ML19224D007

Notifies That DOE 790612 Meeting of Energy Facility Siting Council Authorized DOE to Request Info Re Auxiliary Feedwater Sys,Environ Qualification of Equipment & Control/Protective Interactions Altering Safety

ML19224D007
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	06/27/1979
From:	Frank L ENERGY, DEPT. OF
To:	Goodwin C PORTLAND GENERAL ELECTRIC CO.
References
TAC-11299, NUDOCS 7907100462
Download: ML19224D007 (5)

Text

.

r

' g eg Department of Energy

..c'f, ^, ';" "

LABOR & INDUSTRIES OUILDING. ROOM 111. SALEM CPEGCN 97310 PHONE 378-404o u

60 -3h June 27, 1979 Charles Goodwin Portland General Electric 121 SW Salmon Street g p} pgpqy p n) y g

jf h[a n tt][ h.-d y g.

5 du i

[

Portland, OR 97204

Dear Mr. Goodwin:

At its June 12, 1979 meeting, the energy Facility Siting Council authorized the department to request certain information about the Trojan Nuclear Plant from Portland General Electric pursuant to CAR 345-10 015.

The purpose of this information is to determine whether any improvements in the auxiliary feedwater syste;., environmental qualitication of equipment or control and protective system interactions would make a significant difference in the level of Trojan safety.

Attachments 1, 2 and 3 identify the scope of this information request.

Even so, the attachments are general in nature and will require PGE's thoughtful consideration when performing its analyses so that the resulting information is useful to both organizations.

It is suggested that PGE discuss its progress with 000E periodically so both are assured that the proper areas are being explored.

000E recognized that the information requested may require a substantial effort on the part of PGE.

This effcrt may require the hiring of additional persons or the letting oi contracts outside the company.

Nonetheless, ODGE expects PGE management to assign the resources needed to meet the completion dates established belcw.

00GE also recognizes that some of what is being requested of PGE may already exist in other forms, e.g., studies by the NRC or the industry and existing standards. References to these other d% uments is acceptable if copies are provided to 000E and if PGE provides a technical justification for its re1iance en the documen't.

OCOE suggests that PGE consider documenting i s response to these information requests in a form which could be included page for page in the Trojan Final Safety Analysis Report (FSAF) cr ir, a separate binder (e.g., PGE-1020) which could be referenced ir, the FSAR. This approach would provide documents which could be referred to in the future, both by regulators and PGE. thus preventing duplication of this effort.

r L

%el

/7 p

A

//

32S 223 7 9. 0 ' ] UL,u (w

^o o

u.

Charles Goodwin,

June 27, 1979 Page 2 PGE is requestad to provide the information relating to the auxiliary feedwater system, envircnmental qualification of equipment and control / protective system interacticas by November 30, August 31, and December 3:

1979, respectively.

PGE should expect follow-up questions frca 000E upon submission of these reports.

Sincerely, ontgim

/

/

Lynn Frank Director LF/DG:cs 3483A cc: Ed Whelan, PGE R. H. Engelken, NRC V C. Trammel, NRC A. Nistad, EFSC 4

(

t 0 4

m

• h Y'

t-

'p.

O<.au.o g

q, a w,

't e ~

l L<

}

,. -->..i..

.~.. J C ',1 J G.. J'3_,_._

Auxiliary Feedwater Systen Purpose - To identify, by use of risk assessnient methodology, whether changes to the Trojan auxiliary feedwater fluid and electrical systems would improve its reliability.

Discussion - Unlike most safety related equipment, the auxiliary feedwater system is used routinely for ncrmal plant shutdowns as well as during accident conditions.

The more frequent use of this equipment makes its reliability more important; particularly 'since its f ailure results in the need to operate other safety equipment, thereby reducing the margins of safety provided by the various backup cooling systems.

000E believes that a risk assessment, utilizing f ault trees, would provide the best mechanism for identifying a) how the system can f ail anc b) whether improvements would improve reliability.

