ML20004C172
| ML20004C172 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/26/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Mcgaughy J MISSISSIPPI POWER & LIGHT CO. |
| References | |
| NUDOCS 8106010675 | |
| Download: ML20004C172 (17) | |
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DISTRIBUTION i
Dockets L. Rubensh NRC PDR W. 6wfler Doctet Nos. 50-416 MAY 26 1981 Local POR 7, g,., m and 50-417 TERA j
NSIC j
LB#2 Reading RLTedes co Mr. J. P. McGaughy, Jr.
ASchwencer Assistant Vice President JMartore
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Nuclear Production MService l
Mississippi Power & Light Company 0 ELD Post Office Box 1640 0I&E 3) l Jackson, Mississippi 39205 ACRS 16)
Dear Mr. McGauWiy:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - GRAND GULF NUCLEAR STATION, UNIT NOS.1 & 2 As a result of our review of the infomation contained in the Final Safety Analysis Report for the Grand Gulf Nuclear Station. Unit Nos.1 and 2, we have developed the enclosed request for additional infomation. Included are questions from the Containment Systess Branch.
4 l
We request that you amend your Final Safety Analysis Report to reflect your responses to the enclosed requests as soon as possible and to infom the Pro, ject Manager, Joseph A. Martore, of the date by which you intend to respond.
Sincerely, Cr44ftal *naf br mbat L, T.u.co Robert L. Tedesco, Assistant Director for Licensing l
Division of Licensing i
Enclosure:
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4 l'r. J. P. McGaugby Assistant Vice President - Nuclear Production l'ississippi Power & Light Company P. O. Sox 1640 Jackson, "ississinoi 39205 cc:
Rooert E. I*cGenee, Esq.
Wise, Carter, Child, Steen & Caraway P. O. Box 651 Jackson, }4ississippi 39205 Troy B. Conner, Jr., Esq.
Conner, Moore & Corber 1747 Pennsylvania Avenue, N. W.
Washington, D. C.
20006
!*r. Adrian Zaccaria, 9roject E.igineer Grand Gulf Nuclear Station Bechtel Power Co'rporation Gaithersburg, Maryland 20760 Mr. Alan G. Wagner, Resident Inspector Route 2 Box 150 Port Gibson, Mississippi 39150 Mr. N. L. Stampley, Sr. Vice President Engineering, Production & Construction P.O. Box 1640 Jackson, Mississippi 39205 Mr. L. F. Dale Nuclear Project Manager P.O. Box 1640 Jackson, Mississippi 39205 Mr. John Richardson P. O. Box 1640 J ackson,111 ssissippi 39205 4
ENCLOSURE Containment Systems Branch Request for Additional Information Grand Gulf Nuclear Station, Units 1 and 2 Docket Numbers 50-416/417
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l 021.39 The design of the containment purge and ventilation system consists of both 20-inch and 6-inch lines.
From the discussion in Section 9.4.7.2.2, it is not clear what siz? lines are going to be used to continuously purge the containment. Provide this information.
Also, state your intention to comply with Section B.I.b of BTP CSB,6-4 which provides that on-line purge systems should be limited to one purge line and one vent line.
021,40 Ir response to item 021.02, an analysis for the containment purge and ventilation system was provided that assumed the contain-ment atmosphere was released through two 20-inch lines. However, in aidition to the containment purge system, there is a drywell purge system which.is used during hot shutdown. State whether or not the drywell pirge system was assumed to be operating for the analysis provided in reponse to item 021.02.
Provide a discus-sion of why the assumption is contervative.
21.41 In Section 9.4.7.2.2 of the FSAR, it states that closure of the iso-lation valves in the purge and ventilation system will not be affected by debris which might be generated following a LOCA. The reasons given for this are the high elevation of the isolation valves and the inter-vening concrete floor and steel grating which would shield the valves from turbulence. Since these are qualitative reasons, it is our po-sition that Section B.I.g of Branch Technical Position (BTP) CSB 6-4 should be met. Guidance is provided below which, if followed, would represent an acceptable debris screen design.
2-a.
Tha debris screen should be seismic Category I and installed typi-cally about one pipe diameter away from the inner side of the in-board isolation valve.
b.
The piping between the debris screen and the valve should also be seismic Category I design.
c.
The debris screen should be designed to withstand the LOCA differ-ential pressure.
d.
The debris screen opening typically should be about 2 inches by 1 3/16 inch.
21.42 Section 9.4.7.2.2 of the FSAR states that a small amount of the contain-l ment atmosphere is continuously exhausted during normal operation. How-ever, we believe that purgi'ng/ venting should be minimized during reactor operation because the plant is inherently safer with closed purge valves than with open lints requiring valve action to provide containment iso-f l
1ation.
