ML20134B618
| ML20134B618 | |
| Person / Time | |
|---|---|
| Issue date: | 01/24/1997 |
| From: | Joshua Wilson NRC (Affiliation Not Assigned) |
| To: | Matthews D NRC (Affiliation Not Assigned) |
| References | |
| PROJECT-691 NUDOCS 9701300238 | |
| Download: ML20134B618 (26) | |
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January 24, 1997 MEMORANDUM TO:
David B. Matthews, Chief Generic Issues and Environmental Projects Branch Division of Reactor Program Management, NRR i
FROM:
James H. Wilson, Senior Project Manager
.[h Generic Issues and Environmental Projects Branch Division of Reactor Program Management, NRR 1
SUBJECT:
Su MARY OF JANUARY 22, 1997, PUBLIC MEETING BETWEEN NRC STAFF AND DOE ON TRITIUM PRODUCING BURNABLE ABSORBER R00 (TPBAR) LEAD TEST ASSEMBLY (LTA) TOPICAL REPORT On January 22, 1997, the staff held a public meeting with the Department of 4
Energy (DOE) at NRC headquarters in Rockville, Maryland, to discuss DOE's proposed responses to staff requests for additional information (RAIs).
The staff's RAIs were transmitted to DOE by letters dated January 3, and 13, 1997, and concerned DOE's TPBAR LTA topical report subndtted by letter dated j
i December 3, 1996. This topical report seeks to esteblish that use of a commercial light-water reactor (CLWR) to irradiate 2 limited number of TPBARs in LTAs does not raise generic issues involving ta unreviewed safety question.
4 A list of attendees and their affiliations is provided as Attachment 1.
DOE's proposed responses to the staff's RAls in individual technical areas are provided as Attachments 2, 3, 4, and 5, as discussed below.
Quality Assurag g DOE and its contractor, Pacific Northwest National Laboratory (PNNL),
presented their proposed responses to the staff's RAls, as indicated in The staff and DOE were not able to resolve fundamental questions regarding the safety classification for the TPBARs. DOE has taken the l
position that these components are classified as non safety-related.
Staff action in this area requires determination of the safety function of these assemblies in order to establish the applicability of Appendtx F and Part 21 requirements. DOE stated that it would document the requirements embodied in TVA's procurement documents to Westinghouse and Westinghouse's contractual documents to its suppliers to identify the standards to which the TPBARs are contracted and committed and to clarify the details of the TPBAR QA program in its formal responses to the RAIs.
Materials and Chemical Enaineerina
-9 DOE and (PNNL) discussed the proposed responses to the staff's RAIs, as indicated in Enclosure 3.
The staff requested that DOE provide additional information to justify its conclusion that SS 316 with 20% cold work will not crack under the conditions expected for TPBAR LTAs during irradiation. DOE
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committed to provide this additional information in its formal response to the RAls.
I 13 8 970124 691 PDR W'T f,to 5 mr NilC FILE CENTER COPY
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2 Reactor Systems DOE and its contractor, Pacific Northwest National Laboratory (PNNL) discussed the proposed responses to the staff's RAIs, as indicated in Enclosure 4.
With regard to Reactor Systems Question 4, DOE committed to provide a discussion of the changes to the PHOENIX code that Westinghouse made to account for the presence of the TPBARs in the core. The staff indicated the need for benchmarking of the PHOENIX and VIPRE codes to validate the implementation and i
user application of changes. The staff committed to determine whether examples of the benchmarking of the VIPRE code, discussed in Reactor Systems Question 5, were readily available and to so advise DOE. The staff also raised two additional concerns regarding the potential for, and consequences of, misloading the LTAs into the core and how the presence of the TPBARs in i
the core may affect the analysis of ATWS events. DOE committed to consider these additional issues in its formal response to the RAls.
Security 1
DOE's response to the staff's RAI in the area of security is provided as The staff stated that it is still considering the issue of which agency will conduct security facility approvals. The staff will contact DOE i
to discuss review and approval of facility security plans and subsequent l
inspections.
DOE closed the meeting by stating that responses to the staff's RAls, including proposed text revisions to the topical report, will be submitted by February 7, 1997.
DOE estimates that it will submit Revision 1 to the TPBAR LTA topical report on Narch 3,1997, prior to its briefing of the ACRS full committee.
DOE stated that it has down-selected to one plant, Watts Bar, for the irradiation portion of the LTA phase of its CLWR program.
DOE staff also i
stated that the request for proposal for the production phase of the CLWR program will be available January 28, 1997.
Project No. 691 l
Attachments: As stated cc w/ attachments:
See next page
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2 Reactor Systems DOE and its contractor, Pacific Northwest National Laboratory (PNNL) discussed the proposed responses to the staff's RAls, as indicated in Enclosure 4.
