ML19296B840
| ML19296B840 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/11/1980 |
| From: | Wing J Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19296B831 | List: |
| References | |
| NUDOCS 8002220237 | |
| Download: ML19296B840 (10) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of SACRAMENTO MUNICIPAL UTILITY Docket No. 50-312 (SP)
DISTRICT (Rancho Seco Nuclear Generating Station
)
NRC STAFF TESTIMONY OF JAMES WING ON CHANGING THE SYSTEMS OUTSIDE CONTAINMENT TO VENT INTO CONTAINMENT BUILDING (CEC Issue 5-1)
Q1. Please state your name and your position with the NRC _
A1. My name is James Wing.
I am an employee of the U.S. Nuclear Regulatory Commission in the Effluent Treatment Systems Branch, Office of Nuclear Reactor Regulation.
I am re~ponsible for the review and evaluation of s
radioactive waste treatment and effluent control systems for nuclear power reactors.
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- 02. Have you prepared a statement of professional qualifications?
s A2. Yes. A copy of this statement is attached to this testimony.
Q3. Please state the purpose of this testimony.
^
A3. The purpose of this testimony is to respond to the question the California Energy Comission raised in Contention 5-1:
Whether those systems identified as contributing to releases of radioactivity during the TMI accident, which are outside con-tainment, should be changed to vent into the containment building?
[DY 8002220
Q4.
Identify with specific reference to the Three Mile Island facility each of the systems outside of containment which contributed to releases of radioactivity during the Three Mile Island incident.
A4.
Releases of airborne radioactivity during the THI-2 accident were at-tributed to several sources due to leaks in systems that were located outside containment. Primary coolant flowing through the makeup and purification system was identified as the major contributor.
Radioactive gases released from the makeup and purification system to the radioactive waste gas system were believed to be a major source of radioactivity.
To a lesser degree, the transfer of containment sump water to liquid rad-waste tanks in the Auxiliary Building and the subsequent overflowing of these tanks also contributed to the airborne release.
Specifically, the systems and components outside of the containment which were thought to have released radioactivity in the atmosphere during the TMI ' incident include the weste gas vent header and compressors in the waste gas system, the reactor coolant. bleed holdup tank relief valve in the letdown system, the fuel handling and auxiliary building sump tanks, the radwaste system pumps which took suction from the. reactor coolant bleed tanks, and the valves and instruments in the reactor coolant makeup and purification system. The source of this information is the NRC report NUREG-0600, " Investigation into the March 28, 1979, Three Mile Island Accident by the Office of Inspection and Enforcement,"_specifically Sections 3.1 and 3.2 beginning at p. II-3-1.
e e
QS.
Based on the TMI accident, has the NRC made any recommendations to mini-mize airborne releases of radioactivity from sources outside containment?
AS.
A summary of lessons learned from the Three Mile Island accident is pro-vided in the report, "TMI-2 Lessons Learned Task Force Status Report and Short-Term Recommendations," NUREG-0578.
Recommendations in NUREG-0578 address actions that should be taken to minimize airborne releases of radioactivity from the sources identified at TMI. The systems outside containment that were identified in Lessons Learned Recommendation 2.1.6.a as having potential for contributing to release of radioactivity include residual heat removal, containment spray recirculation, high-pressure in-jection recirculation, sampling, primary coolant makeup and letdown, and waste gas systems. Leakage in these systems would release radioactive material to the air outside the containment.
Q6.
For each system identified in response to the above question should those systems at the Rancho Seco facility be changed to vent into the contain-ment building?
A6.
Recommendation 2.1.6.a in NUREG-0578 addressed actions for post accident control of radioactivity in the systems outside containment that are likely to contain radioactive materials. 'The report stated that the. leakage from these systems, when operated, must be-minimized or eliminated to prevent the release of significant amounts of radioactive materials to the environ-ment.
In addition, the report recommended thct periodic tests be performed to assure that the leakage from these systems is maintained as low as practical and that the plant staff be provided with current knowledge of the system leakage rates..The Task Force indicated its position in the report that operating: reactor, licensees implement a program to reduce j
s.
leakage from systems outside containment that would or could contain
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highly radioactive. fluids during a serious transient or accident to a t
level as low as practical. An outline of the program for implementa-tion with a completion date of January 1, 1980, is.given in the report.
Recommendation 2.1.4 in NUREG-0578 identified the need for all non-essen-tial systems penetrating the containment boundary to be automatically isolated prior to significant releases from the building. Uoon isolation of the containment, the contaminated fluids inside the containment proper would be contained and would not be transferred to the auxiliary building.
The radioactive materials in these fluids,'therefore, would not be released outside the containment. An outline of the program for implemen-tation of this recommendation, with a completien date of January 1, 1980, is given in the report.
Q7.
Are licensees required to implement these recommendationsh
s A7.
