ML20198A940
| ML20198A940 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 12/30/1997 |
| From: | Desmond N BOSTON EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BECO-#2.97.138, NUDOCS 9801060138 | |
| Download: ML20198A940 (5) | |
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Booenn Enneen 10CFR 50.90 Pilgrim Nuclear Power Station
. Rocky Hdi Road 10CFR 50.30(b)
Plymoutn. Massachusetts 02360-5599.
Nancy 1 Desmond Regulatory Relations Oroup Manager Decemoer 30,1967 BECo Ltr. #2.97.138 j
U.S. Nuclear Regulatory Commission Attentiom Document Control Desk Washington, DC 20555 Docket No. 50-293 License No. DPR 35
SUBJECT:
Cisrlfications and Corrections Associated with Amendment No,173's Safety Evaluation ReDort l
The NRC Cranted Boston Edison Company (BECo) Amendment No.173 for Pilgrim Nuclear L
. Power Station on July 3 ' 417. Amendment No.173 l.luded an NRC Safety Evaluation Report (SER) Pilgrim's aview of that SER identified statements that require clarifying ~or correction. - Nene of the following clarifications or corrections aher the conclusions supporting the granting of Amendment No.173.
SX, Statemen* Pace 2. ParaoraDh 2.1st Sentence
'In adurtion, the Ncensee has also' proposed to change the licensing basis service waterinlet
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temperature kom 65f to 75f".
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Clarification The original Pilgrim Final Safety Report (FSAR) identified the peak seawater temperature to i
l be 75'F and normal plant operation was designed for a 75*F service water inlet temperature.
L The1value of 65'F was used as an awrage temperature for long-term containment heat removal for the original design basis accident-loss of cee' ant accident (DBA-LOCA) analysis.
Therefore, BECo considers the licensing basis peak seawater temperature to have always.
been_75*F for Pilgrim but with an incongruous 65'F value used in the LOCA analysis.-
j SE-2983 updated the accident analysis and Updated Final Saiety Report (UFSAR) to use the c
peak value of 75'F as the continuous heat sink temperature rather than the previously used p
L65'F average.'
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1 This comment clarifies that BECo requested a change that would credit containment pressure in post-LOCA emergency core cooling system (ECCS) net positive suction head (NPSH) calculations. We did not specifically request a change to the licensing basis ultimate heat sink (UHS) tempwature; however, the UHS temperature is a necessary component of NPSH calculations and, therefore, integral to the requested amendment.
SER Statement Paae 3. Paraoraph 2. 6th Sentence i
"Therefore, containment cooling in addition to core cooling is affected by this temperature increase".
Clarification The core peak clad temperature (PCT) following a DBA LOCA is not affected by the heat sink temperature since it occurs wnhin the first 10 minutes which is before containment heat removal has been initiated. Although core temperatures during the long term cooldown are affected by the heat transfer conditions, these later core temperatures are far less than those in the first 10 minutes.
3 SER Statement, Paae 4. Paraaraoh 2, item 11 "Init4 v= Hue humidity of 100 percent in the drywoll, and 80 percent in the wetweII".
Crm orku This statement should read, " Initial relative humidity of 80 percent in the dowell, and 100 percent in the wetwell".
This appears to be a transposing error since the correct values are found in the accompanying text.
SER Statement, Pane 6, Paraaraoh S. 2nd Sentence "With regard to Figure 14.5-10, the benchmark analysis indicates.. 18 psia, whereas the original analysis.. 18.8 psla".
Correction The benchmark analysis refers to Calculation M-662 Section 4.C.3 that reproduced the calculations done for Amendment 9 to the original UFSAR. The benchmark compares very closely with the original UFSAR Figure 14.5-10. The comparison of values made in the SER appears to compare pressures for different assumed containment leakage values. When the same leakage values are compared, the results are 18.0 psia at 0.5% and 18.9 psia 5t 5% per day leakage both in the original UFSAR and for the benchmark case.
This correction does not affect the conclusions on benchmarking.
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c SER Statement. Paae 11. Parcaraoh 2. 3rd Sentence
- Since the design basis LOCA analysis using the 75'F SSW temperature assumes a different ccre and contwnment cooling method,...".
