ML20205D605
| ML20205D605 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/18/1988 |
| From: | Gallagher J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | |
| Shared Package | |
| ML20205D578 | List: |
| References | |
| NUDOCS 8810270154 | |
| Download: ML20205D605 (12) | |
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O BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION in tne Matter of Docket Nos. 50-277 Phit &LELHil A ELiCTRIC COMPANY 50-278 APPLICATION FOR AMENDMENT i
OF FACILITY OPERATING LICENSES OPR-44 OPR-56 1
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Eugene J. Bradley 2301 Market Street Pntladelphia, Pennsylvania 19101 I
i Attorney for Philadelpnia Electric Company l
SS10270154 SS1021 ADOCK 0500(jjj7 DR
BEFORE THE UNITED STATES huCLEAR REGULA10Rt LOMMISSION in the Matter of Docket Nos. 50 277 FHILACELPHl3 ELEliRIC COMPAN) 50-278 APPLICATION FOR AMENDMENT OF FACILITY OPERATlhG LICENSES OPR-44 OPR-56 t
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7 Phliadelphia Electric Compan/, Licensee under Facility Operatirg Licenses OPR-44 ana LPR-56, f or the Peach Bottom Atomic Power Station (PBAPS) Unit No. ? and Unit No.
3, respectively. hereby requests that the Technical Specifications contained in Appendix I
A tc the Operating Licenses be amended, Proposed changes to the Technical i
5pecifications are indicated by vertical bars in the margins of the attached pages iv, 103, 103a and Bases page 110. This Application replaces, in its entirety, an App t nation filed on September 7,1988.
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introduction Peach Bottom Technical Specifications (SeClion 3.3.8.4, limiting Conditions for Operation) currently require a Source Range Monitor (SkM) count rate of greater than or i
equal to 3 cps on at least two channels before control rods inay be withdrawn for r
startup.
Tne corresponding Surveillance Requirement Specification 4.3.B.4, requires t
that tnts count rate be verified prior to control rod withdrawal for startup or during retweling. Due to the extended shutdoan of both units (Unit 2 shut down March 14, 1987 drd Unit 3 shut do'n March 31,1987), it appears likely that the present count rate criterton cannot be satisfied when the units are restarted. Consequently, to permit startap of these units without the use of installed neutron sources, a change to the i
Technical Specifications is proposed to allon withdrawal of control rods for startup
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nen at least tnree SRM channels are indicating a count rate as sho n on the proposed figure 3.3.1 "SRM Ccunt Rate versus Signal-to-Noise Rat!o".
i Tne changes proposed in this Application are grouped into two categories.
The Categcry A changes are described above. The Category B changes are administrative j
cnanges whicn correct a typographical error and place back into the Unit 2 Technical Specifications a phrase that was inadvertently deleted in an ameno tnt request dated F e t,r u a r > 19, 1932 and issued oy the NRC as Amendment 861ated June 17, 1982.
Licensee requests that the proposed changes be effective upon date of amendment 1
assance.
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p stea uiscussien - Category A I
The SRM system consists of fcur identical neutron detection channels. Each thannel contains a miniature, in-core fission chamber; a pulse preamplifier; an equiprent oraner; and remote reading indicators. Each aetector is equipped with a motor
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O driven mechanism to allow retraction from the core at neutron flux levels above the SRM range.
i ine 5kN system monitors thermal neutron flux in the core over a range i
sufficient to observe the core snutdown scarce level, the approach to criticality and I
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the overlap into the intermediate Range Monitoring (IliMi system. The indicating range cf tte SRM maj Le extended by retracting the detectors from the core. The SRM system provides four channels of neutron flus level information displayed over a range of 10-I to 106 cps (corresponding to 10'9 to 10*2 of rated thermal power) and fcur cnannels of flux level rate of change information displayed as reactor period over a range of -100 to +10 seconds, e
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The SRM fission chambers are operated in the pulse counting mode and produce 015 crete cutput pulses which represent the composite effect of thermal neutron flux and gamma flux (noise) at the detector. Due to the nature of the detector, the pulses
- I croduced by tnermal neutrons are of much greater magnitude than those produced by gamma, altnough the number of gamma pulses may far exceed the number of neutron pulses. An i
electronic circuit performs a discriminaticn action based on the amplitude of these 1
pulses, thus procucing an output signal proportional only to the neutron count rate.
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Descript 1cn of Changes - Category A I
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ticensee proposes the follo ing cnanges to the fechnical Specifications:
l (l> kevise Specifications 3.3.8.4 and 4.3.B.4 on p. 103 to designate that the coserved count rate, during startup only, may be provided by "at least three i
i source range channels" witn an "coserved count rate and a signal to noise ratio i
on or above the curve shown on Figure 3.3.1".
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(2)
Insert page 103a to depict Figure 3.3.1 "$RM Count Rate versus Signal-to-Noise Ratio".
(3) Revise the Bases to Specification 3.3.5 and 4.3.8 to clarify the count ; per second required for startup.
