ML20214H863
| ML20214H863 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/19/1986 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Ross T Office of Nuclear Reactor Regulation |
| References | |
| 5211-86-2195, NUDOCS 8612010067 | |
| Download: ML20214H863 (3) | |
Text
GPU Nuclear Corporation NggIg{
Post Office Box 480 Route 441 South Middletown, Pennsylvania 17057-0191 717 944 7621 TELEX 84 2386 Writer's Direct Dial Number:
November 19, 1986 5211-86-2195 Mr. Thierry Ross, Project Manager PWR Project Directorate #6 Division of PWR Licensing-B US Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Ross:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Calculations Related to TSCR 162 Concerning TMI-l Main Steam Safety Valve Enclosed please find a calculation for Technical Specification Change Request No.162 concerning TMI-l Main Steam Safety Valve change for testing.
If you have additional questions, please call Joseph Randazzo, TMI-l Licensing Engineer, at (717) 948-8553.
Sincerely, H. D.
u ill Vice President & Director, TMI-l HDH/ JAR /spb Attachments 0711 A 8612010067 861119
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PDR ADOCK 0500 9
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00 GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation gft
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Number of MSSYs Necessary for Heat Removal (Hot Standby)
Page 1 of 2 I.
Assumptions
- 1. Steam conditions are dry, saturated.
- 2. Atmospheric Dump. Valves (MS-V-4A/B) remain closed.
- 3. The plant has been suberitical for at least one hour.
- 4. Multiply ANS decay heat value by 1.2 to conservatively bound all projected fuel cycle schemes for TMI-1.
II.
Calculations The total heat load is made up of the core decay heat and heat from the RC Pumps. The core decay heat is found by assuming that the plant has been subcritical for at least one hour.
^
9 decay heat = 34 (1.2) = 40.8 MWt 100% power time = 0 9RCP heat = 16 MWt 9 Total = 9 decay heat + 4RCP heat 9 Total = 40.8 MWt + 16 MWt = 56.8 MWt 9 Total = (56.8 x 106 Wt) (.05686 BTU / min) (60 min /hr) = 193, 778, 880 BTU Wt Hr 4 Total % 193.8 x 106 BTU /hr.
Main Steam Safety Valves Specifications Capacity (1bs/hr)
Set Point (psig) at 3% Accumulation MS-V-17A/D 1050 792,610 MS-V-20A,D 1050 792,610 MS-Y-18A/D 1060 799,990 MS-V-19A/D 1080 814,955 MS-V-208,C 1092.5 824,265 MS-Y-21A,B 1040 194,900 t
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Number of MSSVs Necessary for Heat Removal (Hot Standby)
Page 2 of 2 The comparison of the heat load to the MSSV capacities must be done using the smallest MSSV, MS-Y-21 A/B.
The setpoint of this valve is at 1040 psig.
It is fully open at 3% accumulation.
P1
= (1040 psig + 14.7 psi) (1.03) = 1086.3 psia hg = 1189.6 BTU /lb QValve = (m) (hg) hValve = (194,900 lbs/hr) (1,189.6 BTU /lb) hValve= 231, 853, 040 BTU /hr% 231.9 x 106 BTU /hr The heat load may now be compared to the heat load for the valve.
hTotal = 193.8 x 106 BTU /hr hValve = 231.9 x 10 6 BTU /hr QTotal < QValve This shows that one MSSV is more than sufficient to relieve the hot standby heat. However, two MSSVs should be operable, one on each OTSG.
III. Conclusion Two MSSVs are required to relieve the hot standby heat with one on each OTSG.
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