ML20155G650
| ML20155G650 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 10/30/1998 |
| From: | Dennis Morey SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20155G654 | List: |
| References | |
| GL-96-06, GL-96-6, NUDOCS 9811090136 | |
| Download: ML20155G650 (8) | |
Text
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Dave Morey -
Siuthern Nuclear.
Vice President Operati;g Compa:y
-e Farley Project.
RO. Box 1295 Birmingham, Alabama 35201 Tel 205.992.5131 October 30, 1998 SOUTHE.RN co Energy to ServehurWorld"
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Docket Nos.:
50-348 10 CFR 50.54 l
50-364 U' S. Nuclear Regulatory Cn==i== ion.
ATTN: Document Control Desk W==hiayna DC 20555-0001 Joseph M. Farley Nuclear Plant
- Resanne To Request For Additional Information (RAI)
Regardmg Generic Letter 96-06, " Assurance Of Equipment
. Operability And Caa*=ia-t Tat =rity Durina Desige Basis Accident Canditinna" Ladies and Gaath-l By letter dated August 25,1998, the NRC issued a Request for Additional Information (RAI) regarding responses to Generic Letter (GL) 96-06. Attachment I contains the response to the RAI.
- A**-h=aat 2 contains requested drawings, Mr. D. N. Morey states that he is a Vice President of Southern Nuclear Operating Company and is authorizC to execute this oath on behalf of Southern Nuclear Operating Company and that, to the
. best of his knowledge and belief, the facts set forth in this letter and enclosures are true.
L' This letter contains no formal NRC commitments and nothmg stated herein should be considered as a license commitment Ifyou have any questions, please advise.
Respectfully submitted, y
fri,pwu Dave Morey Sworn to andsubscribed before me this, %
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l998 N(hfA bS L
Notary Public U L
My Commissim Expires:
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-A O'7 d SLG/EWC/ cit:9606rai.d-e O W!p n o Attachment and Drawings:
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cc:
Mr. L. A. Reyes, Region II Administrator -
j Mr. J. I. Zimmerman, NRR Project Manager Mr. T. P. Johnson, Plant Sr. Resident Inspector 9811090136 981030 ?
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I ATTACHMENT i
f Response To RAI Regarding Generic Letter 964, " Assurance of Equipment Operability and Containment Integrity During Design Basis Accident Conditions" l
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i ATTACHMENT t
Response To RAI Regarding Generic Letter %-06, " Assurance of Equipment Operability and Containment Integrity During Design Basis Accident Conditions" i
In response to submitted information related to Generic Letter 96-06, " Assurance of Equipment Operability j
and Containment Integrity During Design Basis Accident Conditions," the NRC has issued a Request for Additional Information (RAI). He information requested relates to pipe segments residing between closed inboard and outboard containment isolation valves. Accident conditions within containment may affect the temperature and pressure of the water trapped between the valves by heat transfer through the pipe wsil.
%e concern lies in the potential for pressure withm the pipe segment to rise such that adverse consequences occur (i.e., pipe rupture, valve fahre).
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%e NRC questions and the SNC responses are provided below.
1)
Provide the applicable design criteria for the piping and the valves. Include the required load combinations.
The applicable Code for the piping and valves is ASME Section III,1971 Edition, with addenda through Summer 1971. A later edition of the Code is allowed with properjustification.
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%e combined load conditions used for analysis included the dead weight stress as well as stress resulting from the elevated temperature and pressure during post-accident conditions (i.e., post-LOCA). The subject event of elevated piping k..pridore and pressure is a post-accident condition initiated by a postulated faulted event. As discussed in NUREG-1061, Volume 4, LOCA and seismic events are not considered to occur concurrently. In addition, the subject condition of these elevated parameters exists for only a relatively short duration. Herefore, it was considered unnecessary to analyze the loads concurrent with other faulted events (i.e., seismic). NC-3652 equations 8,10 and 11 of the Code (Winter 1972 N2) were used to determine if the loads met Cod allowables.
