ML20063F234
| ML20063F234 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 01/31/1994 |
| From: | Storz L CENTERIOR ENERGY |
| To: | |
| Shared Package | |
| ML20063F232 | List: |
| References | |
| NUDOCS 9402140195 | |
| Download: ML20063F234 (9) | |
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Docket Number 50-346 License Number WPF-3
. . Serial Number 2175 Enclosure Page 1 APPLICATION FOR AMENDMENT TO FACILITY OPERATING LICENSE NPF-3 DAVIS-BESSE NUCLEAR POWER STATION .
UNIT NCHBER 1 l
Attached are requested changes to the Davis-Besse Nuclear Power Station, Unit Number 1 Facility Operating License Number NPF-3. Also included is the Safety Assessment and Significant Hazards Consideration.
The proposed changes (submitted under cover letter Serial Number 2175) ,
concern:
Appendix A, Technical Specification 3/4.1.1.2, Reactivity Control Systems-Boron Dilution Appendix A, Technical Specification 3/4.9.8.1, Refueling Operations -
Decay Heat Removal and Coolant Circulation l
Appendix A, Technical Specification 3/4.9.8.2, Refueling Operations -
Lov Vater Level Appendix A, Technical Specification Bases 3/4.1.1.2, Boron Dilution Appendix A, Technical Specification Bases 3/4.9.8, Coolant Circulation By:
L. F. Storz [- J Vice President -Welear Sworn and Subscribed before me this 31st day of January, 1994.
$1Lr]>fr) . 1 b$
Notary F/blic, State of Ohio EVEYN L DPESS ET/,YJ . e f UEOFOHIO leyCcr::m;;;u; u Ut23,1594 9402140195 940131 PDR .ADOCK 05000346 P PDR
. Docket Number 50-346
' License Number NPF-3 ,
. Serial Number 2175 Enclosure r Page 2 The following information is provided to support issuance of the ,
requested changes to Davis-Besse Nuclear Power Station, Unit Number 1 Operating License Number NPF-3, Appendix A, Technical Specification '
(TS) 3/4.1.1.2 (Reactivity Control Systems-Boron Dilution), TS 3/4.9.8.1 (Refueling Operations - Decay Heat Removal and Coolant ;
Circulation), and associated TS Bases. ;
. i A. Time Required to Implement: This change is to be. implemented i
vithin 90 days after NRC issuance of.the License Amendment. l B. Reason for Change (License Amendment Request Number 93-0002,; :
Revision 0): .l l
Certain maintenance activities during plant outages may require that the RCS level be reduced below the level of the reactor vessel flange. For example, in order to install steam generator I nozzle dams the.RCS is drained down to'approximately.18" above. :
the RCS hot leg centerline. At this level, to prevent vortexing and Decay Heat Removal (DHR) pump cavitation, DHR flovrate is procedurally limited to slightly less than 2800 gpm. In this-situation, TS 3.1.1.2 restrictions vould apply. That is, with t DHR flovrate below 2800 gpm, any water added to the RCS would be !
required to be of higher boron concentration than the RCS. -An ,
exception, applicable in Mcde 6, allows the. addition of water of ;
lower boron concentration than the existing RCS boron ~ _
concentration, provided that the boron concentration of the water ,
to be added meets the requirements specified in TS 3.9.1. ;
In accordance with TS 3.9.1, during-Hode'6 (refueling),-the. boron i concentration of all filled. portions of the Reactor Coolant System (RCS) and the refueling canal must be maintained uniform and sufficient to ensure that the more restrictive of two ;
reactivity conditions is mets keff < 0.95, or boron concentration ;
of > 1800 ppm. ;
The proposed change to TS 3/4.1.1.2 would make the exception applicable in Mode 5 as well as Mode 6, provided that in Mode 5 f the boron concentration of the water to be added is equal to or greater than the boron concentration associated with the shutdown ,
margin requirement of TS 3.1.1.1. 'A related. change is proposed for Bases 3/4.1.1.2 to make it consistent with TS 3/4.1.1.2.