With regard to Reactor Systems Question 4, DOE committed to provide a discussion of the changes to the PHOENIX code that Westinghouse made to account for the presence of the TPBARs in the core. The staff indicated the need for benchmarking of the PHOENIX and VIPRE codes to validate the implementation and user application of changes. The staff committed to determine whether examples of the benchmarking of the VIPRE code, discussed in Reactor Systems Question 5, were readily available and to so advise D0E.
The staff also raised two additional concerns regarding the potential for, and consequences of, misloading the LTAs into the core and how the presence of the TPBARs in the core may affect the analysis of ATWS events. DOE committed to consider these additional issues in its formal response to the RAIs.
Security l
DOE's response to the staff's RAI in the area of security is provided as Enclosurc 5.
The staff stated that it is still considering the issue of which agency will conduct security facility approvals. The staff will contact DOE to discuss review and approval of facility security plans and subsequent inspections.
DOE closed the meeting by stating that it expects to submit its responses to the staff's RAIs, including proposed text revisions to the topical report, by February 7, 1997. DOE estimates that it will submit Revision 1 to the TPBAR LTA topical report on March 3, 1997, prior to its briefing of the ACRS full committee.
DOE staff stated that it has down-selected to one plant, Watts Bar, for the irradiation portion of the LTA phase of its CLWR program.
DOE staff also stated that the request for proposal for the production phase of the CLWR program will be available January 28, 1997.
Project No. 697 Attachments: As stated cc w/ attachments:
See next page CARIBUTION:
See next page Document Name: MEETSUM.122
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LIST OF ATTENDEES AT MEETING WITH DOE HELD IN ROCKVILLE, MD ON JANUARY 22, 1997 88ME AFFILIATION J. H. Wilson NRC L. Phillips NRC D. Terao NRC R. Gramm NRC H. Richings NRC C. Willis NRC K. Kavanagh NRC J. Davis NRC C. Carpenter NRC L. Campbell NRC R. Latta NRC L. Telford NRC T. Wilson ORNL M. Clausen DOE J. Ethridge PNNL G. Sorenson PNNL L. Erickson PNNL B. Reid PNNL S. Bales PNNL B. Schmitt PNNL R. Latorre PNNL R. Smoter PNNL E. Lowe PhNL C. Harmon SNL i
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January 21,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONALINFORMATION DATED 1/3/97 Ouality Assurance Page1 1.
. Provide a description of the components in the tritium-producing burnable absorber rod (TPBAR) lead test assemblies (LTAs) that are considered safety-related and a delineation of the portions of the TPBAR that receive PNNL's " Safety Class" 0A program treatment.
Response
The TPB AR LTAs do not perform a safety function and, consisteat with the guidance of Regulatory Guide 1.26 and Regulatory Guide 1.29, could be considered non-safety related. Such a determination would be consistent with the Plant B utility's determination that the TPBAR is quality-related, but non safety related per the requirements of their QA Program.
Objectives of the CLWR tritium target qualification program include demonstrating fabrication processes for the full production core and ensuring safe and reliable reactor operation. Accordingly, the design and fabrication of TPBARs is accomplished under the PNNL quality assurance program. The design and fabrication of the TPBAR LTAs are designated at the highest classification for activities under the PNNL quality assurance program. Individual components of TPBARs are not separately classified and the full PNNL quality assurance program applies to LTA TPBAR components.
2.
Provide a description of how the relative safety-significance of components in the TPBAR is determined.
Response
See response to Question 1.
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January 21,1997 DRAFT RESPONSE TO NRC I
i REQUESTS FOR ADDITIONALINFORMATION 1
DATED 1/3/97 Ouality Assurance Page 2 3.
Provide a consolidated description of the 0A program j;
controls that will govern design, fabrication, testing and installation of the LTAs.
Specifically, this 0A program
-description should contain a matrix that identifies conformance to each of the 18 Criteria of 10 CFR 50, Appendix B, as well as establishing the correlation with ASME NOA-I 1989.
j
. Response:
As is common for nuclear sub-vendors, PNNL's quality assurance plan describing the QA 4
program controls for design and fabrication of the TPBARs is available for inspection and NRC approval of the plan is not being requested. Qualification of PNNL as a component supplier, assembly of the LTAs, and installation into the host reactor will be performed under the host licensee's and Westinghouse's NRC-approved QA programs (see responses
,j to Questions 4 and 14 below).
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- 4.
