ML20126H690
| ML20126H690 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/09/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20126H683 | List: |
| References | |
| NUDOCS 8104200064 | |
| Download: ML20126H690 (2) | |
Text
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w UNITED STATES 1
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l' i NUCLEAR REGULATORY COMMISSION 7
j riASHING TF tJ. O C. 20%S
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SACETY EVALUAT10!4 BY THE OFFICE OF !!UCLEAR REACTOR REbOLATI.04, 5.3: 00.TIUG A!'.EUD!*EUT N0. 67 TO FACILITY OPERATlHG LICENSE 40. DPR-65_
LORTIEAST UUCLEAR ENERGY COMPANY, ET AL.
I',ILLSTONE NUCLEAR POWER STATION,, UNIT NO. 2 DOCKET $105. 50-336
- ".r :duc ti on E) a: plication dated December 27, 1976, as supplemented by submittals dated J anua ry 16, 1979 and October 31, 1980, HNEC0 proposed that the Fy 27,1977,
- s. : atic test feature of the engineered safety feature (ESF) actuation instru-e-titicq be accepted and, therefore, allow a reduction in the r'anual surveillance
-equirements.
T'sc;ssion and Evaluation i - er:cncy saf ety features actuation system (ESFAS) design for
' rtanc-2 included an automtic test-feature injection ( ATI) which s:ts all conbinations of two out of four bistable trip conditions for e :F ESF AS parareter. The auto test feature autonatically indicates
'dentifies faults and verifies bistable calibration every 27 seconds.
3' b'rtable is tested to check that the t-ip setpoint is functioning E1:5
- -:: e rly. This is accomplished by inserting two test pulses in succession
- E' above and 51 below the trip setpoints.
Actuation nodules and the
- .f s as are returned to the bistables if the equipnent performs propJly,
..e first pulse trips a histable, or the.ccond pulse does not get
~#
t -c.:ch, an ATI f ault is indicated. The tinc_ duration of the test pulses sufficiently short to prevent picking up the output actuation relay.
3-?e test results are indicated locally by a panel ATI FAULT Lamp. Remote C: #ault status is also reported to the computer and an annunciator. An r: T A.tLT ir.dication is held until " cleared" by a reset push button located
- -. e r3dule f ront panel.
- thove descriptico is from MI:ECO's applict ticn for a TS change dated
- i. ;M ar 27,1975.
In the application, the
- ensee enphasized its vie <
ESr'S entonctic test-feature providts a rore comprehensive test than rr-
- - s1 :;.Wiity is provided by thc originti ESFAS logic desion.
neting of April ?6,1977, het 'enn ordcm of tne staff and
' - - t m:
m -::entativts fron U'ECO, the licensee prc :ntei to the staff its
- - -W r#ific2tien to the ESF for manually testino of all the ESFAS Sir
'ifi:ctie-c tists of a r:mully initiated test pulse ell itrify the interrity of the EgrAS loric circuit frc, the input g'.d e t i t',e tc tor.ticn nahle c
- t.
(T'.is nodification a s in P:~M letter d:ted,1aly 27, lo77.) The nodified nanuti
+
w ' "n ) c:msilitv of the IS*ic cir:uitry no'v rirovides a ee nte
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- c. )
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[" " I L '. - '.
':*C' (1' f CP ' ' iti: CptmMe fl.r pills
- 7 4-
- C-cate
.it. sfr 13tter 'i
',(. 6, 1977.
8104200 O &
g Ly letter dated January 16, 1979, tWECO presented an accumulation of data the performance of the continuous ATI surveillance of the ESFAS for over 0:one year of c. oration. This data documents the reliability of the ATI system in that:
When challenced with several hundred intentionally apolied faults, it has e
never f ailed to disccver and identify the f aulted cM.nnel within its over-all test program.
In the five instances reported where ATI identified a real f ailure, all c
occh operations were subsequently detemined to be correct for the situation discoveicd.
in the une instance scre the channel was discovered not functional, ATI t
reported this at the time it hapnened rather than at the next surveillance, as would have been the case with manual testing.
In the fall of 1977 when we were reviewin^ the use of ATI, we concluded that operating experience must be obtained utilizing s ich a test circuit before full credit could be given to reduce manual surveillance requirements. G find the data provided now justifies the ATI systen reliability to the limit that nanual testing of the Millstone-2 ESFAS on a nonthly basis is no longer re-quired. Thus, TS Table 4.3-2 notation should be changed to allow credit for autonatic testing of the ESFAS as modified by the staff and agreed to by NNECO.
Environmental Consideration Ue have determined that the anendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not iesult in any significant environmental inpact. Having made this determination, ut have further concluded that the anendment iwolves an action which is insignificant from the standpoint of cr.vironmental irpact end, pursuant to 10 CFR Hl.5(d)(4), that an environmental irpact statenent or negativ2 declaration and environ-nental impact appraisal need not be prepared in connection with the issunnce of this anendment.
Safety Conclusion Ue have concluded, based on the considerations discussed above, that:
(1) because the a1?ne'm:nt dMs not involve a significant increase in the probbility or ccoseguences of accidents previously considered and does nct involve a significant decrease in a safety margin, the
- H. nt dr-c at iwolvc e significcnt heraris consideration, (2) there is reas aSle assurcnce that the h(alth and safety of the Nblic will not be er.dtnpered by operStlon in the prcposed o nncr, and (3) srch activitios vill he conducted in compliance with the Conmission's re 11 7 ti ?nt md tbn itse=nce of this anend,'nt will not Se inimical to' me comron dcfense and sccurity or to ths h2nith and ufety of a: public.
E'9l April 9. 1901