Asher Etkin

DOE Accelerator Safety WorkshopAugust 18 - 20, 2009

DRAFT DOE STANDARDAPPLICATION OF SAFETY

INSTRUMENTED SYSTEMS USED AT DOE NON-REACTOR

NUCLEAR FACILITIES

DRAFT DOE STANDARDAPPLICATION OF SAFETY

INSTRUMENTED SYSTEMS USED AT DOE NON-REACTOR

NUCLEAR FACILITIES

22

INTRODUCTION

“Safety Instrumented Systems (SIS) that include both analog and

digital control systems are.. used in the U. S. Department of

Energy’s (DOE) non-reactor nuclear facilities for various safety

controls” “Therefore, DOE recognizes a need for establishing a Standard that

defines practices to be applied for SISs used in safety class and

safety significant non reactor nuclear applications.” At the request of the Defense Nuclear Facility Safety Board Pranab

Guha of HS-21 established a working group to develop such a

Standard for SISs. “DOE technical standards, such as this, do not establish

requirements.” “This Standard provides guidance for developing requirements for

design, procurement, installation, testing, maintenance, operation,

and quality to be applied for Safety Class (SC) and Safety Significant

(SS) Safety Instrumented Systems (SIS) used in safety applications in

the Department’s non-reactor nuclear facilities.”

3

OVERVIEW

The standard discusses design and life cycle requirements primarily for safety significant systems. The discussion is a high level introduction to the subject, that is dealt with more fully in consensus standards developed by national and international bodies. They are:

ANSI/ISA 84.00.01-2004 (IEC 61511 Mod), Functional Safety: Safety Instrumented Systems for the Process Industry Sector – Parts 1, 2, and 3 and the Technical reports in the ISA TR84.00.xx series.

3

4

IEC 61511, Functional Safety – Safety Instrumented Systems for the Process Industry Sector – Parts 1, 2, and 3 (this international standard and ANSI/ISA 84.00.01-2004 are compatible)

IEC 61508, Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems (Standard primarily applicable to vendor manufactured products)

And DOE orders and standards applicable to nuclear facilities.

Uses the requirements of ANSI/ISA 84.00.01-2004 Part 1

4

5

Step 1– Develop overall safety requirements (concept, scope

definition, perform hazard and risk assessment)

Step 1– Develop overall safety requirements (concept, scope

definition, perform hazard and risk assessment) Step 2 – Allocate safety requirements

to safety instrumented functions Step 2 – Allocate safety requirements to safety instrumented functions

Step 3 – Design SISStep 3 – Design SIS

Design Safety Instrumented Systems

Step 4 – Testing, Installation, Commissioning and Safety Validation of integrated safety instrumented systems

Step 4 – Testing, Installation, Commissioning and Safety Validation of integrated safety instrumented systems

Step 5 – Operation and Maintenance, Modification and Retrofit, Decommissioning or Disposal

phases of safety instrumented systems

Step 5 – Operation and Maintenance, Modification and Retrofit, Decommissioning or Disposal

phases of safety instrumented systems

Figure 4.1-1: Life-Cycle Steps for Safety Instrumented Systems

Design Safety Instrumented System

Software

6

SIL Level and Performance Ranges for On Demand Mode

SIL Level Designatio

n

Probability of Failure On Demand

PFD(average)

Risk Reduction Factor (RRF)

SIL-1 < 10-1 to ≥ 10-2 PFDavg > 10 to ≤ 100 RRF

SIL-2 < 10-2 to ≥ 10-3 PFDavg > 100 to ≤ 1000 RRF

SIL-3 < 10-3 to ≥ 10-4 PFDavg > 1000 to ≤ 10,000 RRF

SIL-4 < 10-4 to ≥ 10-5 PFDavg > 10,000 to ≤ 100,000 RRF

7

Application Safety Software for Instrumentation and Control Systems

The safety software should be designed to support the following.· Isolation — Critical components are separated from each other in

a manner to preclude undefined interactions. · Independence — Independent hardware inputs are directed to

independent software modules. · Inoperability — Abnormal conditions cause a component to

become inoperable in a safe, predictable manner and before any isolation features are compromised.

· Incompatibility — Components in different parts of the system cannot operate together in a satisfactory manner. To avoid incompatibility, consider that sensors, a logic device (such as a processor), and control devices may have embedded software that needs to be integrated in a networked system. The acceptability of the integration needs to be validated.

8

Software Quality Assurance Requirements Crosswalk With Industry Standards

Software Project Management and Quality Planning Software Risk Management Software Configuration Management Software Procurement and Supplier Management Software Requirements Identification and Management Software Design and Implementation Software Safety Verification and Validation Software Problem Reporting and Corrective Management Training of personnel in the design, development, use and

evaluation of safety software

9

Human Factors Engineering (HFE)

Application of HFE HFE practices and principles need to be factored

into each stage of the SIS development and design process, including planning, analysis, requirements and design, installation, and testing. Improvements for human performance concerns may continue throughout the operation and maintenance phases of the SIS life-cycle.

Human Factors Standards and Guidance Documents for each part of the life-cycle

10

DOE Procurement Requirements Management Process Personnel Competency Maintenance

11

SIS DESIGN REQUIREMENTS

Safety Significant (SS) Safety Instrumented Systems (SIS)· Design· SS SIS Designed as a Defense-In-Depth (DID) Function · Setpoints· Commercial Grade Dedication · Safety Significant Power · SS Functions Not Covered By ANSI/ISA 84.00.01, Part 1

- 1. Evacuation alarms (e.g. nuclear incident monitors (NIM), fire alarms, and public address systems)

- 2. Fire protection/detection systems- 3. Instruments whose sole function is to monitor initial

conditions for process startup

12

Safety Class (SC) Safety Instrumented Systems (SIS) Design Requirements

Code of Record Guidance Appendix A: Safety Integrity Level Determination

Methodology Appendix B: Safety Integrity Level (SIL) Verification

Guidance Appendix C: Illustration of an SIL Determination and

SIL Verification Calculation

13

Conclusions

There is a lot of useful material in this standard. There is also a significant amount of material that is

directed at nuclear facilities and would be a source of confusion for accelerators.

For the accelerator community to benefit from this standard the useful material should be incorporated into a guidance document

14

PLC Code Management Software

Reviewing FactoryTalk AssetCentre and Proficy Change Management products

FactoryTalk AssetCentre is supplied by Rockwell Software the supplier of the software for the PLC’s used in our Particle Accelerator Safety System

GuardLogix and FactoryTalk AssetCentreChange Management

• RSLogix 5000 provides standard functionality

PREVENTION

CONTROL

ACCOUNTABILITY

DETECTION

RECONCILIATION

PREVENTION

CONTROL

ACCOUNTABILITY

DETECTION

RECONCILIATIONVA

LUE

REACTIVE

PROACTIVE

ArchiveArchive

AuditAudit

VerificationVerification

ReportingReporting

Access ControlAccess Control

AuthenticationAuthentication

–Archive–Audit

• Safety specific audit trail additions:– Safety Task Lock/Unlock– Safety Lock Password Changed– Safety Unlock Password Changed– Safety Signature Create/Delete– Tag Mapping Added/Deleted/Modified– GLX Serial Number Match Project

Enable/Disable– Clear Safety Task Fault Log

–Verification/Recovery–Reporting