ML20195F472
| ML20195F472 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/17/1998 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9811200005 | |
| Download: ML20195F472 (8) | |
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l CHART.ES II. CRUSE Baltimore Gas and Electric Company Vice President Calvert Cliffs Nuclear Power Plant
- Nuclear Energy 1650 Calven Cliffs Parkway l
Lusby, Maryland 20657 l
410 495-4455 l
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l November 17,1998 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Response to Request for Additional Information for the Review of the Calvert Cliffs Nuclear Power Plant, Units 1 & 2, Integrated Plant Assessment Report for the Soent Fuel Pool Cooling System
REFERENCES:
(a)
Letter from Mr. C. H. Cruse (BGE) to NRC Document Control Desk, dated August 21,1997," Request for Review and Approval of System and Commodity Reports for License Penewal" (b)
Letter from Mr. D. L. Solorio (NRC) to Mr. C. H. Cruse (BGE),
September 1,1998," Request for AdditionalInformation for the Review of the Calvert Cliffs Nuclear Power Plant, Units 1 & 2, Integrated Plant Assessment Report for the Spent Fuel Pool Cooling System" (c)
Letter from Mr. D. L. Solorio (NRC) to Mr. C. H. Cruse (BGE),
September 24,1998, " Renumbering of NRC Requests for Additional Information on Calvert Cliffs Nuclear Power Plant License Renewal Application Submitted by the Baltimore Gas and Electric Company" Reference (a) forwarded three Baltimore Gas and Electric Company (BGE) system and commodity reports for license renewal. Reference (b) forwarded questions from NRC staff on one of those three reports, the Integrated Plant Assessment Report for the Spent Fuel Pool Cooling System. Reference (c) forwarded a numbering system for tracking BGE's response to all of the BGE License Renewal Application requests for additional information and the resolution of the responses. Attachment (1) provides our responses to the questions contained in Reference (b). The questions are renumbered in accordance with Reference (c).
I 9911200005 981117 PDR ADOCK 05000317 P
PDR C A> ti..t4 NRC Distribution Code A036D
Docum nt Control Desk Novtmber 17,1998 Page 2 i
Should you have further questions regarding this matter, we will be pleased to discuss them with you.
1 Very truly yours,
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STATE OF MARYLAND
- TO WIT:
COUNTY OF CALVERT I, Charles H. Cruse, being duly sworn, state that I am Vice President, Nuclear Energy Division, Baltimore Gas and Electric Company (BGE), and that I am duly authorized to execute and file this response on behalf of BGE. To the best of my knowledge and belief, the statements contained in this document are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other BGE employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it to be reliable.
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Subscribed and sworn before me, a Notary ~ ublic in and for the State of Maryland and County of (411AAt)
,this l700 day of 7dAV,1998.
WITNESS my liand and Notarial Seal:
UfUJU b MLL Notary Public My Commission Expires:
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60 1 Date CilC/KRE/ dim
Attachment:
(1) Response to Request for Additional Information; Integrated Plant Assessment Report for the Spent Fuel Pool System cc:
R. S. Fleishman, Esquire C. I. Grimes, NRC J. E. Silberg, Esquire D. L. Solorio, NRC S. S. Bajwa, NRC Resident inspector, NRC A. W. Dromerick, NRC R.1. McLean, DNR
- 11. J. Miller, NRC J.11. Walter, PSC
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ATTACHMENT (1)
RL3PONSE TO REQUEST FOR ADDITIONAL INFORMATION; INTEGRATED PLANT ASSESSMENT REPORT FOR THE SPENT FUEL POOL COOLING SYSTEM Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant November 17,1998
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1 ATTACHMENT (1) l RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION; INTEGRATED PLANT ASSESSMENT REPORT FOR Tile SPENT FUEL POOL COOLING SYSTEM l
NRC Ouestion No. 5.18.1 The simplified diagram of the Spent Fuel Pool Cooling System (SFPCS) on page 5.18-3 in Subsection 5.18.1.1 shows system interfaces with the Solid Waste Disposal System and the Demineralized Water and Condensate Storage System. These interfaces show boundary valves l
(diaphragm valves) with small pipe segments extending a short distance beyond the boundary valve and l
then ending (no pipe support, isolation valve or apparatus is apparent). Are these small pipe segments within the scope oflicense renewal? If so, specify the interfaces at the end of these pipe segments that separate the portions of the system within the scope oflicense renewal from those portions of the system l
outside the scope oflicense renewal.