Define the contractual relationship among the participants identified in Figure 7-1 of PNNL-11419, including a detailed description of the programmatic controls and responsibilities related to 10 CFR Part 50, Appendix B, and 10 CFR Part 21.
l
Response
l Contracts were placed by Battelle, operator of Pacific Northwest National Laboratory (PNNL) with both the Tennessee Valley Authority and Georgia Power Company as candidates for the host utility to perform the LTA irradiation services, and Westinghouse Electric Corporation has existing nuclear component related contracts with each of the host utility candidates. PNNL has a separate contract with Westinghouse for the modification of the Westinghouse owned, and NRC approved computer code methodology that is needed to perform the necessary reload core design.
The host utility quality program and quality system requirements are being imposed on Westinghouse and PNNL and comply with 10 CFR 50, Appendix B. The final supplier of the completed LTAs to the host utility will be Westinghouse. As an approved supplier meeting utility quality requirements, Westinghouse provides QA oversight of PNNL in 4
January 21,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONALINFORMATION DATED 1/3/97 Ouality Assurance Page 3 accordance with their NRC-accepted 10 CFR 50, Appendix B program. Planned Westinghouse oversight activities include:
a)
Performance of a supplier qualification audit to evaluate PNNL's compliance with 10 CFR 50, Appendix B and ASME NQA-1, Basic and Supplementary Requirements. (See response to item 17, below.)
b)
Oversight of PNNL manufacturing operations and subcontractor control of quality.
c)
Providing the utility a report summarizing the adequacy of PNNL's QA program, prior to insertion of the LTAs into the core.
The utility may conduct, in addition to Westinghouse oversight, effectiveness assessments of PNNL and PNNL's suppliers, utilizing a graded approach consistent with 1
the importance, complexity and quantity of items and services procured. Assessments may consist of checks, reviews, verifications, examination, and witnessing of activities related to fabrication, testing, inspection and shipment of the LTAs. PNNL will fumish Westinghouse with certified subcomponents (TPBARs), and Westinghouse will complete the fabrication, certification, and delivery of the LTAs to the utility. Utility final acceptance of the LTAs will be based upon receipt inspection utilizing graded approach criteria contained in the utility's NRC-approved QA Program. Authorization to insert the LTAs into the core is contingent upon satisfactory results of these oversight activities.
PNNL also utilizes an LTA project-specific plan for the reporting of defects and noncompliances in response to 10 CFR Part 21.
5.
Information contained in non-mandatory guidance sections (Appendices 2A1, 2A-2, 2A-3, 3A-1, 4A-1, 7A-1, 17A-1, and 18A-1) of NOA-1,1989, specify information that is typically found necessary by the staff to implement the programmatic requirements of 10 CFR 50, Appendix B. Provide a copy of the current PNNL QA program that implements NOA-1 and describe how the PNNL quality assurance program implements those provisions.
Response
The project QA plan, in combination with PNNL-wide and/or project-specific procedures, implements applicable portions of non-mandatory guidance of NQA-1
January 21,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97-
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Ouality Assurance Page 4 Appendices 2A-1,2A-2,2A-3,3A-1,4A-1,7A-1,17A-1 and 18A-1. (Also see response 4
to Question 3.)
6.
Describe the.PNNL Regulatory Compliance and QA program to i
provide audit / oversight of component and service suppliers utilized by. PNNL Design and' PNNL Fabrication.
Response
4 The project QA plan specifies that component and service suppliers are subject to PNNL QA oversight.- This oversight includes: pre-award surveys, periodic audits, source inspections, in-process monitoring, and receipt inspection of delivered product.
7.
Describe what quality provisions from the PNNL QA program are passed on to component and service suppliers utilized by PNNL Design and PNNL Fabrication.
Also describe row PNNL j
determines the acceptability of the suppliers.
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Response
1 Procurements for design and fabrication require supplier implementation of a QA i
program that meets applicable portions of NQA-1, Basic and Supplementary
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requirements. Supplier acceptability is established based upon pre-award surveys, periodic audits, source inspections, in-process monitoring, and receipt inspection of delivered product.
8.
If PNNL receives commercial grade items that are not manufactured in accordance with Appendix B OA requirements or the PNNL 0A program for use in the TPBARS, describe the process employed by PNNL to determine the acceptability of those items (i.e. commercial grade item dedication).
Response
No procured items for the TPBAR LTAs meet the NQA-1 or NCIG-07 defm' itions of commercial grade. PNNL will ensure that failures to comply are identified and corrected and that items are acceptable by appropriate combinations of testing, source inspection, review of supplier quality control plans, review of supplier documentation, and receipt inspection. Methods used will be appropriate to the characteristics to be verified.
i January 21,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Ouality Assurance Page 5 9.
Describe the management assessments and QA audits performed by PNNL Regulatory Compliance and QA to verify ;he effectiveness of the PNNL 0A program implementation.
