ML18064A640
| ML18064A640 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/03/1995 |
| From: | Haas K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9503140093 | |
| Download: ML18064A640 (6) | |
Text
..
consumers Power KurtM. Haas Plant Safety aiid Licensing Director POW ERIN&
MIClll&AN"S PIUl&RESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 March 3, 1995 Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT REQUEST FOR APPROVAL FOR USE -OF CODE CASE N-416-1 The ASME Code Case N-416, "Alternate Rules for Hydrostatic Testing of Repair or Replacement of Class 2 Piping" allowed for hydrostatic testing at nominal system operating pressure of Class 2 piping following welded repair or replacement activities.
Code Case N-416 has been endorsed for use by the NRC under Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability ASME Section XI Division I." Code Case N-416-1, "Alternative Pressure Test Requirement for Welded Repairs or Installation of Replacement Items by Welding, Class 1, 2 and 3 Section XI, Division l" expands the scope of the N-416 alternate rules for Class 2 piping to Class 1, 2 and 3 systems.
Due to its recent approval, Code Case N-416-1 has not yet been endorsed by the NRC in Regulatory Guide 1.147. It is our understanding, however, that NRC approval has been granted for other Licensees to use this Code Case.
Therefore, in accordance with footnote 6 to 10 CFR 50.55a, we request approval for use of Code Case N-416-1 for plant testing beginning with the 1995 refueling outage, which is scheduled to start in late May of this year.
Pursuant to 10 CFR 50.55a(a)(3) and the justification provided in Attachment 1 to this letter, we believe that Code Case N-416-1 provides an acceptable alternative to the current NRC requirements.
In letters dated June 3, 1994 and January 24, 1995, we requested that the NRC address the use of two other Code Cases for the Palisades Plant. The June 3, 1994 letter requested relief from the requirements stated in Code Case N-437 for accuracy of digital pressure measuring instruments.
The June 3~
1994 letter specifically requested that we be allowed to use installed plant pressure instrumentation when performing a primary coolant system hydrostatic A CMS' ENERGY COMPANY
2 test. The January 24, 1995 letter requested approval of the use of Code Case N-498-1, which allows the use of nominal operating system pressure in place of hydrostatic system pressure when performing 10 year hydrostatic pressure tests, and allows the use of installed plant instrumentation in place of the requirements for special test gauging when performing nominal system operating tests.
With the approval of Code Cases N-416-1 and N-498-1 for the Palisades Plant,*
testing at nominal operating system pressure using installed plant instrumentation.will be allowed following welded repairs or replacement of items by welding, and for 10 year interval hydrostatic pressure tests.*
Therefore, the specific relief requested in our June 3, 1994 letter will not be needed.
Accordingly, we hereby withdraw the request for relief contained in ou~ June 3, 1994 submittal, based on our confidence that the other two relief requests will be approved prior to next plant refueling outage, presently scheduled to start at the end of May, 1995.
SUMMARY
OF COMMITMENTS This letter contains two new commitments which are summarized as follows:
- 1.
When Code Case N-416-1 is used on Class 3 components and when NOE is to.*
be conducted per Subsection N0-5222, an additional surface examination shall be performed on the root (pass) layer.
- 2.
W~en Code Case N-416-1 is used for Code Class 3 repair or replacement activities involving socket/fillet welds, a surfa~e examination shall be performed on the subject socket/fillet welds.
Kurt M Haas Plant Safety and Licensing Director CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector - Palisades Attachment
ATTACHMENT Consumers Power Company Palisades Plant Docket 50-255 REQUEST FOR APPROVAL FOR USE OF CODE CASE N-416-1
- 3 Pages
Code Classes:
JUSTIFICATION FOR USE OF CODE CASE N-416-1 1, 2, and 3 1
Subject:
Alternate Testing for Class 1, Class 2, and Class 3 Welded Repaired/Replaced Components.
Component Numbers: All Class 1,*c1ass 2, and Class 3 pressure retaining components subject to Hydrostatic Testing per IWA-4000.
CODE REQUIREMENT The 1983 Edition, Summer 83 Addenda of ASME Section XI, IWA-4400(a) requires a*
hydrostatic test to be performed per IWA-5000 after welded repair/replacement of classed components, except those exempted by IWA-4400(b).
IWA-5214 requires a pressure test per IWB-5222, IWC-5222, or IWD-5223, as applicabie to the system which contains the repaired or replaced component.
