ML042730342
| ML042730342 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/17/2004 |
| From: | Abney T Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BFN-TS-405, TAC MB5733, TAC MB5734, TAC MB5735, TS-405 | |
| Download: ML042730342 (28) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 BFN-TS-405 10 CFR 50.90 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 -
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION (RAI)
RELATED TO TECHNICAL SPECIFICATIONS (TS) CHANGE NO. TS-405 -
ALTERNATIVE SOURCE TERM (AST) (TAC NOS. MB5733, MB5734, MB5735)
This letter provides additional information requested by NRC in support of TS-405. TS-405, which was submitted on July 31, 2002, and supplemented on February 12, 2003, requested a license amendment and TS changes for application of AST methodology for BFN Units 1, 2, and 3.
NRC provided the RAI on August 26, 2004. The questions were discussed with the staff in teleconferences. Enclosure I provides TVA's response to the NRC's questions. The staff requested that TVA address operator training and procedure revisions necessary to be able to establish an alternate pathway to the Unit 1 condenser. TS-436 dated July 9, 2004, establishes the need to provide procedural requirements for establishing the alternate pathway.
However, for completeness, TVA is committing to provide training and ATal(
Ped on p
U.S. Nuclear Regulatory Commission Page 2 September 17, 2004 procedures commensurate with that for Units 2 and 3 for the establishment of the Unit 1 alternate pathway. This commitment is found in Enclosure 2.
If you have any questions, please telephone me at (256) 729-2636.
Pursuant to 28 U. S. C. § 1746, 1 declare under penalty of perjury that the foregoing is true and correct. Executed on September 17, 2004.
- 1. Response To The August 26, 2004, Request For Additional Information (RAI) Relating To Technical Specifications Change No.
TS-405 Altemative Source Term (AST).
- 2. List of commitments.
U.S. Nuclear Regulatory Commission Page 3 September 17, 2004 Enclosures cc (Enclosures):
State Health Officer Alabama State Department of Public health RSA Tower - Administration Suite 1552 P.O. Box 30310 Montgomery, Alabama 36130-3017 (Via NRC Electronic Distribution)
U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-3415 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, AL 35611-6970 Kahtan N. Jabbour, Senior 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
ENCLOSURE I TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1,2, AND 3 RESPONSE TO THE AUGUST 26, 2004, NRC REQUEST FOR ADDITIONAL INFORMATION (RAI) RELATING TO TECHNICAL SPECIFICATIONS (TS)
CHANGE NO. TS-405 ALTERNATIVE SOURCE TERM (AST)
NRC Request 1 In a letter dated July 2, 2004, TVA submitted Facility Risk Consultants (FRC) report entitled, MSIV Seismic Ruggedness Verification At Browns Ferry Nuclear Plant, May 2004. Page 5-2 of the FRC report states that "[s]upport components that may exhibit non-ductile behavior are accepted based (on) the following stress allowables:" Clarify whether "support components" are component supports or components for piping supports or something else. Provide justification for the provision that the allowable stress is greater than material yield stress for the non-ductile behavior support components.
TVA Response 1 Support components include items such as American Institute of Steel Construction (AISC) rolled sheets and plates and manufactured standard components such as rods and spring cans. A review was performed of the support components discussed in Section 5.1.3 on page 5-2 of the Facility Risk Consultants (FRC) Report, " MSIV Seismic Ruggedness Verification at Browns Ferry Nuclear Plant Unit 1," provided in Enclosure 2 of the July 2, 2004 (Reference 1) letter, and it was determined that rolled shapes and plates meet AISC code allowables and manufactures' standard components that may exhibit non-ductile behavior were not observed. This is consistent with the results obtained for Units 2 and 3 at BFN as shown in TVA Calculation CDNO 001 99 0113, also provided in Enclosure 2 of the Reference 1 TVA letter to NRC.
NRC Request 2 Page 5-3 of the FRC report states that "[w]hen test data are available, acceptable loads on test data consider mean less one standard deviation capacity." Provide technical justification for the above provision.
TVA Response 2 A review of the analysis provided by MSIV Seismic Ruggedness Verification at Browns Ferry Nuclear Plant Unit 1 was performed and it was determined that the element discussed in Section 5.1.3 on page 5-3 of the FRC Report was not used for the Unit I analyses. This is consistent with the methods used for Units 2 and 3 at BFN as shown in TVA Calculation CDN0 001 99 0113.
NRC Request 3 Page 5-3 of the FRC report. states that "[p]ipe supports not meeting the above criteria may be accepted if adjacent supports and the resulting pipe span can resist dead loads with a factor of safety of 2.0." Provide technical justification for the above provision.
TVA Response 3 A review of the piping analysis on pipe support analyses in Section 5.1.3 on Page 5-3 of the FRC report performed it was determined that there are no configurations that require adjacent supports to resist loads from adjacent supports. This is consistent with the results obtained for Units 2 and 3 Calculation CDNO 001 99 0113.
