Energy and Water Development Appropriations for 1982

FIXED SITE NEUTRALIZATION MODEL

POSITRON ANNIHILATION FOR NON-DESTRUCTIVE EXAMINATION
ADEQUACY OF CURRENTLY UTILIZED RADIATION TEST SOURCES.
AN ECONOMETRIC STUDY OF ELECTRICITY DEMAND

LWR STATUS MONITORING DURING ACCIDENT CONDITIONS.
DOSE-RATE CONVERSION FACTORS FOR EXTERNAL EXPOSURE.
VISUAL AESTHETIC IMPACT OF ALTERNATIVE COOLING SYSTEMS.
PERIPHERAL SHEARING STRENGTH OF CONCRETE STRUCTURAL ELEMENTS

TABLE OF CONTENTS

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DATE ISSUED

BIL TITLE: HIGH TEMP OXIDATION OF ZIRCALOY FUEL CLADDING IN STEAM
SPONSORING OFFICE(S): RES

RES UNIT

RES

TECHNICAL LEAD

THE REPORTED RESULTS IMPROVE OUR UNDERSTANDING OF THE BEHAVIOR OF ZIRCALOY FUEL CLADDING IN AN ENVIRONMENT REPRESENTED BY A LOSS OF
COOLANT ACCIDENT (LOCA). THEY INDICATE THAT THERE WOULD BE SIGNIFICANTLY LESS DEPTH OF EMBRITTLEMENT IN THE FUEL CLADDING WALL,
CALCULATED FOR ANY POSTULATED LOCA AND MORE WALL MATERIAL WILL BE LEFT WHICH IS CAPABLE OF SUSTAINING LOADS LATER IN THE SEQUENCE
OF SUCH AN ACCIDENT. THIS INFORMATION, TOGETHER WITH DATA ON THE RATE OF GROWTH OF OXIDE & OXYGEN STABILIZED LAYERS IN CLADDING,
PROVIDES A MORE SCIENTIFIC BASE FOR ESTABLISHING FUEL CLAD EMBRITTLEMENT CRITERIA FOR EMERGENCY CORE COOLING SYSTEM ACCEPTANCE.
THESE RESULTS CONFIRM THAT THERE IS A DEGREE OF CONSERVATISM IN THE EVALUATION MODEL BEING USED BY THE REGULATORY STAFF FOR
CALCULATING THE OXIDATION OF ZIRCALOY DURING A POSTULATED LOCA. THIS INFORMATION IS BEING CONSIDERED AS A PARTIAL BASIS FOR
MODIFICATION OF THE PRESENT ECCS RULE (10 CFR 50, APPENDIX K). RIL'S 8 & 9 ARE BOTH UNDER CONSIDERATION BY NRR FOR POSSIBLE
INCLUSION IN A MODIFICATION TO THE EMERGENCY CORE COOLING SYSTEMS (ECCS) RULE PROVIDED IN APPENDIX K OF 10 CFR 50. THESE RIL'S
REPORTED ON COMPLETED RESEARCH PROJECTS IN FISSION PRODUCT DECAY HEAT AND ZIRCALOY OXIDATION WHICH RESULTED IN DATA BASES AND
CORRELATIONS WHICH INDICATE THAT THOSE IN CURRENT USE IN THE ECCS RULE ARE HIGHLY CONSERVATIVE. A COMMISSION PAPER WAS PREPARED
(SECY 77-368) ON JULY 1, 1977, TO PRESENT STAFF PROGRESS ON A PROPOSED ACTION PLAN REGARDING POSSIBLE MODIFICATION TO THE ECCS
RULE. THE COMMISSION PAPER (SECY 78-26) PRESENTING THE PROPOSED ACTION PLAN WAS PREPARED ON JANUARY 18, 1978. RIL #9 HAS BEEN
REVIEWED BY HRR, NMSS, IE, AND SD. THIS MATERIAL WAS INCLUDED IN THE BRIEFING OF THE ACRS FULL COMMITTEE BY NRR IN SEPT. 1977.
CONCERNING A POSSIBLE REVISION OF APPENDIX K 10 CFR 50. THE ACRS DISCOURAGED A REVISION OF THE ECCS RULE AT THIS TIME.

NEW DATA MAY BE CONSIDERED AS PARTIAL BASIS FOR MODIFICATIONS OF PRESENT ECCS RULE (10 CFR 50, APPENDIX K) NEW DATA MAY BE USED IN "BEST ESTIMATE CODES. THESE CODES ARE INTENDED TO BE USED IN PROBABILISTIC ASSESSMENTS OF SAFETY MARGINS.

*** NRR: IMPACT OF RESULTS ***

NEW DATA CONFIRMS MARGIN ALLOTTED IN PRESENT ECCS RULE IS CONSERVATIVE.

IF ACCEPTED FOR USE IN LOCA LICENSING CALCULATIONS, VENDORS COULD USE ADDITIONAL MARGIN IN DESIGN (I.E., INCREASE PEAK KW/FT).

