ML19257A250

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Response to First Set of Interrogatories.Provides Info Re Plant Transient Conditions Requiring Use of Natural Circulation for Core Cooling.Lists Witnesses to Be Called in Proceeding.Affidavit of DC Holt Encl
ML19257A250
Person / Time
Site: Rancho Seco
Issue date: 12/04/1979
From: Holt D
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
CALIFORNIA, STATE OF
Shared Package
ML19257A247 List:
References
NUDOCS 8001030291
Download: ML19257A250 (9)
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December 1, 1979 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of

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SACRAMENTO MUNICIPAL UTILITY DISTRICT

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Docket No. 50-312

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(Rancho Seco Nuclear Generating Station)

LICENSEE'S ANSWERS (SET NO. 3) TO THE FIRST SET OF INTERROGATORIES OF THE CALIFORNIA ENERGY COMMISSION DATED NOVEMBER 15, 1979 5.

INTERROGATORY:

What plant transient conditions require or may require use of the high pressure injection system?

ANSWER:

Plant transient conditions which require or may require use of high pressure injection to assure core cooling are as follows:

(a)

Any transient which results in a decrease in the

Any transient which results in a decrease in the reactor coolant system pressure (below the HPI actuation setpoint) due to a mass decrease in the RCS inventory - e.g., loss of coolant accident.

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(c)

In the unlikely event of a transient for which auxillary feedwater would normally be required and such is not available, the HPI may be utilized to maintain adequate core cooling.

6.

INTERROGATORY:

What plant transient conditions require or may require use of natural circulation for core cooling?

ANSWER Plant transient conditions which require or may require use of natural circulation to assure core cooling are any transients for shich all reactor coolant pumps are not operating - e.g., loss of normal plant AC power.

30. INTERROGATORY:

Identify each person who SMUD expects to call to testify at the hearing in this proceeding.

Fo r each person identified, provide: the subject (s) upon which the person may testify; a description of the substance of the testimony; and a description of the person's educa-tional background and professional qualification,s.

ANSWER:

Attached is a statement of qualifications for Mr. B. A. Karrasch and a description of the substance of testimony which Mr. Karrasch is currently expected to provide relative to the following items:

Issue CEC-1-1 Board Question CEC-1-2 Board Question CEC-1-4 Board Question CEC-1-7 Board Question CEC-1-10 Issue CEC-1-12 Hursh-Castro Contention 2 Hursh-Castro Contention 4 Hursh-Castro Contention 6 Hursh-Castro Contention 10 Hursh-Castro Contention 16 1666 406 Eursh-Castro Contention 21 Hursh-Castro Contention 24 Hursh-Castro Contention 26 FOE Contention III(a) 9 STATEMENT OF QUALIFICATIONS Name Bruce A.

Karrasch Business Babcock & Wilcox Company Address Nuclear Power Generation Division P O Box 1260 Lynchburg, Virginia 24505 Education BS, Nuclear Engineering, The University of Wisconsin, 1967 MS Nuclear Physics, Lynchburg College, 1971 Exoerience June 1967-June 1969; Engineer, Thermal Hydraulics Group, Fuel Engineering, B&W; Performed fuel assembly fluid flow and heat transfer calculations June 1969-June 1971; Engineer, Nuci tar Analysis Group, Fuel Engineering, B&W; Performed three-dimensional power peaking calculations June 1971-March 1974; Engineer and Supervisory Engineer, Control Analysis Unit, Plant Analysis Section, B&W; Assisted in NSS design and analysis March 1974-September 1975; Manager, Control Analysis Unit, B&W; Responsible for transient and steady state NSS analysis September 1975-August 1976; Manager, Core Integration Unit, B&W; Responsible for defining and controlling analytical and hardware interfaces between fuel assembly and balance of NSS August 1976-Present; Manager, Plant Integration, B&W; Responsible for defining and controlling analytical and hardware interf aces among the various elements of the NSS 1666 307 9.

Issue CEC-1-1 Despite the modifications and actions of Subparagraphs (a) through (e) of Section IV of the Commission's Order, will reliance upon the High Pressure Injection System to mitigate pressure and volume control sensitivities in the Rancho Seco primary system result in increased challenges to safety systems beyond the original design and licensing basis of the facility?

Issue CEC-1-12 Despite or because of the modifications and actions of Subparagraphs (a) through (e) of Section IV of the Commission's Order of May 7, will Rancho Seco experience an increase in reactor trips resulting from feedwater transients that will increase challenges to safety systems beyond the original design and licensing basis of the facility?

Description of Substance of Testimony Due to changes in reactor coolant system pressure set-points (high pressure trip and pressurizer relief valve actuation), and the addition of anticipatory reactor trips (on turbine trip and loss of feedwater), an increase in plant trips will be experienced.

The design basis for the safety systems so challenged will be discussed and com-pared with anticipated challenges.

(See also Licensee's Answers (Set No. 2).]

Board Question CEC-1-2 Can poor understanding of natural convection in the Rancho Seco system result in a situation that will lead to inade-quate cooling despite the modifications and actions of Subparagraphs a-e?

Hursh-Castro Contention 6 Rancho Seco, being a Babcock & Wilcox designed reactor, has a low steam generator elevation, relative to the reactor vessel, which prevides a smaller driving head for natural circulation, and, therefore, is unsafe and endan-gers the public health and safety of Petitioners, const,it-uents of Petitioners and the public.

1666 308 Description of Substance of Testimony The natural circulation phenomenon and experience will be discussed, including a description of the B&W reactor coolant system configuration and the adequacy of the driving head for natural circulation.

