ML20245G906
| ML20245G906 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 08/08/1989 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | Swenson W NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| CON-NRC-89-098, CON-NRC-89-98 VPNPD-89-436, NUDOCS 8908160248 | |
| Download: ML20245G906 (7) | |
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Wisconsin Electnc POWER COMPANY 231 W %chigan. Ro. Box 2046. Milwaukee. WI 53201 (414)221-2345 VPNPD-89-436
.NRC-89-098 August 8, 1989 Document Control Desk U.S.
NUCLEAR REGULATORY COMMISSION Mail Station Pl-137
' Washington, D.C 20555 Attention:
Warren Swenson, Project Directorate III-3 Gentlemen:
I I
DOCKETS 50-266 AND 50-301 CRITERIA FOR DETERMINING JUSTIFICATION FOR CONTINUED OPERATION WHEN ENCOUNTERING MAJOR DISCREPANCIES IN "AS-BUILT" SAFETY RELATED PIPING POINT ELACH NUCLEAR PLANT, UNITS 1 AND 2 The above referenced document is being submitted for NRC review and approval for use at Point Beach Nuclear Plant.
These criteria are intended-to be used for operability evaluations for safety related piping and associated supports on an interim basis when it is determined that FSAR stresses are exceeded.
These criteria are the same as those previously submitted to the NRC by Northern States Power Company under Docket Nos. 50-282 and 50-306 for the Prairie Island Nuclear Plant.
The allowables used in the criteria are based on the ASME Sectinn TTT Annenaiv ? values (1983 Edition through Winter 1965 Addenda).
These criteria have been submitted to NRC Region III by letter dated August 4, 1989, as part of our response to IE Bulletin 79-14 inspections.
If you have any questions, please contact me.
-Very truly yours, l
.W du f
C. W.
Fa Vice. President Nuclear Power Copies to NRC Regional Administrator, Region III NRC Resident Inspector g6 fd hhk kD 0
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CRITERIA FOR DETERMINING JUSTIFICATION-FOR CONTINUED OPERATION WHEN ENCOUNTERING MAJOR DISCREPANCIES IN "AS-BUILT" SAFETY RELATED PIPING i
WISCONSIN ELECTRIC POWER COMPANY Point Beach Nuclear Plant l
l
TABLE OF CONTENTS D.EE -
1.0 INTRODUCTION
& SCOPE 3
2.0 CRITERIA 3
3.0 CONCLUSION
5
4.0 REFERENCES
5' 1
i l
l _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. _
__ a
l l
1.0 INTRODUCTION
& SCOPE These criteria are intended to assure the operability require-ments of safety related piping and associated supports if it is determined that stresses exceed allewables presented in the Point Beach Nuclear Plant (PBNP) FSAR.
These criteria permit operation for an interim period only.
Modifications will be made which return the system to within FSAR allowables by the next refueling outage or sooner if operation permits.
These criteria are intended to expeditiously perform necessary evaluations to determine interim operability and not to delay appropriate actions.
For cases involving components classified as ASME Code Class I where FSAR allowables are exceeded, the Regulatory Engineer -
PBNP shall be notified upon discovery.
He shall evaluate deportability requirements per 10CFR50.
2.0 CRITERIA 2.1 Piping Operability Criteria The piping analysis shall be in accordance with ASME,Section III NC-3600 service level D limits (Ref. 1).
The design loading conditions to be applied in the analysis shall include the DBE earthquake.
Following is the pipe stress criteria for justifying continued operation of the plant:
[Sgp + SWT + bDBE < 2.0 Sy]
(Ref. 1 equation 9)
Where:
S
= Longitudinal Pressure Stress gp S
= Dead Weight Stress WT S
= Stresses Resulting From Design Basis DBE Earthquake S
= Material Yield Stress (Reference 1 y
Appendices)
Code Case N-411 allows for increased damping values, independent of pipe diameter, for seismic analysis.
Therefore, increased damping values, in accordance with reference 2, will be acceptable when performing these analyses to meet operability.
Should the piping stress analysis exceed the value of 2.0 Sy, or pipe supports do not meet their operable limits (see Section 2.2), then additional iterative analysis of the piping may be required.
The iterative analysis may use the knowledge that a support is not capable of withstanding the loads, and can be removed from the analysis.
Where feasible, the actual support stiffness may be included in the iterative analysis, along with other refinements. _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _
g For cases' where piping secondary stresses are determined lto-exceed FSAR allowables, a specific case by case approach
-will be.used to' determine interim operability.
2.2 Pipe Support & Hanger Operability Criteria-As a first step in evaluating the support, a' linear elastic analysis method will'be used.to determine the stress in the support. members.
In addition to the loading in Sectdon 2.1, the support loads must include pipe thermal loads and results_from free end displacement and anchor motion.
Supports'will be analyzed using the allowables listed below to meet operability requirements.
L Structural Steel l
1.20 Sy but L
Tension F
=
t l
0.70 Su 1.20 Sy but Bending F
=
b 0.70 Su 0.72 Sy but Shear F
=
y 0.42 Su
' Compression F
F but not to exceed a
t2/3.Per Combined Stress For axial compression and bending or axial tension and bending, use XTSC 1.6.,
(Ref. 6)-
1.0 Sy Web Crippling
=
0.42 Su (of weld material)
Weld Stress F,
=
Anchor Bolts Use Factor of Safety of 2 against ultimate tension and shear values Snubbers Hydraulic:
Load < manufacturers one time load capacity.
Movement < total travel Springs Load within catalog range without bottoming out Struts FS = 2 and
< 2/3 Per __.
1 l
All remaining Use manufacturers publisned faulted Catalog Items load rating.
Where level D allow-ables are not given, and the factor of safety is specified in the catalog, use design allowables but j
with FS = 2.
(Typical catalog l
FS = 5, therefore use 2.5 x catalog capacity.
Where:
F
= All wable Tensile Stress l
t I
F
= All wable Bending Stress b
F
= Allowable Shear Stress y
F,
= Allowable Axial Compressive Stress F,
= Allowable Weld Stress Per
= Maximum Strength of Axially Loaded Compression Member Sy
= Specified Minimum Yield Strength at Temperature (See Note 1)
Specified Minimum Tensile Strength Su
=
Temperature Factor of Safety FS
=
Note 1:
Actual yield strength may be ar.ed where CMTR's are available for the material.
If a support fails using the linear elastic method, then a more refined analysis may be performed using plastic analysis techniques.
The plastic analysis will follow the design rules of ASME Section III, Appendix F, (Ref. 1)
3.0 CONCLUSION
If the above criteria cannot be met, deportability per 10CFR50 must be evaluated and system operability requirements per Plant Technical Specifications must be evaluated and appropriate actions taken.
4.0 REFERENCES
1.
American Society of Mechanical Engineers, Boiler and Pressure Vessel Codes,Section III, 1983 Edition, through Winter 1985 Addenda.
2.
American Society of Mechanical Engineers, Boiler and Pressure Vessel Codes, Case N-411, Dated 9/17/84. 1 i
i
r o
3.
NRC-IE Bulletin 79-02, " Pipe Support Base Plate Designs Using Concrete Expansion-Anchor Bolts," Revision No. 1 (Supplement No. 1), Dated 8/20/79.
4.
USAS B31.1.0-1967, Power Piping Code.
5.
" Manual of Steel Construction," American Institute of Steel Construction, Inc., Eighth Edition, 1980.,.
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