ML20086L401
| ML20086L401 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/14/1995 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9507210178 | |
| Download: ML20086L401 (10) | |
Text
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p ienni's~s~n Vaney Authority. Post Office Box 2000. Decatur Alabama 35609 e
July 14, 1995 U.S.
Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 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 SUPPLEMENTAL INFORMATION FOR PROPOSED TECHNICAL SPECIFICATION (TS) NO. 349 - REACTOR VESSEL PRESSURE-TEMPERATURE (P-T)
CURVES AND BOLTUP TEMPERATURES The enclosure to this letter provides supplemental information verbally requested by the NRC Staff in a June 29, 1995, teleconference for the review of proposed TS No. 349.
TVA submitted this proposed TS on March 31, 1995, to revise the Units 1, 2 and 3 reactor vessel P-T curves.
This proposed change lowers the temperature at which the reactor vessel head bolting studs may be fully tensioned (boltup temperature).
The lower boltup temperature will decrease the length of the Unit 2 Cycle 8 and Unit 3 Cycle 6 outages.
There are no new commitments contained in this letter.
If you have any questions, please telephone me at (205) 729-2636.
Sinpf'r ly, W
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I sd :5 '
' pedro Salas Manager of Site Licensing Enclosure cc:
see page 2 0
9507210170 950714 PDR ADDCK 05000259 p
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A U,.S.; Nuclear Regulatory Commission
-Page 2' July.14, 1995 i
cc (Enclosure):
i Regional Administrator U.S.
Nuclear Regulatory Commission
. Region ~II
'101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. Mark S.
Lesser, Acting Branch Chief U.S.
Nuclear Regulatory Commission Region II r
101 Marietta Street, NW, Suite 2900 Atlanta.,' Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama'35611 Mr. J.
F. Williams, Project Manager U.S.SNuclear Regulatory Commission One White' Flint, North 11555 Rockville Pike Rockville, Maryland 20852 l
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ENCLOSURE TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
SUPPLENENTAL INFORMATION FOR PROPOSED TECHNICAL SPECIFICATION (TS) NO. 349 TVA submitted this proposed TS on March 31,.1995, to revise the Units 1, 2 and 3 reactor vessel pressure-temperature (P-T) curves.
This proposed change lowers the temperature at which the reactor vessel head bolting studs may be fully tensioned (boltup temperature).- The lower boltup temperature will decrease the length of the Unit 2 Cycle 8 and Unit 3 Cycle 6 outages.
This enclosure provides supplemental information verbally requested by the NRC Staff in a June 29, 1995, teleconference for the review of proposed TS No. 349.
1.
NRC REQUEST Provide fluence values'at 12 effective. full power years (EFPY) for all three units.
TVA RESPONSE The 12 EFPY fluence.of 2.87 x 10"nyt'for Unit 1, and 4.01 x 10"nyt for Units 2 and 3 was used in the calculation of the P-T curves.
2.
NRC REQUEST Provide the reference temperature of nil-ductility (RTmn) at one quarter thickness ( %T) and three quarter thickness ( %T) at 12 EFPY for the beltline region.
TVA RESPONSE The fluence values at 12 EFPY for the beltline region are provided below:
THICKNESS UNIT 1 UNITS 2 AND 3
%T 1.97 X 10"nyt 2.75 x 10"nyt
%T 9.21 X 10"nvt' 1.29 x 10"nyt
'The impact on adjusted reference temperature (ART) due to irradiation in the beltline materials is determined according to the methods in Regulatory Guide 1.99, Revision 2, Radiation Embrittlement of Reactor Vessel Materials, as a function of neutron fluence and the element contents of copper and nickel.
The specific relationship from Regulatory Guide 1.99 is:
ART = Initial RTuin. ART ot + Margin N
Where:
[CF] fn2s atuoso ARTmg
=
2 23)%
Margin 2(o
+ a
=
Chemistry factor from Tables 1 or 2 of CF
=
The copper and nickel content of each material was previously provided by TVA as documented in the NRC's April 19, 1994 letter to TVA and TVA's May 23, 1994 and March 27, 1995 responses.
2
%T fluence (n/cm ) divided by 10
f
=
Standard deviation on initial RTmg.
The ai
=
precision of the Charpy impact test used in determinin, the initial RTmg is estimated to be 10*F.
Tnerefore, as is estimated to be 10*F.
Standard deviation on ARTuor, is 28'F for a3
=
welds and 17'F for base material, except that a3 need not exceed 0.50 times the ARTmn value.
Since the controlling metals for BFN were welds, the standard deviation is 28'F or 0.5 times the value of ARTmg, whichever is smaller.
Each beltline plate and weld ARTmn value is determined by multiplying the CF from Regulatory Guide 1.99 by the fluence factor for the EFPY being evaluated.
The Margin term and initial RTmg are added to get the ART of the material.
The 12 EFPY ART values are shown in Tables 1 through 3.
The results show that the beltline welds are limiting at 12 EFPY for all three units.
The resulting ARTS at 12 EFPY are 87.2*F for Unit 1 and 74.8'F for Units 2 and 3.
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3.
NRC REQUEST Provide the fluence factors, initial and shift in RT n, and m
margins for the analyzed materials.
TVA RESPONSE q
The initial and shift in RT y,
and margins for the analyzed m
materials are included in the attached Tables 1 through 3.
As discussed above, the fluence factor is determined by using the calculation provided in Regulatory Guide 1.99, Revision 2.
4.
NRC REQUEST Provide the area of the non-beltline region used for the P-T curve analysis.
TVA RESPONSE The non-beltline curves were developed for two regions:
the upper vessel region, governed by the feedwater nozzle limits, and the bottom head region, governed by the Control Rod Drive (CRD) penetration limits.
