management Aging Management Program NUREG -
1801 Vol. 2 Item Table 1 Item Notes Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASTM A 540 Grade B23)
Inside Air (external)
Loss of bolting function due to wear.
Bolting Integrity Program (B.2.1.16)
IV.C1.2-d None F, 1 Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASTM A 540 Grade B23)
Inside Air (external)
Loss of bolting function due to stress relaxation.
Bolting Integrity Program (B.2.1.16)
IV.C1.2-e None F, 1 Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASTM A 540 Grade B23)
Inside Air (external)
Loss of bolting function due to fatigue.
None IV.C1.2-f None F, 1, 9 Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASME SA 193 Grade B7 and ASTM A 540 Grade B23)
Inside Air (external)
Loss of bolting function due to wear.
Bolting Integrity Program (B.2.1.16)
IV.C1.3-e 3.1.1.26 B
Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASME SA 193 Grade B7)
Inside Air (external)
Loss of bolting function due to stress relaxation.
Bolting Integrity Program (B.2.1.16)
IV.C1.3-f 3.1.1.26 B
Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASME SA 193 Grade B7)
Inside Air (external)
Loss of bolting function due to fatigue.
None IV.C1.3-g 3.1.1.1 A
Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASTM A 540 Grade B23)
Inside Air (external)
Loss of bolting function due to stress relaxation.
Bolting Integrity Program (B.2.1.16)
IV.C1.3-f None F, 2
E-12 Table 3.1.2.4:
Reactor Recirculation System (068) - Summary of Aging Management Evaluation Component Type Intended Function Material Environment Aging Effect Requiring Management Aging Management Program NUREG -
1801 Vol. 2 Item Table 1 Item Notes Bolting (RCPB)
MC, SS Carbon and Low Alloy Steel (ASTM A 540 Grade B23)
Inside Air (external)
Loss of bolting function due to fatigue.
None IV.C1.3-g None F, 2, 9 Bolting (non-RCPB)
MC, SS Carbon and Low Alloy Steel (ASME SA 193 Grade B7)
Inside Air (external)
Loss of bolting function due to general corrosion.
Bolting Integrity Program (B.2.1.16)
V.E.2-a 3.2.1.18 B
Bolting (non-RCPB)
MC, SS Carbon and Low Alloy Steel (ASME SA 193 Grade B7)
Inside Air (external)
None None V.E.2-b None I, 3 Bolting (non-RCPB)
MC, SS Carbon and Low Alloy Steel (ASME SA 193 Grade B7)
Inside Air (external)
Loss of bolting function due to general corrosion.
Bolting Integrity Program (B.2.1.16)
VII.I.2-a 3.3.1.24 B
Bolting (non-RCPB)
MC, SS Carbon and Low Alloy Steel (ASME SA 193 Grade B7)
Inside Air (external)
None None VII.I.2-b None I, 3 Bolting (RCPB)
MC, SS Stainless Steel Inside Air (external)
Loss of bolting function due to wear.
Bolting Integrity Program (B.2.1.16)
IV.C1.3-e 3.1.1.26 B
Table Notes:
Industry Standard Notes:
Note A Consistent with NUREG-1801 item for component, material, environment, and aging effect. The AMP is consistent with NUREG-1801.
E-13 Note B Consistent with NUREG-1801 item for component, material, environment, and aging effect. The AMP takes some exceptions to NUREG-1801.
Note D Component is different, but consistent with NUREG-1801 item for material, environment, and aging effect. The AMP takes some exceptions to NUREG-1801.
Note F Material not in NUREG-1801 item for this component.
Note G Environment not in NUREG-1801 item for this component and material.
Note H Aging effect not in NUREG-1801 item for this component, material and environment combination.
Note I Aging effect in NUREG-1801 item for this component, material and environment combination is not applicable.
Note J Neither the component nor the material and environment combination is evaluated in NUREG-1801.
Plant Specific Notes:
1 In some cases, chrome plated carbon steel bolting is used for reactor water recirculation pump closure bolting. No aging effects are eliminated based on the presence of the chrome plating. The aging effects and AMP identified for these chrome plated carbon steel bolting is consistent with industry guidance for carbon steel bolting.
2 The aging effects identified for this material/environment combination are consistent with industry guidance.
3 High yield strength heat-treated bolting, >150 ksi, is not used in non-RCPB bolting applications at BFN. Cracking due to high cycle fatigue is not considered a license renewal concern since it would be discovered during the current license period and corrected. Therefore, SCC and cracking due to cyclic loading are not concerns for BFN license renewal.
E-14 4 There are no applicable aging effects for this material/environment combination. This is consistent with industry guidance.
5 The additional aging effects identified for this material/environment combination are consistent with industry guidance.
6 Based on system design and operating history, MIC and biofouling are not applicable to the treated water portions of this system.
7 General corrosion is not an aging effect since the external temperature is above 212°F.
This is consistent with industry guidance.
8 This item includes flow restrictors as well as fittings, thermowells, and flow elements. The intended function, FR - flow restriction, is only applicable to flow restrictors.
9 Fatigue is evaluated as a TLAA to ensure that the BFN CLB is maintained for the period of extended operation. See Section 4.3.