ML20059H466
| ML20059H466 | |
| Person / Time | |
|---|---|
| Issue date: | 09/10/1990 |
| From: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Rossi C Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20059H469 | List: |
| References | |
| AEOD-E90-08, AEOD-E90-8, IEIN-82-45, IEIN-89-032, IEIN-89-32, NUDOCS 9009170219 | |
| Download: ML20059H466 (5) | |
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. MEMORANDUM FOR:
Charles E.sRossi, Director, L.
Division of Operational.: Data t
Office of Nuclear Reactor Regulation m-
-FROM:
, Thomas M.~Novak, Director.
Division of Safety: Programs Office forf.nalysis and Evaluation l
of Operational Data!
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SUBJECT:
TESTING PORVs'WITH THE ALTERNATE PNEUMATIC-SUPPLY L
a Enclos'ed is an Engineering Evaluation report on testing PORVs with the safety.
. grade pneumatic supply. Most PORVs are provided with a non-safety grade air; a
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system,_which:is:the primary source, and a safety grade pneumatic. system, usually nitrogen'as the backup. However,' in most cases, the testing of the
< valves,1s done using the.non safety grade air system.
In these cases,:the
' ability of the. safety. grade pneumatic system to perform its function is not-1
' confirmed.':This-study stems from five reported cases since 1987 where the.
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. safety grade supply system (nitrogen) for actuating PORVs in their LTOP mode was found degraded.-
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- The, effectiveness of the safety grade backup pneumatic supply for PORVs was
- discussed in'Information Notice (IN) 82-45. We
- have compiled 12 LERs.from T
.-1982 to'present, when the backup safety < grade pneumatic system.was found.
-j ri adegraded. Under these conditions, a~ loss of instrument air _ would close the fletdown isolation valves, there would not.be:a motive force to.open the PORVs
.quickly, thuslthe LTOP protection would.be defeated.
. The:stahdard Technical: Specifications do not_ explicitly require the testing of h
the. LTOP with the safety grade pneumatic system.. It-is essential that-the
.LTOP system be periodically tested using the safety grade pneumatic ' system to
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" demonstrate conformance with the stroke time-values used in the safety J
'ianalyses.'
Enclosed is a draft of a' proposed' supplement to11N 89 32, which delineates y
stroke-time testing of the LTOP system using the safety grade pneumatic t!
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. system. We believe this supplement = is needed to-point out. to licensees the need for.such testing.
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Engineering Evaluation 2.
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4 EMDRANDUM FOR.
Charles E. Rossi, Director' l
Division of Operational Events' Assessment n
Office of Nuclear Reactor Regulation-i
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-U FRON:
Thomas M. Novak, Director
' ' Em Division of Safety Programs m
Office for Analysis and Evaluation of Operational Data I
50cJECT:
TESTING PORVs WITH THE ALTERNATE PNEUMATIC SUPPLY
~
Enclosed is an' Engineering Evaluation report on testing PORVs.with an alternate' i
pneumatic su) ply to confirm that the opening times are consistent with the. valuer assumed in tie safety analyses for low-te.nperature, overpressure protection (LTOP. This study stems from five reported cases of inadequate backup nitrogen j
4 supp for actuating PORVs in their LTOP mode since 1987.
The effectiveness of 6
the ckup_ pneumatic supply for these valves was initially discupsed in IN 82-m,
- 45. We have compiled 12 LERs on this issue from 1982 to the pr,esent. A loss of instrument air could initiate an overpressure transient by el ting the letdown l
valves and defeat LTOP if the backup pneumatic supply was no adequate. Thus, this_ issue involves a reduction in safety margin.
a 1
A' review of sample Technical Specifications shows that t ting of the LTOP system s'C lwith;the backup pneumatic supply is not always required I believe this syst61
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should be periodically tested assuming loss of air to sure that the backup-pneumatic su) ply is operable and that the LTOP systemjineets licensing commitments' for the stro(e time of the PORV with the backup pneuWatic supply.
Also enclosed is a draft of a proposed supplement Information Noiice 89 32-which promotes surveillance testing of LTOP syst,1 s.
