ML20198N390
| ML20198N390 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 12/28/1998 |
| From: | Eric Simpson Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20198N395 | List: |
| References | |
| LCR-H98-10, LR-N98564, NUDOCS 9901060117 | |
| Download: ML20198N390 (22) | |
Text
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3 Pubic servce
, Electre and Gas Cornpany E. C. simpson Public Service Electric and Gas Company Po. Box 236, Hancocks Bridge, NJ 08038 6m 339-1700 Sono Vwe Presiaent Nuc ear Erpneenng DEC 281998 LR-N98564 LCR H98-10 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:
REQUEST FOR CHANGE TO TECHNICAL SPECIFICATIONS l INCREASE OF ALLOWABLE MSIV LEAKAGE RATE AND 1 DELETION OF MSIV SEALING SYSTEM HOPE CREEK GENERATING STATION FACILITY OPERATING LICENSE NPF-57 4 DOCKET NO. 50-354 l
, i l In accordance with 10CFR50.90, Public Service Electric & Gas (PSE&G) Company hereby requests a revision to the Technical Specifications (TS) for the Hope Creek Generating Station (HC). In accordance with 10CFR50.91(b)(1), a copy of this g submittal has been sent to the State of New Jersey.
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i This submittal requests an amendment to the TS, to permit an increase in the allowable !
leak rate for the main steam isolation valves (MSIVs) and to delete the MSIV Sealing System. PSE&G proposes to utilize the main steam drain lines and the main condenser as an alternate MSIV leakage treatment method. While certain main steam piping and components, including the drain lines and main condenser, are not currently classified as seismic category 1, a detailed evaluation indicates that the main steam piping and equipment are seismically rugged and meet the intent of Appendix A to 10 CFR 100 for seismic adequacy. Similar changes have been approved by the NRC in a Safety Evaluation Report, dated March 17,1994, for Georgia Power Company's Edwin
- l. Hatch Nuclear Plant, Unit 2, and in a Safety Evaluation Report, dated January 25, ! ,
! 1996, for PECO Energy Company's Limerick Generating Station, Unit 1.
l The basis for the requested change is provided in Attachment 1 to this letter. A 10CFR50.92 evaluation, with a determination of no significant hazards consideration, is provided in Attachment 2. The marked up Technical Specification pages affected by the proposed changes are provided in Attachment 3. A report entitled, " Hope Creek 9 0\
Nuclear Plant Main Steam Isolation System Alternate Leakage Treatment Pathway JDR901060117 981228 '"
p ADOCK 05000354 l PDRj l
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lEC 281998 Document Control Desk LR-N98564 Seismic Evaluation," discussing the seismic adequacy of the main steam piping and main condenser, including the results of a walkdown of plant piping and equipment,is provided as Attachment 4. One exemption request is also associated with the proposed TS changes, which is an application for a specific exemption from the requirements of 10 CFR 50, and is contained in Attachment 5 of this submittal.
The proposed changes have been evaluated in accordance with 10CFR50.91(a)(1),
using the criteria in 10CFR50.92(c), and a determination has been made that this request involves no significant hazards considerations. Upon NRC approval of this proposed change, PSE&G requests that the amendment be made effective on the date of issuance, but allow an implementation period to be established such that required plant modifications and associated administrative activities be completed during Hope Creek's ninth refueling outage (RFO9).
Should you have any questions regarding this request, please contact Mr. James Priest at 609-339-5434.
Sincerely, i
Affidavit Attachments (5) i i
4 95-4933
I DEC 2 8 Ig!B Document Control Desk LR-N98564 C Mr. H. Miller, Administrator - Region i U. S. Nuclear Regulatory Commission 475 Allendale Road
. King of Prussia, PA 19406 Mr. R. Ennis Licensing Project Manager - Hope Creek l U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 14E21 11555 Rockville Pike Rockville, MD 20852 Mr. S. Pindale (X24) l USNRC Senior Resident inspector- HC I
Mr. K. Tosch, Manager IV Bureau of Nuclear Engineering P., O. Box 415 Trenton, NJ 08625 1
l
Document Control Desk E28 g LR-N98564 JPP BC - Senior Vice President - Nuclear Operations (X04)
Senior Vice President - Nuclear Engineering (N19)
General Manager - Hope Creek Operations (HO7)
Director - QA/NT/EP (X01)
Director - Licensing / Regulation and Fuels (N21)
Director- Design Engineering Manager - Financial Control & Co-Owner Affairs (N07)
Program Manager - Nuclear Review Board (N38)
Manager - Hope Creek Operations (H01)
Manager - System Engineering - Hope Creek (H18)
Manager- Hope Creek Licensing (N21)
B. Barkley (N29)
J. Keenan, Esq. (N21)
NBU RM (N64)
Microfilm Copy Files Nos.1.2.1 (Hope Creek),2.3 (LCR H98-10) l i
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- REF
- LR-N98564 i LCR H98-10 STATE OF NEW JERSEY )
) SS.
COUNTY OF SALEM )
E. C. Simpson, being duly sworn according to law deposes and says:
I am Senior Vice President- Nuclear Engineering of Public Service Electric and Gas .
Company, and as such, I find the matters set forth in the above referenced letter, concerning Hope Creek Generating Station, Unit 1, are true to the best of my knowledge, information and belief.
