ML19240B995
| ML19240B995 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/31/1981 |
| From: | Yost M EG&G IDAHO, INC., EG&G, INC. |
| To: | Shemanski P Office of Nuclear Reactor Regulation |
| References | |
| CON-FIN-A-6429 EGG-EA-5386, NUDOCS 8104170692 | |
| Download: ML19240B995 (7) | |
Text
ECG-EA-5386 March 1981
~
PR0l'OSED CHANCES FOR MAIN STEAM LINE ISOLATION AND SUPPRESS 10!i CHAMBER INSTRUMENTATION REQUIREMENTS, 11ROWNS FERRY UNITS 1, 2 AND 3 M.. W. Yost du deSB8TCh Dnd TeC ElC89 G((
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This is an informal report intended for use as a preliminary or working document DC Research anGectu.
ca A3bsstance 3' eport I repared for the U.S. Nuclear Regulatory Comaission er DOE Ccmtract No. DE-AC07-76ID01570 ggg 81041706M
n EGr G...........
g 4. l.46.4 61. e ep P ies.
I I / 9, INTERIM REPORT Accession No._
Report No. EGG-pc >Mp Centract Prc gram or Project Titie:
fic h i t ed ope rat i ra, React ors I s s ui. s Program (III)
Subject of this Document:
P r op<u ni Ch.mges for Main Steam Line Isolation and Suppression Char.ber i ns t r inien t a t ien Req ui r emen t s, Browns Ferry Units I, 2 and 3 Type of Document:
'l e i h u i <. i l Fs aluation Report Author (s):
!1.
W.
Yost NC lesearc! anc ecmica Date of Document:
Ass" stance Repor.-/
i ma,, h.
Responsible NRC Individual and NRC Office or Division:
P C
';heru n:.Li, N RC-lid L This dnrument was prepared primanly for prehminary orinternat use it has not recen, d fullieview and apptc val Since there may be substantive changes.this document shouM not tm considered final EG&G Idaho. Inc Idaho Falls, Idalo 83415 Prepared f or the U S. Nuclear Regulatory Commission Washington, D.C.
Under DOE Contract No. DE-AC07-761001570 NRC FIN No.
A6429 INTERIM REPORT
Or4J PROPOSED C11ANGES FOR MAIN STEAM LINE ISOLATION AND SUPPRESSION CilAMBER INSTRUMENTATION REQUIREMENTS liROWNS FERRY UNITS 1, 2, AND 3 Docket Nos. 50-259, 50-260, 50-296 March 1981 M. t!. Yost Reliability and Statistics Branch Engineering Analysis Division EG&G Idaho, Inc.
NRC Research and ~ec1nica Assistance Report TAC Nos.
42805, 42806, and 42807
ABSTRACT The Tennesee Valley Authority requested, by letter dated August 12, 1980, design and technical specification changes to the Browns Ferry Units 1, 2,
and 1.
The proposed changes included removal of th.' high t emperat ure in the main st eam li ne tunnels as a cause for main stears lite isolation for Unitr 1, 2, and 3; and reducing the technical specification suppression chamber high-level instrument channel requirements from two to one f or lin i t 3.
After r~ view of the re ference material in Section 4.0 of this report, it was recommended that the proposed changes be rejected.
FOREWORD This report is supplied as part of the " Selected Operating Reactor Issues Program (III)" being conducted for the U.S. Nuclear Regulatory C ommi : 4 ion, Office of Nuclear Reactor Regulation, Division of Licensing, by EG6G Idano,
'nu.,
Reliability and Statistics Branch.
The U.S.
Nuclear Regulatory Commission funded the work under the autnorizatiin, B6R 20 19 01 06, FIN No. A6429.
\\RC Researcl anc Tec1nica Assistance Report ii
CONTENTS 1.0 INTRODUCI' ION.....................................................
1 2.0 E/ALUATION.......................................................
1
3.0 CONCLUSION
S 2
4.0 REFERENCES
2 111
PROPOSED CHANGES FOR MAIN STEAM LINE ISOLATION AND SUPPRESSION CHAMBER INSTRUMENTATION REQUIREMENTS BROWNS FERRY UNITS 1, 2, AND 3 e
1.0 latroduction the Tenaessee Valley Authority (TVA) requested, by letter data August 12, 1980, design anu technical specification changes to Browns Ferry Units 1,
2, and 3.
One change consisted of removing the main steam 'ine isolation by high-temperature in the main sceam line tunnels.
It was also reque4ted to change the Browns Ferry Unit 3 technical specifications reducing the required minimum number.if suppression chamber high-level instrument channels for Unit 3 from t,.o channels to one channel.
2.0 l' val ua t i on Th" TVA has proposed the following design and technical specification etanges for Browns Ferry Units 1, 2, and 3:
1.
Presently, the main steam line tunnel, reactor core injection coolant (RCIC) stetm line space, and the high pressure coolant injection ("PCI) steam line space instrument channels have high-temperature, high-flow, and low pressure actions which can initiate steam line isolation.
TVA proposes to remove the nign-temperature isolation functions and use the instruments for alarms.
Technical specification changes are also proposed to reIlect these alterations.
Tne TVA justified these changes by stating that the consequences of an isolation from the steam line space high-temperature func-tions could cause nunconservative reactor water level fluctua-tions, and ather instrument channels are available which can init iate isolation in the event of a steam line break.
The TVA also stated that, after the change and in the event of a steam s p.t c e nign-temperature alarm on the HPCI, RCIC, or main steam line system, the operator will be directed, through operating instructions, to verify the validity of the alarm by:
a.
Other instrumentation such as steam flows, pressure, an!
radiation monitors ti.
Direct observation of the area involved.
Alter review of the TVA submittals and other referenced documents, I n :i v e determined that tne original General Electric design of tne BWR and tne Browns Ferry FSAR have provided a water level margin to compensate for this type of aluctuation.
The review of Licensee Event Reports (LERs) fo_ Browns Ferry Units 1, 2, and 3 from 1978 tbrougn 1980 have not shown any operational problems or occurrences of steam line isolations from high-t mperature ac ti ons.
NRC Researc1 and Technics Assistance Report -
1
The present Standard Technical Specificationc for General Elec-tric BWRs (NUREG-0123 Rev. 1) requires main steam line tunnel nigh-temperature isolation action. Analysis has not been pro-vided by TVA to show that high-temperature isolation is not i
required. Removal of high-temperature isolation could decrease safety as tne stean line high-temperature instrumentation would most likely be the first to detect a leak of any size.
2.
The ITA has also proposed to change Brouns Ferry Unit 3 technical specifications for the miniuum required suppression chamber high-levol instrument channels to agree with Units 1 and 2.
Precently, Unit 3 teennical specifications require the minimum number of operable instrument channels to be two, while Units 1 and 2 tech-nical specifications require only one.
Tne Standard Technical Specifications for General Electric BWRs (NUIEG-0123, Rev. 1) requires the minimum number of operable enannels per trip system to be two.
No analysis or justification nas been provided by TVA to demonstrate that this :;ange would not lower toe safety capabilities.
1.0 Conclusions As discussed in Section 2.0, the TVA proposed design and technical specification c;ianges will not correct any operational problems or imprave reactor safets.
Present design agrees with the current NRC licensing requirements.
Therefore, it is recommended that the TVA proposed changes be rejected.
4.0 Rof"renc.s 1.
Genera r:l ec t r i c Standard Technical Specifications for Bolling Water Reactorn, hUREG-0124, Rev.
1.
2.
Licensee Evtat Report: for BWRs ( 1.E R s ), 1978 through 1980.
2