ML20133E741
| ML20133E741 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/02/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20133E739 | List: |
| References | |
| NUDOCS 8510090533 | |
| Download: ML20133E741 (5) | |
Text
o O Kuruqk UNITED STATES 4
E NUCLEAR REGULATORY COMMISSION o
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WASHINGTON, D. C. 20555
%... +,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENTS NOS.III AND 115 TO FACILITY OPERATING LICENSES NOS.
DPR-44 AND DPR-56 PHILADELPHIA ELECTRIC COMPANY PUBLIC SERVICE ELECTRIC AND GAS COMPANY DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY PEACH BOTTOM ATOMIC POWER STATION, UNITS NOS. 2 AND 3 DOCKETS NOS. 50-277 AND 50-278 INTRODUCTION In a letter dated April 19, 1984, as supplemented October 2, 1984, the licensee (Philadelphia Electric Company (PECO)) proposed changes to the Peach Bottom Atomic Power Station, Units 2 and 3 Technical Specifications (TSs).
The proposed changes reflect the PECO effort to:
(1) correct errors and establish consistency in the reactor water level setpoint values (2) lower the main steam line isolation valve low water isolation setpoint from low-low to low-low-low reactor water level, and (3) revise the audit frequency of the Facility Emergency Plan and implement procedures to conform with the Comission's regulations. A discussion of each of the proposed changes is presented below:
1.
Reactor Water Level Setpoint Values a)
The current TSs specify reactor water level setpoints to three different reference points, e.g., in terms of inches above top of active fuel, inches above vessel zero, and instrument indicated level. This inconsistency results in multiple values that are confusing to the reader and may result in possible misinterpretation of the specifications. The proposed changes would establish consistency by identifying the setpoint in terms of the " instrument indicated level," with reference to the
" inches above vessel zero."
b)
The current TS on page 12 identifies the Core Spray and LPCI actuation setpoint as minus 159.5 inches indicated level (low-low-low level) and 378 inches above vessel zero. Tables 7.4.2, 7.4.3 and 7.4.4 of the Peach Bottom Final Safety Analysis Report, as well as design infomation provided by General Electric Company, confims the 378 inch value.
However, since the level instrumentation reference zero is set at 538 inches above vessel zero, the indicated level should be minus 160 inches, not 159.5 inches.
General Electric Company also confirms this minor error.
l 8510090533 851002 PDR ADOCK 05000277 P
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c)
The current TSs on pages 12, 61 and 79 identify either minus 49.5 or minus 49.0 inches indicated level (low-low level) as the setioints for i
j HPCI/RCIC actuation, recirculation pump trip, and primary containment isolation. According to Tables 7.3.2 and 7.4.1 of the Peach Botton Final i
Safety Analysis Report, as well as design information provided by General i
Electric Company, the correct value should be minus 48 inches indicated j
level which corresponds with 490 inches above vessel zero. The low-low level on page 64 of the TSs was originally specified at minus 49 inches.
4 The origin of this error appears to be an error during the preparation of the original license. The proposed change would specify the correct j
value of minus 48 inches indicated level.
,
- d)
The proposed change on page 21 of the TS Bases would correctly state the t
relationship between the scram setting and the nomal operating level.
1 The normal operating level is at plus 23 inches indicated level, which is approximately the midpoint between the reactor high water level trip (trips High Pressure Coolant Injection, Reactor Core Isolation Cooling, and Turbine Stop Valves) set at plus 45 inches indicated level and the i
reactor low water level trip (scram setpoint) set at zero inches indicated level, in order to minimize spurious trips due to feedwater s
transients. Therefore, the scram setting is approximately 23 inches, not e
31 inches, below the normal operating range, e)
The final change involving reactor water levels specified in the TSs deals with the minimum water level required in the shutdown condition.
The Standard Technical Specifications for General Electric Boiling Water Reactors (NUREG-0123, Rev. 3, page 2-2) require the reactor water level to be maintained above the top of the active irradiated fuel in the shutdown mode. The Peach Bottom TSs had conservatively set this safety 4
~t limit to correspond with the low-low-low level setpoint (378 inches above vessel zero). Based on the original top of active fuel elevation of 360.3 inches above vessel zero, a value of 17.7 inches above the active fuel was specified. The specification erroneously specifies 17.7 inches j
as a result of a typographical error. The proposed change would correct
(
this error and identify the safety limit in tems of the format described l
in (a) above.
4 2.
Lowering the Main Steam Line Isolation Valve (MSIV) Low Water Isolation Setpoint l
In response to the NRC approved Mark I containment modification program, PECO made design modifications which lowered the water level trip setpoints for MSIV closure.
In its Amendment Application dated April 19, l
1984, PECO requested a change in its TSs to reflect the lowering of the MSIV water level trip from level two (low-low) to level one (low-low-low).