Safeln Ciscussion - Category A The necessity for maintaining a minimum count en the SRMs at all times is based on tne most conservatise evaluation which includes fress fuel loaded in the initial fuel cycle with no neutron sources present. A multiplying medium with no neutrons present forms the basis for the accident scenario in hich reactivity is gradually but inadvertently added until the medium is highly supercritical. The introduction of some nectrons at this point would cause the core to undergo a sudden power burst, rather than a gradaal startup, with no warning frcm the nuclear instrumentation.
This scenario is of concern nen a reactor is loaded with fresh fuel, but is of less concern when loaded witn irradiated fuel.
Irradiated fuel continuously produces neutrons by spontaneous fission of
.ertain pluton 1uta isotopes, by photo fission, and by photo disintegration of deuterium naturally present in the moderator.
The neutron produttion in irradiated fuel is normally great enough to meet the minimum count for a full core af ter a refueling outage. Due to the extended shutdown of the Peach Bottom units, the minimum count level of 3 cps ma, not ce obtainable.
The Peach Bottom Tecnnical Specifications Bases state that "the requirement of at least 3 counts per second assures that any transient, should it E n r. Degins at or above the initial value of 10'O of rated power used in analyses of transient cold conditions." A review of St(. tion 14 of the Peach Bottom UFSAR nas confirmed the use of 10'8 of rated power witn the reactor critical in anal,ses of transient cold conditions, in addition, no credit is taken for the SRMs in the Se: tion 14 accident analyses.
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Since 0./ cps, the lowest count rate shown on Figure 3.3.1, corresponds to appresimately 7 s 10'9 of rated poaer, it is concludeit tnat reducing the downscale setpoint in accordance with Figure 3.3.1 will not invalidate the assumptions used in the transient analyses.
Stipulating a signal-to-noise ratio in accordance with Figure 3.3.1 j
assures that the SRM's are indeed responding to neutrons and the neutron flux level with i
tre reactor critical will be well above 10*8 of rated pc.er due to subcritical multiplication.
The curse presented 'n Figure 3.3.1 was decisea by General Electric Company for s
tne Pea <.n Bottom reactors. The curve ensures the same level of confidence at lower cps l
set;-cints as is provided at the existing 3 < ps setpoint. The 3 cps already included in
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ine fecnnical Specificattens is based on an assumed signal-to-noise ratio of two. At tnis 1& vel of signal noise, there is a statistical neutron monitoring confidence of 95%
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tnat tne Indicated signal is correct. At lower cps setpoints, a higher signal-to-noise rati:, is required to maintain the same level of counting uncertainty.
The inverse I
j relation between cps and signal-to-noise ratio depicted on Figure 3.3.1 ensures the 95%
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confidence level.
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Na $Nnificant Hazard 5 Consideration - Category A i
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Pursuant to 10 CFR 50.92, allo.ing withdrawal of control rods for startup when
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4 at least three SRM channels are indicating a count rate and signal-to-noise ratio in j
accordance with figure 3.3.1 has been reviewed, it has been cesermined that this change does not involse a significant ha:ards consideration for the following reasons
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The proposed Category A chanaes do not involve a significant increase in r
the probability or consequences of an accident previously evaluated, i
f These changes reduce the minimum SR.M count rate required to permit
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withdrawal of control rods to achieve criticality during startur.
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revised count rate is still within the design range of the SRM and specifying a minimum signal-to-noise ratio assures the SRMs are responding to thermal neutron flux. No hard=are changes are required to the SRM system; therefore, malfunction of an SkM alil still produce the required rod withdrawal blocks, lhe only accidents related to the proposed changes are those during startup: the rod drop accident (RDA) and tne continuous rod withdrawal error.
The ROA is the more limiting. Ho ever, no credit is taken for the SRMs in either of these accident analyses. Accidents involving refueling scenarios are not related to these change requests since these changes apply to startup only.
Section 14 (Sections 14.5 and 14.6) of the UFSAR assumes 10-8 of rated power with the reactor critical in analysis of transient cold conditions including the design basis RDA.
In addition to l
the SRMs not b'eing required to mitigate the consequences of any of the l
Section 14 accidents, reduction of the minimum SRM count rate required to withdraw control rods as sho.n in Figure 3.3.1 still ensures criticality
-ill be achieved. ell above 10'8 of rated power.
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l ii) Tne proposed Category A changes do not creste the possibility of a new or 1
different Lind of accident from any accident previously evaluated, l
No hardware "edifications are required to implement these changes.
The design functions of the SRM system are not being changed.
The only effect of these changes is a reduction in the minimum count rate required for centrol rod withdranal.nich remains bounded by the assumptions utilized in the UFSAR.
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iii) The proposed Category A changes do not in.olve a significant reduction in a margin of tafety.
The Bases for Tet'inical Specification 3.3.8 and 4.3.B state in part "the requirement of at Itast 3 counts per seccnd assures that any transient, should it occur, begins at or above the initial value of 10-8 of rated poner used in analyses of transient cold conditions."
In fact, any observable neutron count rate on the SRM is suf ficient to ensure the analyses remain valid.