BGE Response The subject pipe segments are within the scope oflicense renewal. They are addressed in Baltimore i
Gas and Electric Company (BGE) License Renewal Application (LRA), Section 3.l A, " Piping Segments that Provide Structural Support." As stated in LRA Section 3.l A, the system's seismic structural boundary extends beyond the boundary valve to the first seismic anchor or equivalent. In some instances, the valve itself may be anchored. However, in most cases, the anchor is beyond the valve, and the support system includes the piping segments that provide structural support for the boundary valve. These components ensure the integrity of the safety-related/non-safety-related functional boundary under all design basis loading conditions.
l NRC Ouestion No. 5.18.2 Calvert Cliffs Nuclear Power Plant (CCNPP) Updated Final Safety Analysis Report (UFSAR) Figure 9-7 l
(BGE Drawing 64-314, Revision 2) shows an additional interface (five piping connections to the demineralizer compared with the four shown on Figure 5.18-1) with the Spent Fuel Pool Demineralizer.
The line appears to be from the Instrument Air System and is not addressed in Section 5.18. Please provide an evaluation of this line including its scoping boundaries for license renewal.
J1GE Resnonst The instrument line in question is not shown on the SFPCS Simplified Diagram because it is not a l
primary flow path. The line is a temporary instrument air hose connection for deminerali2.er maintenance. The line segment from the demineralizer vessel connection up to and including the first isolation valve is !a the scope of license renewal and is included in LRA Section 5.18. The l
instrument conr.ection in the line segment is included in LRA Subsection 5.18.1.2 and Table 5.181, l
and is evaluated in Section 6.4," Instrument Lines." The remaining portions of the instrument air line are non-safety-related and do not perform any system intended functions as defined in l
10 CFR 54.5(a)(1), (2), (3), and (b) and, therefore, are excluded from the scope oflicense renewal.
NRC Ouestion No. 5.18.3 Calvert Cliffs UFSAR Figure 9-7 shows a portable resin addition tank connected to the spent fuel pool (SFP) demineralizer by a spool piece. Figure 5.181 does not clearly indicate where the scoping boundary for the sections of piping up to and including the resin addition tank. Please provide the basis for why this portion of the SFPCS line including its boundaries were excluded from the scope of license
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renewal or a cross reference to where it is addressed in the LRA.
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O, ATTACHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION; INTEGRATED PLANT ASSESSMENT REPORT FOR TIIE SPENT FUEL POOL COOLING SYSTEM BGE Response The portable resin addition tank and associated piping up to the diaphragm boundary valve (excluding the pipe segment addressed in Question No. 5.18.1 above) are non-safety-related and do not perform any system intended functions as defined in 10 CFR 54.4(a)(1), (2), (3) and (b) and, therefore, excluded from the scope oflicense renewal. The scoping boundary for this line is shown from the top of the demineralizer to the Demineralized Water and Condensate Storage System on Figure 5.18-1.
NRC Ouestion No. 5.18d Calvert Cliffs UFSAR Figure 9-7 includes the following " device" that is not included in Table 5.18-1, "SFPCS Device Type Disposition" FG. Three of these devices are located in the piping connected to the demineralizer. Please explain what device type these symbols represent and how they are dispositioned for license renewal.
BGE Response The devices in question are sight flow indicators and are located in portions of the SFPCS that are outside the scoping boundary for license renewal.
NRC Ouestion No. 5.18.5 Section 5.18.1 indicates that there were several instances of cracking of SFPCS piping and a detailed study was performed in early 1990 to determine the root cause and appropriate remedy. The study determined that the cracking was due to high-cycle fatigue caused by cavitation-induced vibration.
Subsequently, certain orifices and valves were modified to eliminate system cavitation. This section of the LRA also indicated that implementation of these improvements has prevented recurrence of cracking in SFPCS piping. Please address whether the piping susceptible to cracking is subject to an aging management review (AMR). If so, please provide a summary discussion of the AMR performed for this piping that demonstrates there is reasonable assurance that the intended functions for these components will be maintained during the period of extended operation by managing high-cycle fatigue and other aging effects of the SFPCS piping. If not, provide the basis for excluding these components from an AMR.