The non-beltline region results were established by adding the highest RTmn values for applicable non-beltline components to the CRD penetration and feedwater nozzle limits.
Table 4 lists the various non-beltline region components along with their RTmg values.
The limiting RTmn values are also provided on Table 4.
The %*F adjustment was made to the curved portions of the non-beltline curves, but not to the straight line and step portions, which are based on 10 CFR 50, Appendix G.
5.
NRC REQUEST Provide the Stress Intensity Factors (K:) and their methods of derivation.
TVA RESPONSE The developmont of the P-T curves includes consideration of the change tc the allowable fracture toughness equation in ASME Cod 2 Section XI, Appendix G, which occurred in 1992.
The coefficient 1.233 in the Km/Ku equation in Figure G-2210-1, became 1.223.
The result of the revision is an increase of about %*F to the calculated temperature for a given pressure on the P-T curves (i.e.,
all curved portions of the P-T curve shift % *F to the right).
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6.
NRC REQUEST Verify that the vessel thickness at the beltline is 6.125 inches and the internal radius is 125.5 inches.
TVA RESPONSE The minimum vessel thickness at the beltline-is 6.125 inches and the internal radius is 125.5 inches.
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. TABLE 1 BELTLINE ADJUSTED REFERENCE TEMPERATURES (ARTS)
FOR BROWNS FERRY UNIT 1 HEAT OR INITIAL 12 EFPY 12 EFPY 12 EFPY COMPONENT I.D.
HEAT LOT RT Delta RT m NARGIN SHIFT ART 3m PLATES:
Lower Shell 6-127-1 A0999-1
-20 17.1 17.1 34.2 14.2 Lower Shell 6-127-2 B5864-1
-20 17.3 17.3 34.6
-14.6 Lower Shell 6-127-4 A1009-1
-10 16.3 16.3 32.6 22.6
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Low-Int Shell 6-139-19 C2884-2 14 13.9 13.9 27.9 41.9 Low-Int Shell 6-139-20 C2868-2 30 9.9 9.9 19.8 49.8 Low-Int Shell 6-139-21 C2753-1 2
8.7 8.7 17.4 19.4 WELDS:
Lower to SAW WF154 20 33.6 33.6 67.2 87.2 Low-Int Girth k
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TABLE 2 BELTLINE ADJUSTED REFERENCE TENPERATURES (ARTS)
FOR BROWNS FERRY UNIT 2 l
12 EFPY 12 EFPf 12 EFPY HEAT OR INITIAL RT nT Delta RTor NARGIN SHIFT ART CONPONENT I.D.
HEAT LOT s
N PLATES:
Lower Shell 6-127-14 C2467-2
-20 23.6 23.6 47.2 27.2 Lower Shell 6-127-15 C2463-1
-20 24.5 24.5 49.0 29.0 Lower Shell 6-127-17 C2460-2 0
18.5 18.5 3.
0 37.0 Low-Int Shell 6-127-6 A0981-1
-10 20.5 20.5 41.0 31.0 Low-Int Shell 6-127-16 C2467-2
-10 23.6 23.6 47.2 37.2 Low-Int Shell 6-127-20 C2849-1
-10 15.3 15.3 30.6 20.6 WELDS:
Lower to ESW*
10 32.4 32.4 64.8 74.8 Low-Int Girth ESW' chemistry based on (average + 1 sigma) of several qualification weld chemistries.
Specific weld heat chemistries are not available.
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a TABLE 3 BELTLINE ADJUSTED REFERENCE TEMPERATURES (ARTS)
FOR BROWNS FERRY. UNIT 3 HEAT OR INITIAL 12 EFPY 12 EFPY 12 EFPY RT ny Delta RT nr NARGIN SHIFT ART CONPONENT I.D.
HEAT LOT 3
3 PLATES:
Lower Shell 6-145-4 C3222-2 10 22.2 22.2 44.3 54.3 Lower Shell 6-145-7 C3213-1
-20 19.0 19.0 37.9 17.9 Lower Shell 6-145-12 C3217-2
-4 21'.3 21.3 42.6 38.6 Low-Int Shell 6-145-1 C3201-2
-20 19.1 19.1 38.2 18.2 Low-Int Shell 6-145-2 C3188-2
-20 13.6 13.6 27.3 7.3 Low-Int Shell 6-145-6 B7267-1
-20 18.5 18.5 37.0 17.0 WELDS:
Lower to ESW*
10 32.4 32.4 64.8 74.8 Low-Int Girth ESW chemistry based on (average + 1 sigma) of several qualification weld chemistries.
Specific weld heat chemistries are not available.
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TABLE 4 NON-BELTLINE RTyg'S AND LIMITING VALUES NON-BELTLINE RTyg's NON BELTLINE LIMITING RTmg'S UNIT COMPONENT / REGION RTmg UNIT REGION RTmn 1
Closure Region 20*F 1
Upper Vessel 48'F Bottom Head Region 56'F Bottom Head Region 56'F Recirc. Inlet Nozzle 48*F 2
Upper Vessel 54*F Recirc. Outlet Nozzle 42 F Bottom Head Region 42'F Core Spray Nozzle 46*F 3
Upper Vessel 58'F All Other Non-Beltline 540*F Bottom Head Region 58*F 2
Closure Region 22'F Bottom Head Region 42'F Jet Pump Nozzle 54 F All Other Non-Beltline
$40*F 3
Closure Region 10*F Bottom Head Region 58*F Recirc. Inlet Nozzle 46'F Rocirc. Outlet Nozzle 50*F Steam Outlet Nozzle 42'F Feedwater Nozzle 42 F Jet Pump Instr. Nozzle 58'F All Other Non-Beltline
$40*F E-8
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