The proposed change to TS 3/4.9.8.1, which would add an exception !
applicable to Mode 6, makes TS 3/4.9.8.1-consistent with the ,
current TS 3/4.1.1.2. Technical Specification 3/4.9.8.2 refers to Surveillance Requirement 4.9.8.1 in its own. Surveillance :)
Requirement and, therefore, the proposed change makes TS ;
3/4.9.8.2 consistent with TS 3/4.1.1.2. A related change to TS !
Bases 3/4.9.8 vould add a corresponding discussion of the Mode 6 .!
exception. .
C. Safety Assessment and Significant Hazards Consideration: See l Attachment ,
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D'ocket Number 50-346 ;
. Licensee Number NPF-3 Serial" Number 2175
- Attachment ,
Page.1 ~l SAFETY ASSESSMENT AND SIGNIFICANT HAZARDS CONSIDERATION FOR j LICENSE AMENDMENT REQUEST NUMBER 93-0002 .:
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TITLE: l Revision of Technical Specification (TS) 3/4.1.1.2, Reactivity Control Systems-Boron Dilution and Associated TS Bases 3/4.1.1.2 to Add an i Exception Applicable in Mode 5, and_ Revision of TS 3/4.9.8.1, Refueling -;
Operations - Decay Heat ~ Removal and Coolant Circulation, and Associated =
TS Bases 3/4.9.8 to-Add an Exception Applicable in Mode 6.
DESCRIPTION:
The purpose of the proposed changes is to modify the Davis-Besse ]
Nuclear Power Station (DBNPS) Operating License NPF-3, Appendix A Technical Specification (TS) 3/4.1.1.2 (Reactivity Control Systems -
Boron Dilution), TS 3/4.9.8.1 (Refueling Operations - Decay Heat Removal and Coolant Circulation), and associated Bases.
Certain maintenance activities during outages may require that the RCS-level be reduced below the level of the reactor vessel flange. As the RCS level is reduced, procedural limits are placed on maximum Decay Heat Removal _(DHR) flovrate to prevent vortexing and pump cavitation. ;
Reactor Coolant System temperature is closely monitored to ensure that 1 the flovrate is adequate to remove decay-heat.
Technical Specification 3/4.1.1.2 currently states: "The flovrate of [
reactor coolant through the Reactor Coolant System shall be 12800 gpm !
whenever a reduction in Reactor Coolant System boron concentration is '
being made.*" As described in TS Bases 3/4.1.1.2, "A minimum flovrate of at least 2800 gpm provides adequate mixing,. prevents stratification and ensures that reactivity _ changes vill be gradual through the Reactor .j Coolant System in the core during boron concentration reductions in the- ,
Reactor Coolant System." l License Amendment 176, issued by the NRC on December 8, 1992, added the i asterisked footnote to TS 3/4.1.1.2 which states: )
l In MODE 6 the Reactor Coolant System (RCS) boron concentration may ,
be greater than the boron concentration of water available for-additlon. If-the flovrate of reactor coolant'through the RCS is.
less than 2800 gpm, vater of lover boron concentration than the existing RCS concentration may-be added to the RCS provided that j the boron concentration of the water to be added is equal'to or i greater than the boron concentration corresponding to the more ,
restrictive reactivity condition specified in Specification 3.9.1.
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.c Docket Number-50-346
. Licensee Number NPF-3 Serial Number 2175
' Attachment ,
Page 2 Since reduced RCS inventory operation could occur in either Mode 5 or Mode 6, adding an exception applicable to Mode 5 as well as Mode 6 vould. result in greater flexibility in the choice of water addition sources when RCS vater addition is necessary. The proposed change to-TS 3/4.1.1.2 would revise the footnote to make the exception read:
In MODE 5 or MODE 6 the Reactor Coolant System (RCS) boron concentration may be greater than the boron concentration of water available for addition. If the flovrate of reactor coolant through the RCS is less than 2800 gpm, water of lower boron concentration than the existing RCS concentration may be added to the RCS provided that in MODE 5 the boron concentration of the water to be l
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added is equal to or greater than the boron concentration associated with the SHUTDOVN MARGIN requirement of Specification 3.1.1.1, or in MODE 6 the boron concentration of the water to be added is equal to or greater than the boron concentration corresponding to the more restrictive reactivity condition '
specified in Specification 3.9.1. ,
The proposed change to TS Bases 3/4.1.1.2 would add a corresponding discussion of the Mode 5 exception, which would read:
In MODE 5 or MODE 6, the RCS boron concentration is typically somewhat higher than the boron concentration. required by-Specification 3.1.1.1 (MODE 5) or Specification 3.9.1 (MODE 6), and could be higher than the boron concentration of normal sources of water addition. At reduced inventory conditions in the RCS, in .
