ML090970582
| ML090970582 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs, Indian Point, Saint Lucie, Vogtle, San Onofre  |
| Issue date: | 04/07/2009 |
| From: | Matthew Yoder NRC/NRR/DCI/CSGB |
| To: | Boyce T, Mark Kowal, Markley M, Melanie Wong Plant Licensing Branch 1 |
| Klein, Paul DCI/CSGB 415-4030 | |
| References | |
| TAC MC6659 | |
| Download: ML090970582 (8) | |
Text
April 7, 2009 MEMORANDUM TO:
Mark G. Kowal, Chief, Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Melanie C. Wong, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Thomas H. Boyce, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Michael T. Markley, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
Matthew G. Yoder, Acting Chief /RA/
Steam Generator Tube Integrity and Chemical Engineering Branch Division of Component Integrity Office of Nuclear Reactor Regulation
SUBJECT:
PHONE CALL
SUMMARY
WITH LICENSEES AND ALION SCIENCE AND TECHNOLOGY ON APRIL 2, 2009 TO ADDRESS NRC STAFF POSITION ON CHEMICAL EFFECTS REFINEMENTS (TAC NO. MC6659)
On April 2, 2009 the Nuclear Regulatory (NRC) staff participated in a phone call with representatives from Calvert Cliffs, Indian Point, Saint Lucie, San Onofre, Vogtle, the Nuclear Energy Institute, and Alion Science and Technology. The purpose of the call was to provide additional clarification of the NRC staff position on various refinements to chemical effect evaluations that have been proposed by Alion Science and Technology and are being considered by the licensees for the aforementioned plants. The enclosure provides a summary of the phone call.
CONTACT: Paul A. Klein, DCI/CSGB (301)-415-4030
M. Kowal, et al.
On April 2, 2009 the NRC staff participated in a phone call with representatives from Calvert Cliffs, Indian Point, Saint Lucie, San Onofre, Vogtle, the Nuclear Energy Institute, and Alion Science and Technology. The purpose of the call was to provide additional clarification of the NRC staff position on various refinements to chemical effect evaluations that have been proposed by Alion Science and Technology and are being considered by the licensees for the aforementioned plants. The enclosure provides a summary of the phone call.
Docket Nos.: 50-317,50-318, 50-247, 50-286, 50-361, 50-362, 50-335, 50-424, 50-425
Enclosure:
Phone Call Summary for April 2, 2009 Call To Discuss Chemical Effects Refinements
ML090970582 OFFICE NRR/DCI/CSGB NRR/DCI/CSGB NAME PKlein /RA/
MYoder /RA/
DATE 04/06/09 04/07/09 ENCLOSURE Phone Call Summary for April 2, 2009 Call To Discuss Chemical Effects Refinements On April 2, 2009, the Nuclear Regulatory Commission (NRC) staff participated in a phone call with representatives from Calvert Cliffs, Indian Point, Saint Lucie, San Onofre, Vogtle, the Nuclear Energy Institute, and Alion Science and Technology. The purpose of the call was to provide additional clarification of the NRC staff position on various refinements to chemical effect evaluations that have been proposed by Alion Science and Technology and are being considered by the licensees for the aforementioned plants.
After introductions, Mr. John Lubinski, Deputy Director for the Division of Component Integrity offered the following opening remarks:
This phone call continues the dialogue between licensees performing chemical effects and head loss testing at Alion Science and Technology and the NRC staff. This conference call follows the November 2008 public meeting, and subsequent phone conversations in December 2008 and January 2009.
During the public meeting in November 2008, Alion presented four options that could be used as refinements to the base chemical model described in topical report WCAP-16530-NP. These refinements were subsequently modified into options A, B, and C in the Alion test protocol document sent to the NRC staff for comment in December 2008. The staff provided initial verbal comments on these options during the January 2009 phone call.
During the January 2009 phone call, the staff indicated some refinements had a greater probability of regulatory acceptance compared to others. Concern about how some of these refinement options would be implemented and technically justified caused the staff to encourage any licensees considering certain options to initiate more thorough, plant-specific, communication with the NRC.
The purpose of the call today is to give more definitive feedback on some of the chemical refinement options previously discussed. The more direct feedback results from:
o The NRCs desire to achieve near-term resolution of GSI-191, o Ten weeks have passed since the last call and the NRC staff has not heard from any licensees, o The staff is concerned about significant delays in time and expenditure of resources occurring pursuing refinements that may ultimately not be accepted by the staff and, o The NRC staff has had the benefit of gaining additional information from chemical effects testing performed for other licensees. The staff has also had additional time to think about refinement options proposed by Alion in the context of all PWR licensee chemical effect evaluations and NRC staff reviews.
Following the opening remarks, NRC staff provided comments on various chemical refinements that are being considered by the licensees participating in the phone call. Table 1 provides a summary of the staff comments. For clarity, the refinement options are referred to using the Alion terminology from the November 2008 public meeting (ADAMS Accession No. ML083250233) and the subsequent draft test protocol sent to the NRC staff in December 2008.
Table 1. Staff Comments on Alion Chemical Effects Refinement Options Nov.
2008 Meeting Option Alion Dec.
2008 Letter Option Option Details NRC Staff Position (1)
Recognizes that aluminum corrosion is time dependent Acceptable to the staff per the conditions outlined in the conditions and limitations of SE to WCAP-16530. This applies a 2x multiplier to the initial aluminum corrosion rate.