*** NRR: COMMENTS AND REMARKS ***

THE COMMISSION APPROVED THE PROPOSED ACTION PLAN TO MODIFY APPENDIX K (SECY 78-26). NRR AND RES ARE PREPARING A REQUEST TO SD TO INITIATE RULEMAKING TO MODIFY APPENDIX K.

THIS PROJECT PROVIDES DATA ON THE AMOUNT OF METAL-WATER REACTION AND HYDROGEN GAS GENERATION FOLLOWING A LOCA AND AIDS IN THE DEVELOPMENT OF REVISIONS TO REGULATORY GUIDE 1.7 AND IN ASSESSING THE CONSERVATISM OF ASSUMPTIONS IN 10 CFR 50 APPENDIX K.

RIL TITLE: PRESSURE VESSEL FAILURE PROBABILITY PREDICTION (OCTAVIA CD.)
SPONSORING OFFICE(S) RES

RES UNII

RES TECHNICAL LEAR

OCTAVIA IS A COMPUTER CODE FOR PREDICTING FAILURE PROBABILITIES IN REACTOR PRESSURE VESSELS AS A FUNCTION OF TEMPERATURES AND
PRESSURES THAT MIGHT OCCUR DURING STARTUP AND SHUTDOWN OPERATIONS. EFFECTS OF MATERIAL PROPERTIES AND OPERATING AGE WERE ALSO
INCLUDED. THE RESULTS INDICATED THAT EXISTING SAFETY MARGINS COULD BE SIGNIFICANTLY REDUCED WITH CONTINUED AGING (RESULTING IN
RADIATION EMBRITTLEMENT) OF THE REACTOR VESSEL, IF THE RATE OF OCCURRENCE OF OVERPRESSURE EVENTS CONTINUES TO BE SIMILAR TO THAT
PREVIOUSLY OBSERVED. FURTHER IMPROVEMENTS IN THE CODE ARE REPORTED ON IN RIL 12. THESE RESULTS WERE USED BY NRR DURING THIS PAST
YEAR IN REVIEWING THE PROBABILITY OF FAILURE OF REACTOR PRESSURE VESSELS DUE TO SUCH EVENTS AND TO GIVE GUIDANCE ON PLANT
IMPROVEMENTS THAT MAY BE NEEDED. THEY MAY ALSO BECOME THE BASIS FOR REVISING REGULATORY GUIDES OR STANDARDS

THE OCTAVIA COMPUTER CODE HAS BEEN USED TO EVALUATE THE PROBABILITY OF REACTOR VESSEL FAILURE FROM OVERPRESSURE TRANSIENTS WHICH
CAN OCCUR DURING PWR OPERATION. THE RESULTS OF THE ANALYSES INDICATED THAT EXISTING SAFETY MARGINS COULD BE SIGNIFICANTLY REDUCED
WITH CONTINUED NEUTRON IRRADIATION OF THE REACTOR VESSEL IF THE HISTORICAL FREQUENCY OF OVERPRESSURE EVENTS CONTINUED.

*** NRR IMPACT OF RESULTS ***

THE ANALYSES ENABLED NRR TO CONFIRM, IN A MORE RIGOROUS, QUANTITATIVE MANNER, INITIAL LICENSING DECISIONS TO REDUCE THE FREQUENCY
AND MAXIMUM PRESSURE OF THE TRANSIENTS. THESE DECISIONS RESULTED IN MODIFICATIONS TO OPERATING PROCEDURES AND REDUCING THE
FREQUENCY OF TRANSIENTS AND THE INSTALLATION OF PHYSICAL DEVICES TO LIMIT PRESSURES IN OPERATING PLANTS TO THOSE SPECIFIED BY THE
PRESSURE-TEMPERATURE LIMITATIONS IN THE TECHNICAL SPECIFICATIONS.

*** NRR: COMMENTS AND REMARKS ***

SEE COMMENTS TO RIL 012.

THIS PROGRAM HAS GENERATED SUBSTANTIAL DATA USED IN PREDICTING IRRADIATION EMBRITTLEMENT AND MARGINS TO FAILURE OF REACTOR PRESSURE
VESSELS WHEN FLAWS ARE PRESENT, CONSIDERING MATERIAL PROPERTIES AND LOADINGS. THIS PROGRAM HAS PROVIDED INPUT TO NRC REQUIREMENTS
FOR FRACTURE TOUGHNESS OF PRESSURE VESSEL MATERIALS DESCRIBED IN APPENDIX G TO 10 CFR 50 AND CONTRIBUTED DATA USED IN THE ASME CODE
WHICH WAS INCORPORATED INTO APPENDIX G. IT HAS ALSO PROVIDED PART OF THE DATA BASE USED IN REGULATORY GUIDE 1.99 CONCERNING THE
REVISIONS TO REGULATORY GUIDE 1.99.
EFFECT OF COPPER IMPURITIES ON SENSITIVITY OF STEEL TO IRRADIATION AND IS EXPECTED TO PROVIDE A SUBSTANTIAL INPUT FOR FUTURE

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Energy and Water Development Appropriations for 1982: Hearings ..., Part 4