ML16343A543
| ML16343A543 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/02/1997 |
| From: | Steven Bloom NRC (Affiliation Not Assigned) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| References | |
| TAC-M95068, NUDOCS 9712090151 | |
| Download: ML16343A543 (18) | |
Text
December 2,
1997
Dear Mr. Rueger:
By letter dated March ll, 1996, Pacific Gas and Electric Company (PG&E) submitted the second ten-year interval inservice inspection (ISI) program plan and associated requests for relief for the Diablo Canyon Power Plant. Units 1
and 2.
By letter dated August 13, 1997. the licensee responded to a March 12,
- 1997, request for additional information (RAI).
The NRC, with assistance from its contractors Idaho National Engineering Laboratory, is reviewing and evaluating the second ten-year interval inservice inspection program plan and associated requests for relief from the ASME Boiler and Pressure Vessel
- Code,Section XI requirements for Diablo Canyon Power Plant, Units 1 and 2.
The additional information in the enclosure is required for the staff to complete its review.
To expedite the review process, please send a copy of the RAI response to the NRC's contractor, INEL. at the following address:
Michael T. Anderson INEL Research Center 2151 North Boulevard PO Box 1625 Idaho Falls, Idaho 83415-2209 We request that you respond within 60 days from receipt of this letter.
Sincerely, Original Signed By Steven D. Bloom, Project Manager Project Directorate IV-2
)ivision of Reactor Projects III/IV Office of
,<uclear Reactor Regulation 97i2090i5i 97i202 PDR ADOCK 05000275 PDR
~gPgf DISTRIBUTION:
Docket Fj]e I PDIV-2 Reading PUBLIC EAdensam (EGA1)
OGC WBateman
- HWong, RIV/WCFO Docket Nos.
50-275 and 50-323
Enclosure:
Request for Additional Information
- cc w/encl
See next page DOCUMENT NAME:
DC95068A.RAI SBloom EPeyton ACRS TMcLellan, ECGB MAnderson, INEEL
- PGwynn, RIV
'r. Gregory M. Rueger, Senior Vice President and General Manager Pacific Gas and Electric Company Nuclear Power Generation N9B P. 0.
Box 770000 San Francisco, California 94177
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING THE DIABLO CANYON POWER PLANT, UNITS 1 AND 2, SECOND 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN AND ASSOCIATED REQUESTS FOR RELIEF (TAC NOS.
M95068 AND M95069)
OFC PDIV-2/PM NAME SB e
DATE 12/ @97 PDIV-2/LA Epey on 12/
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Mr. Gregory H.
Rueger December 2, i997 cc w/encl:
NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach. California 93424 Dr. Richard Ferguson, Energy Chair Sierra Club California 1100 11th Street, Suite 311 Sacramento, Cali forni a 95814 Ms.
Nancy Culver San Luis Obispo Mothers for Peace P. 0.
Box 164 Pismo Beach. California 93448 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Hr. Truman Burns Mr. Robert Kinosian California Public Utilities Commission 505 Van Ness.
Room 4102 San Francisco, Cali fornia 94102 Mr. Steve Hsu Radiologic Health Branch State Department of-Health Services Post Office Box 942732 Sacramento.
California 94232 Diablo Canyon Independent Safety Committee ATM:
Robert R. Wellington. Esq.
Legal Counsel 857 Cass Street, Suite D
Monterey, California 93940 Regional Administrator. Region IV U.S. Nuclear Regulatory Commission Harris Tower
& Pavillion 611 Ryan Plaza Drive. Suite 400 Arlington, Texas 76011-8064 Christopher J. Marner, Esq.
Pacific Gas
& Electric Company Post Office Box 7442 San Francisco.
California 94120 Mr. Robert P.
Powers Vice President and Plant Manager Diablo Canyon Nuclear Power Plant P. 0.
Box 56 Avila Beach. California 93424 Telegram-Tribune ATTN:
Managing Editor 1321 Johnson Avenue P.OS Box 112 San Luis Obispo, California 93406
PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT DOCKET NOS.
50-275 AND 50-323 RE UEST FOR ADDITIONAL INFORMATION SECOND 10-YEAR INTERVAL INSERVICE INSPECTION ISI PROGRAM PLAN 1.
Sco e/Status of Review Throughout the service life of a water-cooled nuclear power facility.
10 CFR 50.55a(g)(4) requires that components (including supports) that are classified as American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Class
- 1. Class 2,
and Class 3 meet the requirements.
except design and access provisions and preservice examination requirements, set forth in the ASME Code Section XI, "Rules f'r Inservice Inspection of Nuclear Power Plant Components", to the extent practical within the limitations of design,
- geometry, and materials of construction of the components.
