ML19354D692
| ML19354D692 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/26/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19354D691 | List: |
| References | |
| NUDOCS 8912290084 | |
| Download: ML19354D692 (5) | |
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umTED STATES I
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ENCLOSURE SAFETY EVALUATION REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION f
INSERVICE PRESSURE TEST PROGRAM
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AND ONE ASSOCIATED RE0 VEST FOR RELIEF l
TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT. UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328
1.0 INTRODUCTION
Section 50.55a " Codes and Standards," of 10 CFR Part 50 requires, in part, that safety-related components meet the requirements of Section XI of the American Sor.iety of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (hereaf ter the " Code").
In order to meet the requirements of this regulation, the Tennessee Valley Authority (TVA) has submitted to the NRC its Revision 4 to the Inservice System Pressure Test (ISPT) Program for the first 10-year interval for Sequoyah, Units 1 and 2 (SQN1 and SQN2). The SQN1 and SQN2 ISPT Program was originally prepared to meet the requirements of Section XI of the Code of record for Sequoyah:
1977 Edition, Summer 1978 Addenda of Section XI of the Code.
In its ISPT Program for SQN1 and SQN2, TVA also reguested relief from the hydrostatic test pressure requirements of IWD-5223(a) of Section XI of the 1977 Edition. Summer 1978 Addenda of the Code for certain ASME Class 3 or equivalent piping and components.
This is request for relief ISPT-1.
Regulation 10 CFR 50.55a(g)(4) requires that Class 1, 2, and 3 components meet the requirements of the applicable edition and addenda of the Code as defined by the regulations.
Regulation 10 CFR 50.55a(g)(4)(iv) for inservice examina-tions (including system pressure tests) permits the use of portions of subse-quent editions and addenda to the Code subject to the limitations of 10 CFR 50.55a(b) and subject to Commission approval and that all related requirements of the respective editions or addenda are met.
For NRC to grant relief from Code requirements, regulation 10 CFR 50.55a(g)(5)(iv) requires TVA to demon-strate that an examination or test requirement of the Code is impractical to perform.
The ISPT Program was originally submitted to the NRC by TVA in its letter dated August 18, 1983.
Revisions to the Program were submitted in TVA letters dated March 10, 1986; September 3, 1987; January 11, 1988; and January 31, 1989.
The request for relief ISPT-1 is in TVA letters dated January 11,1988 and January 31, 1989.
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2 2.0 DISCUSSION 2.1 Use of Portions of Later Code Editions / Addendum for Specific Requirements In lieu of using only the requirements of the Code of record (1977 Edition, Summer 1978 Addenda of Section XI). TVA proposed to use portions of articles in the later 1980 Edition, Winter 1981 Addenda, of Section XI of the Code for the following specific testing requirements in the ISPT Program for SQN1 and SQN2:
1.
System Hydrostatic Test Boundary (IWA-5224) 2.
Maximum Allowable Hydrostatic Test Pressure (IWA-5265 (b))
3.
Hydrostatic Test Pressure for Class 1 (equivalent) Systems (IWB-5222 (a) and(b))
4.
System Leakage Test Boundary (IWA-5221 and Footnote 1 for Cxamination Category B-P in Table IWB-2500-1) 5.
Normal Reactor Operation (Footnote 4 in IWB-1000)
System Hy(drostatic Tesi. Pressure for Class 2 and 3 (equivalent) Com-6.
ponents IWC-5222(a))
7.
Open-ended System and Components (Footnote 1 in IWC-5000)
The ISPT Program is using the entire articles of Section XI of the Code of record except for the seven specific testing requirements listed above.
For these seven requirements, TVA is proposing to use aortions of articles in Section XI of the Code of record and portions of t1e articles in Section XI of the later 1980 Edition, Winter 1981 Addenda, of the Code.
In no case for these seven requirements would the entire article in Section XI of either Edition or Addendum of the Code be used.
Regulation 10 CFR 50.55a(g)(4)(iv) states for inservice system pressure tests that portions of editions and addenda of the Code may be used provided that all the related requirements of the portion of the Code are used.
For the ISPT Program at Sequoyah, TVA is using portions of articles in Section XI of the later 1980 Edition of the Code without including all of these articles. As an exan.ple, the ISPT program does not include tne entire article IWA-5000 of the later Code for system pressure tests.
Insteaa TVA proposes using only selected subarticles, subsubarticles, paragraphs and subparagraphs of the later Code listed above:
IWA-5224, IWA-5265(b) and IWA-5221.
In its letters, TVA did not justify why it was choosing to use only portions of articles in Section XI of the later Code.
TVA did not justify the use of the particular footnotes and 50.55a(a)(3) phs from Section XI of the later Code in terms of 10 CFR subsubparagra or 10 CFR 50.55a(g) for each instance.
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3 For the staff to complete its review of the ISPT Program for SQN1 and SQN2, TVA is requested to provide the justifications for using only portions of articles in Section XI of the later Code for the seven requirements listed above.
The staff also requests that these justifications be provided in the form of requests for relief from the Code of record for Sequoyah, P
The justifications for using definitions of a later Code should be in terms of what the hardships, or impracticalities, are because the inspections would be conducted in accordance with the Code of record.
