ML17296A360
| ML17296A360 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 04/25/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 7905090038 | |
| Download: ML17296A360 (9) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION IIEGION V SUITE 202, WALNUTCREEK PLAZA 1990 N. CALIFORNIA BOULEVARD WALNUTCREEK, CALIFORNIA 9459G April 25, 1979 Docket Nos. ~5~88 50-529 50-530.
~ l Arizona Public Service Company P. 0.
Box 21666
- Phoenix, Arizona 83038 Attention:
Nr.
E.
E.
Van Brunt,.Jr.
Vice President, Construction Projects Gentlemen:
In accordance with our letter dated April l. 1979 transmitting Bulletin 79-05, we are enclosing Preliminary Notification 79-67AF.
Sincerely, Dire tor
Enclosure:
PNO-79-67AF cc w/enclosure:
F.
M. Hartley, APS 79osooo O3$
E ~~in~~',M I
1 IMMEDIATE PRELIMINARY NOTXFICATION, Fpril 2, 19/
PRELIMINARY NOTIFICATION OP EVENT OR UNUSUAI. OCCURRENCE -PNO-79-67AP 4
This relimina notificati'on constitutes summa information of an event of safet or ublic interest si nificance.
The information resented is a
summa of infosmation as of 7:OQ a.m.
on A ril 25 1979.
T~aoiiit:
Three Mile Island Unit 2
~
Hiddletown, Pennsylvania (DN 50-320)
~Snb'eet:
NUCLEAR TNCTUENT AT TNREE MLLE LSLAND L,
s s P1.ant Status.
In the, course of transferring feedwater flow to. the auxiliary nozzles, a carryover. ofwater into the steam line was experienced, resulting in water impingement, in the main turb'ine.
An operator-initiated turbine trip at about 3:00 p.m.
stopped the impingement.
The feedwater was being diverted to the auxiliary feedwater sparger in preparation for secondary system modification for adding a closed cooling system.
Steam is currently being admitted to the main condenser through the turbine bypass valves.
This change in cooling, mode will not affect preparations for natural circulation operations.
The average primary coolant temperature has increased to 224 degrees P.* The highests incore therm'ocouple reading, is 3l2 degrees P.
As a result of changing the charcoal filters in the A Trains of,the Auxiliary and Fuel Handling Building Ventilation Systems, the iodine discharges have been reduced by approximately 80 percent.
The charcoal filters of Auxiliary Building Ventilation System Train B haVe been replaced.
Th~f E:yE:tom wee place@
E,TE acrvicc at 5230 April 25.
Po11owing a briefing of the Governor's Office, a press briefing was held to outline the anticipated schedule for achieving long term cooling status.
A copy nf the press release is attached.
Environmental Status Three Aerial 'Measuring System (ARMS) Surveys were made on April 249 1979.
No radioactivity above natural background was detected.
CONTXNJED IIQKDIATE PREl.LUMINARY NOTIPICATXON
Continued Page 2
April 25, 1979
~
PNO-79<<67M Iodine concentration at Unit 2 ventilation stack (Analyzed by NRC Mobile Laboratory).
Date/Tice Activit (uCi/cc) aa 4/24 (0408) - 4/24 4/24 (0642). - 4/24 4/24 (0815) " 4/24 4/24 (<<2<<7) - 4/24
~
4/24 (1602) - 4/24 4/24 (1958) - 4/25 a
Offsite Measurements Radiation, Levels (0637)
(08<<3)
(1215}
(<<6CQ)
(19~5)
(OQt.'-I}
3.0 x 4.2 x 3 ~ 1 x 1.6 x 2.4 x 2.6 x "8
10-8 10
<<0
'0-8 10',
10 Offsite radiation levels identified by NBC survey teams continue to be consistent with natural background levels (0.02 mR/hr maximum).
These results were obtained from routine daily surveys performed da~~wia u vu, i.I ~ t:~~L ~ide of the Susquehanna River at distahces up to five miles north and south of the site..
Dose rates (47 locations) as measured by NRC thermolueinescent dosimeters (TLDs) for the past 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period continue to be consis-tent with natural backg'round levels.
NRC Environmental Sam les (S~meles taken offsite within 3 miles of site anal zed in mobile laborator air milk daily air 4 2 "25 4/23 4/23-24 Number of Sam les 6
~ 3 1
Results Less than HDA-Iess than BOA Xess than HDA EPA Environmental Sa les (Anal zed at Remote Xaborato air 4/20 air 4/23 air 4/23 Number of Sam les 28 3
Results Less than MDA Range from 2.3 to 7.1 x 10 microcuires per cubic centi-meter {0.23 to 0.71 picocuzies, per cubic meter)
One sample was less than MDA.
One sample indicated ::
168 picocuries per cubic meter of Xe-<<33.~
Both samples indicated approximate background levels of Kr-85.