This section of the regulations also requires that inservice examinations of components and system pressure.
tests conducted during a 120-month inspection interval comply with the requirements in the latest edition and addenda of the Code incorporated by reference'in 10 CFR 50.55a(b) on the date 12 months prior to the start of the 120-month interval. subject to the limitations and modifications listed therein.
The components (including supports) may meet requirements set forth in subsequent editions and addenda of the Code that are incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein and subject to Nuclear Regulatory Commission (NRC) approval.
By letter dated August 13.
1997, the licensee responded to a March 12.
- 1997, request f'r additional information (RAI).
The available information provided by the licensee has been reviewed by the NRC staff.
Additional Information Re uired Based on the above review, the staff has concluded that the following information and/or clariA'cation is required to complete the review of the ISI Program Plan:
a.
In the March 12.
- 1997, RAI the licensee was asked to provide a list of all the Code Cases the licensee intends to implement during the second 10-year ISI interval.
In the August 13,
- 1997, response the licensee stated that the second 10-year ISI program includes the use of all Code Cases approved by Regulatory Guide 1. 147, Inservice Inspection Code Case Acceptability -- ASME Section XI, Division l.
A list of the Code Cases used to develop the Program is needed to
perform a thorough evaluation of the Program, and generically stating that all approved Code Cases will be used is not acceptable.
Therefore.
provide a list of those Code Cases used to develop the ISI Program.
b.
In accordance with 10 CFR 50.55a(c)(3).
and 10 CFR 50.55a(e)(2),
ASME Code Cases may be used as alternatives to Code requirements.
Code Cases that the NRC has approved for use are listed in Regulatory Guide 1. 147, Inservice Inspection Code Case Acceptability, with any additional conditions deemed necessary by the NRC.
Code cases not referenced in Regulatory Guide 1. 147 may be adopted only if authorized by the NRC on a case-by-case basis.
In some cases, unapproved Code cases may be acceptable for use when certain conditions are included.
To ensure consistent implementation, licensees proposing the use of currently unapproved Code case(s),
must commit to such conditions. if applicable.
In the March 12, 1997.
RAI the licensee was asked to provide a list of all the Code Cases.
However, the response contained in the August 13.
1997. submittal did not clearly address the licensee's intentions regarding the use ot unapproved Code Cases, and in some
- cases, specified conditions were not committed to.
For example, in the August 13, 1997, submittal, the licensee referenced a number of unapproved Code Cases by name or in torm, but has not requested authorization to use them.
To use these or any other unapproved Code Cases during the second 10-year interval, the licensee must submit a
proposed alternative in accordance with 10 CFR 50.55a(a)(3)(i) or (ii) for review by the NRC staff.
These proposed alternatives must be submitted f'r the new interval with commitments to conditions, as applicable.
Address each Code Case listed below and provide the requested information, and a specific request for relief, if applicable.
Re uests f'r Relief PRS-2 and PRS-4 Rl - The licensee has not acknowledged the conditions for acceptability of Code Case N-522.
Specifically. that the leak test is performed at the peak calculated containment pressure and use of a test procedure that provides for detection and location of through-wall leakage.
In addition, the licensee has not specifically asked to use the Code Case as an alternative; confirm that Code Case N-522 will be used in its entirety with the conditions above.
Re uest for Relief PRS-1C
- The licensee proposed an alternative similar to Code Case N-533 for bolted connections in Class 1 and 2
borated systems.
However, the proposed alternative is not acceptable as written.
To find the alternative acceptable.
the licensee must (1) commit to use the Code Case in its entirety without considering bolting materials, (2) commit to removing the insulation from both Class 1 and Class 2 systems each refueling outage, and (3) remove any references to "corrective measures" for bolted connections.
~
~
(Note:
See guestion
- n. of this RAI for further detail.)
For Code Case N-416-1, Alternative Pressure Test Requirement for klelded Repairs or Installation of Replacement Items by klelding, Class 1, 2, and 3, the NRC staff finds this alternative to Code requirements acceptable only if the licensee commits to performing a
surface examination of the root pass weld layer for welded repairs and replacements in Class 3 systems, if surface examination is required by ASHE Section III for final acceptance.
Code Case N-498 No additional commitments required.
If the use of Code Case N-498-1 is planned for the second 10-year interval, the licensee must submit a request for authorization to use this Code Case.
Code Case N-524 - In the August 13.
- 1997, response, the licensee stated that "All longitudinal welds that inter sect scheduled circumferential welds are examined by being included in the examination volume specified in the NDE procedure'or the circumferential welds:" which implies the use of Code Case N-524.
If the use of Code Case N-524 is planned for the second 10-year interval, the licensee must submit a request for authorization to use this Code Case.
In Enclosure 16 of the August 13, 1997. submittal, Sumary of Examination Items, a note states:,
"Inspection period depends on maintenance schedule for item in question".