In fact, serious consideration should be given to a plant de-sign such that purging / venting is not required during operation. There-fore, provide a detailed discussion of the reasons why the Grand Gulf l
Station needs to purge, and an estimate of the number of hours per yeav-that purging ir expected through each particular valve.
1 21.43 In Table 6.2.44, the primary and secondary mode of actuation for the con-tainment isolation valves are given. The information provided does not l
state whether or not power-operated isolation valves are automatically op-j erated upon receipt of a containment isolation signal as the primary mode l
of actuation or if these valves can be remote manually operated from the l
main control room as the secondary mode. Provide this infor=ation.
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3-21.44 Figures 6.2.76 through 6.2.80 show the arrangement of the various iso' lation valves listed in Table 6.2.44.
Many of the lines penetrating the containment have test lines between the isolation valves.
(See, for example, penetration No. 43).
Provide justification why these test lines should not be treated as branch lines and included in the containment isolation valve tables and tested in accordance with Ap-pendix J.
21.45 Table 6.2.49 lists the system which penetrates the containment and are not v'nted and drained for the Type A containment leak r.ste test.
e Those systems associated with note 6 do not 'have to be vented and drained for the Type A test provided they meet the following require-1 ments:
1 1)
The system is protected against missiles and pipe whip.
2)
The system is designated seismic Category I.
3)
The system is classified Safety Class 2.
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4)
The system pressure is greater than the containment pressure at all times during the course of the accident.
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- 5) The system will remain full of water for 30 days..
6)
Both items 4 and 5 will be maintained when a single active failure is assumed in the system.
l State whether or not these systems meet the above requirements.,
l 21.46 Note 16 of Table 6.2.49 is not an acceptable reason for not venting
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and draining a system for the Type A containment leak rate test.
It is our position that all isolation valves should be subjected to 6
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4-Type C testing. Therefore, vent and drain should be provided for the Type A containment leak rate test for these systems or provide accept-able justification for not doing so.
21.47 Systems that are associated with containment penetration numbers 11, 12,13, 23, 24, 25, 27, 28, 29, 30, 32, 46 and 67 have lines that are sealed from the containment atmosphere because their lines terminate below the water level of the suppression pool. Therefore, these sys-tems are not vented and drained for the Type A containment leak Nate test.
However, to be considered a sealed system, the piping between the suppression pool and isolation valves should meet the following requirements:
1)
The piping is protected against missile and pipe whip.
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2)
The piping is designated seismic Category I.
3)
The piping is classified Safety Class 2.
State whether or not the piping between the suppression pool and isolation valves meet the above requirements for the penetration mentioned above.
Also, specify the -fluid that is used to pres-surize the valves to perform the Type C test.
t 21,48 The systems for containment penetration numbers 9, 10, 11, 12, 13,-
17, and 22 have branch lines that do not have any isolation valves.
It is our position that these branch lines meet the applicable gen-eral design criteria for isolations and should be tested in accord-ance with Appendix J.
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- 21. 49 Isolation valves E12F308 for Penetration 14, E51F077-A for.Penetra-tion 75, and G33F252 for Penetration 87 listed f a Table 6.2.44 are not shown in Figures 6.2.77 or 6.2.79.
Correct this discrepancy.
I 2 1.50 The system for containment penetration numbers 18, 23, 24, 29, 46, l
48, 67 and 77 have simple check valves located outside--containment -- -
l for containment isolation valves.
Provide justification.for locating l
a simple check valve outside containment as an isolation valve.
Figures 6.2.76 through 6.2.80 show the isolation valves and the' test 2 1.51 connections. However, from the figures it is not clear what test connection is going to be used to test which valve. Provide this information. For any valve that is being tested for leakage in which the pressure is applied in the opposite direction as that when the valve would be required to perform its safety function, provide justification that the results from the tests for the pres-sure applied in a different direction will provide equivalent or more conservative results.
i 21.52 In Table 6.2.44 there are numerous isolation valves' listed in which.
no Type C test will be performed.
It is our position that a Type C l
test should be performed on all isolation valves. Yalves should be pressurized with air or nitrogen unless valves are in a sealed sys-Then valves should be pressurized with the fluid that forms the tem.
seal in t*,e scaled system.
State your intention to comply with this position.
4
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l 021. 53 The response to item 021.17 concerning the determination of bypass leakage paths in dual containments is inadequate. The guidelines of BTP CSB 6-3 were not used in considering potential bypass leakage paths around the leakage collecton and filtration system of the secondary containment. For example, the fact that lines penetrating the primary and secondary containment has isolation valves does not preclude through-line leakage. Therefore, identify all potential bypass leakage paths usi.ng the guidelines of Item 5 of BTP CSB 6-3.
