ML20084E377
| ML20084E377 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 06/19/1972 |
| From: | Koprowski R ROCHESTER GAS & ELECTRIC CORP. |
| To: | Bloch E US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084E344 | List: |
| References | |
| NUDOCS 8304150039 | |
| Download: ML20084E377 (4) | |
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June 19,1972 Mr. Edward J. Bloch, Acting Director Division of Reactor Licensing U.S. Atomic Energy Commission 7920 Norfolk Avenue Bethesda, Maryland 20014 Subj ect: R.E. Ginna Nuclear Power Plant Unit No. 1 Pr2ssurizer Safety Valves
Dear Mr. Bloch:
In March of this year the Rochester Gas and Electric Corporation began a review of the major safety valve installations installed on Class 1 and Class 2 systems at Ginna Station Unit No.1.
A report on the main steam safety valves was submitted to you at a meeting at your office on June 5,1972. We are herewith submitting the results of our dynamic-analysis of the pressurizer safety valve discharge piping at Ginna Station.
The initial analysis of the inlet and discharge piping of the pres-surizer safety valves PCV 434 and PCV 435 indicated the need for installation of additional supports on the Class 2 discharge pipe. During the recent refueling shutdown, eight hydraulic sway braces and four rigid '
pipe supports were installed on the safety valve discharge piping. The first anchor on the downstream Class 2 piping for ea'ch valve was also upgraded to provide additional system rigidity.
A time history hydraulic analysis was performed by Westinghouse Electric Corporation to determine the magnitude and resolution of the.
momentum and pressure forces acting on the discharge piping during the valve relieving condition. The results of this program were used to per-form a dynamic stress analysis of the Class 1 inlet piping and the Class 2 discharge piping. A more detailed description of the methods of'ana1ysis used in both the hydraulic and stress analysis appears in Appendix I to -
. this report.
8304150039 730315 PDR ADOCK 05000244 P
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TABLE I DYNAMIC STRESS
SUMMARY
CLASS I PIPING PCV 434,435 STRESS Ksi LOCATION S
8 D. W +
S long.
St Total E Thermal R ea ction Wi cmi c Pressure Mechanical Expansio 2
- 1) Pressurizer Nozzle PCV 434 at Pt. 286
- 2. 3 (h1 ax) 2. 2
- 3. 5 '
- 8. 0
- 20. 7(Max)
.[
PCV 435 at Pt. 315
- 1. 9
- 7. 7
- 3. I 12.7 12.5
- 2) Max. Stress in Loop PCV 434 at Pt. 240
.8
- 1. 9 3.1
- 5. 8 13.6 PCV 435 at Pt. 260
- 1. 2
- 3. 0 3.1
- 7. 3 12.4
!I
- 3) Safety Valve Inlet PCV 434 at Pt. 223
.8
- 1. 6 3.1
- 5. 5
- 8. 6 PCV 435 at Pt. 242
.4
- 3. 0 3.1
- 6. 5
- 8. 9
>l 5
Material - SA 376 Stainless Grade 316 B31.1 Allowable Stress - Sustained Mechanical Load
+
b
+ b (Deadload + reaction)
Seismic Long. Pressure Sa
- 1. 2 SH=
1.2 (17.05) 20.45 Ksi
=
=
B31.1 Allowable Expansion Stress SE Sa f (1. 25 Sc+,25 S h ).
=
Sa = 1 (1. 25[l8. 75]) +.25 (17.05) = 27. 66 Ksi
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O TABLE II DYNAMIC STRESS ANALYSIS CLASS II PIPING PCV 434, 435 STRESS Ksi LOCATION j
SD. W +
S S
St Total SE Thermal Long.
Reaction Seismic Pressure Mechanic :11 Expansio l
- 1) Safety Valve Discharge i
PCV 434 at Pt. 223
- 0. 6 1.1
- 3. l'
- 4. 8 13.4 PCV 435 at Pt. 234
- 2. 6 (Max)
- 3. 3 3.1
- 9. 0
- 18. 4 (Max i
- 2) PCV 434 at Pt. 210
- 0. 9
- 1. 8 3.1
- 5. 8
- 3. 5 PCV 435 at Pt. 210 1.1
- 3. 2 3.1
- 7. 4
- 3. 0 l
- 0. 2
- 3. 5
- 3. 6
- 7. 3 4.1 PCV 435 at Pt. 104
- 0. 5
- 3. 9
- 3. 6
- 8. 0
- 5. 6 i
I Material SA 106B Carbon Steel B31.1 Allowable Stress - Sustained Mechanical Load SapSt S(Dead Load + reaction)+ 8(Seismic) + 8 (Long pressure) 1 i
Sa = 1. 25H=
1.2(15.0) 18.0 Ksi
=
B31.1 Allowable Expansion Stress S i
E A
f (1.25 Sc + 25 Sh)
S
=
1(1. 25 (15]) +,25 [15] = 22. 5 Ksi S
=
A
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- 2 June 19,1972 Mr. Edward J. Bloch The results of the dynamic stress analysis for the Class 1 piping are summarized in Table I.
The dynamic analysis performed with the new supports installed on the Class 2 system shows that the Class 1 piping is well protected from the effects of the transient forces acting on the dis :harge piping during safety valve relieving condition. The dynamic analysis also indicates that the Class 2 safety valve discharge piping with the new supports meets the design requirements of B31.1 for sustained mechanical and thermal loading. A summary of this anal-ysis is shown on Table II.
The Westinghouse Electric Corporation has also reviewed the nozzle design for each safety valve attachment to the pressurizer. The results of this review show that the structural integrity of the safety valve nozzle remains intact during the transient loading and all the requirements of Section III of the ASME Pressure Vessel Code for primary and secon-dary stress are met.
Very truly yours,
(
R. R. K prowski Vice President and Chief Engineer i
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