The scheduling of examination items based on convenience is not acceptable.
If examinations cannot be scheduled in accordance with IWB-2412
( Inspection Program B) and IWB-2420 (Successive Inspections).
a specific request for relief is required.
Such relief will be evaluated on a case-by-case basis.
Provide a clarification regarding this note or delete it from the Program.
d.
In the August 13.
1997.
RAI response.
the licensee stated that the redistribution of Class 2 welds for examination of thin-walled piping
'in the residual heat removal (RHR). emergency core cooling (ECC),
and containment heat removal (CHR) systems will be incorporated in the next revision of the ISI Program scheduled for issue following the Unit 2, 8th refueling outage.
The NRC staff believes it is technically prudent to examine a portion of the welds in these systems.
However, the distribution of welds and the percentage of surface and volumetric examinations for Class 2 systems cannot be evaluated without a more specific commitment.
Specifically, confirm that a 7.5 percent sample of surface and volumetric examinations will be performed on these systems.
e.
Augmented examinations are established by the NRC when added assurance of structural integrity is deemed necessary.
These augmented examinations are typically incorporated into ISI Programs to meet licensing commitments.
If'hanges to those commitments are
- made, then the licensee must submit information to the NRC requesting deviation from those commitments.
Regarding Branch Technical
4 Position NEB 3-1. the licensee states that "an apportionment of'elds in high energy Class 2 systems outside containment conforms as much as possible with the intent of Branch Technical Position NEB 3-1."
It appears that the "apportionment of welds" discussed by the licensee are those welds required by Section XI.
Therefore, the licensee has not committed to perform augmented volumetric examinations in accordance with MEB 3-1.
Have rupture locations in piping systems been postulated?
Are there previous commitments that".
have been made regarding this document?
Provide a clarification regarding the implementation of Branch Technical Position HEB 3-1.
f.
In the August 13, 1997, submittal. the licensee stated that OCPP Units 1 and 2 were in their first inspection interval on September 8,
1992.
and that all reactor pressure vessel welds were examined meeting the requirements of 10 CFR 50.55a(g)(6)(ii.).
- However, baSed on the relief requests contained in the Program, there are RPV shell welds that cannot be examined to the extent required by the Regulations (at least 90 percent).
For welds that cannot be examined to the extent required by the regulations.
an alternative that provides an acceptable level of quality and safety must be proposed.
In addition, the licensee must demonstrate that coverage has been maximized by examinations from both the internal and external surfaces.
Provide the status regarding the augmented volumetric examination f'r both Units 1 and 2.
and provide a list of the coverage achieved for each RPV shell weld (Items Bl.ll and B1.12).
If the volumetric examination cannot be performed to the extent required by the regulations, submit a proposed alternative in accordance with 10 CFR 50.55a(g)(6)(ii).
Note that second interval requests for relief for RPV shell welds (Item Bl. 10), cannot be evaluated until the regulations regarding the one-time augmented RPV examination are satisfied.
g.
Request for Relief NOE-26 proposes an alternative volumetric examination for the pressurizer support skirt weld in lieu of the surface examination.
The Code requires 100K volumetric or surface examination, as applicable, for the pressurizer support skirt weld as defined by Figures IWB-2500-13,
-14.
and -15.
Examinations are required for both the outside (A-B) and inside (C-D) surfaces-of the weld.
Since the inside surface is not accessible for surface examination, the licensee proposed to perform a volumetric examination of'he support skirt weld.
However. it is not clear if the proposed volumetric examination is intended to supplement the surface examination or if it will be performed in lieu of the surface examination.
The confi'guration described does not appear conducive to ultrasonic examination of the external surface.
Therefore' surface examination should be performed on area A-B.
Confirm that the volumetric examination of the inside surface of the weld will be performed in addition to the Code-required surface examination of A-B.
h.
Requests for Relief NDE-17. Rl and NDE-18 are for limited examinations of Class 2.vessel and nozzle welds in the steam generator, residual heat removal heat exchanger (RHRHX) and the seal injection filters.
Identify the specific welds for which relief is
A
requested and provide sketches of the RHRHX and the seal injection filter and the associated limitations. It appears that the seal injection filter weld(s) are accessible.
but that the welds are in a
What is the estimated radiation exposure to personnel required to perform the examination?
The licensee stated that the penetrant examination will take at least 45 minutes.
Can the, examination time and the resulting radiation exposure be reduced by performance of a magnetic particle examination?
Generally, radiation.
~
exposure does not constitute an impracticality but a burden.
Review
'his request and the regulations and provide the appropriate paragraph of the regulations that apply to this situation.
For Request for Relief NOE-29, the licensee proposed to perform the examination of Class 2 piping welds in Unit 2 on a single stream.