Also, provide a realistic leakage rate for these potential bypass leakage paths and a discussion (including drawing) of provisions made to permit pre-opera-tional and periodic leakage rate testing in a manner similar to the Type B or C tests of Appendix J to 10 CFR Part 50 for each bypass leak-age path.
21.54' The response to. item 021.20 only discussed the initial test program that will be carried out to verify the de' pressurization of the secondary containment to a negative pressure of 1/4 inch. Provide the acceptance criteria for the draw down time.
It is our position that n periodic l
test program also be established to determine the operability of the system.
Also, provide a description of the preoperational and periodic test program that will determine the secondary containment infiltration I
rate, including the acceptance criteria.
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May 26,1981 2
fir. J. P. McGaugny Assir. tar.t Vice President - Nuclear Production fiississippi Power & Light Company P. O. Box 1640 Jackson, "ississippi 39205 cc:
Rooert B. licGenee, Esq.
Wise, Carter, Child, Steen & Caraway P. O. Box 651 Jackson, }4ississippi 39205 Troy B. Conner, Jr., Esq.
Conner, Moore & Corber 1747 Pennsylvania Avenue, N. W.
Washington, D. C.
20006
!;r. Adrian Zaccaria, Project Engineer Grand Gulf Nuclear Station Bechtel Power Corporation Gaithersburg, Maryland 20760 f4r. Alan G. Wagner, Resident Inspector Route 2 Box 150 Port Gibson, Mississippi 39150 Mr. N. L. Stampley, Sr. Vice President Engineering, Production & Construction P.O. Box 1640 Jackson, Mississippi 39205 i
Mr. L. F. Dale fluclear Project f'anager P.O. Box 1640 Jackson, Mississippi 39205 Mr. John Richardson P. O. Box 1640 Jackson, iiississippi 39205 4
ESCLOSURE Containment Systems Branch Request for Additional Information Grand Gulf Nuclear Station, Units 1 and 2 Docket Numbers 50-416/417 021.39 The design of the containment purge and ventilation system consists of both 20-inch and 6-inch lines.
From the discussion in Section 9.4.7.2.2, it is not clear what size lines are going to be used to continuously purge the containment. Provide this information.
Also, state your intention to comply with Section B.1.b of BTP CSB,6-4 which provides that on-line purge systems should be-limited to one purge line and one vent line.
021.40 In response to item 021.02, an analysis for the containment purge and ventilation system was provided that assumed the contain-ment atmosphere was released through two 20-inch lines. However, in addition to the containment purge system, there is a drywell purge system which is used during hot shutdown. State whether or not the drywell purge system was assumed to be operating for the analysis provided in reponse to item 021.02. Provide a discus-sion of why the assumption is conservative.
I 21.41 In Section 9.4.7.2.2 of the FSAR, it states that closure of the iso-lation valves in the purge and ventilation system will not be affected by debris which might be generated following a LOCA. The reasons given for this are the high elevation of the isolation valves and the inter-vening concrete floor and steel grating which would shield the valves from turbulence.
Since these are qualitative reasons, it is our po-sition that Section B.1.g of Branch Technical Position (BTP) CSS 6-4 should be met.
Guidance is provided below which, if followed, would represent an acceptable debris screen design.
. ~.. -
2-a.
The debris screen should be seismic Category I and installed typi-cally about one pipe diameter away from the inner side of the in-board isolation valve.
b.
The piping between the debris screen and the valve shou'd also be seismic Category I design.
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c.
The debris screen should be designed to withstand the LOCA differ-l l
ential pressure.
d.
The debris screen opening typically should be about 2 inches by 1 3/16 inch.
21.42 Section 9.4.7.2.2 of the FSAR states that a small amount of the contain-ment atmosphere is continuously exhausted during normal operation. How-ever, we believe that purgi'ng/ venting should be minimized during reactor operation because the. plant is inherently safer with closed purge valves than with open lines requiring valve action to provide containment iso-l ation.
In fact, serious consideration should be given to a plant de-sign such that purging / venting is not required during operation. There-fore, provide a detailed discussion of the reasons why the Grand Gulf Station needs to purge, and an estimate of the number of hours per year that purging is expected through each particular valve.
21.43 In Table 6.2.44, the primary and secondary mode of actuation for the con-tainment isolation valves are given. The information provided does not state whether or not power-operated isolation valves are automatically op-erated upon receipt of a containment isolation signal as the primary mode of actuation or if these valves can be remote manually operated frem the main control room as the secondary mode. Provide this inform? tion.
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. t 21.44
- Figures 6.2.76 through 6.2.80 show the arrangement of the various iso-1ation valves listed in Table 6.2.44.