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[l Subscrib and Swor to before me thisOb day o I Uml1LL1998 1tYn b)LLhk i iD u r ;
Nftary Public $f Nh Je'rsey My Commission expires on ////l0,[Jfb3 i
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D: cum:nt Central Duk LR-N98564 Attachm:nt 1 LCR H98-10 L
l HOPE CREEK GENERATING STATION l FACILITY OPERATING LICENSE NPF-57 l DOCKET NO. 50-354 REVISIONS TO THE TECHNICAL SPECIFICATIONS (TS) t BASIS FOR REQUESTED CHANGE:
l Public Service Electric & Gas Company (PSE&G), licensee under Facility Operating License No. NPF-57 for Hope Creek Generating Station, Unit 1, requests that the TS contained in Appendix A to the Operating License be amended, as proposed herein, to permit an increase in the allowable leak rate for the Main Steam isolation Valves (MSIVs) and to delete the MSIV Sealing System. These proposed changes are based on the General Electric (GE) report prepared for the Boiling Water Reactor Owners' Group (BWROG), "BWROG Report for increasing MSIV Leakage Rate Limits and Elimination of Leakage Control System," NEDC-31858P, Revision 2, submitted to the NRC by BWROG letter dated October 4,1993.
In order to justify the capability of the main steam piping and main condenser as an alternate treatment pathway, the BWROG reviewed earthquake experience data on the performance of non-seismically designed piping and condensers. As summarized in the above referenced GE report, this study concluded that the possibility of a failure which could cause a loss of steam or condensate in Boiling Water Reactor (BWR) main steam piping or condensers in the event of a design basis (i.e., safe shutdown) -)
earthquake is highly unlikely, and that such a failure would also be contrary to a large l body of historical earthquake experience data. The BWROG determined that main steam piping and main condenser designs are extremely rugged, and that the design ,
requirements applied to the main steam system piping and main condenser contain i substantial margin based on the original design requirements. ;.
PSE&G has evaluated the seismic adequacy of the Hope Creek main steam piping and I main condenser consistent with the guidelines discussed in NEDC-31858, Revision 2, I to provide reasonable assurance of the structuralintegrity of these components. This !
evaluation is provided as Attachment 4 of this letter. The results of the evaluation !
clearly demonstrate that the proposed MSIV leakage treatment pathway meets the intent of 10 CFR 100, Appendix A, with regard to seismic qualification. Except for the requirement to establish a proper flow path from the MSIVs to the condenser, the proposed method is passive and does not require any additional logic control and l interlocks. The method proposed for MSIV leakage treatment is consistent with the i i >
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D: cum:nt Central D=k LR-N98564 Attachm:nt 1 LCR H98-10 philosophy of protection by multiple barriers used in containment design for limiting fission product release to the environment.
A plant-specific radiological analysis has also been performed in accordance with NEDC-31858P, Revision 2, to assess the effects of the proposed increase to the allowable MSIV leakage rate in terms of Main Control Room (MCR) and off-site doses following a postulated design basis LOCA. This analysis utilizes the hold-up volumes of the main steam piping and condenser as an alternate method for treating the MSIV leakage. As discussed earlier, there is reasonable assurance that the main steam piping and condenser will remain intact following a design basis earthquake. The radiological analysis uses standard conservative assumptions for the radiological source term consistent with Regulatory Guide (RG) 1.3, " Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss-Of-Coolant Accident for Boiling Water Reactor," Revision 2, dated April 1974.
The analysis results (see Table 1 of this attachment) demonstrate that dose contributions from the proposed MSIV leakage rate limit of 200 scfh per steam line, not to exceed a total of 400 scfh for all four main steam lines, along with the proposed deletion of the MSIV Sealing System, result in an acceptable increase to the LOCA doses previously evaluated against the regulatory limits for the off-site doses and MCR doses contained in 10 CFR 100 and 10 CFR 50, Appendix A, General Design Criterion (GDC) 19, respectively. The off-site and MCR doses resulting from a LOCA are currently discussed in Sections 15.6.5 and 6.4 of the UFSAR, respectively. The off-site and MCR doses resulting from a LOCA associated with the proposed changes are the sum of the LOCA doses evaluated by PSE&G for the containment leakage and Engineered Safety Feature (ESF) leakage outside containment pathways, as we s the additional doses calculated using the proposed MSIV leakage treatment method.
This method of calculating the revised doses is highly conservative since the revised doses were calculated using more conservative design basis assumptions such as the inclusion of system response times and increased allowable leakage rates. Table 1 of this attachment shows the previously calculated doses and the new calculated doses based on the proposed changes.
In summary, the proposed changes do not result in a significant increase in the radioiogical consequences of a LOCA when the same bounding assumptions and methods specified in the UFSAR are used, recognizing that radiological consequences
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calculated in the UFSAR, as well as for these proposed changes, are significantly lower when using more realistic assumptions and methods. The calculated off-site and MCR doses resulting from a LOCA, even wth conservative assumptions, remain well below ,
the regulatory limits. Although the revised LOCA doses are higher for low MSIV Page 2 of 10 I
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Dscumint Central Dick LR-N98564 Attachm:nt 1 LCR H98-10 i
leakage rates, the effectiveness of the proposed leakage treatment method, even for .
leakage rates greater than the proposed increased MSIV allowable leak rate, ensures that off-site and MCR dose limits are not exceeded.