order to reduce the possibility of vortexing, the flovrate through the decay heat system may be procedurally restricted to somewhat <
1ess.than 2800 gpm. In this situation, if water with a boron concentration equal to or greater-than the boron' concentration associated with the SHUTD0VN MARGIN requirement of Specification 3.1.1.1 (MODE 5), or the boron concentration' corresponding to the 9 more restrictive reactivity condition specified in Specification I 3.9.1 (MODE 6), is added to the RCS, the RCS boron concentration is i assured to remain above the minimum boron concentration associated ~!
vith the Specification 3.1.1.1 or Specification 3.9.1' requirement, j and a flovrate of less than 2800 gpm'is not of concern' . 1 The proposed change to TS'3/4.9.8.1 vould add an asterisked footnote to the-Limiting Condition for Operation and the Surveillance Requirements which vould read- 1 l
Water of a lover boron concentration'than the existing RCS I concentration may be added to the RCS, with the flovrate of reactor coolant through the RCS less than 2800 gpm, provided that the boron concentra* ion of the water to be added is equal to or greater than the boron incentration corresponding to the more restrictive reactivity condition specified in Specification 3.9.1.
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- Docket Number 50-346
- Licensee Number NPF-3 Serial Number 2175 =r
' Attachment Page 3 This change vill make TS 3 '4.9.8.1 consistent with the current TS 3/4.1.1.2. Mode 6 exception. Since TS 3/4.9.8.1 applies only in Mode 6, ,
it vould.not be appropriate to include.a Mode 5 exception. Technical !
Specification 3/4.9.8.2, Refueling Operations - Lov Vater Level,'would also be.similarly affected because its own Surveillance Requirement refers to performing the Surveillance Requirement'of TS 3/4.9.8.1.
The proposed change to TS Bases 3/4.9.8 would add a corresponding discussion of the Mode 6 exception, which would read:
In MODE 6, the RCS boron concentration.is typically-somewhat higher l' than the boron concentration required by Specification'3.9.1, and could be higher than the boron concentration of normal. sources of -
water addition. -The flovrate through the decay heat system may at In this' times be reduced to somewhat less than 2800 gpm. ,
situation, if water with a boron concentration equal to or greater t than the boron concentration required by Specification 3.9.1'is j added to the RCS, the RCS is assured to remain above the Specification 3.9.1 requirement, and'a flovrate of less than 2800-gpm i not of concern. !
SYSTEMS, COMFONENTS, AND ACTIVITIES AFFECTED:
RCS Boron. Dilution in Mode 5-(Cold shutdown) and Mode 6 (Refueling)
SAFETY FUNCTIONS OF THE AFFECTED SYSTEMS, COMPONENTS AND ACTIVITIES: -
The TS 3/4.1.1.2 (Reactivity Control Systems-Boron Dilution) Limiting .
Condition for Operation (LCO)-is based en the requirement.to maintain a-minimum RCS flovrate in order to provide adequate mixing of the RCS. ,
Adequate mixing prevents stratification, and ensures that reactivity changes vill be gradual through the RCS in the core during boron concentration reductions. A gradual reactivity change rate ensures ,
that the boron concentration reduction evolution vill be vithin the operator's capability to recognize and control. j Maintaining a required boron concentration of all filled portions of i the RCS and the refueling canal. ensures that there vill be adequate i*
reactivity control and that the required shutdown margin vill be maintained.
1 EFFECTS ON SAFETY:
Reduced. inventory operation' can occur in either Mode 5 or' Mode 6. As . ,
discussed above, with the RCS in a reduced inventory condition, the DHR j flovrate may be procedurally limited in order to prevent vortexing and ;
pump cavitation. As a result, the flovrate may be less than 2800 gpm.
