ML13070A078
| ML13070A078 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/06/2013 |
| From: | George Gellrich Constellation Energy Group, EDF Group, Calvert Cliffs |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML13070A078 (7) | |
Text
p George H. Gellrich Vice President Calvert Cliffs Nuclear Power Plant, LLC 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410.495.5200 410.495.3500 Fax CENG a joint venture of Cwwtel~ation 6F Energy eD CALVERT CLIFFS NUCLEAR POWER PLANT March 6, 2013 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
SUBJECT:
Document Control Desk Calvert Cliffs Nuclear Power Plant Unit Nos. 1 and 2; Docket Nos. 50-317 and 50-318 Response to Request for Additional Information Regarding Calculated Peak Containment Internal Pressure License Amendment (a)
Letter from Mr. C. R. Costanzo (CCNPP) to Document Control Desk (NRC), dated July 2, 2012, License Amendment Request:
Revise Calculated Peak Containment Internal Pressure (b)
Letter from Ms. N. S. Morgan (NRC) to Mr. G. H. Gellrich (CCNPP),
dated February 6, 2013, Request for Additional Information Regarding Calculated Peak Containment Internal Pressure License Amendment (TAC Nos. ME9081 and ME9082)
REFERENCES:
In Reference (a), Calvert Cliffs Nuclear Power Plant, LLC submitted a license amendment request to revise the calculated peak containment internal pressure described in Technical Specification 5.5.16 and the initial internal containment pressure limit in Technical Specification 3.6.4. In Reference (b), the Nuclear Regulatory Commission requested additional information to support their review of Reference (a). Attachment (1) provides the responses to the Nuclear Regulatory Commission's request for additional information contained in Reference (b).
These responses do not change the No Significant Hazards Determination provided in Reference (a). No regulatory commitments are contained in this letter.
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o Document Control Desk March 6, 2013 Page 2 Should you have questions regarding this matter, please contact Mr. Douglas E. Lauver at (410) 495-5219.
I declare under penalty of perjury that the foregoing is true and correct. Executed on March 6, 2013.
Very truly yours, George H. Gellrich Vice President GHG/PSF/bjd
Attachment:
(1)
Response to Request for Additional Information Regarding Calculated Peak Containment Internal Pressure License Amendment cc:
B. K. Vaidya, NRC W. M. Dean, NRC Resident Inspector, NRC S. Gray, DNR
ATTACHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING CALCULATED PEAK CONTAINMENT INTERNAL PRESSURE LICENSE AMENDMENT Calvert Cliffs Nuclear Power Plant, LLC March 6, 2013
ATTACHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING CALCUALTED PEAK CONTAINMENT INTERNAL PRESSURE LICENSE AMENDMENT
RAI 1
Provide which version of the GOTHIC Code was used for the revised analyses for the peak containment internal pressure (Pa). Has the installation of this version of the code been verified and validated against the previous analyses?
CCNPP Response 1:
The version of GOTHIC used for this analysis is 7.2A. This version of the code was verified and validated previously. It is the same version of GOTHIC that is used for the current analysis of record.
So, there was no change to the GOTHIC version used for the analysis of record and the analysis used to calculate the containment peak pressure proposed in this license amendment.
RAI 2
Verify that the non-conservative LOCA mass and energy release input for the containment response analysis is not related to the recent EPITOME computer modeling errors discovered by Westinghouse.
CCNPP Response 2:
The EPITOME code applies to Westinghouse nuclear steam supply systems.
Calvert Cliffs is a Combustion Engineering nuclear steam supply system. Computer codes approved for use on Combustion Engineering plants, namely CEFLASH-4A and FLOOD3, were used to develop the mass and energy release inputs. The EPITOME computer code was not used in the development of the mass and energy release inputs for Calvert Cliffs.
RAI 3
- a. What is the typical containment pressure range that plant operators maintain at Calvert Cliffs during normal plant operation?
- b. If any, what challenges would the plant operators experience while trying to maintain the new upper limit proposed?
CCNPP Response 3:
- a.
The typical containment pressure range during normal operation is approximately 0.0 psig to
+0.5 psig.
