ML19322C364
| ML19322C364 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/14/1971 |
| From: | Dopchie H BELGIUM |
| To: | Beck C US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8001160900 | |
| Download: ML19322C364 (3) | |
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ASSOL,ATION V/NQOTTE -1640 R110DE-SAI!TI-dENESE - BELGIUM.
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Association sans but lucratol
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T616 phone: (02) 58 35 80 76 tex : (02) 225 50 -
Ct.&qas Postaux: ;$/7 U2 Socible G&ndrale 'de Banque: 78 222 Dr. C11iford K. BECK Banque de Bruxe!!es: A. 02/2165 Deputy Director of Regulation Banque do Paris et dos Pays Bas: 30635 DGPARTEMENT SGCURITG NUCLGAIRE U.S.A. - WASilINGTON D.C. 20545.
Nucicar Safety 02/00.
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Dear Dr. Beck,
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I received on october 5 the letter dated september 13, 1971, and v'
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signed by Dr. Stephen D. llanauer,in your absence at Ceneva where we 6
met.
I an deeply inpressed by the attention your staff provided to ray concerns, in the midst of your ECCS review. For this, and for our i
amiable conversation in Geneva, I reiterate my expresion of continued i
gratitude.
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Please find hereunder the information requested by your letter; it concerns one Doel unit:
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- reactor type : Westinghouse P.W.R.,
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- reactor power : 1192 FM-th, j
- station power : 390 W-e net, i
- number of loops : 2, 3
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- containment free volume : 43',000 m.,
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- purging rate (2 alternate motors for one inlet ventilator, 2 alter-
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nate motors for one outlet ventilator) : 60,000 or 150,000 m / hour, 3
- purging valves closure time (2 valves per duct) : 2 seconds, (plus I valve per duct for secondary containment, closing automatically at a later presently unavailable time),
- safety injection and containment closure and containment full inter-2 nal ventilation, high containment pressure set point : 0.29 kg/cm crt.
4.1 psig'(2 out of 3 system),
- containment spray, high containment pressure set point : 1.45 kg/cm2ef f = 20.6 psig (2 out of 3 system, fully independant from 1-system above),
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Nuclear Sa fety 02/017.
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- containment closure, high radioactivity set point : not available (1 out of I systen for radioactive gases, 1 out of I system for radioactive dust).
I do hope that the present unavailability of the high radioactivity set point shall not preclude your exanination of our problem. Indeed, if the loss-of-coolant accident originating in the vapor portion of the pressurizer, should occur at hot shut-down, while the containtnent is being purged at full flow, it appears that
- the high radioactivity signal could be a single 1 out of I system to close the containnent building, allow the pressure to rise, and finally generate the safety injection signal,
- the initial radioactivity in the containment atmosphere and in the priciary water could be 109, hence delaying the containment closure until fission products start escaping.
Indeed I should be obliged if you would care to specify the set
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The questions I raised in my previous letters are as follows :
- 1. Is the present situation acceptabic, in view of the postuJated loss-of-coolant accident originating in the vapor portion of the pressurizer ?
- 2. If not, vould you suggest a solution, such as a safety injection and containment closure signal, to supplement the low Icvel signal in the coincident prescurizer low-pressure-low-level signal (a high 1cvel signal may not be adequate, as indicated in my letter of June 25, 1971) ?
- 3. In the examination of this postulated accident, should a larger breach than a rupture of the largest connecting pipe be assured ?
A nan-way is provided on top of the pressurizer.
I would take advantage of your continued cooperation to raise a fur-ther question, which is presently under discussion here. This question is related to a loss-of-ccolant accident originating anywhere in the primary circuit.
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- 4. Since there does not seem to be any fundamental difference betueen a loss-of-coolant accident occurring at hot shut-down, and a loss-of-coolant accident occurring at full reactor power : should contain-cent purging be prohibited while the reactor is at powcr ? If not, would you provide an c>:planation ?
I thank you much again, and renain, Sincerely yours m
. DOPCIIIE Directeur.
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