NRC Request 4 TVA submitted a letter dated July 9, 2004, regarding main steam isolation valve leakage rate limits. Page El -26 of the July 9, 2004, submittal states that "[t]he NEDC-31858P-A survey of this type of industrial structure has, in general, confirmed that excellent past seismic performance exists. There are no known cases of structural collapse of either turbine buildings at power stations or structures of a similar construction. Based on the above design bases for the BFN Turbine Building, and the excellent seismic performance of similar types of industrial structures in past strong-motion earthquakes as documented in NEDC-31858P-A, it was determined that the BFN Turbine Building will remain structurally intact following a DBE." Provide locations in the NEDC-31858P-A that support the statement that structures exhibit excellent past seismic performance.
As the NRC staff has not endorsed using seismic experience data for qualifying structures subjected to earthquakes, provide additional technical justification that supports the contention that the BFN Turbine Building will remain structurally intact following a design basis earthquake.
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TVA Response 4 N EDC-31 858P-A Appendix D section 4.4 of NEDC-31 858P (other structural performance considerations) states in part, "A survey was conducted of the BWR Owner's group member to gather information on the design and construction of the turbine buildings which house the majority of main steam and condenser components...
The structures have a range of design bases. Most commonly Uniform Building Code (UBC), American Institute of Steel Construction (AISC) and American Concrete Institute (ACI) - 318 Standards have been applied....The earthquake past performance of this type of industrial structure has in general been excellent.
There are no known cases of structural collapse of either turbine buildings at power stations or structures of similar construction."
It should be noted that the performance of non-seismic Category I structures of interest to the issue of MSIV leakage is only to the extent that the non-seismic structures and components should survive and not degrade the capabilities of the main steam and condenser fluid pathways. The turbine building evaluation developed in this program was not intended to be a seismic qualification rather it was intended to be a seismic ruggedness verification to demonstrate that the BFN Turbine Building will remain structurally intact following a design basis earthquake.
Seismic Ruggedness Verification of BFN-1 Turbine Building The following is an excerpt from the revised Unit 1 FRC Report describing the analysis TVA performed to verify that the BFN-1 Turbine Building will remain structurally intact (i.e., maintain position retention) following a Design Basis Earthquake.
3.10 SEISMIC Il/I VERIFICATION OF TURBINE BUILDING Many of the ALT pathway components are physically located in the Turbine Building, which is a seismic Class II structure. An evaluation was performed to verify that the BFN-1 Turbine Building will remain structurally intact (i.e., maintain position retention) following a DBE (TVA Calculation CDN0 303 2004 0233, Revision 1). This evaluation validates that the Turbine Building itself is not a seismic 11/1 hazard for the ALT pathway piping, equipment, and the condenser.
The portions of the Turbine Building that are of interest to the MSIV seismic ruggedness verification program include the following:
Lower reinforced concrete frame and shear wall structure Turbine pedestal Steel superstructure E1-3
These portions of the Turbine Building are shown in Figure 3-2. The seismic 11/l structural evaluations performed for each of these portions of the Turbine Building are discussed, in turn, in Subsections 3.10.1 to 3.10.3. As further seismic 11/l verification of the Turbine Building, a seismic-experience-based review was performed that demonstrates the BFN-1 Turbine Building is similar to and at least as rugged as other turbine buildings that experienced and performed well in earthquakes stronger than the BFN DBE. The seismic-experienced-based review is described in Section 3.10.4.
3.10.1 Lower Concrete Structure Seismic Evaluation As described in the FSAR (Reference 7-12), the lower concrete portion of the Turbine Building between Column Lines M and J, which is adjacent to the Reactor Building, was designed using the seismic provisions of the Uniform Building Code (UBC, Reference 7-13). The intent of this seismic design was to ensure that the Turbine Building will not damage the Reactor Building during a DBE. The lower concrete portion of the Turbine Building between Column Lines M and J has high inherent strength. It consists of reinforced concrete floor slabs which act as rigid diaphragms. The concrete walls, which were provided primarily for shielding purposes, are 48 to 54 inches thick. These walls support the floor slabs and act as seismic load-resisting shear walls.
As further seismic l1/I verification of the lower concrete portion of the Turbine Building between Column Lines M and J, an evaluation of the shear strength of the base elevation (El. 565 ft.) columns and shear walls was performed. The base elevation was selected for the evaluation because it has the highest seismic demand shear loads and it has less shear wall area than the floor above it.
The seismic capacity of the shear walls and columns above El. 565 ft. between column lines M and J was determined to be 25,500 kips in the north-south direction and 20,300 kips in the east-west direction. This shear capacity is based on nominal cross sectional properties of the walls and columns and concrete shear strength as specified in the ACI 318-89 code.
The seismic demand shear load was determined to be 15,200 kips for both the north-south and east-west directions of motion. The seismic demand shear load is based on the total weight of the building above floor elevation 565 ft. between column lines M and J, times the seismic demand spectral acceleration. The weight of the building is 31,600 kips, which conservatively includes the total dead load plus the design live load for all floors above elevation 565 ft. The seismic demand spectral acceleration is 0.48g. This seismic demand spectral acceleration is based on a soil amplification coefficient of 1.6 times the 0.30g peak of the 5% damped DBE ground response spectrum curve. The 1.6 soil amplification factor is applicable to soil-founded Class I structures at BFN, as described in the FSAR.