Below are the design criteria for the piping and valves for each of the applicable penetrations.
Design Criteria for Piping:
Penetration No.
Size Schedule Material Function 3
29 3/4" 160 Stainless Steel Accumulator Test j
l 43 3"
160 Carbon Steel RCP CCW Return 49 1"
160 Stainless Steel Accumulator Fill 50 3/8" 0.065" StainlessSteel Sample Line thickness i
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ATTACHMENT Design Criteria for Valves:
Penetration No.
Valve #'s Size Ratmg Type Actuator 29 Q1(2)E21V049 3/4" 1500lb.
Globe Air Q1(2)E21V050 3/4" 1500 lb.
Globe Air 43 Q1(2)Pl7HV3045 3"
1500 lb.
Globe Air Ql(2)Pl7HV3184 3"
1500 lb.
Globe Air 49 Q1(2)E21V052 1"
1500 lb.
Check N/A J
Ql(2)E21V091 1"
1500 lb.
Globe Air 50 Q1(2)P15HV3334 3/8" 1500 lb.
Globe Air i
Q1(2)P15HV3766 3/8" 1500 lb.
Globe Air i
Note: Properties for Unit I and Unit 2 piping and valves for each penetration are the same.
Material Properties.
Parameter Stainless Steel Carbon Steel Water Modulus of Elasticity 2.83E7 3E7 E (psi)
Poisson Ratio y 0.3 0.3 Linear Coefficient of 9E-6 6E-6 Expansion a. (1/ F)
Bulk Modulus (psi) 3.2E5 A-2 l
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ATTACHMENT 1
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2)
Provide a drawing of the piping run between the taal=*Ia= valves. Include the lengths and l
thick-== of the piping segenents and the type and thickness of the insulation.
UNIT I I
Penetration Drawing -
Pipe Insulation No.
Numbers Length nickness Type nick =s (Inside/Outside Containment) 29 D-518105 8.2 A.
0.219 in.
N/A N/A R/0 (0.8 A / 7.4 ft)
D-518643 R/0 i
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49 D-518106 29.7 A.
0.250 in.
N/A N/A R/0 (1.3 A / 28.4 A) l D-518570 l
- Note:Inside contamment only.
l UNIT 2 Penetraten Drawing Pipe Insulation No.
Numbers Length
'Huckness Type nickness (Inside/Outside -
Containment) 29 D 515C78 20.8 A.
0.219 in.
N/A N/A
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R/0 (1.1 A/19.7 A) l D-515939 i
R/0 l'
1 49' D-515690 20.1 A.
0.250 in.
N/A N/A R/0 (1.8 A/18.3 A) j' D-515875 R/0 l
- Note: Inside contamment only.-
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ATTACHMENT 3)
For penetrations 29 and 49, provide the maximum calculated temperature and pressure for the pipe run. Describe,in detail, the method used to calculate these pressure and temperature values. Please include a discussion of the heat transfer model used in the analysis and the basis for the heat transfer coefficients used in the analysis.
Penetration No.
Twgirdure (*F)
Pressure (psig)
Unit 29 275 3006 1
49 275 2418 2
Note:
The penetrations used in this analysis was chosen to provide the most conservative results. 'Ihe difference between the two units is primarily in pipe length between the two containment isolation valves.
When trapped water is heated, the temperatum increase causes the water to expand. Assuming there is no trapped air, pressunzation of the water volume is limited by the expansion of the pipe material and the compressibility of the water 'Ihe pressures resulting from relative expansion of the water and the piping are solved to provide internal pressures.
The temperature of the fluid inside the piping inside containment is maximized by conservatively assuming the water and pipe steel follow the contamment saturation temperature without delay.