Response
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The project QA plan establishes requirements for periodic audits and management assessments. To date, PNNL has conducted four management assessments of QA plan implementation in the areas of: overall program adequacy and implementation, training, records, and design. No fabrication activities have commenced, so no assessments have been performed on such activities. Additional management assessments and at least one PNNL QA audit will be performed during 1997 to assess compliance with 10 CFR 50, Appendix B and NQA-1.
10.
Provide a description of the PNNL verification processes that will be employed to assure that TPBARs conform to desigri specification requi rements.
Response
The project QA plan establishes requirements for source inspections, receipt inspections, review of supplier documentation, in-process and final acceptance inspections. The in-i process and final acceptance inspections will be performed in accordance with written procedures. In addition, they will be specified in a Manufacturing And Quality Plan (MAQP) which will be reviewed and approved by Westinghouse.
11.
Describe how design information will be controlled and transmitted across the interfaces between PNNL, Westinghouse, host utility organizations, and design services suppliers.
Response
The control of design information within each orgaf..uion is established by procedures in accordance with each organization's quality program. Transmittal of information between utility, Westinghouse and PNNL organizations is via designated organizational points of contact.
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January 21,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONALINFORMATION j
DATED 1/3/97 j
& $;y;a sn Page 6 1
12.
Describe.the methods that wili ]e used by host utilities to provide 0A oversight of PNNL, Westinghouse, and sub-suppliers.
Will Appendix B audits, surveillances, inspections be conducted by the host utility?
Response
See response to Question 4.
l 13.
A limited number of licensees have committed to NOA-1.
i Describe how host utility quality requirements (typically 4
conform to NRC Regulatory Guides and endorsed ANSI N45.2 series standards) were transmitted to Westinghouse and PNNL and the method whereby the PNNL quality program was found acceptable by the host licensees.
Response
i l
See response to Questions 4 and 17.
i 14.
Identify the Westinghouse quality program (such as the NRC-approved Quality Management System) that will be applied to activities associated with the LTAs.
Response
Westinghouse will apply their NRC-approved Quality Marapment System (QMS) and implementing procedures to Westinghouse activities associated with the LTAs, including QA oversight. The Westinghouse QMS, Rev. I was approved by NRC letter from Quality Assurance and Mcntenance Branch, Division of Reactor Controls and Human factors, Office of Nuclear Reactor Regulation, dated February 23,1996.
15.
Describe which organization is responsible for the LTA/TPBAR design.
Discuss how design reviews and design verification will be carried out by this organization.
Responce:
The design of the TPBARs is the responsibility of PNNL. This responsibility includes not only the design of the TPBARS to make tritium, but also the responsibility to
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<4 January 21,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONALINFORMATION DATED 1/3/97 Ouality Assurance Page 7 consider the implications to safety when the LTAs are loaded into a reactor core. Tritium release levels are also considered relative to the limits identified in 10 CFR. Project procedures control documentation and independent review of analyses and calculations j
by the PNNL design team. In addition, a series of design reviews by independent design review boards has been initiated in accordance with a project design review plan. The design review plan includes phased reviews by personnel with appropriate experience and expertise. Utility, Westinghouse and other personnel familiar with commercial reactor design, operation and regulation participated in the most recent design review held in December 1996.
1 As fuel supplier to the host plants, Westinghouse will provide a reload evaluation to the i
host utility that documents their evaluation of the acceptability of the TPBAR design l
relative to plant operation under the facility operating license.
16.
Discuss how nonconforming conditions will be reported uy supplier organizations to client organizations.
Discuss how the client organizations will evaluate those nonconforming conditions.
Response
PNNL addresses the reporting of nonconforming conditions through a formal mechanism established in the PNNL procurement quality system. PNNL procurement documents require that a supplier submit a " Contractor Nonconformance Request" (CNR) i documenting any nonconforming condition tendered for acceptance of a variance from PNNL specifications. The supplier must describe the deficient condition, recommend a disposition and provide ajustification. The supplier muy mbmit the CNR for PNNL's review and approval. The recommended supplier dispd :n may be approved, modified or disapproved by PNNL and PNNL must provide an appropriate technicaljustification to support the disposition. During the review of the CNR, PNNL will make a determination regarding the type of verifications that are necessary to assure that CNR disposition has been completed correctly.
LTA-related nonconformance reports, whether genera.ted by PN% or a PNNL supplier will be made available to Westinghouse and the host utility as part of the process. The host utility reserves the right to review and concur in all repair and use-as-is dispositions of nonconfonnances with the utility requirements.
17.
Describe the process whereby Westinghouse qualified PNNL cs an approved supplier for LTA design and fabrication.
,f January 21,1997.