Clarification Changes to the DBA-LOCA assumptions for the operation of the RHR system for core and containment cooling were made to reconcile the accident analysis with Pilgrim's Emergency Operating Procedures (EOP's) and expected operator actions. The changes were not otherwise required for raising the SSW temperature from 65*F to 75 F.
This clarification is made to avoid possible misinterpretation that the assumptions were revised to offset an impact on dieselloading.
SER Statement. Paae 13. Paraaraoh 1. Last Sentence "The licensea's review identified...for which additional infonnation (test results) was required to complete document files."
Correction Our statement referenced " analysis" as the basis, not " test results".
SER Statement. Paae 15. Paraaraoh 1,1st Sentence
.. licensee indicated that the Arrhenius equation has been applied starting at time zero and includes the LOCA transient as part of the calculation for degradation."
Clarification No equipment qualified at Pilgrim Str' ion requires the use of Antenius methodology until after the blowdown stage is completed even though some existing documentation reflects application at time zero.
SER Statement. Paae 15. Paraaraoh 4.1st Santence
"...that RocVbestos wire is qualified with a 17% margin and all other equipment is qualified with a margin two times greater than the 10% margin requ; ed by IEEE 323-1974..."
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Clarification The Rockbestos wire is part of the Limitorque operator and as such is qualified to the Division of Operating Reactors (DOR) Guidelines. DOR Guidelines do not require the inclusion of margin.
We have covered this point with a " sound reasons to the contrary" position as required under 10CFR50.49.
SER Statement. Paoe 16. Paraaraph 3. Entire Narrative
" penetrations have been environmentally qualified and tested at accident temperatures with an applied short circuit".
Correction The third paragraph of this section of the SER states that "...the electrical penetrations have been environmentally qualified (i.e., tested at accident environments while being subject to fault current) to demonstrate their capability for maintaining safety function--containment integrity". This statement is not correct for the specific model of penetrations installed at PNPS. The General Electric canister type penetrations used at PNPS were only short circuit tested at room temperature.
The General Electric Series 100, FO2 modular typs electrical containment penetrations were tested for short circuits under accident conditions. The test results for the FO2 penetrations are documented in General Electric report " Low Voltage Power and Control Nuclear Containment Loss of Coolant Accident Qualification Test 100 Series Electrical Penetration FO2 Program",
dated September 13,1973. The short circuit testing of these penetrations was performed with the penetrations installed in a test chamber maintained at 340 " F (168 " C). The fault current, interrupting time and the initial ambient temperature of two test circuits indicates that the penetration conductors inside the chamber reached a maximum temperature. Of more than 325 "
C during the test. The worst case penetration conductors at the outer seal Cocated outside the 8
test chamber) would have reached approximately 150 C based on the fault curmnt, it's duration, and a 25 C ambient temperature.
The FO2 penetrations use the same conductor sealing techniques and the saine sealing epoxy and conductor insulation as the Pilgrim canister penetrations. Based on the FO2 testing, Pilgrim installed short circuit protection to limit the temperature of ine penetration conductors inside primary containment to less than 250 C. The maximum allowable fault current is based on an initial conductor temperature of 193
- C. This initial temperature O based on the maximum accident ambient temperature plus the maximum allowable conductor heatup during normal plant operation. The maximum conductor temperature at the outer penetration seal, which is located in the secondary containment, will be approximately 105 C based on the maximum allowable fault current (calculated for primary containment conditions) and a 65
- C initial conductor temperature (40 C plus 25 C rise due to conductor energization). The temperatures of Pilgrim's penetration conductors are limited to temperatures significantly lower than the conductor temperatures encountered during the FO2 test program; therefore, Pilgrim's penetrations will maintain their integrity during short circuits under accident conditions.
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r-r Should you require further information on the clarifications and corrections provided by this letter, p! ease contact P.M. Kahler at (508) 830-7939.
Nancy L. Desmond PMK/dmc/am173 cc:
Mr. Alan B. Wang, Project Manager Project Directorate 13 Office of Nuclear Reactor Regulation Mail Stop: OWF14B2 U. S. Nuclear Regulatory Commission 1 White Flint North 11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region 1 475 ;.:,endale Road King of Prussia, PA 19406 Senior Resident inspector Pilgrim Nuclear Power Station 5
.,.