ML20086E439
| ML20086E439 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/21/1991 |
| From: | Beck G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20086E441 | List: |
| References | |
| NUDOCS 9112020100 | |
| Download: ML20086E439 (14) | |
Text
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10 CPR 50.90 10 CFR 50.91 I'lllLADEl. Pill A El.ECTItIC COhll%NY NUCLI!AR GROUP lil!ADQUARTliRS 955-65 Cill!STliRHROOK llLVD.
WAYN!!, PA 19087 5691 (215) 640-6000 NUrLi'.AR l'.NGINilklNG & $LRVICl3 DI:l%K1Ml;N1 November 21, 1991 Docket No. 50-278 License No. DPR-56 U.
S.
Nuclear Regulatory Commission ATTN: Document Control Desk Washingt.c, DC 20555
Subject:
Peach Bottom Atomic Power Station, Unit 3 Emergency Technical Specifications Change Request Dear Sir.
Philadelphia Electric Company (PECo) hereby submits an emergency Technical Specifications Change Request 91-10, in accordance with 10 CFR 50.90, and 10 CFR 50.91, paragraph (a)(5),
requesting an amendment to the Technical Specificat.lons (Appendix A) of Operating Licence No. DPR-56.
We believe that this requested change is consistent with the Standard Technical Specifications.
Information supporting this change request is contained in Attachment 1 of this letter and the proposed replacement pages are conta.ined in Attachment 2.
Guidance provided in DL Operating Procedure 229
(" Emergency License Authorization", dated August 14, 1985) was used in the preparation of this emergency Technical Specifications Change Request.
This submittal requests an emergency temporary change to the Technical Specifications to allow fuel loading to take place without all control rods fully inserted into the core.
We are requesting this change to be in place by November 27, 1991.
If you have any questions regarding t his matter, please contact us.
Very,truly yours,
,lc-l4l/
G.
J.
Beck, Manager Licensing Section Attachments cc:
T.
T.
Martin, Administrator, Region I, USNRC J.
J.
Lyash, USNRC Senior Resident Inspector, PB 00 3,O Ui.,1m m'jn,v;7
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COMMONWEALTH OF PENNSYLVANIA:
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COUNTY OF CHESTER D.
R. Helwig, being first duly sworn, deposes and says:
That he is Vice President of Philadelphia Electric Company; that he has read the foregoing Application for Amendment of Nility Operating Licenea DPR-56 (Technical Specifications Change Request No. 91-1.
fuel loading to take place without all fuel rods ful.
nto the core, and knows the contents thereof; and that and matters set forth therein are true and correct tr hiu knowledge, information and belief.
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Vice Presi ! t Subscribed and sworn to 37, before me thiscO/ day of M/t [L -
1991.
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Notary Public Pktarat $oal Dolons A. CWatt invy P:24c TrabtwiTe.Ctetor County M Conv*mnEx;*w Aly24 iWa
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ATTACHMENT 1 PEACH BOTTOM ATOMIC POWER STATION UNIT 3 Docket No. 50-278
- l License No. DPR-56 TECHNICAL SPECIFICATIONS CHANGE REQUEST i
No. 91-10
" TEMPORARILY ALLOW FUEL LOADING WITHOUT ALL CONTROL RODS INSERTED" l
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.T.SCR 91-10 November 21, 1991 Page 1 A discussion of circumstance surrounding the situation, and a determination of why the need for prompt action could not have been avoided; Philt-
-phia Electric Company is seeking a Technical Specifications change to allow removal of control rods while refueling activities occur.
This Technical Specification change is necessary to minimize delay of fuel inspections while evaluating inspection results and preparing for cleaning activities during the Peach Bottom Atomic Power Station Unit 3 Cycle 8 refueling outage.
During recent fuel inspections associated with fuel which incurred failures during Cycle 8, debris was observed in the fuel bundles.
This debris appears to be the cause of the majority of fuel failures which occurred during Cycle 8.
It was determined that the bottom head drain of the reactor is clogged, presumably with the same type of debris.
In order to prevent similar fuel failures in Cycle 9, an inspection and cleaning program is underway to clear debris from all fuel that has been reinserted from Cycle 8.
Preparations are also being made to clear the bottom head drain and inspect the bottom of the reactor vessel for debris.
This inspection and cleaning activity requires the removal of the four fuel assemblies, control rod and control rod guide tube, control rod housing thermal sleeves, and the fuel support piece for several fuel cells.
In order to minimize the overall time required for this evaluation, it is necessary to
.TSCR 91-10 November 21, 1991 Page 2 remove, inspect, and reload fuel while several fuel cells are disassembled.
The granting of this proposed Technical Specifications chango will allow refueling activities to continue while several fuel cells are disassembled.