DRAFT RESPONSE TO NRC
- REQUESTS FOR ADDITIONALINFORMATION DATED 1/3/97 Ouality Assurance Page 8
Response
Westinghouse performed a qualification audit of PNNL in accordance with the NRC-approved Westinghouse Quality Management System (QMS) (see response to Question 14). The scope of this audit included verifying PNNL's compliance with
.10 CFR 50, Appendix B and ASME NQA-1, Basic and Supplementary Requirements.
As a result of the audit, Westinghouse placed PNNL on the Westinghouse Qualified Supplier List. The listing on the Westinghouse Qualified Supplier List is conditional.
upon: 1) satisfactory corrective action response to identified audit findings; and 2) a follow-up audit to verify PNNL QA program implementation in the manufacturing area.
(No fabrication had occurred at the time of the audit.) Upon satisfactory implementation of corrective actions and closure of any findings resulting from follow-up audits, Westinghouse will update the status of PNNL to " approved."
18.
Describe the process employed by Westinghouse to provide 0A oversight of PNNL and sub-suppliers.
Will Appendix B audits and inspections be utilized?
Response
See response to Question 4.
19.
Describe the processes that will be utilized by Westinghouse (eg. receipt inspection, dimensional and configuration verification, and material verification) to verify TPBARs conform to Westinghouse technical requirements prior to assembly in LTAs.
Response
j See response to Question 4. In addition to the activities described in response to Question 4, Westinghouse will review PNNL supporting documentation certifying the 3
TPBAR was built in accordance with the design and quality requirements, provides unique identification for traceability, and performs receipt inspection in accordance with approved pre %es.
i 20.
Describe the processes that will be utilized by host facilities (eg. receipt inspection, dimensional and
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' January 21,1997 DRAFT RESPONSE TO NRC L
REQUESTS FOR ADDITIONALINFORMATION DATED 1/3/97 Ouality Assurance Page 9 configuration verification,. and material verification) to confirm that LTAs are suitable for installation in the core.
Response
See response to Question 4 and PNNL-11419, Section 6.2.
21.
Describe whether Westinghouse special processes (eg.
welding) have been re-qualified as necessary to account for differences in TPBAR material from that typically used in LTA assemblies.
Response
Special process procedures (including welding) will be developed and qualified by PNNL and are, therefore, not considered to be re-qualified Westinghouse special processes. The special process controls, however, will be subject to oversight by Westinghouse and PNNL QA. Special processes will be identified and key parameters defined in a Manufacturing And Quality Plan (MAQP) which is subject to review and approval by Westinghouse.
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I January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Materials and Chemical Engineering Page1 1)
Section 1
.The design life for the assembly is 550 EFPD. What were the fluence levels used to establish the design life? Also, does the design take into account possible power uprate or extended cycles?
l
Response
The neutron fluence values used in the design of TPBARs are identified in Table 2-5 of the Topical Report. The TPBAR was not specifically designed to take into account possible power uprates or extended operating cycles. Neither Plant A nor Plant B plan to implement a power uprate or extended cycle for the period of LTA irradiation.
2)
Section 1.1 "The TPBAR design has been developed to demonstrate...
tritium leakage consistent with a TPBAR design goal of <6.7 Ci per rod per year...." This appears to imply that for full operation, the reference plant will be leaking thousands of curies of tritium per year of operation.
Response.
The design goal for TPB AR tritium leakage to the RCS for a full production core is less than 20,000 curies per year. Assuming approximately 3000 TPBARs in a production core, this equates to the <6.7 curies per rod per year used for evaluation of the LTAs.
(The acceptability of the design level ofleakage for the production core will be evaluated as part of the license application to support production.) Note that, although the design goal is less than 6.7 Ci per rod per year, dose calculations in Chapter 6 of PNNL-11419 (and in response to Reactor Systems' requests for additional information, item 7) are conservatively based on 6.7 Ci per rod per year.
3)
Sections 2.2.1 & 5.3.1 - Why was 316 SS with 20% CW selected as the material for cladding and end plugs? Were higher strength, corrosion I
resistant alloys (e.g., Alloy 690, Inct.el 718, Zircaloy-4) considered?
Response
The LTA TPBAR is an evolutionary target design and 300-series SS has been the material historically used for tritium target claading. The processes for permeation barrier application were developed using 300-series SS cladding. Sufficient experimental and performance data for barrier-coated tubing using other materials is not available. 316 SS
January 20,1997 -
DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Materials and Chemical Engineering Page 2 l
with 20% CW was specified to maximize strength while staying within the experience base established for 300-series SS.
4)
Section 2.2.4 - What is the basis for selecting 302 SS for the plenum spring material?
