ML20091K910
| ML20091K910 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 01/16/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20091K897 | List: |
| References | |
| NUDOCS 9201270153 | |
| Download: ML20091K910 (3) | |
Text
_
8[psneuq'o, l
UNITED STATES i
' 'p NUCLEAR REGULATORY COMMIT;lON i
WASHING T ON, D. C. 20$N 5,....+
SAFETY EVALUATION BY_THE OfflCE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.16a TO TACILITY OPERATING LICENSE NO. NPT-3 TOLEDO-EDISON COMPANY l
CENTER 10R SERVICE COMPANY i
f.N,0 THE CLEVELAND ELECTRIC ILLUMINATING COMPANY
-davis-BESSE NUCLEAR p0WER STATION. UNIT NO. 1 DOCKET NO. 50-346
1.0 INTRODUCTION
v
'By-letter dated May any(thelicensee),
31,1990,lSpecifications(1S)ithe Toledo Edison requested changes to Technica 3
Gas Control Hydrogen Analyzers, by adding an addit onal action statement which would apply when both hydrogen analyzers are inoperable, ar.d allow 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to return one of the two inoperable hydrogen analyzers to operable status, or be in at least hot standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. This request is consistent with the NRC's Generic Letter (GL) 83-37, dated November 1, 1983, NUREG-0737 item II.F.1.6, which in the situation of both hydrogen analyzers being Inoperable, allows for,72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />s-to repair one of the analyzers prior to having to shut down the plant.
2.0 EVALUATION In the present TS, if both hydrogen analyzers were to become inoperable. TS 3.0.3 would be entered which requires action to be initiated within I hour to place the plant in a MODE in which the TS does not apply. The function of the. hydrogen analyzers-is to provide the control room with indication of-containment vessel hydrogen concentration,.following a loss of coolant
'i faccident(LOCA).
Besed on the hydrogen concentration the reactor operator can-initiate the Combustible Gas Control System (CGCS}:to ensure that the 3
concentration does not exceed the conservative value of three volume percent. The proposed revision to TS 3.6.4.1 would-add an additional action statement which requires _that, with both-hydrogen analyzers inoperable, one analyzer must be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or be in at least HOT STANDBY within the text 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
l
-9k01270153920116ADOCK 05000346'.
P PDR' p
2 The hydrogn analy:ers are designeo to r.onitor containment vessel atraosphere.
Following a LOCA, hydropr. Cas may accunulate within the vessel from various sources. When b)tiogen is genertted, it may react with oxygen present in the vessel leading to high temperatures and overpr(5:.urizv.ios.. Tht bidatto Safety Ana$ysis Report (lT/I) assuu s that the lower flam. ability limit foi hydropn in air stttrated with water vapor at roota twptrattie and atiaosphei n pressure to be four volume percent.
In the hRC's Safety Evaluation Report for theOperatingLittnse,section6.2.5citesthattheanalysisofhydrogen generation f ollowir.g a LOCA *
- onsistent with Regulatory Guide 1.7, Control of Combustible Gas Concentre e," which indicates that the concentration within the vessel would reach four solume percent in 37 days af ter the accident.
The USAR assumes a contentration of three percent is reached at approxinutely 21 days af ter the LOCA, ar.d assunes no operator action was taken to initiate the hydrogen dilution system.
The CGCS is designed to control the concentration of hydrogen which may be released into the containment vessel atmosphere following a LOCA. The systm was originally comprised of the Containment Hydrogen Dilution Syr, tem (CHDS), the Hydrogen Purge System (HPS), and the Containaent Rccirculation System (CRS). The CRS is no longer required and wat, removed f rom the TS by Amendment C6, dated January 20, 1984 As a backup to the CHDS and HPS, the licensee has the capability to install an external Hydrogen Recombiner System.
The CGCS comporents are designed to be operated as necessary to maintain hydrogen concentration in the vessel at or below three volume percent following c LOCA.
The proposed change to TS 3.C.4.1 would allow both hydrogen analy ers to t,e inoperabic for a 72-hour period, if, durir.g this time, a LOCA shou 1G oct.ur, the cortairmert hydrogen ctircentration would be deterrained using the Fcst Accidtnt Sampling System (PASS). The Pl.SS containment air portion has the upbii t t) of obtainirg samples f rom the containment vit the contv u..ent reoiaticn nonitorir.g system. Based on the hydrogen content deterrnnou ty at al) tis of the PASS sanples, the reactor operbtor can tien ini t u.tt tht CGCS as necessary.
Orider the present TS, in the event that both analyztri are incperable, TS 3.0.3 must be entered requiritC plant shutdown within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The istpositior, of a shutdown solely for this purpose would be undesirable from an equirfrent cycling standpoint and is not consistent with NRC pLidence. Ceneric Letter 83-37, "NUREG-0737 Ttchnical Specifications",
states that with both hydrogen trenitors inoperable, restore at least one monitor to operable status within 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 5 or be in at least hot standby uithin the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The licensee has stated that no hardware changes are being made and no testing is being degraded.
There exists an alternate nethod for chtaining and analy:ing containt.ent air firples so that the reactor operator may it.itiate cotrt:ctive action es necessary. Based on the above, the staff has deterrnined that the 7 eposed change to allow both hydrogen analyzers to be inoperable for 721ours would have no effect on the safety of the plent and is therefore acceptable.
_-__.__%.m._.____.__
3
3.0 STATE CONSULTATION
in accordance with the commission's regulations, the Ohio State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Comission has previously issued a proposed finding that the amendnent involves no f.ignificant hazards consideration and there has been no public comment on such finding (56 FR 13670). Accordingly the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the pro)osed manner, (2) such activities will be conducted in compliance wit 1 the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the comon defense and security or to the health and safety of the public, principal Contributor:
J. Lombardo Date: January 16. 1992 l
l 1
.