This will result in an estimated savings of two days of critical path.
These two days will be used for the analysis of bottom head findings, planning of future activities, and to allow for necessary downtime to support equipment repairs or tool fabrications.
An addition of two days to the refueling outage would result in an estimated economic penalty of $700,000 for replacement generation costs.
Revised Technical Specification pages Proposed Technical Specification pages 225, 226 and 229 are contained in Attachment 2.
Licensee requests the following changes:
1)
Licensee proposes to modify Limiting Conditions for Operation (LCO) 3.10.A.1 by adding reference to LCO 3.10.A.2.
2)
LCO 3.10.A.2 currently states:
.TSCR 91-10 November 21, 1991 Page 3 "Puol shall not be loaded into the reactor core unless all control rods are fully inserted."
Licensee proposes tc modify the above LCO to state:
" Fuel shall not be loaded into the reactor core unless all control rods are fully inserted with the following exception *:
a.
The reactor modo switch shall be locked in the
" Refuel" position.
The refueling interlock which prevents fuel from being loaded with a control rod withdrawn may be bypassed for any number of control rods, and those control rods withdrawn or removed from the core, if the four fuel assemblies surrounding each control rod or control rod mechanism to be withdrawn or removed from the core and/or reactor vessel are removed from the core cell.
Additionally, all fueled cells face and diagonally adjacent to each cell with a control rod withdrawn or removed shal) have their control rod fully inserted and their control rod's directional control valves electrically disarmed.
All other refueling interlocks shall be operable.
This exception is in effect during the period prior to completion of tensioning the reactor
.TSCR 91-10 November 21, 1991 t
Page 4 vessel head bolts for the Unit 3 Cycle 8 refueling outage."
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3)
Licensee proposes to add the following Surveillance Requirement 4.10.A.3:
" Prior to loading fuel in the core without all control rods fully inserted it shall be i
demonstrated analytically that the core is subcritical with a margin of at least 1.0% d k assuming a single fuel loading error into a cell with the control rod withdrawn.
This requirement is in effect during the period prior to completion of tensioning the reactor vessel head bolts for Unit 3 Cycle 8 refueling i
outage."
4)
Licensee proposes to add the following temporary asterisks to Bases page 229:
This requirement is not in effect during the period prior to completion of tensioning _the reactor vessel head bolts for Unit 3 Cycle 8 l
refueling outage."
i i
I
,TSCR 91-10 November 21, 1991 Page 5 l
l Safety Evaluation with a no significant hazards consideration determination; Change request (1) adds a reference to LCO 3.10.A.1 which will allow refueling interlocks to be bypassed as discussed in the temporary change to LCO 3.10.A.2.
Change request (2) allows the bypass of the refueling interlock which would prevent fuel from being loaded with a control rod withdrawn.
In support of this, Change request (2) requires that the four fuel assemblies surrounding each control rod or control rod drive mechanism to be removed from the core and/or reactor vessel will be removed from the cell.
The removal of these four bundles results in a less reactive core and increases the margin to criticality.
With all four fuel bundles removed, one error resulting in the inadvertent insertion of a single fuel assembly in this cell cannot result in an inadvertent criticality.
Several fuel assembly insertion errors in the same cell would be required to cause an inadvertent criticality.
Strict control and compliance with the Core Component Transfer Authorization Sheets is required by plant procedures.
Also, plant procedures specifically require that before loadin,g any fuel bundle it must be verified that a blade is inserted in the cell.
The strict compliance with procedures and practices along with the visual indications of a withdrawn
.TSCR 91-10 November 21, 1991 Page 6 control blade make a single bundle insertion error highly unlikely.
The combination of errors that would be required to result in a multiple fuel insertion error make this event non-credible.
Change request (2) also requires that the control rod drives face and diagonally adjacent to the cell with the control rod removed are fully inserted and have their directional control valves disarme:.
The purpose of this requirement is to increase the core shutdown margin in the event of a fuel assembly insertion error in the defueled_ cell.
A bundle misload analysis was performed to show that an inadvertent criticality cannot occur due to the single insertion error.
Therefore, the next logical concern is the shetdown margin that exists directly following the error.
The main effect of this error on shutdown margin will be to possibly shift the location of the strong rod to the area of the error.
The_ greatest impact will be on the face adjacent rods, followed clos.ely by the diagonally adjacent rods.
By disabling these-rods, they no longer need to be considered as possible strong roda in determinatica of shutdown margin.
The effect of this error on the worth of rods outside the adjacent rods is negligible and will have a minimal effect on the overall shutdown margin.
Therefore, this requirement will add to the margin-of safety by ensuring that the withdrawal of a control rod following the original loading error will still not result in an inadvertent criticelity.