Response
302 SS was selected for the TPBAR plenum spring since this material has been successfully used in burnable poison rod and fuel rod plenum spring applications in Westinghouse reactors. An analysis of the TPBAR plenum spring demonstrates that spring stresses are well within allowable stresses for this material during worst-case combinations of preload, manufacturing tolerances, pressure conditions, and component thermal and radiation growth.
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January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Materials and Chemical Engineering Page 3 5)
Section 2.4 - Provide additional details regarding the nondestructive I
testing. What techniques are used for each component? What are the applicable standards?
Response
See Table 5.
TABLE 5 Nondestructive Testing Techniques and Applicable Standards for Acceptance of TPBAR and TPBAR Components Applicable TPHAR Component
%ethod Standard Characteristic j
Nondestructive Tests Performed by PNNLm Coating thickness, unif rmity f thickness Coated Cladding Eddy Current along the tube, and inter-metallic phase Final TPBAR Assembly Radiography NE F3-10 m Welds, component placement i
i ASME B&PV, Rod cladding integrity Final TPBAR Assembly Helium Leak Test Section V (leak tightness)
Article 10 Nondestructive Tests Performed by Subvendors 316 SS Bar Stock Ultrasonic ASTM E213-93 Defects 316 SS Bar Stock Liquid Penetrant ASTM E165-95 End defects Cladding tubing Ultrasonic ASTM E213-93 Wall thickness, flaws Plated getters (tubes X-ray P ating thickness and l
ASTM B568-91 and dips spectrometry coverage NOTES.
- All personnel performing acceptance inspections will be certified to ASNT-TC-1 A.
- DOE specification developed for fast breeder reactor program.
January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONALINFORMATION DATED 1/3/97 Reactor Systems Page1 1)
Table 2 What Li enrichment was used to calculate the axial power?
Many power and burnup-related parameters are well beyond the conditions sustained in prior tests.
Viewed in this way, the TPBAR appears to be a large jump beyond prior experience.
Response
The Tritium-Producing Burnable Absorber Rod (TPBAR) axial power is based upon the
'Li enrichments listed in Table 2-5.
The tests performed in research reactors were accelerated tests at higher flux levels, which, with the display of data in Table 2-5, can give the illusion of a large jump from current experience when it is not. For example:
TPB AR Effective Full Power Days (EFPD), which is a reactor-specific value dependent on the reactor's full power rating, increases by a factor of two or more over those of the listed test rods; whereas the predicted TPBAR thermal neutron fluence is clearly bounded by the listed tests.
Rod average percent 'Li burnup for the TPBARs is a factor of four greater than the listed tests; whereas a more appropriate parameter related to pellet stability would be total Li burnup which is directly related to Gas Volume Ratio (GVR)L (Pellet GVR is analogous to fuel MWD /MTU.) In the case of GVR, Table 2-5 does not include all tests used as bases for TPBAR design; for example, test results shown in Table 2-6 are among those that provide an experience base for pellet behavior up to a GVR of 216, which bounds the design GVR for the TPBAR.
2)
Section 3.1.1 - Are WIMS-E and MCNP codes qualified for NRC use? Are auditable calculation files available for review of inputs, assumptions, and other details of the calculations?
Response
i Neither of these two codes are qualified by NRC for use in safety calculations. The neutronic studies performed for this repon using WIMS-E and MCNP were scoping calculations only, therefore no auditable calculations are available for review. The
' Ratio of gas volume (at standard temperature and pressure) to pellet volume.
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January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Reactor Systems Page 2 analyses of record will be performed by Westinghouse using an NRC-approved methodology (PliOENIX) and documented in auditable calculation files. As stated in l
Section 3.4, the excellent agreement found in comparisons between PNNL WIMS-E and PHOENIX-L establishes confidence that the Westinghouse calculations will provide i
predictions of the reload core comparable to those in the WIMS-E scoping calculations.
j Additional calculations required by Westinghouse or the licensee will be performed in a j
manner that meets Westinghouse QA requirements.
j 3)
Section 3.1.1 - Provide an explanation for why the reactivity difference j
between MCNP and WIM-E of 0.5% appears high.
Response
The 5 mK difference seen in the cross code comparison between WIMS-E and MCNP for a fuel assembly model containing TPBARs is considered quite good. The WIMS-E code is a deterministic, transport theory code and MCNP employs a statistical, Monte Carlo solution methodology. In addition, each code uses an independent set of nuclear cross section data libraries (European vs ENDF/B, respectively). In consideration of the substantial differences in calculation methodologies and the use of unrelated nuclear data libraries, some differences in calculated reactivity are to be expected, and in this case the difference is relatively small.
4)
Section 3.4 - Will the differences between PHOENIX-L and PH0ENIX-P be documented in a topical report?
