ML20085J986
| ML20085J986 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/03/1974 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 246-74, NUDOCS 8310190296 | |
| Download: ML20085J986 (3) | |
Text
>1 i
@. Ono Firstg,onii Plaza. Chictgo, Ilknois O
Comm e:lth Edison 50-249 Addrtss Rrply to: Post Othc3 Box 767 Chicago, Ilhnois 60690 BBS Ltr.f246-74 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 i
April 3,1974 1
Mr. J. F. O' Leary, Director Directorate of Licensing U. S. Atomic Energy Co:nmission Washington, D. C.
20545 i
SUlUECT: LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT #3, REPORT OF ABNORMAL OCCURRENCE PER TABLE 3.2.1 OF THE TECHNICAL SPECIFICATIONS.
_ TECHNICAL SPECIFICATION VIOLATION OF HIGH PRESSURE COOLA?TT INJECTION SYSTEM AREA TEMPERATURE DETECTORS._
References:
,1) Letter from W. P. Worden to, Mr. A. Giambusso. dated March 26, 1973,..
- 2) Notification of Region III of AEC Regulatory Operations Telephone: F. Maura, 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br /> on March 25, 1974 Telegram: J. Keppler, 1445 hours0.0167 days <br />0.401 hours <br />0.00239 weeks <br />5.498225e-4 months <br /> on March 25, 1974
- 3) Drawings P & ID M-51 S & L 12E2527
Dear Mr. O' Leary:
This letter is to report a condition relating to the operation of the unit on March 25, 1974. On this date, 8 of the '16 area temperature switches for the high pressure coolant injection system (HPCI), were found with high operating points. This malfunction is contrary to Table 3.2.1 of the Technical Specifications which requires the switches to be set at 62000F.
PROBLEM At the time of the occurrence, Unit 3 was being refueled and scheduled refuel surveillance was in progress. The following trip points were found on the HPCI area temperature sensors.
Switch No.
As Found As Left
, yh
^~
l, 2371A
'... > 212 0F
- 1900F '
- [., -
4M l
23718 2050F 1950F
/
,, /4 2372B 72120F 1920F N
7 23735 72120F 190er '
1,Q57,'N kf )
.c k " >a > )
a s
..c
%;:6Nki?.*,"G.OWkih, W:5'YQNNi$.Q.!
hh.'
..Y.Yr..W h.* ',
'l
.h$$[
- 0 5 ?
0310190296 740403 J,4,}-
d~
- gl.
7i DR ADOCK 0S000
. gg i
r COPY SENT REGION k.
- 1' t
O O
I r.'J. F.' 0' Leary April 3, 1974
~
M l
Switch No.
As Found As Left 2370C P2120F 1900F 2371D 2050F 1934 2372D 72124 1930F 2373D 2080F 1920F f
The switches were immediately reset to the "as lef t" values indicated.
INVESTIGATION l
On March 16,197",, tie same problem occurred on the Unit 3 HPCI temperature switches, and was reported to Mr. Giambusso. At that time,13 of 16 switches were t d with high setpoints. The corrective action taken as a result of ti...t occurrence was to consult the manufacturer and confirm that the calibration methc,d used by the Isresden Instrument Department was acceptable. The manufacturer (Fenwel) stated that the Dresden hot water technique was adequate. Also, four temperature sensors were checked approx-imately five months after the March 16, 1973 occurrence. At that time, the following setpoints were found:
Switch No.
As Left 3-16-73 As Found 8-9-73 2370C 1930F 1974 2371D 1950F 1920F 2372B 1930F 193 F 0
2372C 1930F 1970F The maximum change in setpoint was +40F, which although above the stated repeatability error of + 34 for a Fenwal series 17000 switch c was considered to be acceptable considering the number of sources in which a one degree error may be introduced. The "as found" data taken on March 25, 1974 shows that 3 of the 4 switches tested on August 9,1973 had trip point changes which violated the 200 F limit. The greatest 0
change occurred in switch 2372B which varied in excess of 190F. (1930F to 2120F). The exact setpoint of the switch is unknown because of the 2120F limit of the hot water method used for calibration.
)
CORRECTIVE ACTION The corrective action to solve this problem will be as follows:
,1.
order a cal.ibration kit from the panufacturer. This. kit.,
includes'al' equipment necessary to se't'Fenwal swit'c'hos
' 1 and is used by Fenwel for calibration purposes.
if:l.}..'~M-Q.i.MU%i htM.Q$k&.W.O.% h'h$i ?$U.dl$4.~.1V.K*:2$EGi:;.$.U 1065.Wihl+##%k **M@
O O
- Mr. J. F. 0' Leary April 3, 1974 2.
Order a new set, plus two spares, of calibrated Fenwel switches (1900F - 1950F) and install them in the Unit 3 HPCI area.
3.
Varify the repeatability of the spare switches by doing a series of repeatability tests using the calibration kit.
4.
Evaluate the findings to determine if additional corrective action is needed.
EVALUATION The HPCI area temperature sensors are arranged in a "one out of two twice" logic array in that a 2370 or 2371 sensor plus a 2372 or 2373 sensor will isolate the HPCI turbine. Analysis of the setpointa indicates that the "B" area (steam pipe area) would have operated at above 212 F and the "D" area (steam chest area) would have operated at 208 F.
The "A" and 0
"- C" sensors are located in the same room and would have operated at 1940F...
It is therefore determined that the safety of the plant personnel or the general public was not seriously jeopardized as a result of this occurrence.
Sincerely,
/
f (//[/g phenso
.'.S Superi endent BBS:WEH:do nM.:39s3.+..o.v.:.nu.=S4..wn anP4'.wai&%..~.8:.w swit.:it%q&q..p.&z.5pk f
I h