'Iherefore, no heat transfer analysis is performed for these pipes, Pressures for these pipes are calculated at 275'F, thus boundmg the maximum containment saturation t-spi. hare postulated followmg a LOCA. 'Ihe piping volume outside containment is considered when calculatmg pressure.
4)
For penetrations 43 and 50, in which pressure in the pipe segment is relieved by valve leakage, provide a drawing of the isolation valves. Provide the pressure at which the valve was determined to lift offits seat or leak and describe the method used to estimate this pressure. Discuss any sources of uncertainty associated with the estimated lift off or leakage pressure.
As listed above under question 1, the following values were analyzed as the lifting pressure for penetration 43 and 50:
Penetration No.
Valve TPNS No.
Valve Seat Lift Pressure (psig) 43 Q1(2)Pl7HV3184 680 50 Q1(2)P15HV3334 4047 Each of these valves is an air-operated, fail-closed globe valve. In establishing the required line pressure to unseat the valve, the following process was utilized.
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ATTACHMENT The actuator force required to lift the valve plug from the seat, actmg against the preload of the spring and the valve frictmnal forces, is considered equivalent to the hydraulic force needed to lift the valve plug. The hydraulic force is equal to the product of the line pressure and the exposed area of the plug. For the calculations, the assumed air pressure to lift the valve plug was established as the available supply air pressure. There were no uncertainties included in these calculations The basis of omitting any uncertainties is discussed below.
Assuming the available supply air pressure in the calculations is considered conservative, the air pressure required to fully open the valve would be less than the available supply air pressure. The air pressure to fully open the valve consists of the pressure required to unscat the valve plus the additional pressure to raise the valve stem through its full travel. Therefore, the actual pressure required to unscat the plug would be less than the full open air pressure. The difference between the unseat pressure and the full open pressure value is determined by considering the installed spring rate, the actual valve travel, and the diaphragm area. The conservatism in using the supply air pressure would encompass any associated uncertainties with spring rates, diaphragm area, etc.
These penetrations are also equipped with an inside and an outside containment air-operated isolation valve. The valves are installed such that any pressure build-up in the piping section between the valves is applied to the under plug area of the outboard valve for penetration 50, and the inboaid valve for penetration 43. The pressure required to lift the valve and relieve the pressure is less than the allowable pressure of the piping and enm:-ats within the pressure boundary. Once une=*d penetration 50 will relieve to the Volume Control Tank (VCT), which will support the addition of this small amount of fluid with no adverse effect to the VCT. For penetration 43, the inboard valve is designed to reverse leak when pressure is applied under the seat to a section of CCW piping protected by pressure relief valves.
Drawings of the valves are =***M They are listed below.
Drawina Valve TPNS No.
Penetratim No.
U-176882 QlP17HV3184 43 U-209211 Q2P17HV3184 43 U-258078 QlP15HV3334 50 QlP15HV3766 U-213131 Q2P15HV3334 50 A-5
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ATTACHMENT
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For penetrations 43 and 50, provide the maximu n calculated stress in the piping run based on l
the estimated liR off or leakage pressure.
Penetration No.
Valve Seat Lift Pressure Maximum Pipe Stress at (psig)
Valve Seat Lift Pressure (psi) 43 680 1358 50 4047 5837 l
The principle stresses on the pipe wall under net internal pressure are determined by the following formula:
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PD.
1 a=
4tn r
where:
l o = principle stress (psi) l P =internalpressure(psi)
D.= outer diameter (in) j.
- t. = thickness of pipe (in) l Using the values for the pipe listed under question 1, and the maximum pressure in the pipe for stem lift in the valves listed under question 4, the above equation can be used to find the maximum stress experienced by the pipe.
The above valve seat lift pressures and the associated pipe stresses are within the Code allow %les as listed in ASME Section III,1971 Edition, Appendix I, Table I-7.1. Based upon a review of the l
piping configurations and support systems, adequate margin exists to Code allowables to l
accommodate dead weight and thermal stresses.
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