We believe that this i
supplement is needed to alert licensees to the ed for testing backup pneumatic M
supplies.- For further information regarding t s study, please contact S. Salah
.(x24432)'or S. Israel (x24437) of my staff.
4 v
T mas M. Novak, Director vision of Safety Programs.
ffice for Analysis and Evaluation of Operational Dcta 4
Enc 15sure:
As stated 5
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- R. Jones, NRR M. Shymlock, RII c
Distribution:
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. 'ROAB R/F Pla.m TNovak SRubin KRaglin, TTC' DSP.R/F.
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' MElWORANDUM FORT Charles E. Rossi, Director j
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Division of Operational Events Assessment l
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Office of Nuclear Reactor Regulation e
p FROM:--
Thomas M. Novak, Director Division of Safety Programs PT Office for Analysis and Evaluation 4 '
of Operational Data
SUBJECT:
TESTING PORVs WITH THE ' ALTERNATE PNEUMATIC SUPPLY j
f Enclosed is an Engineering Evaluation report m testing PORVs with n alternate pneumatic supply to confirm that the opening times are consistent with the,dlues assumed r
in the safety analyses for low-temperature, overpressure protection P). This study
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stems from five reported cases of inadequate backup nitrogen supply ctuating PORVs in their LTOP mode since 1987. The effectiveness of the backup pneu ic supply for these valves was initially discussed in IN 82 45. We have compiled 12 LE#s on this issue from 1982 to the present.. A loss of instrument air could initiate an ovpfpressure transient by j
closing the letdown valves and defeat LTOP if there is not an adeguate backup pneumatic l
supply. Thus, this issue is important because it involves a reducti6n in the expected safety i
a
' margin.'
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Also enclosed is a draft of a proposed supplement to Infp[rmatio
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. promotes surveillance testing of LTOP systems.
- e lieve that this supplement is
.F important to ensure that the backup pneumatic supp is tested also.
For-further
- information regarding this study, please contact S. Sala (x24432) or S. Israel (x24437) of -
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'my staff, l
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Th as M. Novak, Director 1
D ision of Safety Progrsms L
ffice for Analysis and Evaluation j
Qj, of Operational Data J
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Enclosure:
As ' stated
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l R! Jones, NRR M. Shymlock, RII
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Central File Plam LSpessard KRaglin, TTC y
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- MEMORANDUM FOR: Charles E. Rossi, Director
~
Division of Operational Events Assessment i
C-Office of Nuclear Reactor Regulation FROM:
' thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation of Operational Data
SUBJECT:
TESTING PORVs WITH THE ALTERNATE PNEUMATIC SUPPLY Enclosed is an Engineering Evaluation report on testing PORVs with an alternate neumatic supply to confirm that the opening times are consistent wip(LTO t the values assumed p
in the safety analyses for low-temperature, overpressure protectio 9 3
stems from five reported cases of inadequate backup nitrogen supply for actuating PORVs
)
in their L'IDP mode since 1987. The effectiveness of the backup pneumatic supply for these valves was initially discussed in IN 82-45. We have compiled }2 LERs on this issue from u
l 1982 to the present. A loss of instrument air could initiate an overpressure transient by closing the letdown valves and defeat LTOP if there is not ad adequate backup pneumatic
}
supply. Thus,~ 'his issue is important because it involves a ' eduction in the expected sdety l
. margin.
t i
Also enclosed ~is a draft of a proposed supplement o Information Notice 89-32 which promotes surveillance testing of.LTOP systems. jWe believe that this supplement is 1
important to ensure that the backup-pneumatid supply is tested also.
For further information regarding this study, please contact. Salah (x24432) or S. Israel (x24437) of my staff.
Thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation of Operational Data i
Enclosure:
As stated i
/
x7 cc.w/ enclosure:
R. Jones, NRR M. Shymlock, RII Distribution:
PDR-SIsrael VBenaroya MTaylor, EDO Central File PLam LSpessard KTaglin, TTC ROAB R/F JRosenthal GZech PBaranowsky, NRR
" DSP R/F EJordan SRubin
' AEOD R/F Dross MWilliams T SSalah TNovak RSavio, ACRS ROAB:DGP:iAEOD ROAB:DSP:AEOD ROAB:D
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