ML20237G745
| ML20237G745 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 08/14/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20237G729 | List: |
| References | |
| NUDOCS 8708240209 | |
| Download: ML20237G745 (8) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 7 TO FACILITY OPERATING LICENSE NO. NPF-39 L
PHILADELPHIA ELECTRIC COMPANY l
LIMERICK GENERATING STATION, UNIT 1
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DOCKET NO. 50-352
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1.0 INTRODUCTION
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By letter dated April 3,1987, Philadelphia Electric Company (PECo or the l
licensee) requested an amendment to Facility Operating License No. NPF-39 j
for the Limerick Generating Station, Unit 1.
The proposed amendment would revise the Technical Specifications (TSs) to: 1) incorporate the operating. limits (e.g., core physics, thermal and hydraulic limits, etc.)
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for all fuel types for Cycle 2 operation of Limerick, Unit 1; 2) incorporate a change in slope of the flow-biased Average Power Range l
Monitor (APPM) scram and rod block setpoints for operating flexibility or j
margin improvement options and 3) modify the Bases associated with core reloads.
l Limerick, Unit 1 shutdown May 15, 1987 for the first refueling following coastdown. During the refueling, 268 of the 764 fuel assemblies will be replaced with General Electric Company (GE) manufactured 8X8 fuel bundles. The analyses for the reload were performed by GE for PECo using
,NRC approved procedures and methodologies. The April 3, 1987 submittal (Reference 1) included the necessary changes to the operating limits in the TSs as determined by the analyses for Cycle 2 operation and other supporting documents (References 2, 3 and 4).
The reload for Cycle 2 is generally a normal reload with no unusual core features or characteristics. TS changes are few and primarily related to Maximum AveraCe Planar Linear Heat Generation Rate (MAPLHGR) and Linear Heat Generation Rate (LHGR) limits for the new fuel and Minimum Critical Power Ratio (MCPR) limits for all of the fuel using Cycle 2 core and transient parameters and extended operating regions and conditions. The new fuel is the extended burnup type which has been used in several recent GE reloads.
The submittal proposes an extension of the current allowed operating region on the reactor power-flow map vic an extended load line analysis (ELLLA). Increased core flow (ICF), final feedwater temperature reduction (FFWTR) and feedwater heaters out service (FH005) modes of extended operation have been approved previously (Ref. 5). Except for changes to the flow biased neutron flux scram and rod block setpoints necessary for ELLLA and some changed or additional MCPR limits, these extensions require no other changes to Cycle 2 TS. Revised MCPR limits for operation with inoperable recirculation pump trip (RPT) are also proposed.
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I J 2.0 EVALUATION 2.1 Reload Description The LIC2 reload will retain 496 BP8x8R GE fuel assemblies from the previous cycle and add 268 new GE8x8EB fuel assemblies. The reload is based on a previous cycle core nominal average exposure of 8.6 GWD/ST and Cycle 2 end of cycle exposure of 16.5 GWD/ST. The loading will be a conventional scatter pattern with low reactivity fuel on the periphery. This loading is acceptable.
2.2 Fuel Deeign
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The new fuel for Cycle 2 is the GE extended burnup fuel GE8x8EB. The fuel designation is BC320A. This fuel type has been approved in the Safety Evaluation Report for Amendment 10 to GESTAR II (Ref. 6 and 7). The specific descriptions of this fuel have been submitted in Amendment 18 to GESTAR II, but since this amendment has not as yet been accepted, the fuel description has also been presented for LIC2 in Reference 3.
This fuel description is acceptable.
In operation the GE8x8EB fuel will be assigned a number of axial lattice regions and appropriate MAPLHGR limits, which have been determined by 1
approved thermal-mechanical and loss of coolant analyses (LOCA) j calculations, will be applied to each of these regions. There was
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extensive interaction between the staff, GE and utilities in deciding on an acceptable format for presentation of this information, suitable for plant use and staff requirements for TS. The process computer contains, and acts on, full details of the MAPLHGR information. The agreed upon TS
.present the least and most limiting lattice MAPLHGR as a function of burnup. When hand calculations of MAPLHGR are required (process computer inoperative) the most limiting values are used for all limits. These TS are acceptable. A proprietary report, reviewed by the staff, available to the Limerick engineering staff provides complete details of the lattice definitions and MAPLHGR limits.