Many of the lines penetrating
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the containment have test lines between the isolation valves.
(See, for example, penetration No. 43). erovide justification why these test lines should not be treated as branch lines and included in the l
containment isolation valve tables and tested in accordance with Ap-t l
pendix J.
I 21.45 Table 6.2.49 lists the system which penetrates the containment and j
arenotvientedanddrainedfortheTypeAcontainmentleakratetest.
Those systems associated with note 6 do not ~have to be vented and j
drained for the Type A test provf ded they meet the following require-j ments:
j 1)
The system is protected against missiles and pipe whip.
f 2)
The system is designated seismic Category I.
3)
The system is classified Safety Class 2.
l 4)
The system pressure is greater than the containment pressure at f
~
i all times during the course of the accident.
- 5) The system will remain full of water for 30 days..
6)
Both items 4 and 5 will be maintained when a single active failure is assumed in the system.
1 State whether or not these systems meet the above requirements.
l l
21.46 Note 16 of Table 6.2.49 is not an acceptable reason for not venting and draining a system for the Type A containment leak rate test.
It is our position that all isolation valves should be subjected to l
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4-Type C testing. Therefore, vent and drain should be provided for the Type A containment leak rate test for these systems or provide accept-able justification for not doing so.
21.47 Systems that are associated with containment penetration numbers 11, 12,13, 23, 24, 25, 27, 28, 29, 30, 32, 46 and 67 have lines that are l
sealed from the containment atmosphere because their lines terminate below the water level of the suppression pool. Therefore, these sys-
~
tems are not vented and drained for the Type A containment leak fate test. However, to be considered a sealed system, the piping between the suppression pool and isolation valves should meet the following requirements:
I 1)
The piping is protected against missile and pipe whip.
~
- 2) The piping is designated seismic Category I.
- 3) The piping is classified Safety Class 2.
State whether or not the piping between the suppression pool and isolation valves meet the above requirements for the penetration mentioned above.
Also, specify the fluid that is used to pres-surize the valves to perform the Type C test.
l 21,48 The systems for containment penetration numbers 9, 10, 11, 12, 13,-
l 17, and 22 have branch lines that do not have any isolation valves.
It is our position that these branch lines meet the applicable gen-eral design criteria for isolations and should be tested in accord-I ance with Appendix J.
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- 21. 49 Isolation valves E12F308 for. Penetration 14,. E51E077-A for_ P.enetra-tion 75, and G33F252 for Penetration 87 listed in Table 6.2.44 are not shown in Figures 6.2.77 or 6.2.79.
Correct this discrepancy.
2 1.50 The system for containment penetration numbers 18, 23, 24, 29, 46, 48, 67 and 77 ~have simple check valves located outside containment-for containment isolation valves. Provide justification for locating a simple check valve outside containment as an isolation valve.
l 21.51 Figures 6.2.76 through 6.2.80 show the isolation valves and the' test i
connections. However, from the figures it is not clear what test connection is going to be used to test which valve. Provide this information. For any valve that is being tested for leakage in which the pressure is applied in the opposite direction as that when the valve would be required to perform its safety function, provide justification that the results from the tests for the pres-l sure applied in a different direction will provide equivalent or more conservative results.
21.52 In Table 6.2.44 there are numerous isolation valves' listed in which.
no Type C test will be performed.
It is our position that a Type C test should be performed on all isolation valves. Yalves should be pressurized with air or nitrogen unless valves are in a sealed sys-l Then valves should be pressurized with the fluid that forms the tem.
seal in the sealed system.
State your intention to comply with this position.
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6-021. 53 The response to item 021.17 concerning the determination of bypass leakage paths in dual containments is inadequate.' The guidelines of BTP CSB 6-3 were not used in considering potential bypass leakage paths. _..
around the leakage collecten and filtration system of the secondary containment. - For example, the fact that lines penetrating the primary.
and secondary containment has isolation valves does not preclude through-11.. : leakage. Therefore, identify all potential bypass leakage paths usi.ng the guidelines of Item 5 of BTP CSB 6-3.
Also, provide a realistic leakage rate for these potential bypass leakage paths and a discussion (includ'ng drawing) of provisions made to permit pre-opera-tional and periodic leakage rate testing in a manner similar to the Type B or C tests of Appendix J to 10 CFR Part 50 for each bypass leak-age path.
l 21.54-The response to item 021.20 only discussed the initial test program that will be carried out to verify the depressurization of the secondary containment to a negative pressure of 1/4 inch. Provide the acceptance criteria for the draw down time.
It is our position that a periodic test program also be established to determine the operability of the system.
Also, provide a description of the preoperational and periodic test program that will determine the secondary containment infiltration rate, including the acceptance criteria.
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