PURPOSE AND DESCRIPTION OF CHANGES:
The proposed TS changes are requested for Hope Creek because the elimination of the MSIV Sealing System provides a more effective means, in terms of reliability, to ensure that the resulting doses from the MSIV leakage, in the unlikely event of a LOCA, l do not exceed regulatory limits. Additionally, the proposed changes will provide an economic benefit to PSE&G by eliminating the high maintenance and operational ,
! expenses associated with the MSIV Sealing System. Although the calculated accident ;
doses resulting from the proposed changes are higher than those previously calculated,
! the capacity of the proposed leakage treatment pathway is significantly higher than that of the MSIV Sealing System. Furthermore, the proposed changes will result in a reduction in occupational exposure from the reduction in MSIV-related maintenance work. If the proposed TS changes are not approved, the MSIVs and MSIV Sealing System will continue to be maintained to the current requirements. Maintenance of the l MSIVs and MSIV Sealing System will continue to require the expenditure of manpower and the exposure of maintenance workers to occupational radiation. For Hope Creek, several hundred man-hours per cycle are spent on maintaining the MSIV Sealing System and MSIVs. Compared with maintaining the current requirements, implementation of the proposed changes will require less occupational radiation exposure per operating cycle and a significant reduction in the expenditure of resources.
The proposed changes to the TS are set forth in Attachment 3 of this submittal. In !
- summary, PSE&G is requesting that
- i L 1. Allowable leak rate specified in TS 3.6.1.2 be changed from 46.0 total standard l cubic foot per hour (scfh) to 200 scfh per main steam line, as well as a 400 scfh l leak rate combined for all four steam lines. This proposed change reflects a
! higher, but still conservative allowable leak rate for MSIVs. Furthermore, l PSE&G will incorporate into the MSIV maintenance and test program, as well as into the Technical Specifications, a requirement stating that any MSIV exceeding the proposed 200 scfh limit, will be repaired and re-tested to meet a leakage rate i of less than or equal to 11.5 scfh. This will assure continuation of high quality L repair and refurbishment efforts to improve the overall performance and reliability of the MSIVs.
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D:cumnnt Central DNk LR-N98564 Attachm:nt 1 LCR H98-10
- 2. .Section 3.6.1.4 and its associated Bases be amended to permit the deletion of the MSIV Sealing System from the TS. PSE&G oposes an alternative to Regulatory Guide 1.96, " Design of Main Steam isolation Valve Leakage Control Systems for Boiling Water Reactor Nuclear Power Plants." Utilization of the main steam lines and condenser, as an alternate method for MSIV leakage treatment, nas been demonstrated to be more effective than the MSIV Sealing System in terms of reliability. In place of the current TS 3.6.1.4, a new Limiting Cendition for Operation (LCO), associated Action Statements and surveillance requirements will be added for the proposed MSIV Leakage Treatment Pathway.
- 3. Table 3.6.3-1 be amended to permit the deletion of the MSIV Sealing System valves and associated main steam line drain valves from the TS. These lines will be cut and capped as part of the modifications associated with these proposed changes.
- 4. The Index be administratively amended to reflect the above changes.
JUSTIFICATION OF REQUESTED CHANGES:
Introduction The MSIV Sealing System licensing basis design function is to redirect MSIV leakage back into containment where it can be processed as a filtered release and reduce the potential contribution to off-site and control room dose. Historically, this system has been susceptible to numerous failures and very costly repairs. In order to improve the performance of the power plant, both from a nuclear safety viewpoint and elimination of a high cost and high maintenance system, the "MSIV leakage treatment pathway" has been established, which will serve to provide a more effective means to process the MSIV leakage.
- PSE&G has performed evaluations which demonstrate the functional and seismic j adequacy of the proposed treatment pathway. The conclusion of these evaluations is that with the recommended modifications installed, the "MSIV leakage treatment l pathway" will provide the necessary protection to mitigate the consequences of an l accident.
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l Decum:nt Control D=k LR-N98564 Attachment 1 LCR H98-10
System Description
Figure 1-1 in Attachment 4 shows the proposed Hope Creek MSIV leakage treatment l pathway. As specified in NEDC-31858P, Revision 2, the leakage treatment pathway l establishes a seismically equivalent route, which will serve to contain and direct leakage to the high pressure shell of the main condenser from the MSIVs during a design basis LOCA. This proposed pathway will function to hold-up the potential release of fission products which is postulated to occur during a Design Basis LOCA.
Figure 1-1 in Attachment 4 identifies the design boundaries of the MSIV leakage 1 I
treatment pathway. The designated boundary (block) valves (e.g. the Main Steam Stop Valves (MSSV)) will function to contain the MSIV leakage in the drain pathway. The ;
boundary valves also identify the functional and design boundary of the MSIV leakage !
treatment pathway. All lines which interface with the designated drain pathway shown I in Figure 1-1 in Attachment 4 will either: 1) be cut and capped; 2) contain boundary valves that will undergo inservice testing; or 3) lead back through Seismic Category I piping back into containment (primary or secondary) and as such do not represent I potential leakage pathways.
