ML20154Q134

Forwards AEOD Engineering Evaluation Rept That Discusses Several Events of Immersion Heaters Inside Primary Sys Being Energized While Not Covered W/Liquid

ML20154Q134
Person / Time
Site:	Rancho Seco
Issue date:	09/19/1988
From:	Rosenthal J NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Serpan C NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
Shared Package
ML20154Q117	List: ML20154Q113 ML20154Q134 ML20154Q232
References
NUDOCS 8810030319
Download: ML20154Q134 (4)

Text

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~i MEMORANDUM FOR: Charles Z. Serpan, Jr., Chief Materials Engineering Branch Division of Engineering Office of Nuclear Regulatory Research FROM: Jack E. Resenthal, Chief Reactor Operations Analysis Branch Division of Safety Programs Office for Analysis and Eva'uation of Operational Data

SUBJECT:

POTENTIAL LOCA DUE TO ENERGIZED UNCOVERED PRESSURIZER HEATERS Enclosed 15 an AE00 Engineering Evaluation report that discusses several events of imnarsion heaters inside the primary system being energized while they were not covered with liquid. In the first event, at a foreign reactor, the uncovered immersion heaters continued to operate and heated the primary system piping to 1400F at a primary system pressure of 1500 psig. At these conditions, the piping abruptly failed with rapid primary system pressure and inventory loss.

In another event, at a domestic PWR, the uncovered imersbn heaters in the pressurizer remained energized and produced a localized hot spot temperature of 1000F. However, at the time of peak temperature, the reactor pressure was very low. It would appear this type of event could occur at the more unfavora-ble condition of normal PWR operating pressure.

We have also enclosed a 1979 remorandum from R. Mattson to R. F. Fraley (ACRS) relating to earlier discussions of this type of event. The memorandum said that the issue would be investigated further. We are not aware that this evaluation was completed. We suggest that the safety aspects of the consequen-ces of such an event be evaluated.

/M Jack E. Rosenthal, Chief Reactov Operations Analysis Branch Division of Safety Programs Office for Analysis and Evaluation of Operational Data

Enclosure:

As stated Distribution:

PDR CHeltemes ROAB R/F EJordan TCintule. MTaylor Glanik TNovak JRosenthal VBenaroya MW1111 &ms KBlack

• See previous concurrences ROAB:DSP:AE00 ROAB:DSP:AE00 ROAB:DSP:AEOD l TCintula:as* Glanik* JRosenthal*

8/ /88 8/ /88 8/ /88 l

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'l MEMORANDUM FOR: Charles Z. Serpan, Jr. , Chief Materials Engineering Branch .

Division of Engineering Office of Nuclea ' legulatory Research FROM: Jack E. Rosenthal, Chief Reactor Operations Analysis Branch ,

Division of Safety Prograns  !

Office for Analysis and Evaluatier, i of Operational Data

SUBJECT:

POTENTIAL LOCA DUE TO ENERGIZED UNCOVERED PRESSURIZER HEATERS Enclosed is an AEOD Engineering Evaluation . report that discusses several events of immersion heaters inside the primary system being energized while they were not covered with liquid. In the first event, at a foreign reactor, the uncovered immersion heaters continued to operate and heated the primary system piping to 1400F at a primary system pressure of 1500 psig. At these conditions, the piping abruptly failed with rapid primary system pressure and 1

inventory loss.

In another event, at a domestic PWR, the uncovered inversion heaters in the

pressurizer remained energized and produced a localized hat spot temperature

of 1000F, However, at the tire of peak temperature, the reactor pressure was very Icw. It would appear this type of event could occur at the more unfavora-

' blo condition of normal PWR operating pressure.

We have also enclosed a 1979 memorandum from R. Mattson to R. F. Fraley (ACRS) a relating to earlier discussions of this type of event. The memorandum said 4

that the issue would be investigated further. We are not aware that this evaluation was completed. We suggest that the safety aspects of the consequen-ces of such an event be evaluated. Accordingly, it is requested that RES calcu-

late the margin of safety for the unanalyzed condition of localized overheating

] to 1000F at a primary system pressure of 2485.psig to determine whether this

! issue merits further regulatory pursuit.

l Jack E. Rosenthal, Chief

Reactor Operations Analysis Branch

Division of Safety Prograns 1 Office for Analysis and Evaluation l of Operational Data J.