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'The proposed LHGR limit for the GE8x8EB fuel is 14.4 kW/ft (rather than the 13.4 for other GE fuel). This LHGR has been reviewed and accepted for this fuel in the GE extended burnup fuel review (Ref. 6). (See the referrals in Reference 6 to References 18 and 19. These references are responses to questions and presentations relating to the GE8x8EB fuel which provide information on the 14.4 kW/ft LHGR.). This LHGR is acceptable l
for the fuel in LIC2.
2.3 Nuclear Design The r,uclear design for (102 has been performed by GE with the approved methodology described in GESTAR II (Ref. 7). The results of these analyses are given in the GE reinad report (Ref. 2) in standard GESTAR 11 fonnat. ~
The results are within the range of those usually encountered for BWR l
. l reloads.
In particular, the shutdown margin is 2.0 and 1.0% delta k at BOL and at the exposure of minimum shutdown nargin respectively, thus fully meeting the required 0.38% delta k.
The Standby Liquid Control System also meets shutdown requirements with a shutdown margin of 3.6%
delta k.
Since these and other LIC2 nuclear design parameters have been obtained with previously approved methods and fall within expected ranges, the nuclear design is acceptable.
2.4 Thermal-Hydraulic Design The thermal-hydraulic design for LIC2 has been performed by GE with the approved methodology described in GESTAR II and the results are given in t.
the GE reload report (Ref. 2). The parameters used for the analyses are those approved in Reference 7 for the Limerick class BWR 4.
The GEMINI system of methods (approved in Ref. 8) was used for relevant
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transient analyses.
The revised constants used to calculate the mean scram time, and which are a pa'rt of the TS changes for LIC2 (TS 3.2.3), were also approved in 4
Reference 8.
These methods and parameters are acceptable.
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The Operating Limit MCPR (OLMCPR) values are determined by the limiting transients, which are usually Rod Withdrawal Error (RWE), Feedwater l
Controller Failure (FWCF) and Load Pejection Without Bypass (LRWBP). The l
analyses of these events for LIC2 using the standard, approved (Ref. 71 ODYN Option A and B approach for pressurization transients provide new Cycle 2 TS values of OLMCPR as a function of average scram time, for j
operation in both standard and extended operating regions. For all standard operating conditions LRWBP is controlling at both option A and B i
. limits. With the selected rod block setting of 107% the RWE is not limiting. These OLMCPR results are reflected in TS changes. Approved methods (Ref. 7) were used to analyze these events (and others which could be limiting) and the analyses and results are acceptable and fall within expected ranges.
The Limerick 1 TS have standard staff approved provisions for incore neutron detector monitoring of thennal-hydraulic stability according to the recommendations of GE SIL-380. Thus cycle specific stability calculations are not required, either for standard conditions or the extended temperature and power-flow conditions proposed for Cycle 2 operation.
2.5 Transient and Accident Analyses The transient and accident analysis methodologies used for LIC2 are described and NRC approval indicated in GESTAR II. The GEMINI system of methods (Ref. 8) option was used for transient analyses. The limiting MCPR events for LIC2 are indicated in Section 2.4. The core wide transient analysis methodologies and results are acceptable and fall within expected
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1 4 The RWE was analyzed on a plant and cycle specific basis (as opposed to the statistical approach) and a rod block setpoint of 107% was selected to provide an OLMCPR of 1.26 for all fuel types. The mislocated assembl event is not analyzed for reload cores on the basis of NRC approved (ysee Reference S.2-59 of Ref. 7) studies indicating the small probability of an event exceeding MCPR limits. The disorientation event is not analyzed for (symetric gap) C lattices. The local transient event analyses are thus acceptable.
The limiting pressurization event, the main steam isolation valve closure I
with flux scram, analyzed with standard GESTAR II methods gave results for peak steam dome and vessel pressures well under required limits. These are acceptable methodologies and results.
LOCA analyses, using approved methodologies (SAFE /REFLOOD) and paraneters were performed to provide MAPLHGR values for the new reload fuel assemblies.
These analyses and results are acceptable.
Since Banked Position Withdrawal Sequence rod patterns are used for i
Limerick 1, a cycle specific control rod drop accident analysis is not I
required. The basis for this position and NRC approval is presented in -
l Amendment 9 in Reference 7.
2.6 ELLLA, ICF, FFWTR, FH005 and Inoperable RPT Extensions The LIC2 reload submittal proposes extensions to standard operating regions in the GESTAR 11 standard category of " Operating Flexibility cr Margin Improvement Options". The selected options are ELLLA, ICF, FFWTR, FHOOS and RPT. These have become commonly selected and approved options for a number of reactors in recent years. These options are described and
' discussed in Appendices A and B of the GE reload report (Ref. 2) and in a j
GE topical report for Limerick (Ref. 4) on the ELLA extension. The
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topical report provides generic analyses of transients and accidents. A similar topical report was previously reviewed for the ICF, FFWTR and FH005 extensions approval (Ref. 5).