, Specifically, the lines that will be cut and capped include the MSIV Sealing System "B" channel supply lines (between the outboard MSIVs and valves HV-F5834B through HV-F58378) and the drain line between the MSIVs (between valve HV-F068 and the main condenser). The MSIV leakage treatment pathway valves and the associated boundary valves will be inservice tested as appropriate to ensure that the MS!V leakage treatment pathway can be established.
Functional Adequacy of System PSE&G has evaluated the ability of the MSIV leakage treatment pathway to function under the conditions specified in NEDC-31858P, Revision 2. The evaluation described in the following paragraphs are from a functional system perspective, and will not include a seismic evaluation. The seismic evaluation is contained in Attachment 4 of this submittal and is discussed later.
As specified Section 6.2.6 of the Hope Creek Safety Evaluation Report (NUREG-1048),
the MSIV Sealing System is manually initiated approximately 20 minutes after the onset of a LOCA. As described below, use of the MSIV leakage treatment pathway will also require the use of operator actions to control valve position following a LOCA. PSE&G
, has concluded that the operator actions necessary to functionally align the system can l
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Docum: nt Centrcl Drak LR-N98564
- Attachment 1 LCR H98-10 be accomplished within the time currently required for initiation of the current MSIV Sealing System. To ensure that the required actions are taken by the plant operators, plant emergency response procedures will be modified to incorporate the required post-
' the MSIV Sealing System.
NEDC-31858P, Revision 2, states that all drain pathway valves required to be open in post-LOCA conditions will be supplied with Class-1E power. For the proposed MSIV.
. leakage treatment pathway, valve 1 ABHV-F072 (a non-1E MOV that is normally closed) needs to be in the open position to establish the leakage treatment pathway.
. Therefore, Hope Creek will implement a modification to supply this MOV with Class-1 E power.
Valves 1 ABHV-F070A, B, C and D, are non-1E MOVs that are normally closed. These L valves are also required to be open to establish tN Icckage treatment pathway.
l However, in lieu of providing Class-1E power to thoe i30Vs, PSE&G will credit the !
permanently installed orifice lines to establish the required leakage treatment pathway. i Since these ' orifice elements are currently sized at 1/8* inch, a modification will have to i be made to increase their size to 0.6 inch. Installation of the 0.6 inch orifice in each of the four lines will provide a total flow area of 1.1 square inches, which is sufficient for j the proposed leakage treatment pathway. Therefore, no electrical modifications are ;
necessary for the 1ABHV-F070A, B, C and D valves. However, these valves will be )
opened by the operating procedure for establishing the leakage treatment pathway. If any of these valves can not be opened (e.g., due to non-safety related power being unavailable), the leakage from the outer MSIVs will pressurize the space between the outer MSIVs and the Main Steam 8 top Valves until equilibrium flow is established through the 0.6 inch orifice elements. Normally, the flow through these orifice elements l will be isolated (via the 1 ABHV-F069 and 1 ABHV-F072 valves) during startup in accordance with plant operating procedures.
Valve 1 ABHV-F069 is a fail closed air operated valve. This valve will provide a backup l in the case of a failure of 1 ABHV-F072 to open. Since the proposed leakage treatment ;
l pathway will require flow through either 1 ABHV-F069 or 1 ABHV-F072, valve 1 ABHV- l F069 will be modified from a fail closed valve to a fail open valve. In addition the
- current 1/8* inch flow orifice in the 1 ABHV-F069 line will be replaced with a 0.8 inch i diameter orifice. Consequently, if valve 1 ABHV-F072 failed to open as required, the j bypass drain path around valve 1 ABHV-F072 would be available to convey MSIV l l
l leakage to the condenser. Consequently, the radiological dose assessment for this backup pathway is essentially equivalent to the dose assessment for the primary path.
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D cumInt Central Dnk LR-N98564 Attachmsnt 1 LCR H98-10 Valve 1 ABHV-F071 is a normally open MOV with Class-1E power. This valve has no bypass and must be open in order to establish the leakage treatment pathway. The valve will fail "as-is" on a loss of power, and it is very unlikely that it would ever be in the closed position if the main steam line drains were required for treatment of MSIV leakage.
Based on the above discussion, PSE&G has concluded that the operator actions necessary to functionally align the system can be accomplished within the required time i frame. To ensure that the proper required actions are taken by the plant operators, plant emergency response procedures will be modified to incorporate the required changes to ensure the MSIV leakage treatment pathway is lined up instead of the MSIV Sealing System.
Finally, the proposed LCO 3.6.1.4 and associated surveillance requirements contained in Attachment 3 of this submittal will ensure that the MSIV alternate leakage pathway remains capable of performing its post acciJent functions or appropriate actions are taken to place the plant in a safe condition. The proposed LCO is similar to that approved for the Limerick Generating Station, Unit 1, in an NRC Safety Evaluation ,
dated January 25,1996. l Radiological Evaluation of the System The main purpose of the MSIV leakage treatment pathway is to process the MSIV leakage to prevent the limits of 10CFR100 from being exceeded. The radiological dose analyses have been revised to document the evaluation of the Hope Creek design and configuration for its ability to process the MSIV leakage and limit the total calculated doso to less than the requirements of 10CFR100. The radiological analyses calculated the effects to the proposed allowable MSIV leak rate in terms of control room and off-site doses. However, the calculation methodology for the revised dose exposures were performed in a manner that included more conservative design basis assumptions (e.g.,
inclusion of system response times, and increased allowable leakage rates) than in the existing Hope Creek licensing basis.