The risk assessment should ccnsider mechanical (e.g., cue to aging, quality control, or design deficiencies), procedural (e.g., operations, tests or maintenance) and human errors. Where meaningful failure rate data is available, it should be identified and used to estimate overall reliability of the system.

The results of the risk assessment should be used by PGE to evaluate the effectiveness of various measures which could improve reliability. For example, what is the benefit of using alternative pump drivers, of converting the electric driven pumps to a third safety related pump, eliminating valves which could be mispositioned, of continually running the pumps or of starting the pumps earlier? PGE should identify and evaluate other potential modifications.

A a

(:

1 4

.sL]x,,

t.

Environmental Qualification of Equipment Purpose - To determine the ability of Trojan safety equipment to perform its function in an accident envircnment and to identify where changes would improve equipment reliability.

Discussion - During an accident equipment needed to mitigate the consequences of the accident must perform in an unusual environment of high temperatures, pressures, radintion levels, humidity and chemical conditicns.

PGE's Final Safety Analysis Report, NRC's Safety Evaluation Report and PGE's response to Bulletin 79-01 provides some information on the qualification of equipment; however, the information is either incomplete or has not been assembled in a cohesive presentation.

Information should include, but not be limited to, the follcwing:

1.

Justification of a) the choice of the accident environment, and b) tne selection of time periods during which equipment must remain operable (reference documents which can be reviewed to verify that all appropriate equipment and its location have been considered);

9 2.

Identify the environment that can be withstood by existing equipment and the time period during which equipment will remain operable; 3.

Justify the adequacy.of tests used to qualify equipment with particular emphasis on the duration of tests and the need for concurrent versus sequential testing for temperatures, pressure etc.;

and

~

4.

Identify the cost to replace or qualify Trojan equipment so that it will perform its functions during an accident.

ww

s

=

Control / Protective System Interactions Purcose - To identify, by use of risk assessment methodologies, whether changes to the existing Trajan control and protective systems would increase the reliability of these systems.

Discussion - In some cases at Trojan, control signals are derived frcm inoividual protection channels.

Isolation suplifiers are used to prevent failures in the control circuitry from adversely affecting the protection cb *ne ls (FSAR Secte 7.7.3.1).

At the Zion Nuclear Plant improper action by plant operators caused loss of both pcottc+ ion and oatrol functions. Trojan procedures provide cuct?c.* r pr 2c.de this type of event.

Nonetheless, it is apparent t.

e. er ecview is needed to determine whether other adverse interact uns can occur.

Thc folion:og process parameters required for protective functions provide

, *o control systems: reactor power, pressurizer pressure, pressur izer level, steam generator level and average coolant temperature

,F5l.I 7.2.2.3).

PGE also identified four additional interactions:

turbine impulsa pressure, feed flow, steam flow and steamline pressure (PGE letter to 000E May 25, 1979). PGE should reference documents that could be checked to verify that all interactions have been identified.

000E believes that a risk assessment, utilizing f ault tree analysis, would provide the information needed to determine a) how the shared functions might be disadvantageous and b) where beneficial changes could be made.

The risk assessment should consider all failure methods incitJing mechanical, procedure and human errors for each of the previously identified process parameters. For example, isolation amplifiers should be analy.'d to determine how they could permit or cause adverse interaction; due to failure of components, improper maintenance or testing procedures, etc. Meaningful failure rate data should be used, when available, to estimate overall reliability of the existing arrangements.

The results of the risk asse1sment should be used to identify areas where improvement would be useful and to compare the alternative to the existing design. PGE should identify the costs of the potential improvements as well.

DG:cs 3521A Qs g }\\

4 m

h !I.1Kji.f7.Ih7 6 ti y

Q.., L u QN{h QN U d h

• q((Ik $'

E7

.d y

's

.. ~. _. -

~.

_.. -.. ~....... _.