ML20207L207
| ML20207L207 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/30/1986 |
| From: | Russell Gibbs TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20207K584 | List: |
| References | |
| 221.2-(B), 221.2-(B)-R01, 221.2-(B)-R1, NUDOCS 8701120009 | |
| Download: ML20207L207 (12) | |
Text
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. TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.;. (B)
SPECIAL PROGRAM
( REPORT TYPE: SEQUOYAH ELEMENT REVISION NUMBER: 1 TITLE: PIPE SUPPORT DESIGN Evaluation of Difference in Analyzed Design Loads for Pipe Supports PAGE 10F 11 REASON FOR REVISION:
- 1. To incorporate comments by SRP, TAS, and TVA, to include 7VA's corrective action plan information (see Section 10), and to comply with current format.
PREPARATION W:!1 PREPARED BY:
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SRP:0 L/ /2/?O/ff, SIGNATURE DATE
- SRP Secretary's signature denotes SRP concurrences are in files.
/ SIGNATURp / ' DATE APPROVED BY:
s - 6\ ', - h h .A , . p l U /il_c_ N/A 6.ECSP HANAGER DATE MANAGER OF NUCLEAR POWER DATE CONCURRENCE (FINAL REPORT ONLY)
TVA EMPLOYEE CONCERNS REPORT NUM8ER: 221.2 (B)
SPECIAL PROGRAM
,. REVISION NUMBER: 1 PAGE 2 0F 11
- 1. CHARACTERIZATION OF ISSUE (S):
Concern: Issues:
SQN-86-002-05 1 In certain piping configurations, ZPA "During the exit interview the CI loads may be greater than the low stated that Zero Period frequency seismic excitation loads.
- Acceleration (ZPA) has not been addressed at SQN. ZPA has been 2. Management does not want to discussed but management does not discuss the ZPA issue as it may want to bring up any new items delay the startup, to Power which might affect startup."
- 2. HAS ISSUE BEEN IDENTIFIED IN ANOTHER SYSTEMATIC ANALYSIS? YES X NO Identified by TVA/IMPELL/Bechtel Date 3/86.12/16/85, and 03/26/86
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Documentation Identifiers:
- a. Status summary of preliminary review of ZPA in Sequoyah Nuclear Plant, (03/86)
IMPELL
- b. " Preliminary ZPA Review" by Bill West, IMPELL, dated 12/16/85, TVA accession No. B25 851216 300. (12/16/85)
Bechtel
- c. Letter f rom R. Dunham, Bechtel, to R. O. Barnett, TVA, on
" Implementation of Zero Period Acceleration (ZPA) ef fects in Watts Bar's Piping Analysis," (03/26/86)
- 3. DOCUMENT NOS.. TAG NOS.. LOCATIONS. OR OTHER SPECIFIC DESCRIPTIVE IDENTIFICATIONS STATED IN ELEMENT:
None
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9 TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (B)
SPECIAL PROGRAM REVISION NUMBER: 1 l'
PAGE 3 0F 11
- 4. INTERVIEW FILES REVIEWED:
Review of interview files for concern #SQN-86-002-05 shows the following information:
o Generic applicability sheet o K-Form o Form A o Preliminary evaluation sheet
- 5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
See Appendix A.
- 6. WHAT REGULATIONS. LICENSING COMMITMENTS. DESIGN RE0VIREMENTS. OR OTHER APPLY OR CONTROL IN THIS AREA?
See Appendix A.
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- 7. LIST OF REQUESTS FOR INFORMATION. MEETINGS. TELEPHONE CALLS. AND OTHER DISCUSSIONS RELATED TO ELEMENT:
See Appendix A.
- 8. EVALUATION PROCESS:
- a. Reviewed FSAR of Sequoyah Nuclear Plant for specific l commitment to consider ZPA effects in piping analysis.
- b. Reviewed NRC regulatory guide for any requirements to l consider ZPA effects.
- d. Performed independent review including calculations as l required.