Table 1 of this Attachment shows the calculated dose exposures from these analyses.
Regulatory limits and calculated doses from the existing LOCA radiological analysis are also included in Table 1 for comparison purposes. The results of this analysis demonstrate that an MSIV leakage rate of 200 scfh per main steam (not to exceed 400 scfh total for all four lines) line results in an acceptable increase to the dose exposures to the control room, Exclusion Area Boundary (EAB), and the Low Population Zone (LPZ). The revised LOCA doses remain well within the guidelines of 10CFR100 for Page 7 of 10 l
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l offsite doses and 10CFR50, Appendix A, (General Design Criteria 19) for the control
! room doses.
l Therefore, the proposed method provides a substantial safety margin for mitigating the i
radiological consequences of MSIV leakage beyond the proposed TS leak rate limit of l
200 scfh.
Seismic Evaluations of Systems / Structures l In support of this submittal, PSE&G has performed evaluations of the proposed MSIV leakage treatment pathway for seismic adequacy as specified in Attachment 4. The provisions of 10CFR100 currently require that all systems, which serve to limit the ;
offsite dose, shall be seismically qualified. Since the system being utilized is an existing system, and to redesign the system to Seismic Category I requirements would be
! exceedingly costly, an alternate evaluation method has been utilized to demonstrate seismic adequacy. This alternate evaluation methodology is outlined in Attachment 4, and identifies four areas of review (Piping, Turbine Building, Interconnected systems, and Main Condenser). l l
Attachment 4 is a seismic database, which has been assembled by EQE Engineenng
- inc. This database is a documentation of the historical performance of non-seismic ,
! designed piping systems and main condensers at various power plants throughout the l world which have experienced varying levels of seismic events. The " Experience Database" as documented in Attachment 4 provides the basis for demonstration of ;
seismic adequacy of non-seismically designed systems. In order to demonstrate that the proposed MSIV leakage treatment pathway falls within the bounds of the
" Experience Database," two reviews were performed. First, a review of the construction codes was performed to demonstrate that the designated components in the pathway were built to standards similar to those for the plants identified in the " Experience Database". Second, a " Seismic Walkdown" was performed by the developers of the
" Experience Database" to ensure that the MSIV leakage treatment pathway design details are consistent with those good performing designs described in the " Experience Database".
Based on the evaluations contained in the Attachment 4 report, PSE&G concludes that seismic analysis of the MSIV leakage treatment pathway provides a reasonable
! assurance that the system will function per the design requirements of NEDC-31858P durirm and following an SSE. The design changes required to implement these changes, particularly the cutting and capping of MSIV Sealing System lines previously 4
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D: cum:nt Centrol D:gk LR-N98564 Attachm:nt 1 LCR H98-10 discussed, will be reviewed to ensure that the conclusions regarding the seismic adequacy of the proposed MSIV leakage treatment pathway are not adversely affected.
CONCLUSIONS:
Based on the above analyses, once all modifications and procedure changes have been performed, it is the conclusion of this evaluation that the Hope Creek MSIV leakage treatment pathway meets the design requirements (i.e., functional adequacy, radiological, seismic and operational) as established in NEDC-31858P and meets the intent for seismic qualification as specified in 10CFR100, Appendix A. PSE&G concludes that these proposed changes are adequately justified and result in No Significant Hazards Consideration as described in Attachment 2 of this letter.
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Table 1 i Dose Comparisons Dose (rem)
Current Hope Regulatory Reconstituted Creek UFSAR Limits Design Basis Analysis with Proposed MSIV Leakage Treatment Pathway (400 scfh MSIV Leakage). i Exclusion Area Boundary (2-hour)
Whole Body Gamma 1.3 25 2.6 (10CFR100)
Beta Skin -- -
1.1 i Thyroid 175 300 121 (10CFR100)
Low Population Zone (30-day) 1 Whole Body Gamma 0.2 25 0.6 )
Thyroid 18 300 36 l (10CFR100)
Control Room (30-day)
Whole Body Gamma 0.04 5 (GDC19) 0.09 l Beta Skin 0.9 30 (GDC 19) 1.6 Thyroid 0.3 30 (GDC 19) 5.0 ;
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Attachm:nt 2 LCR H98-10
- HOPE CREEK GENERATING STATION l
FACILITY OPERATING LICENSE NPF-57 '
DOCKET NO. 50-354 REVISIONS TO THE TECHNICAL SPECIFICATIONS (TS) 10CFR50.92 EVALUATION Public Service Electric & Gas (PSE&G) has concluded that the proposed changes to the Hope Creek Generating Station (HC) Technical Specifications do not involve a significant hazards consideration. In support of this determination, an evaluation of each of the three standards set forth in 10CFR50.92 is provided below.
REQUESTED CHANGE The proposed changes affect sections 3.6.1.2,3.6.1.4 and 3.6.3 of the Hope Creek TS.
