ML20199J951
| ML20199J951 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 01/30/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20199J924 | List: |
| References | |
| NUDOCS 9802060067 | |
| Download: ML20199J951 (6) | |
Text
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NUCLEAR REGULATORY COMMISSION
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- '4, *.., *,e SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO EXEMPTION FROM SECTION 111.0 0F APPENDIX R TO 10 CFR PART 50 FACILITY OPERATING LICENSE NO. NPF-3 TOLEDO EDISON COMPANY CEN1ERIOR SERVICE COMPANY MD THE CLEVELAND ELECTRIC ILLUMINATING COMPANY PAVIS-BESSE NUCLEAR POWER STATION. UdIT 1 QQf1ET NO. 50-346
1.0 INTRODUCTION
Appendix R. " Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1,1979," to Title 10 of the Code of Federal Reaulations (10 CFR Part 50, establishes fire protection features required to satisfy General) Design Criterion 3. " Fire Protection," of Appendix A to 10 CFR Dart 50 with respect to certain generic issues for nuclear power plants licensed to operate prior to January 1, 1979.
By letter dated November 18, 1997, as supplemented by facsimile dated December 9,1997, the Toledo Edison Company, Centerior Service Company, and The Cleveland Electric Illuminating Company, the licensees for the Davis-Besse Nuclear Power Station (DBNPS), Unit 1, requested an exemption from certain technical requirements of Appendix R.
2.0 EXEMPTION RE00ESTED Section 111.0 of Appendix R to 10 CFR Part 50 requires that the licensees have a collection system " capable of collecting lube oil from all potential pressurized and unpressurized leakage sites in the reactor coolant pump (RCP) shall include lift pump and piping, overflow lines, points to be protected lube oil systems."
at also specifies that " leakage lube oil cooler, oil fill and drain lines and plugs, flanged connections on oil lines, and lube oil reservoirs where such features exist on the reactor coolant pumps." The underlying purpose of the rule is to ensure that leaking oil will not lead to a fire that could damage safe shutdown systems during normal or design basis accident conditions.
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'. 0-The licensees requested an exemption from the technical requirements of Section !!!.0 to the extent that they require that the RCP lobe oil fill lines i
4 be protected with an oil collection system.
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3.0 DISCUSSION Periodically, as a result of oil consumption during power operations, the licensees need to add oil to the RCP motor lube oil reservoirs.
Prior to i
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1990, the licensees accomplished this by going into the containment building l
cavities (inside the D-rings) and adding the oil using the fill connection at j
the motor.
In 1990, the licensees added remote oil fill lines to each of the four RCP motors so that oil could be added to the lower reservoir, if i
necessary, from a low-dose area during power operation.
Use of the fill lines i
would reduce personnel dose, increase personnel industrial safety (for-example, by reducing heat-stress), and reduce the risk of spilling oil in the j
l immediate area of the RCP during oil addition.
I The licensees stated the following:
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At the time of their design, the remote oil fill lines were 1
considered a means to facilitate maintenance and were not viewed as part of the RCP oil system. Therefore, they were not designed l
to meet the requirement that any potential leakage would be collected as specified by 10 CFR 50, Appendix R, Section !!!.0.
In early 1997, the DBNPS became aware that another licensee had i
submitted an exemption request regarding the lack of an enclosure on remote oil fill lines.- On February 19, 1997, a Potential Condition Adverse to Quality Report (PCAQR) was initiated by the i
DBNPS staff to track resolution of this issue.
This condition was
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later reported to the NRC as a condition outside the design basis
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l of the plant (Licensee Event Report 97-004-00 dated March 3, 1997). The remote oil fill lines have since been disabled to prevent their use.-
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The Dayls-Besse remote oil fill system is a non-pressurized, gravity-feed design. Each fill line has a stainless steel (SS) fill pot located outside of the D-ring,- and- %-inch SS tubing and SS flexib's hose from the fill pot to the F
RCP motor lower oil reservoir fill connection. The fill lir.e system is designeC to be leaktight, with each line sloped to prevent oil from being trapped in the:line.
Therefore, a significant quantity of oil is _only present
-in the lines during use.
Each fill line terminates inside of the existing oil 4
collection = enclosure for the lower reservoir above normal oil lovel.
Since the ' oil: reservoirs are vented to the atmosphere, a signific. ant amount of oil can:not'back up=into the-fill lines.
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.- o 3-i Any leakage from the fill system within a D-ring would contact the top of the RCP insulation, the reactor coolant system (RCS)ded so that any significantcold leg containment floor.
The containment floor is gra q
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oil leakage would be funneled to the floor drains below each RCP. The insulation that would be contacted is metal reflective with s normal surface
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~ temperature about 200'F lower than the flash point of the oil.
Therefore, this insulation would not nomally be an ignition source.
In addition,-this 4
insulation is configured so that oil wo d be diverted away from hot sources.
and not retained (as would be expected witn fibrous insulation). There are no f
i other credible ignition sources during normal operation.
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Any leakage outside of D-ring #1 would migrate directly to a floor drain that 0
empties into the containment normal sump.