The sufficiency of the means available to the operator to detect and manage natural circulation will be addressed.

[See also Licen-see's Answers (Set No. 2). ]

Board Question CEC-1-4 Will the failure of safety and/or relief valves in the Rancho Seco primary system result in an unsafe condition despite the modifications and actions of Subparagraphs a-e?

Board Question CEC-1-7 Do the operator training actions responding to Subpara-graph (d) of Subparagraphs a-e for Rancho Seco f ail to give sufficient attention to providing appropriate analyt-ical bases for operator actions?

Hursh-Castro Contention 10 Rancho Seco, being a Babcock & Wilcox designed reactor, has not completed an adequate analfit.s for potentia L small breaks in a loss-of-coolant accident nor developed and implemented operating instructions to define operatar action in such event, and, therefore, is unsafe and endan-gers the health and safety of P4titioners, constittents of Petitioners and the public.

Descriotion of Substance of Testimony The failure of a reactor coolant system relief or safety valve in effect is a small break loss of coolant a:cident.

Small break LOCAs have been analyzed and guideline s devel-oped which describe the characteristics of the event and identify appropriate operator actions.

Small break LOCAs can be safely mitigated.

[See also Licensee's Answers (Set No. 2). ]

1666 309 Board Question CEC-1-10 Is the physical configuration of the Rancho Seco primary system such as to permit unsafe accumulation of steam or other gases despite the modifications and actions of Subparagraphs a-e?

Hursh-Castro Contention 24 Rancho Seco, being a Babcock & Wilcox designed reactor, is unable to avoid or control bubble formation in the primary system which may occur subsequent to a loss of feqdwater accident, and, therefore, is unsafe and endangers the health and safety of Petitioners, constituents of Peti-tioners and the public.

Descriotion of Substance of Testimony For anticipated loss of feedwater transients, void forma-tion does not occur in the B&W nuclear steam system.

Events which can lead to RCS void formation will be de-scribed.

The procedures for handling such events and assuring an unsafe condition does not develop will be addressed.

Hursh-Castro Contention 2 Rancho Seco, being a Babcock & Wilcox designed reactor, is designed with a steam generator which operates with rela-tively small liquid volume in the secondary side and, therefore, is unsafe and endaf.gers the health and safety of Petitioners, constituents of Petitioners and the public.

Hursh-Castro Contention 26 Rancho Seco, being a Babcock & Wilcox designed reactor, has a once through steam generator which makes the plant more susc'.ptible and sensitive to a loss of feedwater transient, and, therefore, is unsafe and endangers the health and safety of Petitioners, constituents of Peti-tioners and the public.

Desriotion of Substance of Testimony The transient response characteristics of the B&W nuclear steam system have been adequately considered in the con-trol and safety features of the unit.

The once through 1666 310

steam generator and its operation will be described.

The response of the system to an anticipated loss of feed-water transient, including, how the Rancho Seco design satisfies applicable criteria for assuring safe operation following a LOFW, will ba addressed.

Hursh-Castro Contention 4 Rancho Seco, being a Babcock & Wilcox designed reactor, has a reliance on integrated control system to automatic-ally regulate feedwater flow, and, therefore, is unsafe and endangers the health and safety of Petitioners, con-stituents of Petitioners and the public.

Hursh-Castre Contention 16 SMUD, the licensee, has done insufficient analysis of the failure mode and effects analysis of the integrated con-trol system, and, therefore, Rancho Seco is unsafe and endangers the health and safety of Petitioners, constitu-ents of Petitioners and the public Description of Substance of Testimony The design and function of the ICS will be described.

The design of the plant and operator actions to properly handle anticipated loss of feedwater transients, whether or not control system related, will be addressed.

Also, a failure modes and effects analysis of the integrated con-

. trol system has been performed and the results demonstrate the system is reliable for its intended function.

Hursh-Castro Contention 21 Rancho Seco, being a Babcock & Wilcox designed reactor, has a pressurizer tank and quench tank which are of inade-quate size to accommodate the volume of gas or liquid that may be required to be stored in the event of a loss of feedwater transient, and, therefore, is unsafe and endan-gers the health and safety of Petitioners, constituents of Petitioners and the public.

1666511 Descriotion of Substance of Testimony The pressurizer and quench tank in the B&W nuclear steam system are designed to handle the transient effects of an anticipated loss of feedwater event.

The sizing of these components will be compared with the anticipated results for a LOFW transient to demonstrate their adequacy.

FOE Contention III(a)

The NRC orders in issue do not reasonably assure adequate safety because the orders f ail to evaluate or comment upon the acceptability of 27 feedwater transients over the past year in nine Babcock & Wilcox (B&W) reactors, a frequency which is 50 percent greater than the corresponding rate for other pressurized reactors.

Description of Substance of Testimony Feedwater transients are anticipated operational events and the plant is designed to respond appropriately.

1666 312 9.

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of

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SACRAMENTO MUNICIPAL UTILITY DISTRICT

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Docket No. 50-312

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(Rancho Seco Nuclear Generating Station)

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AFFIDAVIT OF D. C. HOLT County of Sacramento)

SS State of California )

D. C. Holt, being duly sworn according to law, deposes and says that he is a Senior Engineer in the Nuclear Power Generation Division of the Babcock and Wilcox Company; and that the answers contained in " Licensee's Answers (Set No. 3) to the First Set of Interrogatories of the California Energy Commission dated November 15, 1979" are true and correct to the best of his knowledge and belief.

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C. Holt f '"I."'"'NILUAM K. PFINGS Sworn to and subscribed before

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