ML19259D486
| ML19259D486 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/20/1974 |
| From: | Arnold R METROPOLITAN EDISON CO. |
| To: | |
| References | |
| GQL-0097, GQL-97, NUDOCS 7910240753 | |
| Download: ML19259D486 (5) | |
Text
AEC DIS"IRUTION FOR PART 50 DCCKET MAT 7'I3 i
(TEMPORARY FOTdi)
CONTROL NO:
5878 FILE: ENMft0 /J./[
FRCti:
DATE OF DCC DATE REC'D LTR TWX RPT OTHER Metropolitan Edison Company Reading, Pa. 19603 6-20-74 6-27-74 X
R. C. Arnold TO:
J. P. O'Reilly 1 signed SENT LOCAL PDR X
CLASS UNCLASS PROP INFO INPUT NO CYS REC'D DOCKET NO:
XXX 1
50-289 DESCRIPTION:
ENCLOSURES:
Ltr reporting enviro abnermal occurrence E. I.
50-289/74-6, regarding excessive free chlorine concentration Tt the plant river discliarge......
g ACKNOWLEDGED PLANT NAME: Three Mile Island Unit #1 FOR AC"7C:/IN7CR'iATICN 7-1-74 GC BUTLER (L)
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W/ CYS W/1 CYS (info)
W/ CYS W/2 CYS CLARK (L)
STOLZ (L)
DICKER (E)
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YOUNGBLOOD (E) 1459 l99 W/ CYS W/ CYS W/ CYS W/ CYS
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INTERNAL DISTRIBUTION EG FIL TECH REVIEW WOENTON LIC ASST A/T IND tE w(TENDRIE GRIMES DIGGS (L)
BRAITMAN OGC SCHROEDER GAMMILL GEARIN (L)
SALTZMAN
./hUNTZING/ STAFF MACCARY KASTNER A ULBOURNE (L)
B. HURT CASE KNIGHT v8ALLARD KREUTZER (E)
GIAMBUSSO PAWLICKI OANGLER LEE (L)
PLANS BOYD SHA0 MAIGRET (L)
MCDONALD MOORE (L)(LWR-2)
STELLO ENVIRO vdEED (E)
CHAPMAN DEYOUNG (L)(LWR-1)
HOUSTON MULLER SERVICE (L)
DUBE w/ input SKOVHOLT (L)
NOVAK DICKER SHEPPARD (L)
E. COUPE COLLER (L)
ROSS KNIGHTON SLATER (E)
P. COLLINS IPPOLITO YOUNGBLOOD SMITH (L)
D. THOMPSON (2)
DENISE TEDESCO REGAN TEETS (L)
KLECKER
/ REG OPR LONG ROJECT MGR WILLIAMS (E)
EISENHUT FILE & REGION (2)
LAINAS St. Marv (2)
WILSON (L)
MORRIS BENAROYA HARLESS 7910240 ~7 M STEELE VOLLMER
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METROPOLITAN EDISON COMPANY POST OFFICE BOX $42 READING, PENNSYLVANI A 19603 TELEPHONE 215 - 929-3001 June 20, 197h GQL 0097 e
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3 Mr. J. P. O'Reilly, Director
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Regulatory Operations, Region 1 i
U. S. Atomic Energy Ccemission
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gj 631 Park Avenue
% -_ fje King of Prussia, Pennsylvania 19h06 a-1
Dear Mr. O'Reilly:
Operating License DPR-50 Docket #50-289 In accordance with the Environmental Technical Specifications for Three Mile Island Nuclear Station, Unit 1, we are reporting the following Environmental Incident:
(1)
Reporting Number:
E.I. 50-289/Th-6 (2a) Report Date: June 20, 197h (2b)
Occurrence Date: June 13, 197h (3)
Facility:
Three Mile Island Nuclear Generating Station, Unit 1 (h)
Identificaticn of Incident:
Excessive Free Chlorine Concentration at the Plant River Discharre which is a violation of Environmental Technical Specifications, paragraph 2.2.la, and constitutes exceeding a limiting condition for operation.
(5)
Conditions Prior to Occurrence:
Hot shutdown with major plant parameters as follows:
S't sf['N C'~
Power:
Core:
0
/, \\,
Elec:
0 th E'Y.
RC Flow:
1005 u.
[Q u(l,\\f y# IR%G.
[$';,hl RC Pressure:
2155 psig i,;,
C
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S
,G.
1.
y kS n
5, rw p' u
m.
-, /
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Mr. J'.
P. O'Reilly June 20, 197h PC Te=perature:
532 F PRZR Level:
100 in.