Using a single stream approach.
terminal ends and high stress welds in the other streams will not be examined.
Provide a technical discussion describing how this alternative provides an acceptable level of quality and safety when terminal ends and high stress welds will not be examined.
Request for Relief NOE-28 proposes an alternative pursuant to 10 CFR 50.55a(a)(3)(ii) to the Code-required visual examination of the seal injection filter component supports.
However
. the stated alternative for this request was "none".
Describe how reasonable assurance of the integrity of the support will be provided.
In addition. discuss why the Code requirements cannot be met by performance of a remote visual examination.
k.
Request for Relief PRS-5 seeks relief from the pressure testing requirements for the containment spray header.
The paragraph cited by the licensee (IWC-5222(d)). states that "For open ended portions of discharge lines beyond the last shutoff valve in nonclosed systems (e.g.,
demonstration of an open flow path shall be performed in lieu of the system hydrostatic test".
This aragraph indicates an open flow path test in lieu of the system ydrostatic test.
which in accordance with Examination Category C-H.
is only required once during the inspection interval.
It is not clear what Code requirement the licensee is proposing an alternative to.
Provide a clarification regarding this request.
l.
Request for Relief NDE-24 proposes an alternative to Paragraphs IWB-
- 2420, IWC-2420, and IWF-2420 which require that the sequence of component examinations.established during the first inspection interval be repeated during each successive inspection interval, to the extent practical.
The licensee stated:
"Reasonable effort shall be made to repeat the sequence of examinations established in the first inspection interval.
Exceptions shall be permitted for differences in schedule requirements between the 1977 Edition with Summer 1978 Addenda and the,1989 Edition.
Exceptions shall also be permitted when plant conditions or maintenance requirements limit availability of the subject component during a given outage,
- however, another similar
(~
C component shall be substituted for the original component whenever practical.
or the original component shall be examined during the next refueling outage".
This request is generic in nature and cannot be authorized as such.
As proposed by the licensee, the scheduling of many components would not be required and could be examined as convenient.
Other plants have submitted similar proposals but have provided specific information regarding the components and the change in schedule.
For this request to be found acceptable, provide the specific changes that are proposed.
m.
In the August 13, 1997.
RAI response, the licensee stated that PRS-l, Rl has been previously revised and submitted as PRS-lA and PRS-1B.
Confirm that PRS-1.
Rl has been withdrawn.
Also, PRS-lA and 1B have not been provided for evaluation.
If not evaluated elsewhere.
they should be submitted for evaluation with the program.
Request for Relief PRS-1C proposes an alternative to the requirements of IWA-5242(a), which requires the removal of insulation f'r VT-2 visual examination of pressure-retaining bolted connections in borated systems.
This alternative is not acceptable as written.
First, the Code does not differentiate based on bolting materials.
Therefore. this alternative should apply to all bolted connections.
not just carbon steel bolted connections.
Second, to use Code Case N-533 for Class 2 systems, the licensee must commit to the same frequency of'nsulation removal as for Class 1 systems'pecifically, each refueling outage.
Finally. within this proposed alternative, the licensee is also proposing an alternative to the requirements of IWA-5250(a)(2) which requires the removal of bolting from leaking bolted connections to perform VT-3 visual examinations.
This is an additional requirement that must be submitted separately as an alternative to the requirements of IWA-5250(a)(2).
Other plants have proposed acceptable alternatives that include a systematic engineering evaluation of bolted connections.
To obtain authorization for Request for Relief PRS-1C. the licensee must (1) commit to use the Code Case in its entirety without considering bolting materials, (2) commit to removing the insulation from Class 2
systems each refueling outage.
and (3) remove any references to corrective measures for bolted connections.
o.
Request for Relief CNT-1. appears to be proposing an alternative to the VT-1 and VT-3 examination rules in subsection IWA, including examiner qualification details, of the 1989 Edition. applicable to the examination of the containment structure, including the concrete shell and metal liner. It is not clear where this request fits into the ISI Program and what specific requirement the licensee is requesting relief from.
Furthermore, it appears that this request is administrative in nature.
Provide clarification regarding this request.
especially.
the specific requirement the licensee is requesting relief from.
4 (I
~'
p.
Request f'r Relief DOC-1 proposed an alternative to the Code recording and reporting requirements.
In the March 12,
- 1997, RAI, the NRC staff pointed out that the use of Code Case N-532, Alternative Requirements to Repair and Replacement Documentation Requirements and Inservice Sunmary Report Preparation and Submission as Required by IMA-4000 and Ih/A-6000, which has been approved by the ASME Code Committee, has been found acceptable for use at other plants.
Completely eliminating reporting is not an acceptable alternative.
Therefore, this request should be revised to incorporate the use of Code Case N-532 as the proposed alternative or withdraw the request from the Program.
P