Response
The differences between the two versions of the PHOENIX code will be documented in a Westinghouse report that will be provided to the host utility and PNNL. These differences will also be documented internally at Westinghouse in the computer software verification and validation documentation.
-~
. January 20,1997 DRAFT RESPONSE TO NRC L
_ REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Reactor Systems Page 3 l
5)
Section 4.1.2 - Is the VIPRE code NRC-qualified? Are auditable l
calculation files available for review of inputs, assumptions, and other j
details of the calculations?
Response
l The VIPRE code has been reviewed by NRC. A technical evaluation r port (TER) was issued in 1994, ITS-NRC-93-1 " Technical Evaluation Report: VIPRE-01 Mod-02 for PWR and BWR Applications, EPRI-NP-2511-CCM-A, Revision 3" The application of j
the code for Plants A and B does not use plant-specific heat transfer or CHF correlations.
l The application uses only the well known Dittus-Boelter single phase heat transfer j
correlation, and the cylindrical heat conduction model (for heat conduction across a guide
{
thimble wall, between the fuel channel and TPBAR channel). These are described in the l
TER. Flow is provided by the utility / Westinghouse, and is used as a bounday condition.
The VIPRE code is not used to evaluate flow distribution or core pressure drop.
s The calcuiations presented in the initial report were not final. Final calculations are planned to support Revision 1 to PNNL-11419. The final calculations will be documented in an auditable file.
6)
Section 4.1.2 The last paragraph suggests that the results in Figure 4-1 are preliminary and are more conservativ. than Westinghouse's normal i
method.
Will a final T-H analysis be submitted or is the decision to be based on the results given? What assumptions are more conservative than normal?
i
Response
)_
The calculations were preliminay in that they were not documented in an auditable manner and the model did not include the guide thimble dashpot region. As discussed in 1
response to item 5, final calculations are planned to support Revision I to PNNL-11419.
1 PNNL does not expect significantly different results between the preliminary and final J
calculations. If further calculational results are more limiting than those documented in PNNL-11419, the host utility will be notified such that their safety evaluation adequately l
. addresses the impacts.
For both Condition I and 11 events, the Westinghouse calculations for BP rods took credit for cladding superheat in evaluating (and preventing) the onset of subcooled nucleate e
8 e
January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR.
ITIONAL INFORMATION L
dD 1/3/97 Reactor Systems Page 4 boiling. PNNL calculations do not take credit for cladding superheat, they apply the temperature limit to the bulk coolant.
Also, for Condition I and Il events, the Westinghouse BP calculations used nominal inlet temperature, outlet pressure, and minimum flow (based on dimensional tolerances without an additional 5% flow maldistribution penalty). For Condition I, PNNL calcuations used the most limiting conditions as would be applied to LOCA and DNBR evaluations for inlet temperature, pressure, and flow maldistribution (this results in 5% more flow reduction than just for dimensional tolerances). For Condition 11, PNNL calculations use similar assumptions as Westinghouse (nominal conditions, with dimensional tolerances accounted for).
7)
Section 6.1 - Provide the value of the total off-site exposure and the regulatory limits, rather than stating that the increase due to TPBARs is small.
Response
See the attached Tables 7-A and 7-B which summarize total exposures and regulatory guidelines / limits for Plants A and B. The total body dose was calculated using the following equation:
Total Body Dose = y whole body dose + w
- Thyroid dose + w,*p dose 1
where w Thyroid weighting factor from 10CFR20.1003 ( = 0.03)
=
7 p
Beta skin dose weighting factor from ICRP Publication 60,1990 w
=
Recommendations of the htternational Committee on Radiological Protection, published by Pergamon Press ( = 0.01) 8)
Section 6.1 - Why is the release rate modeled as a constant? As pressure in the TPBAR increases, would the release rate not also increase?
If a constant release rate is used as an approximation, it should be a conservative end-of-life number.
Response
To evaluate this issue, calculations were performed using time-dependent release rates for the TPBARs. Using neutronic data for Plant B, the end-of-cycle tritium inventory increased over that calculated for a constant release rate. The peak tritium concentration
9 January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Reactor Systems Page 5 also increased, which results in an increase in the offsite dose during a SGTR (not reflected in Tables 7-A or 7-B). For the breached rod case, the end-of-cycle tritium inventory decreases compared to the constant release model. The breached rod case assumes all tritium is released to the coolant as it is produced and the production decreases over the cycle due to 'Li depletion. Occupational doses will be impacted accordingly. The time-dependent release rate model will be used in classified calculations for the occupational dose data that will be presented in Revision 1 to the classified topical.
9)
Section 6.2.2 - Does the plant loadirg and handling procedure account for the actual weight of BPRA?