Specifically, the proposed changes permit an increase in the allowable leak rate for the '
Main Steam isolation Valves (MSIVs) and to delete the MSIV Sealing System. These proposed changes are based on the General Electric (GE) report prepared for the Boiling Water Reactor Owners' Group (BWROG),"BWROG Report for increasing MSIV j Leakage Rate Limits and Elimination of Leakage Control System," NEDC-31858P, '
Revision 2, submitted to the NRC by BWROG letter dated October 4,1993.
BASIS-l
- 1. The proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.
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The proposed changes to TS Section 3.6.1.2 do not involve a change to structures, components, or systems that would affect the probability of an accident previously evaluated in the Hope Creek Updated Final Safety Analysis Report (UFSAR).
- . The proposed changes involve eliminating the Main Steam isolation Valve (MSIV)
- Steam Sealing System requirements from the TS. As described in Section 6.7 of the UFSAR, the MSIV Steam Sealing System is manually initiated in about 20 minutes
!- following a design basis Loss of Coolant Accident (LOCA). Since the MSIV Steam Sealing System is operated only after an accident has occurred, these proposed changes have no effect on the probability of an accident. Since MSIV leakage and operation of the MSIV Steam Sealing System are included in the radiological analysis for the design basis LOCA as described in Section 15.6.5 of the UFSAR, the proposed i
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D: cum::nt Centrol D:ck LR-N98564 Attachm:;nt 2 LCR H98-10 changes will not affect the precursors of other analyzed accidents. Analysis of the affects of the proposed changes do, however, result in acceptable radiological consequences for the design ba.,is LOCA previously evaluated in Section 15.6.5 of the UFSAR.
Hope Creek has an inherent MSIV leakage treatment capability as discussed below.
PSE&G proposes to use the drain lines associated with the main steam lines and main turbine condenser as an alternative to the guidance in Regulatory Guide 1.96, " Design of Main Steam isolation Valve Leakage Control System For Boiling Water Nuclear Power Plants," Revision 0, May 1975, for MSIV leakage treatment. If approved, PSE&G will incorporate this alternate method in the appropriate operational procedures and Emergency Operating Procedures. l l
The Boiling Water Reactor Owners' Group (BWROG) has evaluated the availability of ;
main steam system piping and main condenser alternate pathways for processing MSIV l leakage, and has determined that the probability of a near coincident LOCA and a seismic event is much smaller than for other plant safety risks. Accordingly, this ;
proposed MSIV leakage treatment pathway will be available during and after a LOCA. I Nevertheless, the BWROG has also determined that main steam piping and main !
condenser designs are extremely rugged, nd that the design requirements applied to the Hope Creek main steam system piping and main condenser contain substantial margin, based on the original design requirements.
In order to furtherjustify the capability of the main steam piping and main condenser alternate treatment pathway, the BWROG has reviewed limited earthquake experience data on the performance of non-seismically designed piping and condensers during past earthquakes. As summarized in Genera! Electric (GE) Report, "BWROG Report for increasing MSIV Leakage Rate Limits and Elimination of Leakage Control Systems,"
NEDC-31858P, Revision 2, submitted to the NRC by BWROG letter dated October 4, 1993, this study concluded that the possibility of a failure that could cause a loss of steam or condensate in Boiling Water Reactor (BWR) main steam piping or condensers in the event of a design basis (i.e., safe shutdown) earthquake is highly unlikely, and that such a failure would also be contrary to a large bods of historical earthquake experience data, and thus unprecedented.
PSE&G has performed a verification of seismic adequacy of the Hope Creek main steam piping and main condenser consistent with the guidelines discussed in NEDC-31858P, Revision 2, to provide reasonable assurance of the structuralintegrity of these components. This evaluation, " Hope Creek Nuclear Plant Main Steam isolation System Alternate Leakage Treatment Pathway Seismic Evaluation," clearly demonstrates that Page 2 of 7
Decumsnt Centrol D=k LR-N98564 Attachmsnt 2 LCR H98-10 the MSIV leakage treatment drain pathway meets the intent of 10CFR100 Appendix A, with regards to seismic qualification. Except for the requirement to establish a proper flow path from the MSIVs to the condenser, the proposed method is passive and does not require any additional logic control and interlocks. The method proposed for MSIV leakage treatment is consistent with the philosophy of protection by multiple barriers used in containment design for limiting fission product release to the environment.
A plant-specific radiological analysis has also been performed in accordance with l NEDC-31858P, Revision 2, to assess the effects of the proposed increase to the !
allowable MSIV leakage rate in terms of Main Control Room (MCR) and off-site doses following a postulated design basis LOCA. This analysis utilizes the hold-up volumes of the main steam piping and condenser as an alternate method for treating the MSlV leakage. As discussed earlier, there is reasonable assurance that the main steam piping and condenser will remain intact following a design basis earthquake. The radiological analysis uses standard conservative assumptions for the radiological source term consistent with Regulatory Guide (RG) 1.3, " Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss-Of-Coolant Accident for Boiling Water Reactor," Revision 2, dated April 1974.
The analysis results demonstrate that dose contributions from the proposed MSIV leakage rate limit of 200 scfh per steam line, not to exceed a total of 400 scfh for all four main steam lines, and from the proposed deletion of the MSIV Steam Sealing System, result in an acceptable increase 17 the LOCA doses previously evaluated against the i regulatory limits for the off-site doses and MCR doses contained in 10CFR100 and 10CFR50, Appendix A, General Design Criterion (GDC) 19, respectively. However, the calculation methodology for the revised dose exposures were performed in a manner that included more conservative design basis assumptions (e.g., inclusion of system response times, and increased allowable leakage rates) than in the existing Hope Creek licensing basis.