The lower MSIV water level trip causes the MSIV closure actuation to be i
changed from a reactor water level two signal to a reactor water level one signal. The design modification will maintain the main condenser available for a longer time following reactor trip. This allows more l
1 l
i energy to be released to the main condense ~r and will result 'in a slower repressurization rate. The lower MSIV water level trip reduces isolations and SRV challenges.
3.
Revision of the Audit Frequency for Emergency Plans and Procedures The current TSs (Section 6.5.2.8.e) require that the Facility Emergency Plan and implementing procedures be audited at least once per two years.
The NRC issued Generic Letter 82-17 (" Inconsistency between Requirements of 10 CFR 50.54(t) and Standard Technical Specifications for Perfoming Audits of Emergency Preparedness Programs" dated October 1,1982) requesting that licensees revise their TSs for perfonning audits on Emergency Plans and implementing procedures at least once per year rather than once per two years to bring the TSs into conformance with the requirements of 10 CFR 50.54(t). The proposed TS change makes this t
requested change.
EVALUATION The licensee's proposed changes as discussed above (la through le) are influenced by the modification from the 7 x 7 fuel rod array installed at the time of licensing to the 8 x 8 array in use today. The licensee states that the dimensional change associated with the new fuel design does not impact 1
the ECCS evaluations for Peach Bottom since the values for low-low and low-low-low setpoints used in the ECCS analysis are 486.5 and 366.4 inches above vessel zero, respectively. Although the changes appear administrative in nature, from a review of the justification provided in the licensee's evaluation, we were concerned that the setpoints developed for earlier reactor core fuel arrangements may not be conservative for the current fuel rod array and fuel column length, and that sufficient allowances may not have been provided in the setpoints to account for instrument bias and uncertainty.
j It was not clear from a review of the licensee's submittal of April 19, 1984, whether the ECCS evaluation for both fuel arrangements uses 486.5 and 366.4 4
inches as inputs to the calculations and if these values that were developed for the earlier core fuel arrangement would be conservative for the new fuel rod array and column length or whether there are other reasons why the new fuel design does not impact the analysis. Accordingly, we requested (1) the licensee either confirm in the safety anal 1
quoted for the low-lew and low-low-low setpoints (ysis that the values 486.5 and 366.4 inches above vessel zero respectively) are the anelytical values used in the safety analysis for the current fuel rod array and fuel column length as the point where protective action is initiated to demonstrate the design basis accidents or transients will not exceed specified safety limits, allowing for modeling uncertainties and bias or justify their absence, and (2) the licensee confirm that sufficient allowance is provided in the setpoints to account for instrument drift and uncertainty.
In a letter dated October 2, 1984, the licensee provided additional information concerning the Amendment application that resolved these concerns.
i
The proposed changes to the reactor water level setpoints maintai the low-low level (level 2) and low-low-low levels (level 1) at 490 and 378 inches above vessel zero, respectively. The dimensional change associated with the new fuel design is considered in the ECCS reload evaluations for Peach Bottom 2 and 3.
The values for low-low and low-low-low setpoints used in the ECCS analysis, 486.5 and 366.4 inches above vessel zero, respectively, provide sufficient margin to compensate for instrument error and calibration accuracy. Additionally, the licensee confirmed that there is sufficient allowance for setpoint drift between the nominal trip setpoint of the instrument and the TS value.
We find the above proposed changes to the Peach Bottom Atomic Power Station, Units 2 and 3, TSs pertaining to reactor water level pemit the operation of the facilities in a manner that is consistent with the licensing basis and the accident analysis. Based on the above, we conclude that the proposed TS changes concerning reactor water level are acceptable.
The lowering of MSIV water level trip setpoints as discussed in Item 2 above is in response to the approved NRC design modifications under the Comission's Mark I Containment Program. These design modifications and, therefore, the proposed corresponding lowering of the trip setpoints will not adversely affect the plants' perfonnance or safety margins. We, therefore, find the proposed change acceptable.
The pronosed change in the Emergency Plan audit requirements (Item 3 above) is responsive to an NRC request (Generic letter 82-17) and would bring the Peach Bottom TSs into conformance with the Commission's regulations [10 CFR 50.54(t)]. We, therefore, find this change to be acceptable. The licensee notes in its application that an annual audit of the Peach Bottom emergency preparedness program has already been implemented in accordance to 10 CFR 50.54(t).
ENVIRONMENTAL CONSIDERATION These amendments involve a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The amendments also relate to changes in an administrative requirement.
We have determined that the amendments involve 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 Conunission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public coment on such finding. Accordingly, these amendments meet the eligibilit criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9) yand(10).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
t
. CONCLUSION We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the will not be endangered by operation in the proposed manner, and (2) public such activities will be conducted in compliance with the Comission's regulations and the issuance of these amendments will not be inimical to the comon defense and security or to the health and safety of the public.
Dated:
October 2,1985 The following NRC personnel have contributed to this Safety Evaluation:
J. Mauck, K. Desai, and G. Gears
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