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TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (B)
SPECIAL PROGRAM REVISION NUMBER: 1
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- 9. DISCUSSION. FINDINGS. AND CONCLUSIONS Chronoloav:
1972: TVA conducts industry survey to investigate the application of ZPA 1975-76: TVA introduces ZPA rigid response load case capability into the T-PIPE computer code 11/21/85: Mr. R. O. Barnett of TVA directs SQN to investigate ZPA issue 12/85: Impell Corporation conducts preliminary review of ZPA at SQN 03/86: Bechtel, Gaithersburg, reviews the implementation of ZPA at WEN 04/86: TVA performs preliminary review of ZPA at SQN 06/06/86: TVA receives the employee concern Discussion:
Nuclear power plant piping systems that are important to safety must be designed to comply with applicable seismic requirements.
Dynamic analysis for a seismic event is gen 7 rally performed by response spectra method with modal super-position technique. In the modal analysis, the seismic response spectra curves (frequency vs acceleration) of the various structures in the plant are used as design input to generate the response of the piping systems installed within these structures.
, The usual approach is to perform the analysis within a range of frequencies (0 to 33Hz) where the dynamic amplification occurs.
This practice is based on the fact that the seismic excitation mainly contains low frequency waves, and no dynamic amplification is expected in the high frequency range. However, it has been noticed in some cases that the effects of high frequency (above 33 Hz) are significant enough to warrant consideration in the design.
The contribution of these high frequency modes is known as Zero Period Acceleration (ZPA) effects. In recent years, it has become common practice in nuclear plants to consider ZPA ef fects in the design of components.
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TVA EMPLOYEE CONCERNS REPORT NUM8ER: 221.2 (8)
SPECIAL PROGRAN s REVISION NUM8ER: 1 PAGE 5 0F 11 4
l The SQN FSAR Section 3.7.3.6.1 classifies all piping into two 4 4
categories: rigid and flexible. Rigid piping is that which has a natural f requency of. vibration greater than 33 Hz. The FSAR requires that evaluation of rigid piping be based on the maximum 11 acceleration corresponding to the appropriate building elevation.
l This includes the effect of ZPA.
i All piping with the natural frequency of vibration less than 33'Hz is classified as flexible. Some flexible piping systems contain
{ stiff portions which do not respond dynamically below 33 Hz in a
- particular direction. The rigid body response of such portions of i ' flexible piping system should be considered for ZPA effects. There are no specific commitments in the SQN FSAR to address this issue.
There are no regulatory requirements. (refer to NRC Regulatory Guide 1.60) that specifically address the ZPA effects in the piping i'
analysis. However, NRC's Standard Review Plan (SRP) Section 3.7.2 has rules that can be considered adequate to address this issue.
i TVA conducted an industry survey as early as 1972 to investigate
, o the application of ZPA. The survey indicated that the U" consideration of ZPA was not a common practice at.that time period. In the mid 1970's, TVA introduced ZPA rigid response load case capability into the T-PIPE computer code and used this ZPA l j effect in the analysis of rigid piping systems (above 33HZ). A second survey by TVA in 1982 indicated that ZPA was considered by l the industry only at the client's request or to resolve identified problems.
1 On November 21, 1985, Mr. R. O. Barnett of TVA directed SQN to
! investigate ZPA issue. In respense to this memo, a preliminary i evaluation of ZPA effects in SON piping systems was conducted in November and December 1985 by Impell Corporation, which found that ZPA effects on the piping system would not be significant enough to require any hardware modifications. However, Impell concluded that
- the evaluation was based on limited information and recommended a i thorough review.
l A second review was completed by Bechtel - Gaithersburg in March 86 to examine the implementation of ZPA effects in the piping analysis i of Watts Bar Nuclear Plant. Bechtel's report covered a wide range of areas including NRC's Regulatory Guide requirements and common i industry practice with respect to ZPA effects in piping analysis.
lhe report recommended that a parametric study for WBN be performed l l to verify the design margins to cover the ZPA effects.