Please address whether these modified orifices and valves are subject to an AMR. If so, please provide a summary discussion of the AMR performed for these orifices and valves that demonstrates there is reasonable assurance that the intended functions for these components will be maintained during the period of extended operation by managing high-cycle fatigue and other aging effects (e.g., erosion) of these orifices and valves. If not, provide the basis for excluding these components from an AMR.
4 Subsection 5.18.1.1 states that since normal service loads do not result in significant vibration or other dynamic loading conditions, fatigue is not plausible for SFPCS. Please provide the values and the basis for the determination of"significant vibration" and provide a description of the monitoring activkies used to determine any post-modification vibration significance. Please indicate if monitoring is ongoing, performed periodically, or planned for some time in the future to indicate and track any future vibration.
The Calvert Cliffs UFSAR Section 9.4.3.2 states that the SFPCS piping was designed to American National Standards Institute (ANSI) B31.7 Code requirement. While the Code does not require an explicit fatigue analysis for Class 11 and III piping system, it does specify allowable stress levels based on the number of anticipated thermal cycles. Please provide a discussion on the fatigue evaluation for 2
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ATTACIIMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION; INTEGRATED PLANT ASSESSMENT REPORT FOR Tile SPENT FUEL POOL COOLING SYSTEM the SFPCS piping with respect to the requirements of 10 CFR 54.21(c)(1) focusing on why the number of
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thermal cycles expected to occur during the period of extended operation will preclude reaching I
allowable stresses for the SFPCS components.
BGE Response As stated in Section 5.18.1, CCNPP has experienced several instances of cracking of SFPCS piping.
The root cause in all cases was determined to be high-cycle fatigue due to cavitation-induced vibration in the piping system. The sources of vibration were determined to be the SFPCS pumps recirculation line flow orifices and manual throttle valves downstream of the SFPCS heat exchangers.
A modification was performed to replace the pumps recirculation line flow ori6ces with blank orifice plates and the throttle valves with new valves with special anti-cavitation trim. Operating experience l
since component replacement has demonstrated successful mitigation of cavitation, the resultant i
piping system vibration, and the subsequent high-cycle fatigue type piping failures.
The piping that was susceptible to cracking and the replaced components are in the scope of license renewal and subject to aging management review (AMR) as discussed in Section 5.18.1.3. Aging management of all SFPCS components with plausible age-related degradation mechanisms (ARDMs) is addressed in Section 5.18.2 Baltimore Gas and Electric Company has concluded that high-cycle l
fatigue is not a plausible ARDM for the SFPCS piping based on the system modifications described l
above.
l The term "significant vibration" identifies a condition that exceeds normal service loads within the current licensing basis. The root cause analysis determined the piping failures were due to loads induced into the piping system by cavitation and not due to the piping vibration characteristics as designed. Vibration measurements were taken as part of the root cause analysis to determine that cavitation existed, to assess where it was occurring, and to confirm it was mitigated by replacement of components. The vibration measurements taken have no direct impact on normal aging mechanisms l
other than to confirm that the cavitation loads were mitigated and normal service loads established.
The ANSI B31.7 Code specifies that requirements for Class 11 and III pipe design conditions be in accordance with the ANSI B31.1, Power Piping Code. In paragraph 102.3.2, Table 102.3.2(c) of the B31.1 Code, the maximum stress range reduction factor (1.0) represents a maximum of 7,000 equivalent full temperature cycles. As described in the CCNPP UFSAR, Section 9.4, the operating temperature of the SFP water will remain almost constant after initial refueling and throughout the current licensing basis period. This operating condition will result in negligible equivalent full temperature cycles ( 7,000), thus providing reasonable assurance that the thermal cycles expected during the period of extended operation will preclude reaching the allowable stress range for the SFPCS components. Under all normal (Level A and B equivalent) conditions, the operating temperature is less than 150 F.
NRC Ouestion No. 5.18.6 l
Table 5.18 3 indicates that wear is a plausible ARDM for hand valves in the SFPCS, Section 5.18.2 indicates that the local leak rate testing of the containment isolation requires corrective actions as part of l
the program, which will ensure that the intended function of the containment isolation hand valves will be maintained under the current licensing basis during the period of extended operation.
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ATTACHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION; INTEGRATED PLANT ASSESSMENT REPORT FOR THE SPENT FUEL POOL COOLING SYSTEM However, the staff noted in Figure 5.18-1 that the SFPCS includes certain hand valves that are not containment isolation valves and, therefore, are not subject to the local leak rate testing. Please specify any aging management program for these valves to manage the effects of wear in order to maintain their intended function during the period of extended operation.