The proposed ELLLA changes the Average Power Range Monitor (APRM) rod block and scram lines on the power-flow map, and permits operation up to the new APRM rod block line (0.58W + 50%) up to the intersection with the 100 percent power line occurring at a flow of 87 percent. These are standard changes for ELLLA. For ICF the approved flow increase is to 105 percent of rated core flow at 100 percent power. The increased flow is allowed throughout the cycle and after nonnal end-of-cycle (with or without FFWTR) with reactivity coast down. FFWTR involves feedwater temperature reduction up to 60' F (to 360* F at full power) and is proposed only for operation after nomal end-of-cycle. Limiting events have been analyzed for cycle extension to the exposure attainable using ICF and l
FFWTR at full power. Operation with FH005 throughout the cycle has previously been approved (Ref. 5). For LIC2 the limiting MCPR is bounded by the limits for ICF plus FFWTR and may be used throughout the cycle, including cycle extension.
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. j For the ELLLA extension the topical report (Ref 3) discusses A full range of transient and accident events relevant to the region extension, and J
addition the GE LIC2 reload report (previously approved conclusions.Ref. 2) present presents results of calculations or In of limiting MCPR transients specifically for LIC2. The transient analyses demonstrate that the licensing basis results (e.g.,100 percent flow,100 percent power for pressurization transients) bound the ELLLA region results (e.g., 87 percent flow, 100 percent power). These conclusions apply to all relevant MCPR events such as pressurization, rod withdrawal and flow runout events. Changes to MCPR TS are not required because of ELLLA adoption. Other relevant areas such as over pressure protection, LOCA and containment analysis have also been examined, and the analyses indicate that results are within allowable design limits. Thermal-hydraulic stability will be provided for by appropriate surveillance. The analyses have been done with approved methmiologies and the results are similar.to previously approved ELLLA extensions. Thus operation within the ELLLA region is acceptable for LIC?.
The standa.rd (Ref. 7) relevant limiting transients and resulting OLMCPR values were calculated for LIC2 for nonnal operations and for appropriate l
limiting ELLLA conditions. They were also calculated for the previously.
approved ICF, FFWTR and. FH005 extension conditions. These calculations included the cycle extension conditions. The results provide OLMCPR values for the TS (MCPR vs scram speed based on CDYN option A and B limits). They use a standard approved methodology and are acceptable.
It was assumed for.these transients that the RDT is operable. The limiting MCPR event (FWCF) was also calculated for limiting extension conditions assuming an inoperable RPT. This resulted 'in increased MCPR limits.
1 Operation with inoperable RPT is proposed for LIC2 throughout the cycle and for various extension conditions using these increased limits. These calculations follow standard procedures for the inoperable RPT extension and operation within these limits is acceptable for LIC2.
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2.7 Technical Specifications The specific changes to the TS for the Limerick Cycle 2 operation and operation in extended power-flow operating regions are listed below.
These have been discussed above along with the basis for their acceptability.
(a) The new ELLLA APRM scram and rod block flow dependent setnoints. The changes are to Table 2.2.1-1 of TS 2.2.1, TS 3.2.2 and Table 3.3.6-2 of TS 3.3.6 and are acceptable.
(b) The new MCPR limits for Cycle 2, for extended operation.and for the new (GE8x8EB) fuel. -The changes are to TS 3.2.3 and Figures 3.2.3-la and Ib and are acceptable.
(c) The 14.4 KW/ft LHGR limit for the new (GE8x8EB)' fuel..The' changes are to TS 3.2.4 t.nd are acceptable.
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' (d) MAPLHGR limits for the new fuel. The changes are to TS 314.~2.1 and j
Figure 3.2.1-6 and are acceptable.
(e) The Rod Block Monitor maximum trip setting in Table 3.3.6-2 is set at 107% to correspond to the selection in the RWE analysis. This is acceptable.
There is also a change to the listed constants in TS 3.2.3 used to calculate the mean scram time. These constants were approved in the review of Amendment 11 to GESTAR II, (Ref. 8) and are acceptable.
The safety limit MCPR presented in TS 2.1.2 has been increased from 1.06 to 1.07. The latter is the standard safety limit in BWR-4s after the initial cycle of operation. The increased limit provides additional conservatism to account for possible uncertainties in power distribution in relcad cores.