The seismic capacity over demand (C/D) ratios for the lower concrete structure of the Turbine Building between column lines M and J were calculated using the seismic capacity and seismic demand shear loads as described above.
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The results are as follows:
Direction of C = Seismic D = Seismic C / D R Motion Capacity (kips)
Demand (kips)atio North-South 25,500 15,200 1.68 East-West 20,300 15,200 1.34 The resulting C/D ratios are greater than 1.0. Based on these results, the seismic 11/l adequacy of the lower concrete portion of the Turbine Building between column lines M and J is verified.
3.10.2 Turbine Pedestal The turbine pedestal is a separate reinforced concrete structure housed within the Turbine Building. The turbine pedestal was previously evaluated for lateral loads equivalent to 25% of the weight of the turbine generator machinery, applied in both lateral directions.
The evaluation is described in the FSAR (Reference 7-13). This evaluation used working stress allowable loads for determination of seismic capacity. Therefore, the seismic capacity of the turbine pedestal is higher than 0.25g as used in the previous evaluation.
For seismic Il/I evaluation, the capacity of the turbine pedestal structure is taken to be at least 1.7 times greater, based on the design margins in the working stress method. That is, the seismic capacity of the turbine pedestal is at least 1.7 x 0.25 = 0.425g.
The turbine pedestal is a rigid structure, so its seismic demand is the same as the peak ground acceleration (PGA) of the ground motion DBE (0.20g), increased by 1.6 to account for soil amplification effects (as described in Section 3.10.1). This gives a seismic demand acceleration of 0.32g.
The seismic capacity over demand ratio for the turbine pedestal is as follows:
C = Seismic D = Seismic Capacity (g)
Demand (g) 0.425 0.320 The resulting C/D ratio is greater than 1.0. Based on these results, the seismic 11/l adequacy of the turbine pedestal is verified.
3.10.3 Steel Superstructure Excluding the lower concrete portion of the Turbine Building between column lines M and J and the turbine pedestal, the only remaining portion of the Turbine Building of interest to the MSIV seismic ruggedness program is the steel superstructure between column lines A and J. The Turbine Building steel superstructure houses both the BFN-1 and BFN-2 operating floors. The Turbine Building consists of eight (8) two-span high-bay moment resisting frames in the east-west direction (column lines A through H), and braced frames along the T2, T6, and T10 column lines. The original design of the steel superstructure was based on dead and live loads, plus loading due to 100 mph wind (30 psf lateral load on the entire structure) and lift loads for the turbine building crane.
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The bent at column line E is a typical frame directly above the turbine generator machinery. This is shown in Figure 3-3. The north-south lateral load resisting frames along lines T2, T6, and TI0 are all similar. Each line includes 2 braced frames for lateral load resistance, as shown in Figure 3-4.
As further seismic 11/l verification, evaluation of the key lateral and vertical load resisting elements of the Turbine Building steel superstructure was performed. The seismic evaluation addresses the steel superstructure by investigation of models of a typical bent for east-west seismic loads (column line E is used), the T2 line for north-south seismic loads, and the typical bent (column line E) for vertical loads.
3.10.3-1 Analysis Models The analysis models for east-west and north-south evaluation are single-degree-of-freedom representations. Standard structural mechanics analysis methodology was used to determine the stiffness and strength of the east-west and north-south load resisting frames for lateral loads applied at the roof line of the superstructure. Mass is lumped at the roof line. The mass is determined based on the weight of the roof framing of the structural bent, the tributary weight of the roofing, and Y of the weight of the columns, longitudinal framing (including the crane rail), and the siding of the building.
The analysis model for vertical evaluation is a simple beam representation of the roof girder. Vertical flexibility due to column axial deformation is considered to be insignificant so it is ignored. The mass on the roof beam is modeled as a distributed load consisting of the tributary weight of the roofing plus the weight of the structural steel members. Vertical response is calculated based on standard structural mechanics methodology. The boundary condition for the roof beam is taken as the average of pin-pinned and fix-fixed ends.
3.10.3-2 Capacity Evaluation The capacity of structural members and connections is determined based on Part 2 of the AISC specification. This is a conservative means for estimating capacity, since the actual structure has considerable reserve margin for remaining structurally intact beyond this stress level, and collapse prevention is the performance measure of interest to this seismic 11/l verification calculation. The Turbine Building steel superstructure is well detailed and is inherently ductile, so it would have to experience ductility demands well in excess of 3 in order to approach a collapse condition. This reserve ductile response capacity was conservatively neglected in the evaluation.