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TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (B)
SPECIAL PROGRAM REVISION NUM8ER: 1
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PAGE 6 0F 11 A more detailed evaluation was also performed by TVA during March-April,1986, to verify the design adequacy of the components considering ZPA effects in seismically qualified piping systems in
. SQN. Nine problems potentially critical for ZPA loading were '
evaluated. The results of this preliminary evaluation revealed higher loads on some supports due to ZPA effects as compared to loads derived f rom the modal analysis (OBE). However, all support loads were found to satisfy the design limits.
The recommendation and findings of the above preliminary evaluations led the evaluation team to independently examine the ZPA effects on SQN piping systems. All rigorously analyzed isometric drawings were systematically reviewed to identify the areas of piping system potentially critical for ZPA loading. A list of problems was identified through this detailed screening for l further review. Based on judgment, five severe cases from the list were selected by the evaluation team for computation of ZPA loads, priraarily on the equipment nozzles and restraints. These ZPA loads were evaluated by comparing them with analyzed seismic (0BE) loads and allowable design limits.
b The results of the review are as follows:
- a. Loads due to ZPA effects for two out of five cases are higher than analyzed seismic (OBE) loads. However, for all cases the loads are well within the design limits.
- b. No hardware modification is required for any of the evaluated components.
All of the studies and reviews discussed above arrive at the same conclusion: the effect of ZPA on SQN piping system design is insignificant. The evaluation team concurs with the conclusion.
Findings:
- a. The concern that ZPA was not addressed at SQN is not valid based on the results of sample independent studies and reviews performed to evaluate the effect of ZPA on the piping systems.
- b. There is no evidence that TVA management did not want to l discuss the ZPA issue. On the contrary, they commissioned the studies and reviews discussed above,
- c. A final closure of this issue is required, b
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TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (B)
SPECIAL PROGRAM REVISION NUMBER: 1
(. PAGE 7 0F 11
Conclusions:
The Zero Period Acceleration will have insignificant effect on the existing piping design at SQN. However, it is the opinion of the evaluation team that preliminary reviews and studies listed in Section 2(a) and (b) are required to be completed to furnish adequate documentation to close the ZPA issue.
- 10. CORRECTI(E ACTION:
- In its corrective action plan (App. A, 5.r) TVA commits to finalize preliminary reviews and studies for ZPA. The evaluation team concurs with this corrective action which will furnish adequate documentation to close the issue of ZPA.
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TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (8)
SPECIAL PROGRAM
, REVISION NUMBER: 1 PAGE 8 0F 11 APPENDIX A
- 5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:
- a. TVA, Sequoyah Nuclear Plant, Dynamic Earthquake Analysis of l the Additional Equipment Buildings and Response Spectra for Attached Equipment, (11/04/74) 1
- b. TVA, Sequoyah Project Reactor Building, Dynamic Earthquake 1 Analysis of the Interior Concrete Structure and Response Spectra for Attachment Equipment, (01/28/70)
- c. TVA, Sequoyah Nuclear Plant, Dynamic Earthquake Ana'iysis of $
the Condensate Demineralizer Waste Evaporator Building, (12/20/77) ,
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- d. TVA, Sequoyah Nuclear Plant, Dynamic Earthquake Analysis of the Diesel Generator Building and Response Spectra for Attached Equipment, (04/09/73)
- e. TVA, Sequoyah Nuclear Plant, Dynamic Earthquake Analysis of
\ the Additional Diesel Generator Building and Response Spectra '
for Attached Equipment, (06/24/83) -
- f. TVA, Sequoyah Nuclear Plant, Dynamic Earthquake Analysis of the Auxiliary Control Building and Response Spectra for attached equipment.
- g. TVA, Sequoyah Nuclear Plant design isometric drawings of rigorously analyzed piping systems (copies controlled on 06/25/86):
47K400-50 through 47K406-137 47K427-50 through 47K450-59 47K450-60 through 47K464-59 47K464-60 through 47K465-50 47K465-31 through 47K555-62 47K555-63 -through 47Kil10-13
- i. Telecopy of pages 2 through 10, on the subject "Zero Period Acceleration Position Paper" by TVA, (06/24/86)
- j. Memo from K. L. Mogg, SQN, to Sequoyah Engineering Project Files on " Meeting Notes - Feb. 27, 1986 - SNP," Accession No.