There is no safe shutdown equipment in the immediate vicinity of these locations. Any. leakage outside of i
> - ring #2 would pass through grating and migrate to a different floor drain, t
which also empties into the containment normal sump.
Safe shutdown equipment i
in these areas is either adequately separated or is protected by a radiant i
energy shield. There is fire detection equipment on both elevations of concern outside of D-ring #2.
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Additional fire' detection is provided by two heat detectors over each RCP motor. These detectors alarm individually in the control room.
Fire suppression relies on manual firefighting action.
Equipment including portable and wheeled (with hose)- fire extinguishers, is available. A 2binch hose connection that ca'i be used for firefighting is also available on the
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service water system in containment.
In order to minimize the potential for an oil-fire due to a Isak from the fill system that would not be captured by the existing oil collection system. the E
licensees will take the following compensatory actions each time oil is added:
011 will be dded only when a low oil level computer alarm is received on an P.CP motor.
Only a predetermined amount of oil necessary to clear the alam (approximately three pints based on experience) will be initially added of four pints may be added in an attempt-to clear. maximum total volume to the reservoir through the remote fill line. A the alarm.
i-t The oil fill pot will be verified empty before'the technician leaves the immediate area. Any spillage resulting from adding oil to the remote-of1. fill pot will; be eleaned up.
Personnel-rasponsible for adding the oil will be instructed to report
-(to the control.roca) any evidence of smoke during the oil addition process.
If smoke is seen,:the fire brigade will-be immediately d hpatched;to the area; In addition, a visual-inspection will be conducted following refueling outages to confim the integrity..of the remote fill line tv' tem.
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4.0 EVALUATION s
j The principal safety concern with the installation of remote fill lines is j
that damage to the tubing and/or flexible nose could result in an oil leak into the containment dur ng the addition of oil. The leaking oil could j
ignite,-and the resultin fire could affect the ability to achieve and I
maintain post-fire safe hutdown conditions.
The Davis-Besse Appendix R safe shutdown analysis assumed an all-consuming j
fire within.ie D-ring and determined that adequate separation exists between redundant circuits to achieve safe shutdown.
l l-Because redundant components are adequately separat d, a leak from one fill i
l line poses no significant threat' to the safe shutdown capability.
011 from a j
leak would migrate either directh or through a grate to the containment floor and then to the floor drains.
In the event a fire were to. occur, oniv one-half gallon of oil would be present due to the licensees' compensatory l
1 measures.
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The compensatory measures that will be taken during oil filling, the lack of
-oil fill system pressurization, the limited fire size from one-half gallon of 1
oil, the separation between, and the barriers protecting, redundant trains of i
l-safe shutdown equipment, and the anticipated flow paths of spilled oil provide reasonable assurance that significant damage would not occur in the L
containment building, particularly.to safe shutdown equipment, from a worst-case postulatou fire.
l Fire detection and manual fire suppression equipment is available in the vicinity of the lube oil fill lines.
In the event of a fire, it-is expected
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that a detector would alarm and personnel in the imediate area would notify 1
1 the control room. The fire brigade would then respond to extinguish the fire t
in its incipient stages. This further assures that a worst-case postulated j
fire would not damage safe shutdown equipment, t
5.0 -[0NCLUSION Th; staff has determined that the design of the oil filling system and'the level of protection provided durina oil fill operations provide reasonable assurance that a lube oil fire will not occur. This is contingent on the i-application of the compensatory measures itemized in the licensees'
-November 18,:1997, exemption request.
c The; staff has also determined that, in the event of a worst-case postulated 1
fire due to the absence of a, lube oil collection system for the remote lube i
L oil: fill. lines,ithe fire would be of limited magnitude and extent,. ~ In addition -such a fire would not cause significant damage in the containment
~ building and wouldinot prevent the operators-from achieving and maintaining
- safe shutdown conditions..
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The staff has concluded that special circumstances are present in that an oil collection system for the RCP lube oil fill lines is not necessary to achieve the underlying purpose of the rule, and that an exemption as described herein j
is Authorized by law, will not present an undue risk to public health ar.d i
safety, and is consistent with the common defense and security. Therefore,
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the licensees' request for exemption should be granted Principal Contributors:
A. Hansen P. Qualls-Date: January 30, 1998 P
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o 4 Pursuant to 10 CFR 51.32, the Commission has determined that the granting of this exemption will not result in any significant adverse environmental impact ( 63 FR 4678 ).
This exemption is effective upon hsuance.
FOR THE NUCLEAR REGULATORY COMMISSION od#m!sWdby SamuelJ.CoEns Samuel J. Collins, Director Office of Nuclear Reactor Regulation Dated at Rockville, Maryland, this 30th day of January 1998.
DOCUMENT NAME:G:\\DAVISBES\\DBA0161.EX
- See previous concurrence To recolve e copy of tNo document, indcate in the bout *C# = Copy without enclosures *E' = Copy with enclosures
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PD33:LAl E SPLB:BCl PD33:(A)Dl NAME AHansenAff RSanders
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,L.I,iML.,WK hQ:~k OFFICE OGC ORPW:(A)D NRR:AD? f D
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- EAdensam
- BBoger P TfCo W DATE 1/7/98 1/26/98
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OFFICIAL RECORD FILE a
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