The limiting condition that governs the capacity of the steel superstructure in the east-west direction was determined to be the bending strength at the top of the main support columns. The bending strength of the main support columns is 73,000 in-kips. The limiting condition that governs the capacity in the north-south direction was determined to be the strength of the connections for the brace members. The shear strength of a braced frame is 311 kips. The limiting condition that governs the capacity in the vertical direction was determined to be the bending strength at the center of the roof girder. The bending strength of the roof girder is 38,200 in-kips.
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3.10.3-3 Determination of Seismic Demand Seismic demand loads on the limiting condition elements were determined for dead load plus seismic spectral acceleration times the mass. The seismic load cases investigated include east-west plus vertical earthquake, and north-south plus vertical earthquake. The spectral accelerations used for the evaluations are taken from an approximation of the floor response spectra at the El. 617 ft. operating deck. The floor response spectra are approximated based on scaling of the DBE ground motion response spectrum.
The scale factor for horizontal direction motion is taken as 1.6 x 1.5 x 1.5 = 3.6. As described above, the 1.6 coefficient is used to represent the soil amplification. The first 1.5 factor is to account for building amplification up to an elevation of 40 ft. above grade, based on the SQUG GIP (Reference 7-3). Effective grade elevation for the Turbine Building is El. 565 ft. Thus the first 1.5 amplification factor accounts for building amplification up to El. 605 ft. The second 1.5 amplification factor is conservatively used to account for additional building amplification from El. 605 ft. to the operating deck level of El. 617 ft.
In the vertical direction, the scale factor is taken as 2/3 x 1.1 = 0.733. The 2/3 factor is the ratio between vertical and horizontal ground motion as defined in the FSAR. The 1.1 coefficient is for soil amplification in the vertical direction, as described in the FSAR for soil-founded Class I structures at BFN. Note that no building amplification factors are required for the vertical response analysis because the Turbine Building columns are rigid in the vertical direction.
The spectral acceleration values applied for the seismic load analysis are taken from the 5% damped floor response spectra at the natural frequency of the structure. Frequency is calculated using the respective stiffness and mass for the east-west and north-south models, f = 1/2ir (K / M)112. The east-west direction natural frequency is 1.13 Hz. The north-south natural frequency is 2.74 Hz. The natural frequency in the vertical direction is determined using the 1g deflection approximation methodology, f = 1/27t (g / A )1I2. The natural frequency in the vertical direction is 2.34 Hz.
During earthquake loading, the steel super-structure will behave predominately as a single-degree-of-freedom (SDOF) oscillator. The bulk of the mass is from the roofing.
100% mass participation is used in the analysis, and all mass including the roof load, member weights, and siding are taken as moving in-phase. This is considered to be a conservative approach, so no additional dynamic amplification factor is used in the analysis. That is, a multi-mode factor of 1.5 is not used for the seismic load evaluations.
The analysis of the east-west model and the vertical model determined that the demand load bending moments due to east-west earthquake, vertical earthquake, and dead load are 48,500 in-kips at the top of the column and 15,500 in-kips at the center of the roof girder. The analysis of the north-south model determined that the demand shear load on the braced frame is 299 kips.
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3.10.3-4 Steel Superstructure Analysis Summarv The capacity over demand ratios for the steel superstructure are as follows:
Element C = Seismic D = Seismic C / D Ratio Capacity (kips)
Demand (kips)
CIDRai Column Bending Moment (E-W_
73,000 in-kips 48,500 in-kips 1.51 Braced Frame Shear Load (N-S) 311 kips 280 kips 1.11 Roof Girder Bending Moment (Vert.)
38,200 in-kips 15,500 in-kips 2.47 The resulting C/D ratios are greater than 1.0. Based on these results, the seismic 11/
adequacy of the turbine pedestal is verified.
3.10.4 Seismic Experience-Based Seismic 11/1 Verification of Turbine Building A seismic-experienced-based analysis was performed to verify that the BFN-1 Turbine Building will remain structurally intact (i.e., maintain position retention) following a DBE, primarily based on comparison of plant-specific design parameters for the building to those of the seismic experience database. This review of the Turbine Building design basis, coupled with the excellent seismic performance of this type of industrial structure in past strong-motion earthquakes, provides seismic 11/l verification for the MSIV seismic ruggedness program.
3.10.4-1 Earthquake Experience Data Base The turbine buildings included in the seismic experience database investigation are summarized in Table 3-1. This database includes a total of 37 turbine buildings, encompassing turbine buildings constructed from the 1940s to 1989 that experienced earthquake ground shaking from 0.10g to 0.45g peak ground acceleration (PGA). The PGA values listed in Table 3-1 are the average of the PGA's for the horizontal directions at the respective recording sites.
In general, the seismic experience database turbine buildings have reinforced concrete (RC) pedestals, RC frame or steel frame buildings with and without RC shear walls, and steel frame superstructures. Most of the buildings were designed in conformance with or consistent with the seismic provisions of the Uniform Building Code (UBC), for the version of the code that was in effect at the time of the building construction. All of the database turbine buildings performed well. None of the turbine buildings suffered collapse or had significant structural damage. With the exception of minor cracking and spalling of concrete at foundations and building joints for five of the buildings, the database turbine buildings had no structural damage.