B25 860505 001, (05/05/86) k k. U.S. NRC Standard Review Plan (SRP) Section 3.7.2, (07/81) l 1006d - 12/08/86
TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (B)
SPECIAL PROGRAM REVISION NUMBER: 1 PAGE 9 0F 11 APPENDIX A (cont'd)_
- l. NRC Regulatory Guide 1.60
- m. Memo from R. O. Barnett to C. N. Johnson, Accession No.
841 851121 028/24, (11/21/85)
PD-221.2SQN-01, (09/16/86)
- o. Sequoyah Nuclear Performance Plan - Draf t of Volume II, Rev.1, (07/14/86)
- p. Problem Identification Report No. PIRWBNCEB8553, (B41 851121 027) (11/21/85)
- q. Preliminary Position Paper on Zero Period Acceleration (ZPA),
l (8/7/86)
- r. TCAB 004, TVA Corrective Action Plan for Element 221.2 l ,
(11/07/86)
- 6. WHAT REGULATIONS. LICENSING COMMITMENTS. DESIGN REQUIREMENTS. OR OTHER APPLY OR CONTROL IN THIS AREA 7
- a. NRC Regulatory Guide 1.60, Section A
- b. 10CFR50, Appendix A, Criterion 2
- c. U.S. NRC Standard Review Plan (SRP) 3.7.2, Subsection II.1, Paragraph a, Guideline (5)
- 7. LIST OF REQUESTS FOR INFORMATION. MEETINGS. TELEPHONE CALLS. AND OTHER DISCUSSIONS RELATED TO ELEMENT:
- a. RFI #SQN-513, (08/27/86)
- b. RFI #SQN-568, (09/16/86)
- c. RFI #SQN-598 (09/29/86) k.
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TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (B)
SPECIAL PROGRAM ,
REVISION NUMBER: 1
(-
PAGE 10 0F 11 APPENDIX A (cont'd)
- d. Telephone call from W. Kagay, TVA, to D. Mohanty, Bechtel, (08/26/86)
- e. Telephone call from D. Mohanty, Bechtel, to J. Southers, TVA, (09/12/86)
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. TVA EMPLOYEE CONCERNS REPORT NUMBER: 221.2 (B)
SPECIAL PROGRAM REVISION NUMBER: 1 6
PAGE 110F 11 CATD LIST The following CATD identifies and provides corrective action for the findings included in this report:
221.02 SQN 01 (11/04/86) i,
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l REFERENCE - ECPS120J-ECPS121C TENNESSEE VALLEY AUTHORITY PAGE -
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-- FREQUENCY - REQUEST OFFICE OF NUCLEAR POWER RUN TIME - 12:57:19
) ONP - ISSS - RHM EMPLOYEE CONCERN PROGRAM SYSTEM (ECPS) RUN DATE - 12/02/86 LIST OF EMPLOYEE CONCERN INFORMATION CATEGORY: EN DES PROCESS & OUTPUT SUBCATEGORY: 22102 MAJOR DIFF IN ANALYZED LOADS FOR SIMILAR SUPPORTS I ) S GENERIC KEYNORD A H APPL QTC/NSRS P KEYNORD B CONCERN SUB R PLT BBSH INVESTIGATION S CONCERN KEYHORD C NUMBER CAT CAT D LOC FLQB REPORT R DESCRIPTION KEYHORD D
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SQN-86-002-005 EN 22102 N SQN NNYY SS DURING THE EXIT INTERVIEH THE CI STA REPORT TED THAT ZERO PERIOD ACCELERATION (Z PA) HAS NOT BEEN ADDRESSED AT SQN.
) ZPA HAS BEEN DISCUSSED BUT MANAGEMEN T DOES NOT HANT TO BRING UP ANY NEH ITEMS TO P0HER HHICH MIGHT AFFECT ST
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1 CONCERNS FOR CATEGORY EN SUBCATEGORY 22102 1
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