ML19221A640
| ML19221A640 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/06/1979 |
| From: | Haskin F, Thiesing J INDUSTRY ADVISORY GROUP |
| To: | Levenson M INDUSTRY ADVISORY GROUP |
| References | |
| OLP-790406, TASK-101, NUDOCS 7905230496 | |
| Download: ML19221A640 (3) | |
Text
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a To:
Milt Levenson Date:
April 6,
1979 r].
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Subject:
Hydrogen infQRCS.
Fron:
F.
E.
Haskin J.
W.
Thiesing Copies:
J.
Hurley Of:
Industrial Advisory Group At:
TMI Degassing History Rapid degassing of reactor coolant occurred in the make-up
.- t a n k, with the letdown systen in normal alignment (except for bypassing the block orifice), until about 0716 on 3/29/79 at which time the vaste gas decay tank pressures approached the shutoff head of the waste. gas compressors.
At this time, letdown was diverted to the B reactor coolant bleed tank.
Letdown continued using the A, B,
and C RCB tanks until 1920 on 3/30/79 when the A tank went full.
During this tine, makeup to the nakeup tanks was demineralized water and boric acid which reduced nakeup tank pressure from a 65 psig level by redesolving makeup tank gases and injecting then into the PRCS.
By 1440 on 3/30/79, both waste gas decay tanks were essentially at the waste gas compressor shutoff head.
At 2036 on'3/30/79, nakeup to the makeup tanks was shifted to the bleed tanks, letdown from the PRCS was still to the bloed tanks, which also vent to the waste gas conpressor.
Operation
(
)
in this node continued until at least 4/2/79 at 1835 (the cad of available operator log data).
Sonotine after this tine, letdown was shifted back to the nakeup%e.
tank and apparently continues in this code at this 49 RCS nakeup te Nalance RCS leakage and pressurizer leakage is being'taken from the reactor coolant bleed tanks.
Clearly, the waste gas decay tanks have been unable to accomodate additional hydroZen gas since about 1440 on 3/30/79 at which time the tank pressures were about 84 psig, estimated to be the conpressor shutoff head.
During the ensuing p'e r i o d, regardless of whether the makeup tank or the bleed tanks are receiving letdown, offgas.nust have followed one or more of the following paths:
s,_,
1.
Released to the auxiliary building via the reactor coolant bleed tanka relief valves.
2.
Leaked to the auxiliary building through leakage paths, probably downstress of the comprsssor.
3.
Leaked to the auxiliary building from waste gas collection header upstrean of compressors.
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-f gilt Levenson April 6,
1979
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[ {J We estinate that this ao e,'of degassing is probably quite efficient and it is possible, if not probable, that hydrogen
~-
i concentrations in the PRCS are quite low.
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F.
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liaskin J.
W.
Thiesing F Ell / J h'T /d e s Tt is also c f cmportanc e f4af prior to 203C-f/a,nuk'ey kk cy,, 's 79,
letdoa to re d fed in id. preswricaHo~ of t% faa/<,
surnased 4-e a-result of ritpt g;
Of RCS Enabi/;k[h waker y/ed u>rtA.
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P9.0CEDURE FC:t MEASURIM REACTOR CCOLA'(T HYDR
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f gi
!! ring KU ts:t levol to approxie.ately 55* % by transferring.
1.
't G.J, g7. -
. it' necessary,ilquid frco RC Bleed Tcnk.
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Maintain letdown flew at maxirus available rate hold constant. %c.0 < #Sg7;%
'I Align HU-V8 to take reactor coolant letde sn directly to makeup tank
- 2.
Open either MJ-V13 or h"J-V134 and pull the cakeup tank pressure dcun i
far as pcssible with the waste gas compressor.
3.
Promptly close MJ-Vl3 and ht-Y134 to isolate gas syace in (Yi,At, QArd Mlin$ /En es Shau/d UG l$olMW),
4 Record:
a
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U
'j a.
Time 9 s b.
WDG vent hsader pressure c.
Makeup tank pressure d.
Makeup tan.: leYel Makeup tank temperature e.
f.
Letdown fIcw Sm [ r cfur M OM-j Recorti these para:neters at the initiation of Step 3 and every tir:x2 the
'r.ake-up tank pressure increases 1 to 5 psig, depending on ra te of pre increase.
5.
Continue procedure for as long as possible, consistent with makeup tan pressure limits and plant operating rm essities.
6.
Secure frtzs procedure, return to normal operating rode.
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