3.10.4-2 BFN-1 Turbine Building The BFN-1 Turbine Building is classified as a Class II structure in the BFN FSAR.
Table 3-2 summarizes the design basis of the Turbine Building and the applicable design codes used.
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The BFN-1 Turbine Building below the operating floor at El. 617 feet is a reinforced concrete framed structure supported on steel H-piles to the bedrock. Piles are spaced far enough apart within each cluster to ensure that the maximum average unit bearing stress on the rock area is limited to 500 psi. Stresses in the piles are limited to one third of the yield stress. The concrete beams and slabs are designed to ACI 318-63 code using the working stress method. Similarly, the columns are also designed to ACI 318-63 code using the working stress method and checked by the ultimate strength design method using a load factor of 1.8.
The superstructure above the operating deck consists of transverse welded steel rigid frames spanning approximately 107 feet. For longitudinal expansion, the superstructure is provided with joints by using double rows of frames spaced at 4 feet apart. The steel frames, which form the Turbine Building structure above the concrete structure, are braced to provide rigidity in the direction of the Reactor Building as well as to provide support for the turbine cranes. These frames are designed to resist lateral forces from the overhead cranes and wind loads, in addition to supporting the vertical dead and live loads.
The design of the steel superstructure is based on 1963 AISC code. All material conforms to ASTM-36, except for anchor rods which are ASTM A-307 steel. Shop connections are ASTM A-502 Gr. 1 rivets or welded, and field connections are ASTM A-325 high-strength bolts.
3.10.4-3 Comparison of BFN-1 Desicqn Basis Earthquake with the Database The earthquake experience database sites listed in Table 3-1 experienced strong ground motions that are in excess of the BFN DBE at the frequency range of interest (about 1 Hz.
and above), with the exception of the Ormond Beach site. As shown in Figure 3-1, many of the database site ground motions envelope the BFN DBE ground spectrum by large factors at the frequencies of interest. Based on this comparison, it is concluded that the database ground motion response spectra bound the BFN-1 DBE ground spectrum and the DBE ground spectrum increased by 1.6 to account for soil amplification.
3.10.4-4 BFN-1 Turbine Buildinq Concrete Structure This lower concrete portion of the BFN-1 Turbine Building consists of reinforced concrete floor slabs which act as rigid diaphragms. Reinforced concrete walls, 48 to 54 inches thick, support the floor slabs and act as shear walls. The remaining portions of the Turbine Building (on the sides and to the north of the turbine pedestal) consist of reinforced concrete framing and walls. The walls in the Turbine Building are very thick because of shielding requirements. The fossil plants in the seismic experience database do not have shielding requirements, and concrete walls are typically 12 inches thick or less.
The BFN-1 Turbine Building concrete structure is inherently strong in resistance to horizontal loads, and by inspection, its lateral strength significantly exceeds the lateral strength of turbine building structures in the seismic experience database. This is especially true in the portion of the BFN-1 Turbine Building that houses the components associated with the MSIV alternate leakage treatment pathway. The analysis described in Section 3.10.1 confirms this - the seismic capacity of the BFN Turbine Building lower concrete structure is higher than the DBE, even though it was not specifically designed for the DBE.
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The BFN-1 Turbine Building concrete structure is at least as rugged as turbine building structures in the data base that experienced earthquakes exceeding the BFN DBE and had no significant damage. Thus, the BFN-1 Turbine Building concrete structure is not a seismic 11/l concern for the MSIV leakage path piping and components.
3.10.4-5 Comparison of BFN-1 Turbine Pedestal with the Database A one-inch expansion joint separates the BFN-1 turbine foundation from the building frame, above the basement floor. This is standard industrial construction for turbine pedestals. Expansion joints at turbine pedestals were observed on the majority of seismic experience data base sites.
Although the BFN-1 turbine-generator was not specifically designed for earthquake loading, a horizontal force equal to 25 percent of the machine weight was applied at the shaft centerline in both the longitudinal direction and the transverse direction as described in Section 3.10.2. This design case includes foundation dead load, machine load, and floor live load. Stresses for this case are the normal allowable stresses given in Chapter 10 of the 1963 ACI code. This BFN-1 lateral load design force for the turbine generator exceeds that of most of the database sites listed in Table 3-1 of similar vintage to BFN-1.
Prior to 1976, the UBC seismic design lateral load coefficient for Seismic Zone 4 (California) was 0.1g to 0.15g.
Based on the above comparison, it is concluded that the BFN-1 Turbine Pedestal is at least as rugged as those in the data base that experienced earthquakes exceeding the BFN DBE and had no significant damage. Thus, the BFN-1 Turbine Pedestal is not a seismic 11/l concern for the condensers and the piping routed adjacent to the condensers.