The desired source of water (e.g., Borated Water Storage Tank or.a q Clean Waste Receiver Tank):to raise the RCS level may meet'the ,
it y 5m.
m , .m9 9m ----psqq .,
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Docket Number 50-346
. Licensee Number NPF-3
Serial Number 2175
' Attachment Page 4 requirements of TS 3.1.1.1 or TS 3.9.1 but be at or below the RCS boron concentration. The present TS 3/4.1.1.2 provides an exception applicable only in Mode 6. However, in Mode 5, if the boron concentration of the desired source is lower than the RCS boron concentration, the current TS 3/4.1.1.2 vording prevents the use of that source, and requires the use of a source of water of a higher boron concentration (such as the Boric Acid Addition Tank (BAAT)).
This high boron concentration source is used until RCS level is-raised i high enough to support increasing the DHR flovrate above 2800 gpm, at ,
which point the lower boron concentration source may be used. Under TS ,
3/4.1.1.2 this high boron concentration source must be used even if the '
desired source's boron concentration meets the Shutdown Margin of >1%
delta k/k required in TS 3.1.1.1 for Mode 5. The need to perform this change of water addition sources places an extra and unnecessary. burden on the operators during the evolution of changing RCS inventory at lov RCS levels. Provided that shutdown margin requirements of TS 3.1.1.1 .
I are met by the desired source, the proposed TS change would eliminate the need to perform this source change in Mode 5, reduce the complexity of the evolution, remove an unnecessary burden on the operators, and therefore have a positive impact on plant safety.
The proposed change to TS 3/4.1.1.2 would allow the addition of water of lower boron concentration than exists in the RCS in Mode 5 or Mode 6, with the flowrate of reactor coolant through the RCS less than 2800 gpm, provided that in Mode 5 the boron concentration of the water 4 to be added is equal to or greater than the boron concentration associated with the shutdown margin requirement of TS 3.1.1.1, or in Mode 6 the boron concentration of the water to be added is equal to or greater than the more restrictive reactivity condition specified in TS 3.9.1. This exception is acceptable since the resulting RCS boron concentration vill continue to meet the applicable requirement. In this situation, even if incomplete mixing did occur, it would be of no adverse consequence to safety. There vill be adequate reactivity control, and the required shutdown margin vill be. maintained.
The proposed change to TS Bases 3/4.1.1.2 would add a corresponding discussion of the Mode 5 exception. This proposed change vould have no adverse effect on plant safety.
The proposed change to TS 3/4.9.8.1, which would add an-exception ~
applicable to Mode 6, makes TS 3/4.9.8.1 consistent with the current TS 3/4.1.1.2. Technical Specification 3/4.9.8.2, which references Surveillance Requirement 4.9.8.1 in its own Surveillance Requirement 4.9.8.2, vill then also be consistent with TS 3/4.1.1.2. This proposed.
change vould have no adverse effect on plant safety. The proposed _
change to TS Bases 3/4.9.8 vould add a corresponding discussion of the Mode 6 exception. This proposed change vould have no adverse effect on plant safety.
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Docket Number 50-346~
.: Licensee Number NPF-3 Serial Number 2175 ,
' Attachment j Page 5 SIGNIFICANT HAZARDS CONSIDERATION:
The Nuclear Regulatory Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazard exists due to a i proposed amendment to'an Operating License for a facility. A proposed amendment involves no significant hazards if operation of the facility in accordance with the proposed changes vould: (1) Not involve a ;
significant increase in the probability or consequences of an accident .;'
previously evaluated; (2) Not create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Not involve a significant reduction in a nrgin of safety. Toledo e Edison has reviewed the proposed change and determined that.a.
significant hazards consideration does not exist because operation of- I the Davis-Besse Nuclear Power Station, Unit Number 1, in accordance with these changes vould: ,
Not involve a significant increase in the probability of an !