- b. Plant operators have been meeting the +1.0 psig upper pressure limit since the non-conservative mass and energy release data issue was identified in the spring of 2009. Administrative controls were put in place at that time to limit the containment pressure upper limit while analyses were performed to support this license amendment request. There have been no challenges to operator control of this modified upper containment pressure limit.
RAI 4
In Table 14.20-9 of the Updated Final Safety Analysis Report, there are two separate values for the P0 for Unit 1 and Unit 2, respectively, but in TS 5.5.16, Containment Leakage Rate Testing Program, " there is only one Pa value listed. How does this meet the intent of Appendix J regulations in regards to P0 for both units?
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ATTACHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING CALCUALTED PEAK CONTAINMENT INTERNAL PRESSURE LICENSE AMENDMENT CCNPP Response 4:
Historically, the containment pressure value for Pa has been the same for both Units. The analysis of record is performed for both Units. The Updated Final Safety Analysis Report (UFSAR) was updated several years ago without recognizing the link between the UFSAR and Technical Specification 5.5.16.
The Unit 2 containment peak pressure value listed in the UFSAR is lower than the Pa pressure in Technical Specification 5.5.16. The Appendix J integrated leak rate test pressure for both Units has been based on the single conservative value contained in Technical Specification 5.5.16. This issue has been entered into our corrective action program. The UFSAR will be updated with a single value for both Units that matches the revised Pa contained in this license amendment request.
RAI 5
In the LAR, the licensee states that the, "change in the Pa does not adversely affect environmentally qualified equipment within containment. A review of the effects of this change in mass and energy release on the environmental qualification (EQ) of equipment in containment determined that the equipment remained qualified for service in the revised pressure and temperature environment. "
Please provide a discussion of the EQ analysis, in addition to, the EQ overlays and containment temperature and pressure profiles.
CCNPP Response 5:
The containment pressure and temperature response was re-analyzed for a LOCA. The results of this re-analysis are shown in Figures 1 and 2 below.
Various "worst case" breaks are compared to the environmental qualification (EQ) bounding temperature and pressure profiles (EQ overlays), denoted as ES-14.
By inspection, it is concluded that the revised LOCA containment pressure and temperature profiles remain enveloped by the current bounding EQ overlays and therefore, the required equipment inside the containment remains environmentally qualified.
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ATTACHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING CALCUALTED PEAK CONTAINMENT INTERNAL PRESSURE LICENSE AMENDMENT 300 Nn
- C-Cc VAP 280
.1-CCLVAP 26 I. C0-TSAT 260 il ClTSAT 240
- )K o
ES*F.-024 1200 160 140 120 0.01 0.1 1
10 100 1000 10000 100000 1000000 100000000 7huic (Sec)
Figure 1 - Comparison of Containment Temperature with Environmental Qualification Temperature Profile The containment temperature profiles for cold leg (CC) break LOCAs are compared with the ES-0 14 data as shown in Figure 1. In addition to containing the containment temperature profiles calculated for the worst case cold leg (CC) break LOCAs, Figure 1 also contains corresponding saturated temperature at total containment pressure (i.e., steam partial pressure plus the non-condensable gas partial pressure) results for the initial phase of the accident. This saturated temperature element of the environmental qualification temperature peak profile is a required element of the EQ Program to account for steam stratification in the upper region of Containment during the initial phase of the accident. When the recirculation actuation signal occurs at 32 minutes in the event, the containment atmosphere is adequately mixed so that this element is no longer required.
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I ATTACHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING CALCUALTED PEAK CONTAINMENT INTERNAL PRESSURE LICENSE AMENDMENT 65 60 55 U
1 45 P40 3 5 30 d 25 20 is
-F'--
I.E-02 11-01 11+00 11E.01 11+02 11+03 11E+04 1.E+05 11+06 Time (sec)
Figure 2 - Comparison of Containment Pressure with Environmental Qualification Pressure Profile The containment pressure profiles for both cold leg (CC) and hot leg (HH, H2) break LOCA are compared with the ES-014 data as shown in Figure 2.
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