ML19340C531
| ML19340C531 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/16/1980 |
| From: | Hukill H METROPOLITAN EDISON CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-18, TLL-481, NUDOCS 8011170791 | |
| Download: ML19340C531 (2) | |
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Cf4 M4 L F Metropolitan Edison Company Post Office Box 480 4
L Middletown, Pennsylvania 17057 717 9444041 Writer's Direct Dial Number October 16, 1980 7;
TLL 481 o
Ej Office of Inspection and Enforcement Attn:
B. H. Grier, Director tn U. S. Nuclear Regulatory Commission y;2 631 Park Avenue
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King of Prussia, PA 19406 y
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Dear Sir:
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Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 IE Bulletin 80-18 This is to report the results of calculations we have performed for Three Mile Island Nuclear Generating Station Unit 1 in response to your letter of July 24, 1980, concerning 7E Bulletin 80-18, " Maintenance of Adequece Minimum Flow Through Centrifical Charging Pumps Following Secondary Side High Energy Line Rupture".
We have determined that for the conditions reported by the bulletin adequate flow will be available thru the makeup (HPI) pumps.
This determination is based on the following:
A.
The total dynamic head (TDH) developed by the weak pump in the parallel pumping system is 6592' at system minimum flow conditions.
B.
The pressurizer safety valve relief pressure including 1% margin for set point is 2525 psig.
This is a head of 5833'.
C.
Using the result of A above, and allowing for inj.ection system piping head loss, RCS head loss and system static head loss, the head in the RCS pressurizer, for which the minimum flow requirement of the weak pump is maintained, is apprcximately 6233'.
(This result is based on two pumps operating; the three pumps running injection piping loss will be somewhat higher, but as can be seen from this result there is a 400'
" cushion" between the pressurizer relief valve set point of 5833' and the developed head of 6233'.)
8 01117 0 ')PC} l MetroccLtan Ed son Company is a Member of the Geceral Put9c Utit es System
B* H. Grier?' Dire'ctor iLL 481 I
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Additionally, the TMI-l HPI system, as compared to the Westinghouse system, initiates on low RCS pressure (1600 psi) and not on reactor trip. Assuming that the RCS is at normal power levels (2155 psig) and a reactor trip occurs due to secondary side high energy rupture, the RCS would have to shrink approximately 600 psi to initiate the HPI signal.
4 Since the minimum flow requirements for the THI-l HPI pumps are satisfied no j
action is required for Item 2 of the IE Bulletin, The preparation of this response required 75 man-hours.
Sincerely, i
i i
ukill Director-TMI-1 HDH:DGM:lma 1
cc:
J. T. Collins R. V. Reid B. J. Snyder D. DiIanni H. Silver 1
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