The whole body doses at the low population zone (LPZ) outer boundary and MCR increase from about 0.2 rem to 0.6 rem and from 0.04 rem to 0.09 rem, respectively.
These increases are not significant since the revised doses are small fractions of the regulatory limits of 25 rem and 5 rem, respectively. The associated whole body dose at the exclusion area outer boundary (EAB) increases from about 1.3 rem to 2.6 rem, which is well within the regulatory limit of 25 rem. The revised thyroid dose at the LPZ outer boundary increases from about 18 rem to 36 rem, which is well within the l regulatory limit of 300 rem. The revised thyroid dose at the EAB dccreases from about l 175 rem to 121 rem (due to plate out on the steam piping and condenser), which is within the regulatory limit of 300 rem. However, the MCR thyroid dose increases from l
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~
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1
l D: cum:nt Contr:I D:;k LR-N98564 Attachm:nt 2 LCR H98-10 about 0.3 rem to 5.0 rem, which is well within the regulatory limit of 30 rem.
Additionally, the MCR beta skin dose increases from about 0.9 rem to 1.6, which is well within the regulatory limit of 30 rem.
The resulting revised thyroid doses discussed above are dominated by the inorganic radioactive iodine fractions of the accident source term used in this analysis. More than 95% of the initial radioactive iodine inventory is assumed to be in the form of inorganic species in accordance with the guidance in Regulatory Guide 1.3. However, NUREG-1465, " Accident Source Terms for Light-Water Nuclear Power Plants," identifies that at least 95% of the iodine entering containment would be in the form of particulate iodine.
Accordingly, the calculated doses discussed above are consic'aed to be highly ;
conservative relative to realistic radiological source terms resulting from a postulated LOCA.
In summary, the proposed changes discussed above do not result in a significant increase in the radiological consequences of a LOCA when the same assumptions and methods specified in the UFSAR are used, recognizing that radiological consequences calculated in the UFSAR and for these proposed changes are significantly higher than those using more realistic assumptions and methods. Nevertheless, the calculated off-site and MCR doses resulting from a LOCA remain well below the regulatory limits.
Although the revised LOCA doses are higher for low MSIV !eakage rates, the effectiveness of the proposed alternate treatment method, even for leakage rates greater than the proposed increase in the MSIV allowable ;eak rete, ensures that off-site and MCR dose lii..its are not exceeded.
The proposed change to TS Table 3.6.3-1 involves the celetion of MSIV Steam Sealing valves and associated main steam line drain valves frorn the list of primary containment isolation valves. This proposed change is consistent with the proposed deletion of the MSIV Steam Sealing System. The MSIV Steam Saaling System lines and main steam line drain valves that are connected to the main steam piping will be welded and/or capped closed to assure primary containment integrity is maintained. The welding and post weld examination procedures will ba in accordance with American Society of Mechanical Engineers (ASME) Code, Section ill requirements. These welds and/or caps will be periodically tested as part of the Containment Integrated Leak Rate Test (CILRT). This proposed change does not involve an increase in the probability of equipment malfunction previously evaluated in the UFSAR. This proposed change has no effect on the consequences of an accident since the MSIV Steam Sealing lines and associated main steam line drain valves will be welded and/or cap closed, thus assuring that the containment integrity, isolation, and leak test capability are not compromised.
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. - . . - -- - = - - - _- - - - - - - -
I Dacument Centrcl Duk LR-N98564 l Attachment 2 LCR H98-10
( ,
I i Therefore, as discussed above, the proposed changes do not involve a significant increase in the probability or consequences from any accident previously evaluated.
l 2. The proposed change does not create the possibility of a new or different kind of l accident from any accident previously evaluated. l l
l Although the proposed changes will introduce and take credit for a new level of !
I operational performance for existing plant systems and components that have not been l previously evaluated in the accident analysis, the affect on this equipment has been evaluated and found to provide an acceptable level of reliability that will provide the required level of protection. This conclusion is based on the evaluation performed in ;
NEDC-31858P, Revision 2, and the seismic evaluation of the proposed MSIV leakage treatment pathway. Therefore, reliance on different equipment than previously assumed to mitigate the consequences of an accident does not create the possibility of a new or different kind of accident from any accident previously evaluated.
The BWROG evaluated MSIV performance and concluded that MSIV leakage rates up to 200 scfh per line will not inhibit the capability and isolation performar,ce of the MSIVs to effectively isolate the primary containment. Implementation of the proposed changes ,
will not result in modifications that could adversely impact the operability of the MSIVs. i The LOCA has been analyzed using the main steam piping end main condenser as a treatment method to process MSIV leakage at the proposed maximum rate of 200 scfh per main steam line, not to exceed 400 scfh total for all four main steam lines.
Therefore, the proposed change to increase the allowed MSIV leakage rate does not create any new or different kind of accident from any accident previously evaluated.