3.10.4-6 BFN-1 Turbine Building Steel Superstructure The BFN-1 Turbine Building, above the operating floor El. 617, is framed by transverse welded steel rigid frames spanning approximately 107 feet. The steel frames are braced to provide rigidity in the direction of the Reactor Building. The frames provide support for the turbine cranes as well as the girt system which cantilevers eight feet from center of columns to support the metal siding. The BFN-1 framing system is similar to that of the turbine buildings in the seismic experience data base. Figure 3-5 provides a photograph of the Moss Landing Units 1, 2, and 3 Turbine Building, which experienced ground shaking with 0.32g PGA during the 1989 Loma Prieta, CA earthquake. Figure 3-6 provides a photograph of the PALCO turbine building, which experienced 0.45g during the 1992 Petrolia earthquake. Figure 3-7 provides a photograph of the BFN-1 Turbine Building. The framing is similar.
The frames of the BFN-1 Turbine Building are designed to resist lateral forces from the overhead cranes and 100 mph wind-loads, in addition to supporting the vertical dead and live loads. In conventional industrial steel buildings, the superstructure design is typically governed by wind loads and the lateral forces from the overhead cranes, and not the seismic loads. The analysis described in Section 3.10.3 confirms this - the seismic capacity of the BFN Turbine Building steel superstructure is higher than the DBE, even though it was not specifically designed for the DBE. The 100 mph wind speed design for BFN exceeds the design wind speed for the seismic experience database sites. The design wind speed for Califomia (location of all database sites except for Las Ventanas El -10
Power Plant in Chile) is 85 mph. The lift capacity of the BFN-1 turbine crane is significantly higher than that of the database sites, which means that its support structure design loads are considerably higher than that of the database structures.
Because the wind and the crane design loads for the BFN-1 Turbine Building are larger than that of the database turbine building superstructures, it is concluded that the BFN-1 Turbine Building superstructure is at least as rugged as those in the data base that experienced earthquakes exceeding the BFN DBE and had no significant damage. Thus, the BFN-1 Turbine Building Superstructure is not a seismic 11/l concern for the MSIV leakage path piping and components routed above the turbine deck level.
3.10.4-7 Summary of Results of Experience-Based Review The BFN-I Turbine Building is as least as rugged as turbine buildings in the data base that experienced earthquake ground motions that were more severe than the BFN-1 DBE, and survived the earthquakes with no significant damage. This is based on comparison of:
The BFN DBE (including increase for soil amplification) is generally bounded by the database ground motion response spectra with significant margins for frequencies exceeding about 1 Hz.
The BFN-I Turbine Pedestal is at least as rugged as the database turbine pedestals.
The BFN-1 Turbine Building lower concrete structure is significantly more rugged than the turbine building structures in the database.
The BFN-I superstructure is at least as rugged as the database turbine building superstructures.
Based on this review of the BFN-1 Turbine Building design and comparison with the seismic experience database, coupled with the excellent seismic performance of this type of industrial structure in past strong-motion earthquakes, it is concluded that seismic 11/l adequacy is verified for the BFN-i Turbine Building for the MSIV seismic ruggedness program.
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Table 3-1: Earthquake Experience Database Turbine Buildings at NRC-Approved Site-Earthquake Pairings Earthquake &
Vintage I Seismic Design Effects of the Earthquake Ground Motion Record Turbine BudingCapac Description Information..
on the Turbine Building M6.6 (0.20g PGA)
Burbank Power Plant 1958 142MW RC pedestal with steel frame building, steel frame Equivalent static force No damage to turbine bldg.
1971 San Femando, CA Olive Street Unit 1 superstructure, and gantry crane.
of 0.20g Ground Motion Record:
Burbank Power Plant 1961 / 44MW RC pedestal with steel frame building, steel frame Equivalent static force No damage to turbine bldg.
Holiday Inn, Van Nuys, CA Olive Street Unit 2 superstructure, and gantry crane.
of 0.20g Burbank Power Plant 1940s / 1 OMW RC pedestal with steel frame building, steel frame Unknown No damage to turbine bldg.
Magnolia Street Unit 1 superstructure, and cantilevered gantry crane.
Burbank Power Plant 1940s / 10MW RC pedestal with steel frame building, steel frame Unknown No damage to turbine bldg.
Magnolia Street Unit 2 superstructure, and cantilevered gantry crane.
Burbank Power Plant i950s /20MW RC pedestal with steel frame building, steel frame Unknown No damage to turbine bldg.
Magnolia Street Unit 3 superstructure, and cantilevered gantry crane.
Burbank Power Plant 1950s /30 MW RC pedestal with steel frame building, steel frame Unknown No damage to turbine bldg.
Magnolia Street Unit 4 superstructure, and cantilevered gantry crane.
M5.9 (0.43g PGA)
Commerce Refuse to 1985/ 11.5 MW RC pedestal with steel frame building, open UBC No damage to turbine bldg.