BGE Response As stated in Section 5.18.2, page 5.18 18 under Group 3 (wear of hand valve seats and disks), wear is plausible only for cast or forged stainless steel (Type 304/316 or CF-3/CF-8) hand valve seats, and disks for SFPCS containment isolation hand valves. Please see BGE's response to Generic Areas Question No. I1.1 (Reference 1), which describes the circumstances under which BGE performed an AMR of valve internals.
NRC Ouestion No. 5.18.7 Table 5.18-4 in Section 5.18.2 shows the list of subcomponents and materials subject to agir.g. Provide the basis for excluding the SFP heat exchanger tubing, which has the intended function of removing heat from the SFP, the refueling pool water, and maintaining the pressure boundary of the SFPCS from this table.
BGE Response Table 5.18-4 in Section 5.18.2 only applies to subcomponents and materials subject to the ARDMs addressed in Group 1. The subcomponents in Group 1 are composed of some variety of carbon steel.
The SFP heat exchanger tubes are fabricated from stainless steel. Baltimore Gas and Electric Company has concluded there are no plausible ARDMs for the SFP heat exchanger tubes based on an evaluation of the tube material and service conditions.
NRC Ouestion No. 5.18.8 Discuss plans for detection of inadvertent ingress of service water from the shell side of the heat exchanger which is at a higher pressure than that of the tube side, through degraded SFP heat exchanger tubes into SFP water and into other interface systems which could lead to a chloride excursion.
BGE Respo.nic As stated in our response to Question No. 5.18.7 above, an evaluation of the SFP heat exchanger tube material and service conditions resulted in no plausible ARDMs that will cause service water ingress to SFP water at the heat exchanger tube interface. In addition, it should be noted that the closed loop Service Water System uses treated demineralized water, which is monitored to control the concentrations of oxygen, chlorides, and other chemicals and contaminants (reference LRA Section 5.18.2, Group 1, Materials and Environment discussion, page 5.18-10). The demineralized water quality will prevent chloride excursions in the event of service water ingress to the SFP and other interface systems.
NRC Ouestion No. 5.18.9 Are there any parts of the systems, structures and components within the SFPCS that are inaccessible for inspection? If so, describe what aging management program will be relied upon to maintain the integrity of the inaccessible areas. If the aging management program for the inaccessible areas is an evaluation of the acceptability ofinaccessible areas based on conditions found in surrounding accessible areas, please 7
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ATTA,CHMENT (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION; INTEGRATED PLANT ASSESSMENT REPORT FOR THESPENT FUEL POOL COOLING SYSTEM provide information to show that conditions would exist in accessible areas that would indicate the presence of, or result in degradation to, such inaccessible areas. If different aging effects or aging management techniques are needed for the inaccessible areas, please provide a summary to address the following elements for the inaccessible areas: (a) Preventive actions that will mitigate or prevent aging degradation; (b) Parameters monitored or inspected relative to degradation of specific structure and component intended functions; (c) Detection of aging effects before loss of structure and component intended functions; (d) Monitoring, trending, inspection, testing frequency, and sample size to ensure timely detection of aging effects and corrective actions;(e) Acceptance criteria to ensure structure and component intended functions; and (f) Operating experience that provides objective evidence to demonstrate that the effects of aging will be adequately managed.
BGE Resnonse Baltimore Gas and Electric Company can access all SFPCS components if required.
NRC Ouestion No. 5.18.10 Provide a summary description of Calvert Cliffs operating and maintenance experience related to boric acid corrosion of carbon steel components. In particular, characterize the extent to which boric acid corrosion of carbon steel components has changed since the initial implementation of the boric acid corrosion inspection (BACI) program. Also, describe the extent to which carbon steel components in the SFPCS have had to be repaired or replaced because of boric acid corrosion, since the implementation o'f the BACI program.
BGE Resnonse Operating experience for the SFPCS was gathered, as described on BGE LRA page 5.18-1, through electronic searches and discussions with plant personnel. Operating experience obtained through that approach was included in this section. The noted operating experience did not involve boric acid corrosion of SFPCS components.
Reference 1.
Letter from Mr.
C.
H. Cruse (BGE) to NRC Document Control Desk, dated November 12,1998, " Response to Request for Additional Information for the Review of the Calvert Cliffs Nuclear Power Plant, Units 1 & 2, Integrated Plant Assessment, Generic Areas" 5