The Advisory Committee on Reactor Safeguards reviewed the JUREG-0578 re, art and stated in a letter to Chairman Hendrie, dated August 13, 1979, that the Committee agreed with the intent and substance of the Task Force recommendations mentioned above~
In a letter dated September 13, 1979, fromDarrellG.Eisenhut',ActingDirectoroftheDihisionofOperating Reactors, to all operating nuclear power plants, including Rancho Seco Nuclear Generating Station, it was required that all operating reactor licensees begin to implement these recommendations.
4 Q8.
What action has SMUD undertaken to implement these recommendations?
A8.
By letter dated January 7,1979 [ sic 1980], (John J. Mattimoe of the Sacramento Municipal Utility District (SMUD) to Robert W. Reid of NRC),
SMUD provided status on actions that are required by the recommendations in NUREG-0578. With respect to recomendation 2.1.4, SMUD performed a detailed review of the systems associated with each containment penetration at tha Rancho Seco Nuclear Generating Station. The review d2 fined the essential and the non-essential systems.
The non-essential systems are those systems that are not required immediately after the Safety Features Actuation System (SFAS) initiation. SMUD stated that time for operator control of the non-essential systems is available, and that these non-essential systems either are isolated or remain isolated after an SFAS initiation. With respect to recommendation 2.1.6 a, SMUD stated in the letter that the Rancho Seco Nuclear Generating Station had undertaken a leakage reduction program for the following systems: High Pressure In-jection, Seal Injection, and Make-up Systems; Letdown System; Decay Heat Removal System; Reactor Building Spray" System; Coolant Radwaste System; Miscellaneous Radwaste System; Waste Gas System; Reactor Coolant Chemical Addition and Sampling System; Reactor Building Heating, Ventilation and Air Conditioning.
Q9.
As a' result of the TMI accident, has the NRC taken any actions to ensure appropriate containment isolation of potentially radioactive liquids and gases?
A9.
On April 5, 1979, IE Bulletin 79-05A was sent to all Babcock and Wilcox operating plant licensees, requesting certain actions to be taken by the licensees to preclude an occurrence similar to the Three Mile Island
. accident at their facilities.
Item 6 of the Bulletin requested the licensee to:
Review the ' containment isolation initiation design and pro-cedures, and prepare and implement all changes necessary to
. cause containment isolation of all lines whose isola-tion does not degrade core cooling capability upon automatic initiation of safety injection.
Item 9 of the Bulletin requested the licensee to:
Review the operating modes and procedures for all systems designed to transfer potentially radioactive gases and liquids out of the primary containment to assure that undesired pumping.of radioactive liquids and' gases will not occur inadvertently.
In particular, ensure that such an occurrence would not be caused by the resetting of engineered safety features instrumentation. List all such systems and indicate:
whether interlocks exist to prevent transfer a.
when high radiation indication exists; and b.'
whether such systems are isolated by the con-tainment isolation signal.
By a letter dated April 16, 1979 (John J. Mattimoe of SMUD to R. H.
Engelken of NRC), SMUD provided responses to items 6 and 9 of IE Bulletin 79-05A in conformance with the requirements of the Bulletin.
With respect to item 6, SMUD stated that it has reviewed containment isolation design and procedures and has found them acceptable. All lines not required for safety features are isolated upon initiation of contain-ment isolation except lines that are necessary to assure continued opera-tion of the reactor coolant pumps and control rods.
1 With respect to item 9, SMUD stated that for all systems that could transfer potentially radioactive liquids and gases out of the primary containment, a safety features actuation signal on low reactor coolant
-7 system pressure or high reactor building pressure, would close all valves which could cause this transfer. The safety features isolation for Rancho Secocanonlybecherriddenbyplacingtheappropriatecontrolsonthe safety features actuation systems (SFAS) panels in " manual" and depressing the "open" push buttons as desired. The licensee further stated that the operator is cautioned in procedures to consult the Technical Specifications prior to placing any portion of the SFAS out of service. When the safety features actuation signal clears, all valves must be manually repositioned to their normal position. Finally, the licensee stated that if a contain-ment purge was in progress, the purge would be terminated by the SFAS, or by a high radiation signal from the reactor building monitor. Either of these signals will secure the containment supply and the exhaust fans.
Q10.
Has the staff reviewed SMUD's responses with respect to these items?
A10.
An [1RC evaluation of SMUD's responses to items 6 and 9 of IE Bulletin 79-05A is provided in a letter from Robert W. Reid of NRC to J. J. Mattimoe of SMUD, dated flovember 23, 1979. The evaluation found that the licensee's responses to these two items were complete. However, with respect to item 6, it was stated that "The acceptability of not isolating the lines for reactor coolant pumps and control rod operation will be reviewed as part of the licensee's compliance with Section 2.1.4 of tiUREG-0578."