1987 Whittier Narrows, CA Energy Plant turbine deck.
Ground Motion Record:
LA Bulk Mail Center, Bell, CA M7.3 (0.43g PGA)
Coolwater Power Plant 1961 /65 MW RC pedestal with steel frame building, steel frame Unknown No damage to turbine 1992 Landers, CA Unit 1 superstructure, partially open turbine deck, and building. Bolts sheared on Ground Motion Record:
gantry crane.
gantry crane Coolwater PP, Dagget, CA Coolwater Power Plant 1964/81 MW RC pedestal with steel frame building, steel frame Unknown Unit 2 superstructure, partially open turbine deck, and gantry crane.
Coolwater Power Plant 1970's /260 MW Skid-mounted gas turbine. Open sided high-bay Unknown. Likely Concrete foundation Unit 3 & Unit 4 steel frame structure supports the bridge crane.
UBC pedestals cracked and spalled El-12
Table 3-1: Earthquake Experience Database Turbine Buildings at NRC-Approved Site-Earthquake Pairings, Continued Earthquake &
Vintage/
Seismic Design Effects of the Earthquake Ground Motion Record Turbine Building Decintyo Information on the Turbine Building M6.6 (0.43g PGA)
El Centro Steam 1949 /20 MW RC pedestal, steel frame building and Unknown Cracking and spalling of 1979 Imperial Valley, CA Plant superstructure, with bridge crane.
concrete at interface between Ground Motion Record:
Unit 1 units El Centro Diff. Array, CA El Centro Steam 1952 /32 MW RC pedestal, steel frame building and Unknown Cracking and spalling of Plant superstructure, with bridge crane.
concrete at interface between Unit 2 units El Centro Steam 1957 /50 MW RC pedestal, steel frame building and Unknown Cracking and spalling of Plant superstructure, with bridge crane.
concrete at interface between Unit 3 units El Centro Steam 1968 /80 MW RC pedestal, steel frame building and Equivalent static Cracking and spatting of Plant superstructure, with bridge crane.
force of 20% of LL concrete at interface between Unit 4 and DL units M6.6 (0.26g PGA)
Grayson PP Unit 1 1941 / 20 MW RC pedestal, open deck turbine with gantry Unknown No damage to turbine bldg.
1971 San Fernando, CA crane.
Ground Motion Record:
Grayson PP Unit 2 1947 /20 MW RC pedestal, open deck turbine with gantry Unknown No damage to turbine bldg.
Glendale City Hall, Glendale, CA crane.
Grayson PP Unit 3 1953/20 MW RC pedestal, open deck turbine with gantry Unknown No damage to turbine bldg.
crane.
Grayson PP Unit 4 1959 /44 MW RC pedestal, open deck turbine with gantry Unknown No damage to turbine bldg.
crane.
Grayson PP Unit 5 1964 / 44 MW RC pedestal, open deck turbine with gantry Equivalent static No damage to turbine bldg.
crane.
force of 0.20g M5.5 1975 Femdale (0.32g PGA)
Humboldt Bay Power 1950s / 50 MW RC pedestal, RC frame, partially enclosed steel UBC No damage to turbine bldg.
M6.9 1992 Petrolia (0.22g PGA)
Plant Unit 1 superstructure, gantry crane.
M6.2 1992 Petrolia Aftershock Humboldt Bay Power 1950s /50 MW RC pedestal, RC frame, partially enclosed steel UBC No damage to turbine bldg.
(0.24g PGA)
Plant Unit 2 superstructure, gantry crane.
I Ground Motion Record:
Humboldt Bay BWR 1962/55 MW RC pedestal, RC frame, partially enclosed steel 0.50g SSE No damage to turbine bldg.
Humboldt Bay Nuclear PP, CA superstructure, gantry crane.
I El -13
Table 3-1: Earthquake Experience Database Turbine Buildings at NRC-Approved Site-Earthquake Pairings, Continued Earthquake M
Turbine Building entage Capacit Description SeIsmicmDesign Effects of the Earthquake Ground Motion Record Ifrainon the Turbine Building M7.8 (0.23g PGA)
Las Ventanas Power 1964 / 120 MW RC pedestal, RC and steel frame building, 0.16g, upgraded in No damage to turbine bldg.
1985 Chile Earthquake Plant Unit 1 steel frame superstructure, with bridge crane.
1965 Ground Motion Record:
Las Ventanas Power 1977 / 210 MW RC pedestal, RC and steel frame building, 0.28g braced frames, No damage to turbine bldg.
Las Ventanas PP, Chile Plant Unit 2 steel frame superstructure, with bridge crane.
0.16g moment frames M7.1 (0.32g PGA)
Moss Landing Power 1950 / 108 MW RC pedestal, common steel frame building UBC No damage to turbine bldg.
1989 Loma Prieta, CA Plant Units 1, 2, and 3 with RC shear walls, and steel framed Ground Motion Record:
superstructure, with bridge crane.
Watsonville 4-story Bldg., CA Moss Landing Power 1952/ 117 MW Open deck, RC concrete pedestal.
UBC No damage to turbine bldg.
Plant Unit 4 Moss Landing Power 1952 / 117 MW Open deck, RC concrete pedestal.
UBC No damage to turbine bldg.
