ML17208A592
| ML17208A592 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 04/30/1980 |
| From: | Robert E. Uhrig FLORIDA POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-80-03, IEB-80-3, NUDOCS 8005200223 | |
| Download: ML17208A592 (5) | |
Text
P.OBOX 529100 MIAMI,F L 33152 8005@DO 4+~
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FLORIDAPOWER & LIGHT COMPANY April 30, 1980 L-80-131 Mr. James P. O'Reil'ly, Director, Region II Office of Inspection
& Enforcement U. S. Nuclear Regulatory Comission 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
Re:
RII:JPO 50-389 IE Bulletin 80-03 FPL has reviewed the design of all systems that contain low pressure or holdup tanks that can be valved to contain primary system water.
We considered a
tank acceptable if it met one of the following criteria:
(a) non-isolable vent.
(b) design specification of one atmosphere (15 psig) external pressure.
(c) installed in a system such that superheated or saturated condensables cannot enter the tank nor can a significant pumped vacuum be drawn.
The table in Attachment I summarizes the results of this survey.
Note that all tanks with the exception of the holdup tanks can be dismissed for reasons of meeting at least one of the preceeding criteria.
The holdup tanks can receive high temperature condensable gases from numerous relief valves.
Vacuum damage might result from the condensation of these gases if the tank were completely isolated.
In addition vacuum damage might result from pumping out a tank (or tanks) with the holdup drain or holdup recircula-tion pumps under conditions of complete isolation.
Since the tanks are approximately 56 feet tall, the tank internal pressure could drop to the saturation pressure of the liquid being pumped (e.g.
1.,5" Hg for water at 92oF) well before a full tank would be emptied or a pump would lose suction.
Protection against holdup tank vacuum damage is provided by the regulated nitrogen overpressure applied through the common relief valve header.
The capacity of this valve (16 SCFM) is greater than the volumetric discharge rate through any discharge path.
- g ('y'lQ~CQHi" PEOPLE... SERVING PEOPLE
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Office of Inspection 8 Enforcement Page Two Tank nitrogen overpressure is maintained via individual lines from the relief valve header to each of the tanks.
Each of these lines contains a single, locked open, manual diaphram valve.
In addition, the tank upper heads are interconnected via the header line to that regulator discharging to the gas collection header.
Each tank is connected to this header by a second individual line containing a single normally open valve.
E Ill'dpk'~'dd'I 'd'-'d~'Sh~p via four pressure switches.
These annunicators will alarm at internal pressures lower than 3-psig.
This setpoint provides adequate time for the operator to restore isolated nitrogen overpressure or stop the drain pumps before vacuum damage could occur.
In order for holdup tank vacuum damage to occur, there would have to be either inadvertant closure of both the normally open and the locked open valves in the lines to the nitrogen overpressure together with an extended failure to respond to.the. isolated tank low pressure annunication or, in the case of interruption of the nitrogen overpressure supply from the supply header, an extended failure to respond to an annunication of low pressure in all four holdup tanks.
FPL believes these combinations of errors are too improbable for further consideration.
Therefore, FPL considers all systems reviewed in response to this Bulletin to have acceptable vacuum protection.
Very truly yours, O'obert E. Uhrig Vice President Advanced Systems 8 Technology REU/JRP/ah Attachments cc:
Harold F. Reis, Esquire
ATTACHMENT I gl ST. LUCIE UNIT'2 REVIEW OF LOW PRESSURE OR HOLD UP TANKS SYSTEM COMPONENT (TANK)
NON ISOL'ES. PRESS VENT INT/EXT YES/NO (PSIG)
SAT'D CONDESABLES INPUT, YES/NO PUMPED VACUUM YES/NO ACTION RCS CVCS QUENCH NO B.A. MAjKUP REAC. DRAIN YES FLASH NO HOLD UP.
EQUIP.
DR.
CHEM DR.
NO YES YES L'DRY dr.
YES ~
SPENT RES.
~g WASTE"C01fd.
NO YES VOL.
CONTROL NO CHEM. ADDN.
YES
.B.A. BATCH.
YES aOO/15 75/15 25/15 70/15 10/2 SO/O (1)
YES YES DISMISS DISMISS DISMISS DISMISS DISMISS DISMISS DISMISS EVALUATE DISMISS DISMISS DISMISS DISMISS (1)
DISMISS
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. GAS SURGE GAS DECAY NO NO oo/0 190/0 NO NO NO NO DISMISS
, DISMISS
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E ATTACHMENT I CON) T ST; LUCIE UNIT 2 REVIEW OF LOW PRESSURE OR HOLD UP TANKS
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'SYSTEM COMPONENT (TANK)
NON INSOL-.
DES, PRESS VENT INT/EXT YES/NO (PSIG)
SAT'D CONDESABLES iINPUT YES/NO PUMPED VACUUM YES/NO ACTION a
B.A.
COND.
YES B.A'OND.
YES
, RES.
ADDN.
YES SIS
'EFUELING WATER YES DISMISS DISMISS DISMISS DISMISS (1)
ACTUAL WALL THICKNESS OF.354 IN. USED ON THIS SPENT RESIGN TANK (8 FEET DIA.) IS GOOD FOR EXTERNAL PRESSURE OF 20 PSIG PER AS1'lE SECTION III, CLASS 3.