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accident previously evaluated because no accident initiators, j conditions or assumptions are significantly affected by-the i proposed changes. The proposed change to_ Technical Specification ,
(TS) 3/4.1.1.2 vould revise an exception to make it applicable in )
Mode 5 as well as Mode 6. The revised exception vould.allov vater- l of a 1..ver boron concentration than the Reactor Coolant System l (RCS) to be added to the RCS, with the flovrate of reactor coolant i through the RCS less than 2800 gpm, provided that the water to be !
added meets the requirements of TS 3.1.1.1 (Mode 5) or TS 3.9.1 ;
(Mode 6). TS 3.1~.1.1 requires that in Mode 5, the boron concentration of the RCS be maintained such that the Shutdown j
Margin shall be > 1% ok/k. TS 3.9.1 requires that in Mode 6, the boron concentration of all filled portions of the RCS and the i refueling canal shall be maintained' uniform and sufficient to !
ensure that the more restrictive of two reactivity conditions is-met. If the RCS meets these reactivity condition requirements, .
and water is added to the RCS that also meets'the reactivity .I condition requirements of TS 3.1.1.1 or TS 3.9.1, then the RCS is assured to remain in compliance with the reactivity condition j requirements. The possibility that the added water may be of lower boron concentration than the RCS, therefore,-does not \;
significantly. increase the probability of an accident previously evaluted.
The proposed change to TS 3/4.9.8.1 makes TS 3/4.9.8.1 and TS 3/4.9.8.2 consistent with the current TS 3/4.1.1.2, and is ,
considered to be administrative in nature. 1 l
The proposed changes to TS Bases 3/4.1.1.2 and TS Bases 3/4.9.8 )
are considered to be administrative in nature. ;
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Docket-Number 50-346
. Licensee Number NPF-3 Serial Number 2175 Attachment Page 6
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lb. Not involve a significant increase in the consequences of an accident previously evaluated because no accident conditions or assumptions are affected by the proposed changes. As discussed in item la. above, the proposed revision of the exception to'TS 3/4.1.1.2 vill not cause a condition that would result in the RCS not meeting the requirements of TS 3.1.1.1 or TS 3.9.1, as applicable. The proposed changs. So not alter the source term, containment isolation, or allowable releases. The proposed changes, therefore, will not increase the radiological consequences of a previously evaluated accident. As also discussed in item la. above, the proposed changes to TS Bases 3/4.1.1.2, TS 3/4.9.8.1, and TS Bases 3.4.9.8 are considered to be administrative in nature.
2a. ~ Not create the possibility of a new kind of accident from any accident previously evaluated because no new accident initiators or assumptions are introduced by'the proposed changes. The proposed changes do not alter any accident scenarios. As discussed in item la.
above, the proposed revision of the exception to TS 3/4.1.1.2 vill not cause a condition that vould result in the RCS not meeting the !
requirements of TS 3.1.1.1 or TS 3.9.1. The proposed changes to TS Bases 3/4.1.1.2, TS 3/4.9.8.1, and TS Bases 3/4.9.8 are considered to
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be administrative in nature. None of the proposed changes creates the possibility of a new kind of accident.
2b. Not create the possibility of a different' kind of accident from j
any accident previously evaluated because no different accident initiators or assumptions are introduced by the proposed changes. The proposed changes do not alter any accident scenarios. As discussed in ~
item la. above, the proposed revision of the exception.to TS 3/4.1.1.2 vill not cause a condition that vould result in the RCS not meeting -
the requirements of TS 3.1.1.1 or TS 3.9.1. -The proposed changes to TS Bases 3/4.1.1.2, TS 3/4.9.8.1, and TS Bases 3/4.9.8 are considered to be administrative in nature. None of the proposed changes creates the possibility of a different kind of accident from any accident -,
previously evaluated.
- 3. Not involve a significant reduction in the margin of safety .
because the proposed change to TS 3/4.1.1.2, as described above, vill l not cause a condition that would result in the RCS not meeting the- '
requirements of TS 3.1.1.1 or TS 3.9.1. The margin of safety vill be maintained by adhering to the limits specified in these TSs. The proposed changes to TS Bases 3/4.1.1.2, TS 3/4.9.8.1 and TS Bases 3/4.9.8 are considered to be administrative in nature.
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Docket Number 50-346
. ' Licensee Number NPF-3 Serial Number 2175
'A t ta chmen t -
Page 7 CONCLUSION:
On the basis of the above, Toledo Edison has determined that the License Amendment Request does not involve a significant hazards consideration. As this License Amendment Request concerns a proposed '
change.to the Technical Specifications that must be reviewed by the Nuclear Regulatory Commission, this License Amendment Request does not' constitute an unreviewed safety question.
ATTACHMENT:
Attached are the proposed marked-up changes to the Operating License.
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