ML20079M124
| ML20079M124 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/21/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20079M117 | List: |
| References | |
| NUDOCS 9111080036 | |
| Download: ML20079M124 (3) | |
Text
pe*"%g
,o.
UNn ED STATES e
E.
> vu " 'g NUCLEAR REGULATORY COMMISSION
.j W ASHINGTON, o. C. 20555
\\, *..../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATCO TO AMENDMENT h0.164 TOFACIL*j;,'y'RATINGLICENSEN0.NPF-3 20^ "ST SON.L '9 NY T
CENTER 10R SERVICE COMPANY AND THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 DOCKET NO. 50-346
1.0 INTRODUCTION
By letter dated February 15, 1991, the Toledo Edison Cor.ny (the lica.see) requested changes to Technical Specification (TS) ' '4 7.1.3 for the Davis Besse Nuclear Power Station, Unit No. 1.
The proposed changes would delete the reference to the deaera. tor storage tanks (DSTs) as conduisate storage facilities for the Aur.liary Feedwater System in TS limiting condition for operation (LCO) 3.7.1.3 and would revise the nomenclature for " Condensate Storage Tanks" and " Condensate Storage Facilities" to " Condensate Storage Tanks" in TS LC0 3.7.1.3, TS Surveillance Requirement 4.7.1.3.1, and TS Bases Section 3/4.7.1.3.
2.0 EVALUATION The original design of the Davis-Besse Auxiliary Feedwater System (AFWS) provided that the two auxiliary feedwater pumps ( AFPs) and the start up feedwater pumps (SUFP) shared a common 10-inch supply header, which received condensate from either tL. )STs or the condensate storage tanks (CSTs). During power opcration, the SUFP was secured, and the CSTs aligned to be the source of water supply to the AFWS.
At that time, the DSTs were considered the first backup to the CSTs and were included within the scope of TS 3.7.1.3.
The licensee has determined that the alignment of the DSTs te the AFPs should not be allowed because the high temperature water from the DSTs could damage the AFPs' bearings, and the AFP discharge would be considered a high energy line if suction were taken from the DST. The condensate from the CSTs is of lower energy, and ranges from 40*F to 80*F.
To allow the AFPs to pump condensate received from the DSTs, the bearing cooling water source would have to be 91110B0036 911021 PDR ADOCK 05000346 P
2 switched over to t~e Service Water System (SWS).
This requires a manual n
actuotion of several bt-aring water sup)1y line valves.
Additionally AFP suctionfromtheDSTswouldclassifyATPdischargeas4highenergyline, which would create high energy line break concerns. The licensee has also dettrmined that there were problems associated with high and moderate energy line breaks in the SUFP supply and discharge lines that run within the AFP rooms. These concerns were resolved by installing a motor driven feedwater pump (MDFP), which performs the functions of the SUFP.
It is capable of providing feedwater to the steam generators in the event of the loss of the steam turbine driven AFPs. The header that brought condensate h om the DSTs to the AFPs and SUFP was then diverted to the MDFP.
Through th h, change and other modifications the licensee has reduced the possibility of supplying DST water to the AFPs and has improved the overall reliability of the AFWS.
The function of the Condensate Storage System (CSS) is to store condensate and deliver it as required to the AFWS. The licensee has stated that the CSTs contain adequate water supply to maintain the Reacter Coolant System (RCS) at hot standby conditions for 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br /> with steam discharge to atmosphere, and to cool down the RCS to less than 280*F under normal conditions. The two CSTs each provide a capacity of 250,000 gallons.
Section 9.2.6 of the Updated Safety Analysis Report (USAR) does not address the CSTs as a backup source of condensate for the AFWS. The primary supply is derived from the non-seismic CSTs, with a seismic Class I backup from the Service Water System (SWS). Therefore, the DSTs are not required and no credit has been taken in the USAR. The proposed change does not involve a significant reduction in a margin of safety, because the condensate voltme requirements to meet the analysis assumptions remain the same. The licensec
-has stated that the DSTs have never been consiaered in meeting the TS volume requirements and that, based on the design and as-built configuration consideration, the DSTs should be removed from TS 3.7.1.3.
The staff has reviewed the proposed change to TS 3.7.1.3 and finds it to be acceptable.
Other changes to SR A.7.1.3 and Bases Section 3/4.7,1.3 are editorial in nature and are found to be acceptable.
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 and changes a surveillance requirement. The staff has determined that the amendment involves no significart increase in the amounts, and no significant i
l 3
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 Commission has previously issued a proposed finding that the amendment involves no significant hazards considerotion and there has been no public concent on such finding (56 FR 24219). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuct:t to 10 CFR 51.22(b), no environmental impact statuaer t or environmental mtwer,t neco be pn pareo in courection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
not be endargered by operation in the proposed manner, (2) y of the public will (1) there is reasonable assurance that the health and safet such activities will be conductec in compliancc with the Commission's regulations, and (3) the issuance of this anentnent will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
J. J. Lombardo Date: October 21, 1991 i
t L
t