In particular, is there a load limit to prevent damage to the fuel assembly from withdrawing a stuck rod assembly?- If so, does the procedure need to be modified to account for the lighter weight of the TPBAR7
Response
The plant handling procedure for the burnable poison rod assembly (BPRA) handling tool contains a precaution stating that if significant resistance is felt during removal that the assembly is either fully withdrawn or stuck and visual verification of position must be made. The BPRAs are removed by a hand winch operated tool. There are no provisions for a load monitoring device to be attached to this tool. This toolis used to handle BPRAs containing as few as six full length pins to as many as 24 full length pins. The LTA weight is bounded by these conditions and no change to the procedure or handling i
equipment is warranted.
January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Reactor Systems Page 6 TABLE 7-A Summary of Off-Site Radiological Consequences for the TPBARs in Plant A Current Total Body Total Body Dose with Increase w/
Reference Value /
Condition Receptor Dose (rem)
LTA Source Normal Operation MEl")
0.000839 0.000840 0.074 %
10Ch'R50, App. I Cladding Breach MEl 0.000839 0.000872 3.93 %
10bF 50, pp.I EAB<2' O.0717 0.0717 3.4e-3%
Steam Generator 2.5 rem /
r23 Tube Rupture LPZW (8 h) 0.0307 0.0307 4.7e-3%
SRP 15.6.3 Fuel Handling EAB 0.0142 0.0142 none Accident (Containment)
LPZ (2 h) 0.0058 0.0058 none Fuel Handling EAB 2.4000 2.4000 none Accident (Auxiliary Bldg)
LPZ (2 h) 0.9500 0.9500 none EAB 3.1060 3.1060 4.0e-4%
25 rem /
LPZ (30 d) 2.8120 2.8125 0.019 %
NOTES:
"' Maximum Exposed Individual.
- Exclusion Area Boundary for 2 h = Fenceline Receptor
- Low Population Zone = MEl Receptor
e January 20,1997 DRAFT RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Reactor Systems Page 7 TABLE 7-B Summary of Off-Site Radiological Consequences for the TPBARs in Plant B Current Total Body Reference Value /
Total Body Dose with Increase w/
Condition Receptor Dose (rem)
LTA Source Normal Operation MEl("
0.0007 0.0007002 0.029 %
10CbR50, App. I Cladding Breach MEl 0.0007 0.000713 1.86 %
10bF50, pp.I EAB(2) 0.8625 0.8625 2.2e-4%
2.5 rem /
Steam Generator Tube Rupture LPZ((8 h) 0.2004 0.2004 2.2e-4%
Fuel Handling EAB 2.0075 2.0075 none Accident (Cor.tainment)
LPZ (2 h) 0.4663 0.4663 none Fuel Handling EAB 0.7815 0.7815 none Accident (Auxiliary Bldg)
LPZ (2 h) 0.1815 0.1815 none EAB 3.2874 3.2874 4.0e-4%
25 rem /
LOCA 10CFR100 LPZ (30 d) 2.0002 2.0007 0.027 %
NOTES:
'" Maximum Exposed Individual.
(23 Exclusion Area Boundary for 2 h = Fenceline Receptor
(') Low Population Zone = MEl Receptor l
e, e
January 20,1997 DRAFT RESPONSE TO NRC 3
REQUESTS FOR ADDITIONAL INFORMATION DATED 1/3/97 Security Page1 1)
Section 8.3 - As indicated in the staff's letter dated November 1, 1996, i
the staff agrees that additional individual access authorization by NRC is not needed. However, the staff is still considering the issue of DOE f
i conducting and granting security facility approvals at NRC licensee sites.
Response
Section 8.3 of PNNL-11419 incorrectly characterized the staffs letter dated November 1, l
1996 by stating that it confirmed that DOE requirements relative to security facility approval satisfy corresponding NRC requirements. PNNL-11419 will be revised to correctly indicate that no additional NRC action is required for personnel access authorizations relative to the CLWR tritium program and that security facility approval will be coordinated between DOE and NRC to meet applicable regulatory requirements.
Regardless of the approving agency, DOE (or its contractor) will review the host facility to ensure that it meets DOE requirements for safeguarding of DOE classified material j
prior to shipment of the material to the site.
I #
44 4
Project No. 697 DOE Tritium Program cc:
Steve Sohinki Office of Commercial Light-Water Reactor Production, DP-62 Tritium Project Office U.S. Department of Energy 1000 Independence Avenue, SW Washington, DC 20585 Max Clausen Office of Commercial Light-Water Reactor Production, DP-62 Tritium Project Office U.S. Department of Energy 1000 Independence Avenue, SW Washington, DC 20585 DP-60 Records Management Office of Commercial Light-Water Reactor Production Tritium Project Office U.S. Department of Energy 1000 Independence Avenue, SW Washington, DC 20585 4