The proposed change to eliminate the MSIV Steam Sealing System does not create the possibility of a new or different kind of accident from any accident previously evaluated because the removal of the MSIV Steam Sealing System does not affect any of the remaining Hope Creek systems, and the LOCA has been re-analyzed using the proposed alternate method to process MSIV leakage. The associated proposed change to delete the MSIV Steam Sealing isolation valves and associated main steam line drain valves from TS Table 3.6.3-1 does not create the possibility of a new or different kind of accident, since the affected main steam piping will be welded and/or J capped closed to assure that the primary containment integ,ity, isolation, and leak I testing capability are not compromised.
j Therefore, as discussed above, the proposed changes do not create the possibility for l any new or different kind of accident from any accident previously evaluated.
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7 Page 5 of 7 l
D: cum:nt Central D:sk LR-N98564 l Attachm:nt 2 LCR H98-10 1
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- 3. The proposed change does not involve a significant reduction in a margin of safety. ,
I The proposed change to TS Section 3.6.1.2 to increase the MSIV allowable leakage i does not involve a significant reduction in the margin of safety. As discussed in the l current Bases for TS Section 3/4.6.1.2, the allowable leak rate limit specified for the MSIVs is used to quantify a maximum amount of leakage assumed to bypass primary containment in the LOCA radiological analysis. Accordingly, results of the re-analysis supporting these proposed changes are evaluated against the dose limits contained In l 10CFR100 for the off-site doses, and 10CFR50, Appendix A, GDC 19, for the MCR doses. As discussed above, sufficient margin relative to the regulatory limits is maintained even when assumptions and methods (e.g., RG 1.3) that are considered highly conservative relative to more realistic assumptions and methods, are used in the analysis.
1 1
Results of the radiological analysis demonstrate that the proposed changes do not involve a significant reduction in the margin of safety. The whole body doses, in terms of margin of safety, are insignificantly reduced by 1.6% at the LPZ,1.0% in the MCR, and by 5.2% at the EAB. The margin of safety for thyroid doses is reduced by 6.13% at '
the LPZ and 15.7% in the MCR, but is actually increased by 17.3% at the EAB. The margin of safety for beta dose is insignificantly reduced by 2.4% in the MCR. These reductions in the margin of safety are not significant since the revised calculated doses are highly conservative yet remain well below the regulatory limits, and therefore a substantial margin to the regulatory limits is maintained.
Furthermore, while the proposed changes will result in a calculated reduction in the margin of safety, this reduction is not significant when considering the increased reliability and capability of the proposed MSIV leakage treatment system. The resulting revised thyroid doses discussed above are dominated by the inorganic radioactive iodine fractions of the accident source term used in this analysis. More than 95% of the initial radioactive iodine inventory is assumed to be in the form of inorganic species in accordance with the guidance in Regulatory Guide 1.3. However, NUREG-1465,
" Accident Source Terms for Light-Water Nuclear Power Plants," identifies that at least 95% of the iodine entering containment would be in the form of particulate iodine.
Accordingly, the calculated doses discussed above are considered to be highly conservative relative to realistic radiological source terms resulting from a postulated LOCA.
The proposed change to eliminate the MSIV Steam Sealing System from TS does not reduce the margin of safety. In fact, the overall margin of safety is increased. The function of this system for MSIV leakage treatment will be replaced by alternate main I
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Dscum:nt Contr::1 Duk LR-N98564 Attachm:nt 2 LCR H98-10 steam drain lines and condenser equipment. This treatment method is effective in reducing the dose consequences of MSIV leakage over an expanded operating range
. compared to the capability of the MSIV Steam Sealing System and will, thereby, resolve i the safety concern that the MSIV Steam Sealing System will not function at MSIV leakage rates higher than the Steam Sealing System's design capacity. Except for the l l requirement to establish a proper flow path from the MSIVs to the condenser, the l l proposed method is passive and does not require any new logic control and interlocks.
This proposed method is consistent with the philosophy of protection by multiple barriers used in containment design for limiting fission product release to the environment. Furthermore, as previously identified, based on the evaluations i discussed in NEDC-31858P, Revision 2, and the seismic evaluation performed for j l Hope Creek, the design of the MSIV leakage treatment pathway meets the intent of the l 10CFR100, Appendix A, requirement for seismic qualification. Therefore, the proposed method is highly reliable and effective for MSIV leakage treatment.
The revised calculated LOCA doses remain within the regulatory limits for the off-site !
and the MCR doses. Furthermore, the revised calculation shows that MSIV leakage rates greater than 200 scfh for all four main steam lines would not exceed the regulatory limits. Therefore, the proposed method maintains a margin of safety for l mitigating the radiological consequences of MSIV leakage beyond the proposed TS leakage rate limit of 200 scfh per main steam line, not to exceed a total of 400 scfh for all four main steam lines.
The proposed change to delete MSIV Steam Sealing valves from TS Table 3.6-3-1 does not reduce the margin of safety. Welded and/or capped closure of the MSIV Steam Sealing lines assures that the primary containment integrity and leak testing capability are not compromised. These welds and/or caps will be periodically leak tested as part of the CILRT. Therefore, the proposed deletion of the MSIV Steam Sealing System isolation valves does not involve a reduction in a margin of safety.
Accordingly, based on the above reasons, the proposed changes do not involve a significant reduction in a margin of safety.
CONCLUSION Based on the above, PSE&G has determined that the proposed changes do not involve a significant hazards consideration.
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