Therefore, reduction of the minimum count rate from the nominal 3 cps to the values listed in Figure 3.3.1 will not significantly reduce this margin of safety because any transient will still begin at or above 10'O of rated power. Further, the SRMs are not required to ensure the margin of safety as analyzed in Section 14 of the OfSAR. For completeness, the Bases have been revised to reference Figure 3.3.1 for startop.
Destetetton of Changes - Category B Licensee proposes the following changes to the Itchnical Specifications:
(1) Correct Specification 4.3.C.1 of the Unit 2 Tecnnical Specifications only to state tnat scram time testing may be accomplished during operational hydrostatic testing or during startup.
This change will once again make the Unit 2 and Unit 3 Specifications 4.3.C.1 identical.
(/)
Correct the abbreviation in Specification 3.3.B.5.a for the Rod Block Monitor from "RM8" to "RBH".
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Safety Discussion - Category B For Change kequest (1), adding the phrase "during operational hydrostatic testing or" to Specification 4.3.C.1 is administrati'.e because this phrase was inadvertently cmitted in a Unit 2 reload Application cated February 19, 1982 and not i
discovered until preparation of the Category A changes described in this Application.
The Unit 3 Specifications contain this phrase, and deletion of it was not discussed by Licensee in the Feorwary 1982 Application. The error was inadvertent and therefore h
reir.stitution of the phrase to the Unit 2 Specifications is administrative.
l The operational hydrostatic test is defined by Licensee as that hydrostatic l
test preceding the commencement of reactor startup, and this definition describes normal t
Peach Bottom practice regarding the test. Other hydrostatic tests conducted at other times are not consioered the operational hydrostatic test. During the operational I
hydrostatic test, pressure is held at normal operating reactor pressure.
for Change Request (2), correcting the abbreviation for the Rod Block Monitor i
will alleviate confusion and ensure accurate interpretation of the specification.
l Designating the Rod Block Monitor as "RBM" is consistent with the abbreviation used in i
esisting Specification 4.3.8.5 and in the Bases on page 110.
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t No Significant Hazards Consideration - Category 8
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i An example (Exsmple i) provided by the Comission of a change involving no l
significant hazards consideration, as stated in 51 FR 7751 is a "purely administrative c.har.ge to tne Technical Specifications." The change requests contained in Category B
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t.cnterm to this eaample and do not constitute a significant hazard consideration in l
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The proposed Category B changes do noc involve a significant increase in the probability or consequences of an accident previously evaluated.
These changes are administrative in nature. One change returns to the Unit 2 Specification the capability to perform scram timing tests during the operational hydrostatic test. This item was previously in the Technical Specifications and was inadvertently removed. This change restores this Unit 2 Specification to its original text and to be identical to that of Unit 3.
This change only corrects an earlier error and hence does not increase the proodbility or consequences of accidents.
Tne remaining Category 8 change corrects the abbreviation for the Rod Block Monitor and makes it consistent with the designation used elsewhere in the Technical Specifications,
- 11) The proposed Category B changes do not create the possibility of a new or different kind of accident from any previously evaluated.
These changes only correct: 1) an earlier inadvertent deletion and will restore the Unit 2 specifications to their intended text and make the Unit 2 and 3 Specifications 4.3.C.1 identical as was true prior to the deletion, and 2) a typographical error in an abbreviation for the Rod block Monitor.
iii) The proposed Category B changes do not insolve a significan'. reduction in a margin of safety.
Tnese changes do not affect any margin of safety. These changes merely correct a previous deletion and a typcgrapnical error.
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Enstronmental Impact Assessment This proposed amendment revises the numoer of.ource range monitor channels and the required counti per second for startup only and corrects administrative errors in lecnnhal Specifications. Licensee has determined that this amendment involves no increase in the stounts and no change in the types of any effluents that may be released of f site, and has also determined that there is no increase in the individual or cumulative cccupational exposure.
Therefore, there is no environmental consideration involved and consequently an environmental report is not submitted.
(cnclusion Ine proposed changes were anal):cd to determine the effect upon the accident analises contained in S?ction 14 cf the PBAPS Updated Final Safety Analysis Report.
In soJition, a determination of No Significant Hazards Consideration was completed.
ine Plant Uperations Review Committee and the Nuclear Review Board have res ieaea these prcposed changes to the Technical Specifications and have concluded that they will not endanger the health and safety of the public.
Respectfully submitted, PHILADELPHIA ELECTRIC COMPANY Nm M
c,i Vice President
COMMOffriEALTil 0F PENtiSYLVANI A ss.
COU!.!? OF FilILADELPHI A J.
W. Unliagher, being first duly sworn, depogas and says Tnat he is Vice President of Philadelphia Electric Company, the Applicant nerein; that he nas read the faregoing Application 4
fcr Amendment of Facility Operating License and knows the eOntents tnetecfr and that the statements and matters set forth tr.ctein are true and correct to the best 9t his knowledge, intormation and belief, b
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v Vice President S u :,m e r i rsed a n d sworn to tiercre me tnis6t" day 1
I ci C ci. 1988.
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