ML20210E292
| ML20210E292 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 09/19/1986 |
| From: | Julie Ward SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| JEW-86-412, NUDOCS 8609220225 | |
| Download: ML20210E292 (2) | |
Text
_
i*
4
$' SMUI3 SACRAf tENTO dAUlW3CH A!. UT UTY IqTPICT G 6201 S 6treet P.O. Box 15830, Sacramento CA 95852 183o,1916) 452-3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CAllFORNIA JEW M-412 o'$
I Septend er i /19%
jA
.o.
G tQ"
=i a
?.
r0 JS A1ARTINREGIONAL ADMINISTRATOR REGION Y OFTICE OF INSPECTION AND ENFORCEMENT 115 NUCLEAR REGULATORY COMMIS$10N 109 M/?IA LANE.SUffI210 WALN1ff CREL CA 945%
DOCEETNO.50-312 LICENSE NO. J)PR-54 DESCRIFfION OF CURRENT PANCHO SECO f/ECAY tiF4T REMOVA L CAPABILITY la order to clarify recen6 events relative to the Decay IIeat removal capability at Rancho Seco, Ibe Dintrict ucreby provideswccinct description pf:I1) the current Decay IIcat removal capability at Rt.acho seto: (2)ht.v ins Decay IIeat System Trains became degraded: (3) the accons that vcit and will be ta ken to correct th9 ideatified degradation, and: (4) the schedule for formally declaring the Decay Heat System Trains opephie pursuant to Technical SpecificMion 1.3 There are a varietyof nethods avaliable to remove the minimal amount of core decay heat at bncho$cco. There systestsinclude two reactor ccolantloops: the two 100% decay heat system traia:t reactor soolant injection'oy the No remaining make-up pumps. and: grtvity draining of the Boraced Fater Storage Tank to the corr.
Of the methodsdes.cribed above, the twe decay heat trains are fun etional, though not currently
" Operable" ra dofined i;t the Technical Specifications. AJso. the make-up pump injection
- nethod and draining the Borated Water Storage Task to the core method are available for core dc;ay bed removal.
The Jegraded cendition of the decay heat system was described in Licensee Event Report (LER)
N02. That LER described the one-inch diameter decay heat pump casing drain lines which have experienced high velocity erosion as a result of undesirable recirculation flow. LER 86-14 reported a leak which was attributed to the same crosion methodology.
Immediate corrt ctive actions for the decay beat system were-(1) radiographic examination of the affected pipe;(2) sealing the discovered leais:(3) seismically analyzing the repaired casing drain linc;(O perforIning of a review of other pumps in the plant to determine if there were othere with similar configuration problems, and. (5) developing a modification package which corrects the piping configuration. These activstics were done consistent with prudent engineering practice in the power industry, and within the contert of the "immediate corrective action" requirement of Technical Specification 31.15 This immediate action was considered to be an interim response, until at least one Reactor Coolant System (RCS) loop could be made operable for decay heat removal.
8609220225 060919 PDR ADOCK 05000312 P
h'-Ok PDR i, 0
f J. B. MARTIN Septembee.1986 The ultimate corrective action will be to implement the desigo modifica: ion package (ECK R-i-
0495) to reconfigure the decay heat pump casing drain lines. Implementatien of the design modification requires the draining of the affected decay heat locp..it is considered prudentio have at least one RCS Joop available for decay heat removal prior to initiating the destgri modification package The current schedule shows the aforementioned prerequisite will be achieved by late-October 1%6, which will then permit the removal of a single decay hest train from service to implement the system modtfications. Immediately following the completion of the modifications on one decay heat train, the companion train willbe remsved from service for implementation of the system modifications.
Both trains of the Decay Heat System are currently scheduled to be operable by December 29, 1%6 If there are any questions concerning this issue. please contact Mr. Ron W.Cclon:bo at the Rancho Seco Nuclear Generating Station.
/s D
h f
CJ0li3FE' WARD
'N j
DEPIHY GENERAL MANMER.
N~'3 NUCLEAR i
Attachment j
cc Region Vf2)
Sid Minor l
l I
l l
I F
.. a