For instance, to define the test pressurization boundaries using IWA-5224 in lieu of the location of the safety class interface valves, the hardships and impracticalities of using the safety class interface valves to define the test pressurization boundaries test pressure using IWA-5265(b)g a limit on the maximum allowable hydrostat should be provided.
For settin where the static head may cause the pressure in the lowest part of the system to exceed the 106% pressure test limit. TVA should address why this is a problem requiring relief from the Code of record.
The staff also notes that TVA in the instance of proposing to adopt only paragraph IWA-5224, System Hydrostatic Test Boundary, of Section XI also modified the words of this particular paragraph.
This modification, to require that the hydrostatic test pressure for piping systems be determined by the component within the test boundary with the lowest design pressure, is not justified.
This could result in either a higher or lower hydrostatic test pressure for a given system than that required by the Code and conflicts with TVA's proposed alternative Code requirements of the 1980 Edition Winter 1981 Addenda, Subparagraph IWA-5224(a).
If relief is needed from the hydrostatic test pressures required by the Code, then such relief should be submitted to the NRC staff pursuant to 10 CFR 50.55a(g)(5)(111).
Each use of such relief must be encompassed by the relief request.
2.2 Request for Relief. ISPT-1 TVA also requested relief from the hydrostatic test pressure requirements for certain ASME Class 3 or equivalent piping and components of the 1977 Edition, 1978 Addenda of Section XI of the Code.
The request for relief, in TVA letters dated January 11, 1988 and January 31, 1989, listed 40 valves in the Class 3 auxiliary feedwater piping system and applies to the valves and the piping between the valves.
2.2.1 Applicable Code Requirements IWD-5223(a):
System Hyorostatic Test (a) The system hydrostatic test pressure shall be at least 1.10 times the system pressure P for systems with Design Temperature of 200'F (93*C) or less,andatleast.V1.25 times the system pressure P for systems with l
Design Temperature above 200*F (93'C). The system kessure P shall be the lowest pressure setting among the number of safety or relllf valves provided for overpressure protection within the boundary of the system to be tested.
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4 2.2.2 Licensee's Basis For Requesting Relief The subject piping sections are Class 3 (equivalent) piping that have a design pressure rating of 1,650 psig, and that are connected to Class 2 (equivalent) piping that have a design pressure rating of 1,085 asig. The Class 2 piping is separated from the Class 3 piping by check valves t1at allow flow only from the Class 3 to the Class 2 piping. Because of this configuration, it is not pos-sible to pressurize the Class 3 piping in these sections without over-pressuri -
ing the Class 2 piping.
2.2.3 Alternative Code Requirements The subject piping sections will be tested at the hydrostatic test pressure used for the Class 2 (equivalent) piping (i.e.,1.25 x 1,085 = 1356 psig in lieu of 1.10 x 1,650 = 1815 psig).
2.2.4 Staff Evaluation The proposed alternative Class 2 test pressure of 1356 psig versus the required Class 3 test pressure of 1815 psig will usually detect the type of defects and operating characteristics of concern.
I The check valves in the lines to be tested make it impossible to set up opera-tional flow in one direction and hydrostatic test flow (and pressure) in the opposite direction.
The hydrostatic test pressure must be performed from the same direction as the operational flow, i.e., from Class 3 to Class 2.
There-i fore, the lower precure limit of Class 2 must apply to these portions of l
Class 3 piping and L,mponents, although designed to a higher pressure with a correspondingly Code required higher hydrostatic test pressure, cannot be isolated because of the characteristics of check valves.
1 The majority of the Class 3 siping will receive the required pressure test pressure, and the scope of t11s relief request is a small portion of the total system.
The replacement of these valves is a significant burden en the licen-see, in that it would require extensive redesign of the systems, possibly requiring other system changes, and the generation of radioactive material and radiation exposure of workers.
3.0 CONCLUSION
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Based on the staff review of TVA's revisions to its ISPT Program for SQN1 and SQN2, the staff requests that TVA provide the justifications for using only portions of articles in Section XI of the later Code. The staff also requests that these justifications be provided in the form of requests for relief from the Code of record for Sequoyah. This is discussed in detail in Section 2.1 above.
Based on the staff review of TVA's request for relief ISPT-1 the staff con-cludes that the request for relief from certain specific requirements of
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5 Section XI of the ASME Code is acceptable.
Relief was requested from the IWD-5223(a) requirement for the pressure test to be conducted at 1.10 times the system design pressure. This is for the valves and connecting piping listed in relief request ISPT-1 forwarded by TVA letter dated January 11, 1988.
This relief is contingent on TVA using the test pressure described in Section 2.2.3 above.
The staff has determined the following for relief request ISPT-1: (1) the Code testing) requirements are impractical to perform and, pursuant to 10 CFR(3 50.55(a an acceptable level of quality and safety; (2) relief may be granted pursuant to 10 CFR 50.55a(g)(6)(1) based on our finding that the Code requirements of Section XI of the Code are impractical; (3) granting relief where the Code alternative testing requirements will not endanger life or property, or the common defense and security, and is otherwise in the public interest considering the burden that could result if the testing requirements were imposed on the facility.
Any additional program changes such as revisions or additional requests for
. relief should be submitted for staff review and should not be implemented prior to review and approval by the staff.
Principal Contributor:
D. E. Smith Dated: Secember 26, 1989 l
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