Enclosure:

As stated i

l Distribution:

j PDR CHeltemes i ROAB R/F EJordan TCintula MTaylor Glanik TNnvak 4 JPosenthal VBenaroya l

MW1111ms KBlack

)<0AB:DSP:AE00

• See previous concurrences P0AB:DSP:AEOD k

FOAB:DSP:AEOD TCintula:as* Glanik* JRosenthal*

8/ /E8 8/ /88 f//6/88

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9 MEMORANDUM FOR: Charles Z. Serpan, Jr., Chief Materials Engineering Branch D' vision of Engineering Office of Nuclear Regulatory Research FROM: Jack E. Rosenthal, Chief Reactor Operations Analysis Branch Division of Safety Programs

N Office for Analysis and Evaluation F

of Operational Data

SUBJECT:

POTENTIAL LOCA DUE TO ENERGIZED UNCOVERED PRESSURIZER HEATERS Enclosed is an AE09 Engineering Evaluation report that discusses several events of immersion heaters inside the primary system being energized while

they were not covered with liquid. In the first event, at a foreign reactor, j the uncovered imersion heaters continued to operate and heated the primary a

system piping to 1400F'at a primary system pressure of 1500 psig. At these conditions, the piping abruptly failed with rapid primary system pressure and inventory loss.

! In another event, at a domektic PWR, the uncovered imersion heaters in the pressurizer remained enenerized and produced a localized hot spot temperature i of 1000F, However, at the time of peak terperature, the reactor pressure was i very low. It would appear this type of event could occur at the more

! unfavarable condition of normal PWR. operating pressure. Accordingly, it is requested that RES calculate the margin of safety for the unanalyzed condition

of localized overheating to 1000F at a' primary system pressure of 2485 psig to l

determine whether this issue merits further regulatory pursuit.

2

\

l Jack E.'Rosenthal, Chief l ' Reactor Operations Analysis Branch 3

Division of Safety Programs Office for Analysis and Evaluation of Operational Data

{

Enclosure:

As stated Distribution

! PDR CHoltemes ROAB R/F EJordan TCintula MTaylor Glanik "-"-

JRosenthal WL=4 9 MWilliwms KBlack VBenaroya

,t, See pre concurrence * [

ROAB:D :AEOD* R SP: AE0D

• SOAB:DSP:AEOD TCintula:as 6L'a ik JRosenthal Vll /88 (/ll /88 p///88

~ ~

MEMOPANDUM FOR: Charles Z. Serpan, Jr. , Chief Materials Engineering Branch Division of Engineering s Office of Nuclear Regulatory Research FROM: Jack E. Rosenthal, Chief Reacter Operations Analysis Branch Division of Safety Programs Office for Analysis and Evaluation of Operational Data

SUBJECT:

POTENTIAL LOCA DUE TO ENERGIZED UNCOVERED PRESSURIZER HEATERS Enclosed is an AEOD Engineering Evaluation report that discusses several events of immersion heaters inside the primary system being ener ed while they weie not covered with liquid. In the first event, at a fo n reactor, the uncovered immersion heaters continued to operate and heated e primary system piping to 1400F at a primary system pressure of 1500 psig. At these conditions, the piping abruptly failed with rapid primary system pressure and inventory loss.

In another event, at a domestic PWR, the uncovered imersion heaters in the pressurizer remained enenerized and produced a localized hot spot +.emperature of 1000F, However, at the time of peak teirperature, the reactor pressure was very low. It would appear this type of event could occur at the more unfavorable condition of normal PWR operating pressure. Accordingly, it is requested that RES calculate the margin of safety for the unanalyzed condition of localized overheating to 1000F at a primary system pressure of 2485 psig to determine whether this issue merits further regulatory pursuit.

Jack E. Rosenthal, Chief Reactor Operations Analysis Branch Division of Safety Programs Office for Analysis and Evaluation of Operational Data

Enclosure:

As stated '

Distribution:

PDP CHeltemes ROAB R/F EJordan TCintula MTaylor Glanik JPartlow JRosenthal WLanning MWilliwms KBlack VBenaroya TNovak ROAB:DSP:AEOD FC k SP:AE0D ROAB:DSP:AE00 TCintula:as CIM k JRosenthal 7/T1/88 7/2$P8 7/ /08