PRZR Temp.:
650 F (6)
Description of Incident:
During a periodic evolution conducted to chlo/inate the systems cooled by the mechanical draft cooling tower, che plant river discharge sample taken 10 minutes after co=cercement of the evolution indicated a free chlorine concen-trati >n of.13 ppm.
In that chlorine addition had been terminated about 15 minutes after commencement of the evolution, it was determined that there were no additional actions which could be taken to get the reading within the specification limit.
(7)
Designation of Apparent Cause of Incident:
a.
Material:
It is considered likely that the instrument used to measure chlorine in the grab samples does not have the design capability to accurately determine chlorine at con-centrations below about.10 ppm. This problem was suspected when it was found that the readings for both free and total chlorine in the 10-minute grab sa=ple were identical.
If these readings are to be believed, then there was no combined chlorine in the sample, which, from past experience, is highly unlikely.
The amperometric analytical technique used to determine chlorine relies on the ability of the analyst to detect a very slight fluctuation of a needle.
Consequently, it is easy to suspect having seen a fluctuation and to add more titrant than was actually required to reach the end-point.
Because the chlorine concentration is determined directly from the amount of titrant added, a higher-than-actual reading results.
b.
Procedure.
An additional, possibly contributing factor is that there are no guidelines to aid in determining how the chlorine feed rate should be varied as a function of existing conditions.
Some of the conditions which can affect the amount of free chlorine consumed as it passes through the systems include:
1.
River cooling water transit time from the river cooling water pump discharge to the cooling tower discharge, which is in turn a function of the number of systems and pumps in use, and 2.
Various river water conditions such as temperature, pH, and organic composition.
It is also possible that there is a random varistien in the concentr" ion of chlorine in the river water.
1459 201
Mr. J. P. O'Reill June 20, 197h (8)
Analysis of Incident:
It is believed that the level of free chlorine in the discharge water was not high enough and did not exist for a long enough period of time to have caused any environmental damage or to have endangered the health and safety of the public. This belief is based on the following significant points of information:
a.
Chlorine addition was secured about 5 minutes after collec-tion of the 10-minute sample.
Free chlorine in the 30- and 50-minute samples was measured as.00 ppt.
b.
Total chlorine in the 10, 30, and 50-minute grab samples was measured as.13,.00, and.00 ppm, respectively. All of these values are well below the.20 ppm limit given in the Technical Specifications.
(9)
Corrective Action:
Immediate corrective action involving termina-tion of chlorine addition was not possible because chlorine addition had already been terminated by the time it was realized the limiting value for free chlorine would be exceeded, and no other immediate actions were taken.
The Station Superintendent was notified of the incident.
He in turn informed the Vice President-Generation and, to provide for an additional precautionary measure, it was then decided to decrease the chlorination feed rate to less than 175 lbs/ day prior to the next chlorination period.
A thorough check of the instrument on which the chlorine analyses were performed was conducted by a trained instrument technician.
The results of this check were negative.
An instrument perfor-mance evaluation was also conducted by supervisory personnel, who concluded that the instrument has a marginal performance capability at chlorine concentrations less than about.10 ppm.
Additional long-term corrective actions relating to this same problem were stated in EI 50-289/Th-2 seven-day letter dated June 5, 197h, and EI 50-289/Th-3 seven-day letter dated June 12, 1974, and vill consist of:
a.
further discussing with a consultant terms of a contract to evaluate 1.
if and how chlorine additien rates should be established as a function of existing conditions, and 2.
the reliability of the chlorine scnitoring apparatus, and b.
utilizing the yet-to-be-established 90-day period referenced in the Environmental Technical Specifications, paragraph 2.2.1.b, to further evaluate (9)a.l. and (9)a.2. above.
'41th regard to Item a., Met-Ed representatives did meet on Monday, June 17, with a consultant.
The consultant's bid proposal is expected within the week.
1459 202
Mr. J.' P. O'Reilly
-h-June 20, 197h (10)
Failure Data:
a.
Previous Failures: Although actual malfunctioning of the instrument used to measure chlorine in the grab samples is not believed to be the cause of this incident, this possibility has been previously noted in EI 50-289/7h-2 seven-day letter Mtad June 5, 197h; EI 50-289/7h-3 seven-day letter dated June 12, 197h; El 50-289/7h b seven-day letter dated June 13, 197h; and EI 50-289/74-5 seven-day letter dated June lk,197h.
b.
Equipment Identification:
It vill not be possible to ascertain if the instrument actually failed until the additional technical analyses centioned in (9)a. and (9)b. above are completed; however, on the basis of what information is available, it is believed that without some kind of codifications the instrument is just not capable of measuring low chlorine concentrations accurately.
Sincereb,
h1
. C. A33 told Vice President-Generation RCA:JFV:sh cc:
Director Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C.
205h5 1459 203 File 20.1.1 7.7.3.11.1