IWB-5222, IWC-5222, and IWD-5223, System Hydrostatic Test, require a Test Pressure of 1.02 to 1.10 times P0 for*Code Class 1 components, 1.10 or 1.25 times Pav (or Pd or Pg) for Code Class 2 components, and 1.10 or 1.25 times Pav (or Pd or Pg) for Code Class 3 components, where P0 is the nominal operating pressure corresponding with 100% rated reactor power, Pav is the lowest pressure setting among the safety or relief valves provided for overpressure protection within the boundary of the system to be tested, Pd is the system design pressure, and Pg is design pressure of vapor or gas space above liquid level within an atmospheric storage tank for which overpressure protection is provided by relief valves.
BASIS FOR JUSTIFICATION Pursuant to 10 CFR 50.55a(a}(3)(i}i relief is requested on the basis that the proposed alternatives provide an acceptable lev~l of quality and safety.
Due to the additional preparation required to safely accomplish the required System Hydrostatic Tests (at pressures above normal operating levels) after welded repairs and replacements on Code Class 1, 2, and 3 components, these tests present unusual difficulties and often hardship situations for Palisades Nuclear Plant.
Some of the specific problems typically encountered when preparing for and performing these tests include:
Complicated or abnormal valve line-ups in order to properly vent, fill, and isolate the component requiring testing.
. ~
JUSTIFICATION FOR USE OF CODE CASE N-416-1 Relief -valves with setpoints lower than the hydrostatic test pressure must be gagged or removed and blind flanged.
This process requires the draining and refilling of the system both prior to the test and prior to system restoration.
2 Valves that are not normally used for isolation (e.g., normally open pump discharge valves) are often required to provide pressure isolation for an elevated pressure hydrostatic test. These valves frequently'require time consuming seat maintenance in order to obtain a leak tight pressure boundary.
The radiation exposure to plant personnel involved in hydrostatic tests is high in comparison to operational pressure testing due to the large amount of time required to prepare the volume for testing (i.e., installing relief valve gags, performing.
appropriate valve line-ups, completing valve maintenance, filling and venting, etc.).
The difficulties encountered in performing a hydrostatic pressure test are unreasonable when weighed against the benefits.
Industry experience, which is supported by Palisades' experience, shows that most through-wall leakage is detected during system operation as opposed to during elevated pressure tests such as ten-year or post-maintenance system hydrostatic tests.
No leakage detection benefit is gained from the added challenge to the piping system provided by an elevated pressure hydrostatic test as compared to a system operational test. The stresses experienced during a hydrostatic test do not include the significant stresses associated with the thermal growth and dynamic lo*ding seen during a system operational test. Thus, the system is more likely to experience any through-wall leakage at operating conditions due to the combination of dynamic/thermal loading and the normal operating pressure parameters than during the careful, slow pressurization of a hydrostatic test.
The ASME Board of Nuclear Codes and Standards has approved Code Case N-416-1, "Alternative Pressure Test Requirements for Welded Repairs or Installation of Replacement Items by Welding, Class 1, 2, and 3 Systems,Section XI, Division l", which incorporates the logic and Alternative Examinations contained within this justification.
It is Palisades' position that system pressure tests and NDE on Class 1, Class 2 and Class 3 systems and components in accordance with the requirements of Nuclear Code Case N-416-1, provides a level of quality and safety equivalent to, or greater than, that provided by the Code hydrostatic testing requirements.
JUSTIFICATION FOR USE OF CODE CASE N-416-1 3
PROPOSED ALTERNATE PROVISIONS After welded repairs or installation of replacement items by welding, the following alternative requirements will be met in lieu of performing the hydrostatic pressure test required per paragraph IWA-4000:
{a}
{b}
{c}
{d}
{e}
NOE shall be performed in accordance with the methods and acceptance criteria of the applicable Subsection of the 1992 Edition of Section III.
Prior to or immediately upon return to service, a visual examination {VT-2} shall be performed in conjunction with a system leakage test, using the 1992 Edition of Section XI, in accordance with paragraph IWA-5000, at nominal operating pressure and temperature.
Use of this Relief Request shall be documented on an NIS-2 Form.
When NOE is to be conducted per Subsection N0-5222 on a Code Class
- 3 component, an additional surface examination shall be performed on the root {pass} layer.
When Code Class 3 repair or replacement activities involve socket/fillet welds, a surface examination shall be performed on the subject socket/fillet welds.
The NOE requirements a,b.and care required when implementing Code Case N-416-1 as specified in the code case. It is our understanding that the additional NOE requirements spetified in d and e above will apply to Class 3 repair or replacement activities when the code case is endorsed by the*NRC.