With respect to item 9, it was stated that the subject of the containment isolation halhes being opened to allov purging during normal operation is presently under staff review.as part of the f1RR Generic Issues Program (Task - B-24: " Venting and Purging of Containment While at Power Operation and Effects on LOCA").
Q1?.
Are any other studies being undertaken to review or develope design
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criteria to minimize radioactive leakage?
All.
Currently, a study is being planned at the U.S. Nuclear Regulatory Commission to review the acceptance design criteria for vent gas systems and the need for leak detection systems to determine if the acceptance criteria should be revised or if additional acceptance design criteria should be developed to minimize leakage under all operating conditions, including accident conditions (Task III.E.1, Controlling Radioactive Material Discharges, Draft NUREG-0660, 12/10/79). An evaluation is also being made on the feasibility and/or the need for installing the letdown /
makeup system in an enclosure provided with venting to the containment structure (Task. III.D.2, Post-Accident Exposure Reduction, Draft NUREG-0660, 12/10/79). The results of these studies and evaluations will be used in determ'ning whether or not those systems at Rancho Seco Nuclear Generat-ing Station locc'ed outside containment, which were identified as con-tributing to the release of radioactivity in the Three' Mile Island accident, should be changed to vent into the containment building.
Q12.
What are the ventilation filter systems at Rancho Seco?
A12.
The ventilation exhaust system for the auxiliary building in the Rancho Seco Nuclear Generating Station consists of two units, each containing a high-efficiency particulate air filter and an activated ciu m al filter.
These filters and.adsorbers provide additional protection by reducing the amounts of radioactive particulates and radiciodines present in the ventilation exhaust. Low-activity waste gases, particulates, and radio-iodine, including those originating from leakage into the auxiliary
)
building, are discharged directly into this system before releasing to' the environment through the plant vent.
High-activity waste gases are
piped to the waste gas surge tanks. From the surge tank, the gases can eitherbedischargedthroughthehentilationexhaustsystemorbestored in waste gas decay tanks.
Ifstoredinthedecaytanks,theradioactihe wastegaseswillbedischargedtothehentilationexhaustsystemaftera suitable storage pertod. Technical Specifications on these engineered safetyfeaturehentili.tionfiltersystemsrequireperiodictestingsfor filter efficienc.ies.
Q13.
Based on the above actions and recommendations, does the staff believe that any systems at Rancho Seco should be changed at the present time to minimize radioacti.ve releases?
A13.
Considering the action status provided by SMUD on the implementation of recommendations 2.1.4 and 2.1.6.a of t'ie Lessons Learned Task Force on Three Mile Island accident, the NRC avaluation of the responses from SMUD to items 6 and 9 of the IE Bulletin 79-05A, and the present plant design of the Rancho Seco Nuclear Generating Station, the staff concludes that at this time there is no need to change the systems outside the "oids and containment of the Rancho Seco Nuclear Generating Station, which were identified as contributing to the release of airborne radioactivity in the Three Mile Island accident, to vent into the containment building.
A final conclusion on whether these systems at the Rancho Seco Nuclear Generating Station should be changed to vent into the containment structure will be made based upon the results of the study currently planned by the Nuclear Regulatory Commission on vent gas systems, leak detection systems, and letdown / makeup systems (Tasks III.E.1 and III.D.2, DraftNUREG-0660).
JAMES WING EFFLUENT TREATMENT SYSTEMS BRANCH DIVISION OF SITE SAFETY AND ENVIRONMENTAL ANALYSIS My name is James Wing..I am a senior nuclear engineer in the Effluent Treat-ment Systems Branch, Division of Site Safety and Environmental Analysis, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission.
I received a Bachelor of Science degree in Chemistry from the University of Tennessee in 1949, a Master of Science degree in Chemistry from Purdue University in 1953, and a Ph.D. degree in Chemistry from Purdue University in 1956.
Before joining the Commission, I was employed by Argonne National Laboratory from 1955 to 1969 as first, Assistant Chemist and then, Associate Chemist.
In this capacity, I performed basic research in nuclear chemistry. From 1969 to 1975, I was employed by National Bureau of Standards as a research chemist and computer prograinmer.
In these two positions, I did research work on radio-chemistry and wrote computer programs for laboratory automation.
I have written 28 technical papers and 10 laboratory reports on various topics, including nuclear chemistry, radiochemistry, air pollution, applied mathematics, and food technology.
In the academic year of 1964-1965, I was a Fulbright Lecturer.
I am a member of the American Chemical Society.
I have been a staff member of the Nuclear Regulatory Commission since January 1975. From 1975 to 1978 I was a member of the Accident Analysis Branch. Since 1978, I have been a senior nuclear engineer in the Effluent Treatment Systems Branch. My duties in this position include review and evaluation of radioactive whste treatment and effluent control systems of nuclear power plants.
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