(2)
A Credit for temperature dependent aluminum precipitate formation (Assumes full precipitate load is added but delayed precipitation timing permits a greater NPSH margin for the acceptance criteria)
Staff has accepted a similar approach, a sound technical basis is needed to justify the assumed temperature Key characteristics for staff review -
repeatable, consistent with other data in the literature, test duration should be longer than the length of time in the plant that this credit is applicable.
Staff suggested demonstration tests go beyond assumed credit conditions (e.g., test shows no precipitation to a lower temperature and for a longer time).
(3)
B Solubility credit, based on shorter term, high temperature vertical loop tests, grab samples used to determine and credit the percentage of aluminum that does not precipitate Staff previously indicated 12/1/08 and 1/22/08 phone calls this option had a high degree of regulatory uncertainty and requested licensees considering this approach contact the NRC with more detailed plans.
Staff does not see this refinement path as successful, see Note 1 below.
(4)
C-1a Phosphate Inhibition Credit See staff comments in Section 9 of the Chemical Effects Review Guidance. Licensee need to justify assumptions such as time for TSP dissolution, mixing, timing of aluminum passivation, etc. Staff recognizes that phosphate inhibition is a real phenomenon but suggests the assumptions contain margin.
See Note 2.
C-1b Silicate Inhibition Credit See staff comments in Section 9 of the Chemical Effects Review Guidance. Staff thinks it is hard to justify since amount of leachable silica very dependent on the pipe break location. Another factor that must be considered is that dissolved aluminum can significantly reduce leaching of silica from fiberglass. This is not present in single effect testing (WCAP-16530-NP) but was observed in ICET (NUREG/CR-6914). See Note 2 C-2a Solubility limit determination with VUEZ head loss data Staff expressed high degree of regulatory risk for this option on the 1/22/09 phone call Todays clarification - staff does not see this path as successful Staff does not see this refinement path as successful, See Note 1 C-2b Solubility limit determination without valid VUEZ head loss data Staff expressed high degree of regulatory risk for this option on the 1/22/09 phone call Staff does not see this refinement path as successful, See Note 1 Note (1) - staff is aware of tests where short-term tests would not have predicted precipitation but 30-day tests indicated some precipitation had occurred. Staff is also aware of a vertical loop head loss test at ANL where precipitation occurred more than 5 days after dissolved aluminum was added and the head loss had been stable and relatively low.
Staff is also relying on long term solubility conservatism to balance other uncertainties in the chemical effects area and to retain margin should other issues arise in the future. Staff also recognizes that it is difficult to extrapolate from short term bench tests to the long-term plant specific environment.
Note (2) - Staff did not perform a formal review of WCAP-16785-NP but had questions related to test coupon placement and re-use of test coupons.
During the technical discussion summarized in Table 1, the staff received several questions related to use of a longer-term test (e.g., 30 days) to establish a plant specific chemical precipitate load. The NRC staff stated that it would be willing to review a test protocol of such an approach in the near term. The staff suggested the following considerations for the development of any longer-term test investigating chemical precipitation:
a) Performed in a representative plant-specific environment b) Tests cant underestimate the amount of precipitation c) A conservative high pH is used to calculate the amount of aluminum d) A conservative low pH is used to minimize solubility during testing e) Licensees need to demonstrate to the NRC staffs satisfaction why the overall chemical effects evaluation is conservative given the uncertainties that exist.
The staff also reminded the phone call participants that development of a longer-term test to establish the plant specific chemical precipitate load carries a greater regulatory risk than following a test protocol already been accepted by the staff.
At the end of the technical discussion, the staff offered a couple general thoughts for licensees considering refinements to chemical effects evaluations:
The more refinements are used to evaluate (reduce) chemical precipitates for head loss testing, the harder it becomes to demonstrate to the NRC staff that the overall chemical effects evaluation remains conservative given uncertainties in this area. Licensees that require significant refinements to demonstrate success should consider alternate approaches including those that involve plant modifications.
As the complexity of the chemical refinement increases, so does the need for documentation to demonstrate why it is acceptable.
Following the technical discussion, the NRC staff expressed interest in having follow-on phone calls with each licensee to discuss their plant-specific chemical effects evaluation plans. The staff asked each licensee to provide an estimate for when they would be prepared for the next call. Table 2 provides approximate periods for a follow-on call.
Table 2. Tentative Schedule for Plant-Specific Phone Calls Plant Plant-Specific Phone Call With NRC Indian Point April 6-10, 2009 Calvert Cliffs late April to early May Vogtle late April to early May SONGS mid-April Saint Lucie mid-to-late April The phone call concluded after the discussion about plant-specific phone call dates.
Phone Call Participants NRC:
John Lubinski, Matthew Yoder Paul Klein Steve Smith John Lehning Robert Martin Siva Lingam Donnie Harrison SONGS Pete Wilkens Ed Kimoto Alan Brough Linda Conklin Vogtle Jimmy Cash Dave Midlick Calvert Cliffs Pat Furio Larry Smith Bill Wilson Steve Kinsey Saint Lucie Bruce Beisler Indian Point Steve Prussman Alion Science & Technology Robert Choromokos Peter Mast Jong-Hee Park Gilbert Zigler Jim Furman NEI John Butler