There are changes to pages iv, vi and viii of the table of contents to reflect the changes associated with the reload. These are administrative changes that have no safety significance.
There are changes to the Bases for Sections 2 and 3/4 of the TSs. Page B 2-1 is revised to state that the Safety Lirtit MCPR will be 1.07 rather than the 1.06 that applied to the first fuel cycle. Pages B 2-2, B 2-3 and B 2-4 presently discuss how the Safety Limit MCPR is detennined, summarizing information in two GE documents - NEDO-10958-A and NEDO-20340.
These documents have been reviewed (and as the "A" indicates) approved by J
NRC; the results are incorporated in the GE Generic Reload topical report I
(Reference 8). The latter report will continue to be referenced in the
_ Limerick TS Bases (e.g., page B 2-2), but the discussion on uncertainties in the MCPR analyses, which is redundant to that in the basic GE licensing reload reports, is being deleted from pages B 2-2, B 2-3 and B 2-4.
Pages B 3/4 2-1 through B 3/4 2-5 presently discuss how the MCPR, MAPLHGR and LHGR limits are calculated for Limerick fuel. The Bases presently cite the SLMCPR of 1.06 which was only valid for cycle one. As part of the reload application, PECo submitted GE document NEDE-31401-P dated February 1987, entitled " Bases of MAPLHGR Technical Specifications for Limerick Unit 1" (Reference 3). The references on page B 3/4 2-5 are being revised by this amendment to include the GE report. Much of the discussion presently on pages B 3/4 2-1 through B 3/4 2-3 on input parameters is redundant to or changed by the referenced reports and is being modified or deleted. Our review of the Bases was inherent in our review of the TS limits developed from the Bases.
3.0 SLHMARY We have reviewed the reports submitted for the Cycle 2 operation of Limerick with extended operating regions. Based on this review we
I 1 conclude that appropriate material was submitted and that the fuel design, q
nuclear design, thermal-hydraulic design and transient and accident i
analyses are acceptable. The Technical Specification changes submitted l
for this reload suitably reflect the necessary modifications for operation in this cycle.
4.0 ENVIRONMENTAL CONSIDERATION
l This amendment involves a change to a requirement with-respect to the installation or use of a facility component located within the restricted-area as defined in 10 CFR Part 20 and chenges to the surveillance requirements. 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 Commission has previously issued a proposed finding that this amendment. involves no significant hazards consideration and there has been no public coment on such finding. Accordingly, this 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 1
statement nor environmental assessment need be prepared in connection with I
the issuance of this amendment.
5.0 CONCLUSION
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The Comission made a proposed detennination that the amendment involves no significant hazards consideration which was published in the Federal Register (52 FR 23104) on June 17, 1987 and consulted with the State of Pennsylvania. No public coments were received and the State of 1
. Pennsylvania did not have any comments.
I 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 proposed manner, and (2) such activities will be conducted in compliance with the Comission's l
regulations and the issuance of this amendment will not be inimical to the I
common defense and security or to the health and safety of the public.
Prinicipal Contributor: H. Richings i
R. Clark Dated: August 14, 1987 i
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6.0 REFERENCES
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Letter, and enclosures, from E. J. Bradley, PECo, to H. Denton, NRC, i
dated April 3, 1987. Application requesting changes to the Limerick i
TS for thE first refueling.
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GE Report 23A5801, dated February 1987, " Supplemental Reload Licensing l
Submittal for Limerick Generating Station, Unit 1, Reload I".
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NEDE-31401, February 1987, " Basis of MAPLHGR TS for Limerick Unit 1".
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NEDC-31139, April 1986, "GE BWR Extended Load Line Limit Analysis for.
Limerick Unit 1".
5.
Letter (andenclosure)forR. Martin,NRC, toe.Bauer,PEco, dated February 17,'1987, " Technical Specification Changes to Allow Operation with Incret. sed Core Flow and Partial Feedwater Heating".
6.
' Letter (and attachment) from C. Thomas, NRC, to J. Charnley, GE, dated May 28,1985, " Acceptance for Referencing of Licensing Topical Report NEDE-24011-P-A-6, Amendment 10".
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GESTAR II, NEDE-24011, Revision 8 " General Electric Standard l'
Application for Reactor Fuel".
8.
Letter (and attachment) from G. Lainas, NRC, to J. Charnley, GE, j
dated March 22, 1986, " Acceptance for Referencing of Licensing l
Topical Report NEDE-24011-P-A, 'GE Generic. Licensing Reload Report',
Supplement to Amendment I?.".
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