Plant Unit 5 Moss Landing Power 1967 /739 MW Open deck, RC concrete pedestal.
UBC No damage to turbine bldg.
Plant Unit 6 Moss Landing Power 1968 /739 MW Open deck, RC concrete pedestal.
UBC No damage to turbine bldg.
Plant Unit 7 M5.8 (0.10g PGA)
Ormond Beach Power 1970, 73/750 MW RC Pedestal.
Likely UBC No damage to turbine bldg.
1973 Point Mugu, CA Plant Units 1 and 2 Ground Motion Record:
Port Hueneme Naval Lab, CA M6.9 1992 Petrolia (0.45g PGA)
Pacific Lumber Mill 1989 / 15 MW RC pedestal, steel frame building and steel UBC No damage to turbine bldg.
Ground Motion Record:
Cogen Plant frame superstructure with bridge crane.
Hwy. 101, Rio Del, CA Units A and B El -14
Table 3-1: Earthquake Experience Database Turbine Buildings at NRC-Approved Site-Earthquake Pairings, Continued Earthquake &
Turbine Building Vintage i Capacity Description Seismic Design Effects of the Earthquake Ground Motion Record
_________Information on the Turbine Building M6.6 (0.20g PGA)
Valley Steam Plant 1954/100 MW RC Pedestal, steel frame building, open deck Unknown No damage to turbine bldg.
1971 San Fernando Unit 1 with gantry crane.
Ground Motion Record:
Valley Steam Plant 1954/100 MW RC Pedestal, steel frame building, open deck Unknown No damage to turbine bldg.
Holiday Inn, Van Nuys, CA Unit 2 with gantry crane.
Valley Steam Plant 1955/157 NW RC Pedestal, steel frame building, open deck Unknown No damage to turbine bldg.
Unit 3 with gantry crane.
Valley Steam Plant 1956 / 157 MW RC Pedestal, steel frame building, open deck Unknown No damage to turbine bldg.
Unit 4 with gantry crane.
El-15
Table 3-2: Browns Ferry Turbine Building Design Basis Design Attribute Description Lateral Force Resisting The Turbine Building above the operating deck is framed by System Above the transverse welded steel rigid frames with fixed bases and Operating Deck braced in the direction of the Reactor Building to provide resistance to lateral forces.
Lateral Force Resisting The Turbine Building below the operating deck is a reinforced System Below the concrete structure. Concrete walls serve as shear walls for Operating Deck the lateral loads in the direction of the Reactor Building.
Design Codes General: Uniform Building Code (UBC)
Concrete: American Concrete Institute (ACI 318-1963)
Steel: American Institute of Steel Construction (AISC) -1963 Seismic Design Basis UBC zone I Wind Design Basis Wind speed of 100 mph El -16
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A;-.4-Hs Figure 3-1: Comparison of BFN DBE increased by 1.6 with the database spectra EI-17
Reactor Building Turbine Building 0
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r.4 4
.1 I
I.wer Concrete Structure Column Lines At to J J Turbine Pedestal Figure 3-2: Portions of the Turbine Building requiring seismic 1/11 verification in the MSIV seismic ruggedness program E1-18
I A
I tj Figure 3-3: Elevation view of typical lateral load resisting (E-W) interior bent, BEN-I and -2 El-19
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.Q-Figure 3-4: Elevation view of longitudinal load resisting (N-S) braced frame EI-20
Figure 3-5: Moss Landing Power Plant Turbine Building El -21
Figure 3-6: Pacific Lumber Mill Cogen Power Plant Turbine Building EI-22
Figure 3-7: BFN-i Turbine Building Superstructure above the Turbine Deck El -23
NRC Request 5 Are the PVC cables identified in TVA's letter dated May 17, 2004, performing any safety related function? If so, provide the environmental qualification, including the test report, which qualifies those cables for Harsh Environment service.
TVA Response 5 The PVC cables identified in Enclosures 2 and 3 of the May 17, 2004, letter (Reference
- 2) do not perform any safety related function.
References:
- 1. TVA letter to NRC dated July 2, 2004: Browns Ferry Nuclear Plant (BFN) - Units 1, 2, and 3 - Response to Request for Additional Information (RAI) Related to Technical Specifications (TS) Change No. TS-405 - Alternative Source Term (AST) (TAC Nos. MB5733, MB5734, and MB5735).
Units 1, 2, and 3 - Response to Request for Additional Information (RAI) and Unit I analysis Results Related to Technical Specifications (TS) Change No.
TS-405 - Alternative Source Term (AST) (TAC Nos. MB5733, MB5734, and MB5735).
El -24
ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 RESPONSE TO THE AUGUST 26, 2004, REQUEST FOR ADDITIONAL INFORMATION (RAI) RELATING TO TECHNICAL SPECIFICATIONS (TS) CHANGE No. TS-405 ALTERNATIVE SOURCE TERM (AST)
LIST OF COMMITMENTS For the Unit 1 main steam isolation valve alternate leakage pathway, TVA will provide training and procedures consistent with that for Units 2 and 3.