ML19210A084

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Discusses Results of Bounding Analysis Justifying 2405 Psig High Pressure Trip & 2500 Psig Pressurizer Code Safety Valve Settings.Further Test Results to Be Submitted May 1978 W/ Refined Cycle 4 Tech Specs
ML19210A084
Person / Time
Site: Three Mile Island Constellation icon.png
Issue date: 04/20/1978
From: Herbein J
METROPOLITAN EDISON CO.
To: Reid R
Office of Nuclear Reactor Regulation
References
GQL-0743, GQL-743, NUDOCS 7910240796
Download: ML19210A084 (3)


Text

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REGULATORY INFORMATION DISTRIGUTION SYSTEM (RIDS)

DISTRIEUTION FOR INCOMING MATERIAL 50-289 PEC: REID R W ORG: HERBEIN J G DOCDATE: 04/20/79 NRC METROPOL EDISON DATE RCVD: 04/24/7S DOCTYPE: LETTER NOTARIZED: NO COPIES RECEIVED

SUBJECT:

LTR 1 ENCL 0 FURNISHING ADDL INFO TO APPLICANT"S LTR DTD 04/17/78 CONCERNING RESULTS OF A BOUNDING ANALYSIS TO JUSTIFY 2405 PSIG HIGH PRESSURE TRIP AND 2500 PSIG PRESSURIZER CODE SAFETY VAL'>E SETTINGS.

PLANT NAME: THREE MILE ISLAND - UNIT 1 REVIEWER INITI AL: XJM DISTRIBUTOR INITIAL. W

                                  • DISTRIBUTION OF THIS MATERIAL IS AS FOLLOWS ******************

GENERAL DISTRIBUTION FOR AFTER ISStfANCE OF JPERATING LICENSE.

(DISTRIBUTION CODE A001) 4 FOR ACTION: BR CHIEF REID**LTR ONLY(7)

INTERNAL: NRC PDR**LTR ONLY(1)

G EG FILE *iLTR ON

. u t**LTR ONLY(2) OELD**LTR ONLY(1) ,

HANAUER**LTR ONLY(1) CHECK **LTR ONLY(1)

EISENHUT**LTR ONLY(1) SHAO**LTR ONLY(1)

BAER**LTR ONLY(1) BUTLER **LTR ONLYil)

EEB**LTR ONLY(1) J COLLINS **LTR ONLY(1)

J. MCGOUGH**LTR ONLY(1)

EXTERNAL: LPDR'S HARRISBURG, PA**LTR ONLY(1)

TIC **LTR ONLY(1)

NSIC**LTR ONLY(1)

ACRS CAT B**LTR ONLY(16)

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f j DISTRIBUTION: LTR 40 ENCL 0 CONTROL NBR: 7S1150041 SIZE: 2P

                                    • -***************** THE END *********************************+

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I f M L:Y Um nwns METROPOLIfAN EDISON COMPANY '

POST OFFICE BOX 542 READitJG, PENNSYLVANI A 19603 TELEPHONE 215 - 929 2601 April 20, 1978 GQL 0743  % i N f'M c  %.:.N kC![*[i..

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Director of Nuclear Reactor Regulation l , u.s APg h/S7g Q Attn: R. W. Reid, Chief ce?' % C2 Np'q I

Operating Reactors Branch No. 4 d N. .

U. S. Nuclear Regulatory Commission &

Washington, D.C. 20555 '/f

Dear Sir:

Three Mile Island Nuclear Station, Unit 1 (TMI-1)

Operating License No. DPR-50 Docket No. 50-289 High Pressure Trip and Pressurizer Code Safety Valve Settings Metropolitan Edison Company letter of April 17, 1978, GQL 0669, submitted the results of i bounding analysis to justify 2405 psig High Pressure Trip and 2500 psig Pressurizer Code Safety Valve settings. This bounding analysis assumed the following:

1. High Pressure trip occurs at 2450 psig (2405 psig setpoint plus 45 psi instrument error).
2. Pressurizer code safety valves open at 2545 psig (2500 psig setting plus 25 psi uncertainty plus 20 psi fluid acceleration delays for the water seal upstream of the safety valves).
3. Pressurizer code safety valves relief rate of 172 lbm/sec at 2500 psig.

2

4. Surge line K - factor of 8.21 x 10-5 lbf-sec2/lbm2/in which bast.d on actual TMI-l as-built geometry yields conservative values of the pressure difference between the reactor coolant loop and the prescurizer.
5. Trip string pressure delay time of 500 ms (Characteristic of the 59PH sensor originally installed).

However, our letter of November 18,1977, GQL 1520, identified two (2) changes that were not considered in the bounding analysis. They are,

1. Pressurizer code safety valves relief rate of 156 lbm/see at 2500 psig (This was identified during an updating of the valve nameplate data).
2. Trip string pressure delay time of 450 ms (Characteristic of the Ros nt sencor which was installed during the 1977 refueling outage).

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