CONTINUED IMMEDIATE PRELIMINARY NOTIIICATXON
l t
Continued Page 3
April 25, 1979 PZO-79-6HZ All EPA samples were taken at distances greater than 2 miles from this site.
+ADA - minimum detectable activity.
aximum Permissible Concentration for Xe-133 is 300,000 picocuries per cubic meter.
The Commonwealth"of Pennsylvania has been informed of these results.
Attachment:
Press Release Dated 4/24/79
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Contact; 1
Distribution:
Transmitted H St 2 "IW Chairman Hendrie Commissioner Bradford Commissioner-Kennedy Commissioner Ahearne Commissioner Gilinsky Transmitted:
HEBE D. V. Gossich, EDO H. L. Ornitein, EDO J. J. Pouchaxd, PA N. M, Hailer, HPA R,
G. Ryan, OSP H., K. Shapar, ELD Qp H.
R.
8, V.
R.
SS W.
S.
Bidg ~go R. Denton, NRR C. DeYoung, NRR J. Mattson, NRR
- Levine, RES P
m-(+~~ p IE (TMX) Site (Provide copy to STATE)
White House Situation Room FDAA (Provide copies to the Administrator EPA DOE/EOO BRP (State of PA)
DCPA HEM (Pickup)
Handcarry (FAA)
S. J. Chilk, SECY C.
C. Kaamexer, CA (For Distribution)
J.
G. Davis, XE Regina I a'.00 Region II Region IXX ~:
OG'egion IV
@pl
~
Region V
J. J.
- Cummings, OXA R. Minogue, SD and the Operations Center)
A PRELIMINARY NOTIFICATION a
- P ar
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Attachment to PNO-79-67AP FOR XMMEDIATKRELEASE April 24, 1979 The.HRC staff today announced a timetable for placing the Three Mile Island Unit 2 reactor on natural circu1.ation cooling.
As stated on previous occasions, it is now possible to cool the reactor, by natural convection circulation if difficulties arise wi.th presently operating equipment.
Xt is, of course, preferable to place the plant on natural circulation in a planned fashion while presently available plant instruments and equipment remain functioning,,However, iX instrumentation. in the plant does not retain its reliability and the various backup methods presently available do not function adequately, it may be necessary to place the plant qn natural circulation at that time.
H r,
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HH, The excessive non-condensable gases in the system have been removed and are now at an acceptable level.
The phased reduction in primary system temperature has now reached approximately 175~Z.
This reduction in temperature is greater than originally anticipated wi.th steaming in the steam generator A.
Assuming current instrumentation continues to perform satisfactorily, the following timetable for a planned transition to natural circula-tion has been established.
The sequences planned to reach this objective are:
1.
The "B" steam generator will be placed in a water solid condition by April 29th.
2.
The "A" steam generator'wi11 be placed in a water solid condition by April 30th.
Hl HI 3,
Action needed to upgrade the backup cooling capability of the existing decay heat removal system will,be.comp1eted by May l.
4.
Mith these steps completed, the primary system recirculation pump vill be shut. off on May 2nd and the system will then go into natural circulation.
There are a number of other ongoing actions at the plant.
1.
Radioactive effluent filter systems within the plant have been upgraded.
An independent redundant charcoal filter
- system, which vill serve as a second stage of removal, has been under construction for. some time.
The new system is expected to be operational by May 2nd.
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2.
Modifications are currently in progress that will permit the
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'econdary side of the "B" steam generator to be operated in a closed system, i.e., without the need for the availability of the main condenser.
This activity is scheduled for comple-tion for May 7th.
Closed system cooling of steam generator B
is not essential to establish stable natural circulation cooling.
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3.
The "A" steam generator also will be modified to permit operation in a closed system.
This modiH.cation also is not required to establish natural circulation.
its schedule for completion is currently'stimated to be the middle of May.
The passive level and pressure control system that will augment existing plant systems is expected to be completed by mid"May.
This system is not needed to achieve natural circula-tion,'ut. it is prudent to add this redundancy to the existing
'plant equipment for long terrd monitoring of natural circula'-
tion cooling.
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~ v Modifications on t.he onsite electrical system are currently being made.
Additional diesel generatois have been'elivered to the site to provide a backup power supply, and are currently being placed on their foundations.
Electrical instrumentation and other necessary connections will be completed by April 27th.
There are' numbe'r of additional modifications 'being made within the facility that are related to the long term recovery from the accident.
Such modifications include; adding an additiona1 decay heat removal system with equipment to process and remove the radioactive materials from the primary coolant system; the installation of additional tanks to provide for storage of contaminated water. that may result-from decontaminatiou activities; installation of additional contaminated water processing equipment, and general decon-tamination.activities needed in the auxiliary building.
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