.TSCR 91-10 November 21, 1991 e
t Page 7 Change request (3) requires that an analytical determination be performed to demonstrate that the loading of single fuel bundle into a cell with the control rod removed is subcritical with a margin of at least 1.00% delta k.
The purpose of this analytical demonstration is to ensure that the margin of safety required by the Technical Specification Bases is met.
The basis of Technical Specification 3.10.A.2 is that inadvertent criticality be prevented by the combination of administrative controls and refueling interlocks.
A bundle misload analysis provides the assurance that inadvertent criticality will be precluded in the event that a single assembly insertion error occurs.
The requirement of 1.00% delta k is highly conservative for this purpose and is consistent with the analysis in the PBAPS UFSAR for a single fuel assembly insertion error.
The UFSAR states that single fuel assembly insertion will 4
not result in inadvertent criticality because the nuclear design of the core requires a_ shutdown margin of 1.00% delta k (the 1.00% delta k margin is the amount the core will remain subcritical after the withdrawal of the highest reactivity rod).
The bundle misload analysis shows that during Peach Bottom Atomic Power Station Unit 3 Cycle 8 the core will remain subcritical by at least a 1.00% delta k margin following a single assembly insertion error.
i Change request (4) will modify the statement in the Bases that all control rods be fully inserted when fuel is being
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-.TSCR 91 November 21, 1991
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Page 8 loaded into the core until the completion of tensioning the reactor vessel head bolts for Unit 3 Cycle 8 refueling outage.
The following evaluation is provided in accordance with the requirements of 10 CFR 50.92:
1.
Do the proposed revisions involve a significant increase in the probability or consequences of an accident previously evaluated?
-No, the proposed revisions do not involve a significant increase in the probability or consequences of an accident previously evaluated.
This amendment incorporates compensatory actions in the Technical Specifications to assure that an inadvertent criticality due to a single fuel assembly insertion error into a discssembled cell would be precluded.
- 2.
Do-the propcsed revisions create the possibility of a new or different kind of accident from any accident previously evaluated?
l No, the. proposed-amendment does not-create the possibility L
-of a new or different kind of accident from any previously evaluated.
The compensatory measures included in the Technical Specifications changes assure that no new or L
different kind of accident is possible.
- .TSCR 91-10 November 21, 1991 Page 9 3.
Do the proposed revisions involve a significant reduction in the ma* gin of safety?
No, the proposed amendment does not involve a significant reduction in the margin of safety.
The nuclear design is required to. provide sufficient reactivity margin so that the core will be subcritical with the strongest rod withdrawn at the most reactive time in the perating cycle.
This change will not alter the core loading and therefore will not change the shutdown margin.
Therefore, the margin of safety in the Bases of the Technical Specifications is not reduced.
A discussion of the proposed interim compensatory measures to be
' imposed; 1.
The four fuel assemblies surrounding each control rod or control rod drive mechanism to be removed from the core L
and/or reactor vessel, will be removed from the cell.
l 2.
An analytical determination has been performed to L
_ demonstrate that the core remains subcritical with-a margin i
of_at least 1.00% delta k when loading a single fuel bundle into a cell with the control rod removed.
l 3.
The control rod drives for fueled cells that are face and l
diagonally adjacent =to the cell with the control rod removed i
iTsCR 91-10 November 21, 1991 Page 10 are fully inserted and have their directional control valves disarmed.
A schedule date for returning inoperable components or systems to an operable condition or the scheduled date for accomplishing required surveillance; As discussed in the Technical Specifications wording, the temporary changes would be in effect during the period prior to completion of tensioning the reactor vessel head bolts for PBAPS Unit 3 Cycle 8 refueling outage.
A statement that a best effort has been made to notify State personnel; Per a telephone conversation between G. J. Beck (PECO) and R.
Janati, Bureau of Radiation Protection, on Thursday,.
November 21, 1991, the Commonwealth of Pennsylvania was notified of this change request.
Information for the NRC to prepare an environmental assessment on the-basis-for NRC to determine that the amendment involves a
-categorical exclusion under 10 CFR Part 51; An, environmental impact assessment is not required for the changes requested by this Application because the requested changes conform to the criteria for " actions eligible for
4.TSCR 91-10 November 21, 1991 Page 11 categorical exclusion" as specified in 10-CFR 51.22(c)(9).
The Application involves no significant hazards consideration as demonstrated in the preceding sections.
The Application involves no significant change in the types or significant increase in the amounts of any effluents that may be released offsite, and there will be no significant increase in individual or cumulative occupational radiation exposure.
Conclusion The Plant Operations Review Committee and the Nuclear
-Review Board have reviewed these proposed changes to the Technical Specifications and have concluded that they do not i
-involve an unreviewed safety question and will not endanger the health and safety of the public.
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